Citation
A mechanistic investigation of P-Xylene and water vapor sorption on soils and clay minerals

Material Information

Title:
A mechanistic investigation of P-Xylene and water vapor sorption on soils and clay minerals
Creator:
Pennell, Kurt Davis, 1962-
Publication Date:
Language:
English
Physical Description:
viii, 159 leaves : ill. ; 29 cm.

Subjects

Subjects / Keywords:
Clay minerals ( lcsh )
Dissertations, Academic -- Soil Science -- UF
Soil Moisture -- Measurement ( lcsh )
Soil Science thesis Ph. D
City of Oldsmar ( local )
Adsorption ( jstor )
Water vapor ( jstor )
Isotherms ( jstor )
Genre:
bibliography ( marcgt )
non-fiction ( marcgt )

Notes

Thesis:
Thesis (Ph. D.)--University of Florida, 1990.
Bibliography:
Includes bibliographical references (leaves 152-158).
General Note:
Typescript.
General Note:
Vita.
Statement of Responsibility:
by Kurt Davis Pennell.

Record Information

Source Institution:
University of Florida
Holding Location:
University of Florida
Rights Management:
Copyright [name of dissertation author]. Permission granted to the University of Florida to digitize, archive and distribute this item for non-profit research and educational purposes. Any reuse of this item in excess of fair use or other copyright exemptions requires permission of the copyright holder.
Resource Identifier:
027771911 ( ALEPH )
26498485 ( OCLC )
AJG3679 ( NOTIS )
AA00004767_00001 ( sobekcm )

Downloads

This item has the following downloads:

mechanisticinves00penn ( .pdf )

AA00004767_00001.pdf

mechanisticinves00penn_0156.txt

mechanisticinves00penn_0020.txt

mechanisticinves00penn_0141.txt

mechanisticinves00penn_0138.txt

mechanisticinves00penn_0061.txt

mechanisticinves00penn_0044.txt

mechanisticinves00penn_0032.txt

mechanisticinves00penn_0124.txt

mechanisticinves00penn_0094.txt

mechanisticinves00penn_0130.txt

mechanisticinves00penn_0005.txt

mechanisticinves00penn_0137.txt

mechanisticinves00penn_0142.txt

mechanisticinves00penn_0146.txt

mechanisticinves00penn_0074.txt

mechanisticinves00penn_0117.txt

mechanisticinves00penn_0099.txt

mechanisticinves00penn_0163.txt

mechanisticinves00penn_0078.txt

mechanisticinves00penn_0025.txt

mechanisticinves00penn_0129.txt

mechanisticinves00penn_0081.txt

mechanisticinves00penn_0016.txt

mechanisticinves00penn_0092.txt

mechanisticinves00penn_0144.txt

mechanisticinves00penn_0059.txt

mechanisticinves00penn_0055.txt

mechanisticinves00penn_0024.txt

mechanisticinves00penn_0058.txt

mechanisticinves00penn_0095.txt

mechanisticinves00penn_0083.txt

mechanisticinves00penn_0038.txt

mechanisticinves00penn_0110.txt

mechanisticinves00penn_0028.txt

mechanisticinves00penn_0046.txt

mechanisticinves00penn_0091.txt

mechanisticinves00penn_0070.txt

mechanisticinves00penn_0064.txt

mechanisticinves00penn_0096.txt

mechanisticinves00penn_0063.txt

mechanisticinves00penn_0164.txt

mechanisticinves00penn_0114.txt

mechanisticinves00penn_0151.txt

mechanisticinves00penn_0113.txt

mechanisticinves00penn_0087.txt

mechanisticinves00penn_0132.txt

mechanisticinves00penn_0029.txt

mechanisticinves00penn_0003.txt

mechanisticinves00penn_0065.txt

mechanisticinves00penn_0120.txt

mechanisticinves00penn_0101.txt

mechanisticinves00penn_0042.txt

mechanisticinves00penn_0169.txt

mechanisticinves00penn_0104.txt

mechanisticinves00penn_0160.txt

mechanisticinves00penn_0118.txt

mechanisticinves00penn_0158.txt

mechanisticinves00penn_0062.txt

mechanisticinves00penn_0097.txt

mechanisticinves00penn_0035.txt

mechanisticinves00penn_0036.txt

mechanisticinves00penn_0102.txt

mechanisticinves00penn_0109.txt

mechanisticinves00penn_0123.txt

mechanisticinves00penn_0082.txt

mechanisticinves00penn_0136.txt

mechanisticinves00penn_0076.txt

mechanisticinves00penn_0011.txt

mechanisticinves00penn_0008.txt

mechanisticinves00penn_0018.txt

mechanisticinves00penn_0041.txt

mechanisticinves00penn_0127.txt

mechanisticinves00penn_0067.txt

mechanisticinves00penn_0093.txt

mechanisticinves00penn_0161.txt

mechanisticinves00penn_0112.txt

mechanisticinves00penn_0006.txt

mechanisticinves00penn_0022.txt

mechanisticinves00penn_0060.txt

mechanisticinves00penn_0056.txt

mechanisticinves00penn_0116.txt

mechanisticinves00penn_0009.txt

mechanisticinves00penn_0165.txt

mechanisticinves00penn_0108.txt

mechanisticinves00penn_0034.txt

mechanisticinves00penn_0015.txt

mechanisticinves00penn_0139.txt

mechanisticinves00penn_0154.txt

mechanisticinves00penn_0030.txt

mechanisticinves00penn_0017.txt

mechanisticinves00penn_0126.txt

mechanisticinves00penn_0057.txt

mechanisticinves00penn_0125.txt

mechanisticinves00penn_0155.txt

mechanisticinves00penn_0050.txt

mechanisticinves00penn_0122.txt

mechanisticinves00penn_0019.txt

AA00004767_00001_pdf.txt

mechanisticinves00penn_0149.txt

mechanisticinves00penn_0079.txt

mechanisticinves00penn_0134.txt

mechanisticinves00penn_0111.txt

mechanisticinves00penn_0086.txt

mechanisticinves00penn_0100.txt

mechanisticinves00penn_0040.txt

mechanisticinves00penn_0159.txt

mechanisticinves00penn_0143.txt

mechanisticinves00penn_0012.txt

mechanisticinves00penn_0007.txt

mechanisticinves00penn_0021.txt

mechanisticinves00penn_0168.txt

mechanisticinves00penn_0047.txt

mechanisticinves00penn_0000.txt

mechanisticinves00penn_0071.txt

mechanisticinves00penn_0068.txt

mechanisticinves00penn_0153.txt

mechanisticinves00penn_0031.txt

EVJI81E6L_M5202E_xml.txt

mechanisticinves00penn_0128.txt

mechanisticinves00penn_0107.txt

mechanisticinves00penn_0033.txt

mechanisticinves00penn_0069.txt

mechanisticinves00penn_0077.txt

mechanisticinves00penn_0048.txt

mechanisticinves00penn_0054.txt

mechanisticinves00penn_0023.txt

mechanisticinves00penn_pdf.txt

mechanisticinves00penn_0037.txt

mechanisticinves00penn_0148.txt

mechanisticinves00penn_0157.txt

mechanisticinves00penn_0115.txt

mechanisticinves00penn_0133.txt

mechanisticinves00penn_0001.txt

mechanisticinves00penn_0039.txt

mechanisticinves00penn_0147.txt

mechanisticinves00penn_0051.txt

mechanisticinves00penn_0105.txt

mechanisticinves00penn_0014.txt

mechanisticinves00penn_0085.txt

mechanisticinves00penn_0150.txt

mechanisticinves00penn_0152.txt

mechanisticinves00penn_0167.txt

mechanisticinves00penn_0106.txt

mechanisticinves00penn_0066.txt

mechanisticinves00penn_0162.txt

mechanisticinves00penn_0027.txt

mechanisticinves00penn_0073.txt

mechanisticinves00penn_0103.txt

mechanisticinves00penn_0135.txt

mechanisticinves00penn_0043.txt

mechanisticinves00penn_0131.txt

mechanisticinves00penn_0072.txt

mechanisticinves00penn_0084.txt

mechanisticinves00penn_0119.txt

mechanisticinves00penn_0026.txt

mechanisticinves00penn_0010.txt

mechanisticinves00penn_0090.txt

mechanisticinves00penn_0053.txt

mechanisticinves00penn_0140.txt

mechanisticinves00penn_0166.txt

mechanisticinves00penn_0049.txt

mechanisticinves00penn_0075.txt

mechanisticinves00penn_0088.txt

mechanisticinves00penn_0045.txt

mechanisticinves00penn_0004.txt

mechanisticinves00penn_0013.txt

mechanisticinves00penn_0052.txt

mechanisticinves00penn_0002.txt

mechanisticinves00penn_0145.txt

mechanisticinves00penn_0098.txt

mechanisticinves00penn_0121.txt

mechanisticinves00penn_0089.txt

mechanisticinves00penn_0080.txt


Full Text









A MECHANISTIC INVESTIGATION OF P-XYLENE AND WATER VAPOR
SORPTION ON SOILS AND CLAY MINERALS














By

KURT DAVIS PENNELL


A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL
OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT
OF THE REQUIREMENTS FOR THE DEGREE OF
DOCTOR OF PHILOSOPHY

UNIVERSITY OF FLORIDA


1990



























Copyright 1990

by

Kurt Davis Pennell












ACKNOWLEDGEMENTS


I have prospered from the knowledge and compassion of many, and I take

this opportunity to thank those persons. First, I would like to thank my advisory

committee chair, Dr. Arthur Hornsby, who not only convinced me to continue my

studies in soil science, but also provided financial and moral support at critical

junctures in my Ph.D. program. His scientific beliefs and convictions have been

an inspiration, and afforded me the freedom to develop a truly independent

research project. The remainder of my advisory committee, Dr. Dean Rhue, Dr.

Suresh Rao, Dr. Joseph Delfino, and Dr. Ramesh Reddy have all made significant

contributions to my graduate education. In particular, I thank Dean Rhue for

providing laboratory facilities and supplies, but more importantly for instilling in me

the value of solid research. I greatly appreciated the invaluable scientific guidance

and challenges given by Suresh Rao. In his spare time Suresh revived my ego

on the tennis court.

One of the finest attributes of the Soil Science Department is the respect

and professional opportunities offered to graduate students. In this regard, I thank

Dr. Randy Brown, Dr. Willie Harris, and Dr. Peter Nkedi-Kizza for their honesty and

encouragement. I would also like to thank Dr. Brian McNeal, whose support and







humor assured that my tenure as graduate student representative to the faculty

was an enjoyable and enlightening experience.

I thank Bill Reve for his initial tolerance and subsequent respect in the

laboratory, which has fostered a true friendship. Our numerous discussions on a

range of issues removed much of the tedium from my laboratory work. Linda Lee

and Ron Jessup also gave generously of their time and knowledge, for which I am

grateful.

I would like to acknowledge the financial support, in the form of a research

assistantship, provided by the State of Florida via the Soil Science Department,

and additional funding provided by the Florida Department of Environmental

Regulation.

I thank my mother and father for their pride in my accomplishments. Their

accepting nature has given me an appreciation for mutual respect which I could

not have otherwise obtained. Finally, I thank Page whose love has given me the

strength to excel and the tenderness to care.













TABLE OF CONTENTS


ACKNOWLEDGEMENTS ............................................................................ iii

A BSTRA C T ................................................................................................... vii

CHAPTERS

1 INTRODUCTION ................................................................... 1

Vapor-Phase Sorption ........................................................... 1
Adsorption on Oven-Dry Sorbents .................................... ..... 2
Competitive Adsorption ........................................................ 11
Sorption at High Relative Humidity................................... ..... 17
Research Sum mary ..................................................................... 19

2 VAPOR-PHASE SORPTION OF P-XYLENE AND WATER
ON SOIL MATERIALS AT HIGH RELATIVE HUMIDITIES.......... 23

Introduction ....................................................... ..................... 23
Materials and Methods ......................................................... 25
Results and Discussion ............................................. ........... 34
Sum m ary......................................................... ...................... 49

3 GAS CHROMATOGRAPHIC STUDIES OF P-XYLENE
SORPTION ON ANHYDROUS AND HYDRATED
QUARTZ SAND ..................................................................... 52

Introduction ....................................................... ..................... 52
Materials and Methods ......................................................... 55
Results and Discussion ............................................. ........... 58
Sum m ary........................................................................... ..... 68








4 COMPETITIVE ADSORPTION OF P-XYLENE AND WATER
VAPORS ON CA-, NA-, AND LI-SATURATED KAOLIN .............. 71

Introduction ....................................................... ..................... 71
Materials and Methods ......................................................... 75
Results and Discussion ............................................. ........... 77
Sum m ary....................................................................... ........ 95

5 THE EFFECT OF HEAT TREATMENTS ON THE TOTAL
CHARGE AND EXCHANGEABLE CATIONS OF CA-, NA-,
AND LI-SATURATED KAOLIN ................................................. 98

Introduction ....................................................... ..................... 98
Materials and Methods ................................................................ 101
Results and Discussion ............................................................... 105
Sum m ary ........................................................................................ 133

6 SUMMARY AND CONCLUSIONS .............................................. 135

APPENDICES

A WATER AND P-XYLENE SORPTION DATA.............................. 141

B SURFACE TENSION DATA........................................................ 150

REFERENC ES ............................................................................................. 152

BIOGRAPHICAL SKETCH ........................................................................... 159













Abstract of Dissertation Presented to the Graduate School
of the University of Florida in Partial Fulfillment of the
Requirements for the Degree of Doctor of Philosophy

A MECHANISTIC INVESTIGATION OF P-XYLENE AND WATER VAPOR
SORPTION ON SOILS AND CLAY MINERALS

By

Kurt Davis Pennell

December 1990

Chairman: Dr. Arthur G. Hornsby
Major Department: Soil Science


Vapor-phase sorption of p-xylene and water on soils and clay minerals was

studied using a flow-equilibration technique that allowed the amount of sorbed

water and p-xylene to be measured independently. Oven-dry sorbents exhibited

a sizable capacity to adsorb p-xylene vapors which was strongly correlated to

sorbent surface area. Increasing the relative humidity to 67 and 90% resulted in

dramatic reductions in p-xylene sorption and a shift from Type-II to Type-Ill

adsorption isotherms, regardless of the organic carbon content of the sorbent. The

observed increase in p-xylene sorption above relative vapor pressures of 0.6

suggests that hydrated sorbents can sorb significant quantities of organic vapors

near the contaminant source. Similar results were obtained for the sorption of p-







xylene vapors on quartz sand using a gas chromatographic technique, which

provided an efficient and versatile alternative to batch methods.

At relative humidities above which the sorbent surface was covered by at

least a monomolecular layer of water, p-xylene sorption by Webster soil was

primarily attributed to partitioning into organic carbon. However, predictions of the

surface excess based on the Gibbs equation indicated that essentially all p-xylene

sorption on sorbents of low organic carbon content was due to adsorption at the

gas-liquid interface. Therefore, it is recommended that vapor-phase sorption be

described by a multi-mechanistic model that incorporates adsorption onto exposed

mineral surfaces, adsorption at the gas-liquid interface, dissolution into adsorbed

water films, and partitioning into organic carbon.

The effect of cation saturation on the adsorption of water and p-xylene

vapors from single- and binary-vapor systems was also investigated. Water and

p-xylene adsorption on Ca- and Na-saturated kaolin was directly related to the

hydration energy of the exchangeable cation. However, Li-saturated kaolin

exhibited reduced adsorption which was attributed to a decrease in total charge

after heating. Therefore, Li-kaolin is not recommended as a reference surface for

the study of vapor-phase sorption. Predictions of the competitive adsorption of

water and p-xylene vapors using two-component Brunauer, Emmett, and Teller

models indicated that the preferential adsorption of water from p-xylene-water

systems was the result of cation hydration effects.












CHAPTER 1
INTRODUCTION


Vapor-Phase Sorption

The widespread detection of volatile organic chemicals (VOCs) in

groundwater and soil has prompted intensive study of vapor-phase sorption and

transport in porous media. Contaminants of this nature, such as petroleum-based

solvents, frequently enter the environment as a result of improper disposal

techniques, accidental spills, and loss from storage tanks. The subsequent

distribution and mobility of VOCs in the unsaturated zone can be directly

influenced by vapor-phase sorption. Previous studies have demonstrated that

anhydrous soils and clays have a sizable capacity to adsorb organic vapors, but

this capacity is greatly reduced in the presence of water (Call, 1957; Chiou and

Shoup, 1985; Rhue et al., 1989). However, a comprehensive understanding of the

processes responsible for VOC sorption in the unsaturated zone has yet to be

attained. This is particularly true for soils at high relative humidity (RH), at which

time a number of mechanisms may contribute to organic vapor retention, including

dissolution into adsorbed water films, partitioning into organic carbon (OC), and

adsorption at gas-liquid-solid interfaces.









Adsorption on Oven-Dry Sorbents

The adsorption of vapors on oven-dry sorbents has been studied in detail,

and provides a basis from which to investigate adsorption in more complex

systems. In his classic treatise on vapor-phase adsorption, Brunauer (1943)

defines adsorption as the accumulation of a chemical species from one bulk phase

at the surface of another bulk phase, without penetrating the structure of the

second phase. Based on the nature of adsorbate-adsorbent interactions,

adsorption can be classified as either physical or chemical (Table 1-1). The

adsorption of nonpolar organic vapors on mineral surfaces is generally considered

to result from nonspecific molecular interactions, such as van der Waals forces,

which are also responsible for vapor condensation and deviations from ideal

behavior. Chemical adsorption of aromatic hydrocarbons has been observed on

Cu-saturated montmorillonite using infrared and ultraviolet-visible spectroscopy

(e.g., Pinnavaia et al., 1974; Pinnavaia and Mortland, 1971). It was postulated that

the chemisorbed species was coordinated with exchangeable Cu(ll) ions via x
electrons. However, interactions of this nature are typically limited to clay minerals

saturated with certain transition metals under anhydrous conditions.

The equations of Freudlich, Langmuir, and Brunauer, Emmett, and Teller

(BET) are frequently used to interpret gas-solid adsorption data. Although the

Langmuir and BET models can be derived theoretically, the Freudlich adsorption

model is based solely on the following empirical equation:

S = kP1" (1-1)









Table 1-1. Comparison of physical and chemical adsorption of vapors on solids.


Property Physical Adsorption Chemical Adsorption


Enthalpy of
Adsorption

Reversibility
of Adsorption



Adsorbed
Layers

Adsorption
Rate

Adsorbate-
Adsorbent
Interaction


< 80 kJ/mole


Reduction in vapor
pressure results in
desorption.


Multilayer formation.


Instantaneous. May be
limited by diffusion.

Nonspecific. Van der
Waals forces.


2 200 kJ/mole


Stronger treatment
required for desorption.
Desorption may result
in chemical alterations.

Limited to monolayer.


Rapid or slow. May
require activation energy.

Specific. Chemical bond
formation.








4
where S is the amount adsorbed (mg/g), P is the equilibrium vapor pressure, and

k and n are constants. The constants k and n are indicative of the extent and

intensity of adsorption, respectively. At low vapor pressures the value of n

frequently approaches one, which results in a linear isotherm. However, the

Freudlich equation rarely fits gas-solid adsorption data over a range of vapor

pressures.

The Langmuir model was the first theoretical treatment of adsorption, and

has been applied with reasonable success to systems exhibiting chemical

adsorption. At equilibrium, Langmuir (1916) considers the rate of evaporation

(desorption) from occupied sites to be equal to the rate of condensation

(adsorption) on the bare surface, which yields the following equation:

S KP
= (1-2)
Sm 1+KP

where S is the amount adsorbed (mg/g), S, is the monolayer adsorption capacity

(mg/g), P is the equilibrium vapor pressure, and K is the rate of adsorption divided

by the rate of desorption. The Langmuir adsorption isotherm is linear at low vapor

pressures and reaches a limiting value at or above vapor pressures corresponding

to monolayer coverage (Figure 1-la).

Implicit in the kinetic derivation of the Langmuir equation are the following

assumptions: (1) the adsorbate behaves as an ideal gas in the bulk phase; (2)

adsorption is limited to monolayer coverage; (3) the energy of adsorption is

constant; (4) no adsorbate-adsorbate interactions occur; (5) adsorption is localized
















E
C)












E
W)


P (mm Hg)


Figure 1-1.


Gas-solid adsorption isotherms characteristic of the (a) Langmuir
model (Type I) and (b) BET model (Type II).


P
0








6
(i.e., site-specific). The assumption of constant adsorption energy and the

absence of adsorbate-adsorbate interactions are rarely valid (Ross and Olivier,

1964). However, the errors associated with these assumptions tend to nullify one

another, and thus the success of the Langmuir equation may be attributed, in part,

to this coincidence.

Brunauer, Emmett, and Teller (BET) extended the Langmuir model to

account for multilayer adsorption by assuming that the Langmuir equation is

applicable to each adsorbed layer (i.e., each layer has a fixed number of

adsorption sites). The first layer is assumed to have a heat of adsorption equal

to Q,, while all successive layers have heats of adsorption equivalent to the heat

of vaporization (Q0). Adsorption and desorption are considered to occur only from

exposed surfaces, and at equilibrium the amount of solute adsorbed on each layer

is at steady state. The BET equation is given as follows:

S C(P/Po)
= (1-3)
Sm (1-P/Po) [1-P/Po+C(P/Po)]

where S is the amount adsorbed (mg/g), Sm is the monolayer adsorption capacity

(mg/g), P is the equilibrium vapor pressure, Po is the saturated vapor pressure,

and Cis a parameter related to the heat of adsorption. The BET equation typically

yields Type-II adsorption isotherms which are characteristic of multilayer formation

resulting from physical adsorption (Figure 1-1b).








7
The values of Sm and C can be obtained from a least squares fit of

adsorption data to the linear form of the BET equation, given as follows:

P/Po 1 (C-1)P/Po
= + (1-4)
S(1-P/P,) SC SC

Estimated values of Sm and C for a range of adsorbate-adsorbent systems are

presented in Table 1-2. In theory, the approximate value of C is given by the

following equation:

(Q,- QC)/RT
C e (1-5)
where R is the gas constant and T is the temperature (K). Provided the heat of

vaporization (Q,) is known, the heat of adsorption (Q1) can be calculated from the

value of C (e.g., Chiou and Shoup, 1985; Jurinak and Volman, 1957). However,

Sing et al. (1985) concluded that the C parameter obtained from the BET model

does not provide a quantitative measure of heats of adsorption, but does indicate

the relative magnitude of adsorbate-adsorbent interactions. In general, the values

of C in Table 1-2 are indicative of the low interactions energies associated with

physical adsorption. The BET equation is considered to yield reliable estimates

of the monolayer adsorption capacity for systems exhibiting Type-II adsorption

isotherms. The surface area of the adsorbent can then be calculated from the

value of Sm and the cross-sectional area of the adsorbate, typically estimated from

the liquid density. This procedure has become standard practice for the

determination of surface area from N2 adsorption isotherms (Adamson, 1982).









Table 1-2.


BET parameters calculated from the adsorption of organic vapors on
anhydrous soil materials.


Adsorbate Adsorbent Sm C Reference"


Benzene
Benzene
Benzene
Toluene
Toluene
Toluene
Toluene
p-Xylene
p-Xylene
p-Xylene
p-Xylene
Ethylbenzene
Ethylbenzene
Dichloropropane
Dichloropropane
Dichloropropane
Dichloropropane
Chlorobenzene
m-Chlorobenzene
p-Dichlorobenzene
1,2,4-trichlorobenzene
Ethylene dibromide
Ethylene dibromide
Ethylene dibromide
Ethylene dibromide
Ethylene dibromide
Ethylene dibromide
Ethylene dibromide


Parsons silt loam
Weller silty loam
Woodburn silty clay
Bentonite
Kaolin
Silica Gel
Webster silty clay loam
Bentonite
Kaolin
Silica Gel
Lula aquifer material
Bentonite
Webster silty clay loam
Parsons silt loam
Weller silty loam
Bernow sandy loam
Summit silty loam
Woodburn silty clay
Woodburn silty clay
Woodburn silty clay
Woodburn silty clay
Yolo silty clay
Yolo loam
Salanis clay
Meloland clay loam
Hanford sandy loam
Aiken clay loam
Staten peaty muck


(1988); (4)


--mg/g--
7.3
11.3
5.6
7.3
4.2
65.3
2.3
7.9
4.6
64.7
1.8
7.8
2.6
8.2
12.7
1.2
8.1
7.5
7.4
5.5
9.5
35.9
18.7
23.9
26.3
3.7
26.9
11.7


1.8
20.0
13.6
10.0
27.0
12.0
12.0
10.0
18.0
17.0
45.0
17.0
14.0
7.8
32.7
18.1
8.1
22.8
24.4
78.5
27.5
73.4
96.2
59.9
41.3
15.0
17.1
12.6


a (1) Poe et al. (1988); (2) Chiou and Shoup (1985); (3) Rhue et al.
Jurinak and Volman (1957).








9
Rhue et al. (1988) reported that adsorption of p-xylene vapors on oven-dry

silica gel was considerably greater than that on kaolin, bentonite, and Lula aquifer

material (Figure 1-2a). However, when the adsorption data were normalized to the

monolayer adsorption capacity (Sm) of each adsorbent, the relative adsorption was

essentially the same for all adsorbents studied (Figure 1-2b). A similar trend was

observed for the adsorption of ethylene dibromide (EDB) on a number of soils

(Jurinak and Volman, 1957). The slight increase in relative adsorption noted for

Lula aquifer material corresponded to a larger value of C, suggesting that specific

adsorbate-adsorbent interactions may have occurred. However, the overall

similarity in relative adsorption is remarkable considering the variation in adsorbent

properties, and indicates that the adsorption of organic vapors on mineral surfaces

is primarily a function of surface area (Jurinak and Volman, 1957; Rhue et al.,

1988).

The significance of the monolayer adsorption capacity obtained from the

BET model has recently come under scrutiny. Rhue et al. (1988) suggested that

for systems exhibiting low values of C, the coverage of the entire surface with a

single monolayer may not occur at any relative vapor pressure. In fact, multilayer

adsorption of EDB on Ca-saturated montmorillonite and kaolinite was observed at

surface coverages of 0.65 and 0.35, respectively (Jurinak and Volman, 1957). The

corresponding values of C for the montmorillonite and kaolinite systems were 24

and 14, respectively. In theory, the onset of multilayer formation prior to

monolayer coverage would result in the formation of discrete adsorbate films or








100
Silica gel
80 Kaolin
o Bentonite
60 o Lula


CO 40-


20


0 0.1 0.2 0.3 0.4 0.5 0.6

2
o

(b) o
1.5 o m *
0

S1 o *
UO 0

0.5 .



0 0.1 0.2 0.3 0.4 0.5 0.6

p-Xylene (P/Po)

Figure 1-2. Adsorption of p-xylene vapors on oven-dry silica gel, kaolin,
bentonite, and Lula aquifer material, expressed as (a) amount
adsorbed and (b) relative amount adsorbed, reported by Rhue et al.
(1989).








11
"patches" on the adsorbent surface. This scenario appears to be reasonable for

the adsorption of nonpolar organic vapors on mineral surfaces based on the

similarity in their heats of adsorption and condensation (Rao at al., 1989).



Competitive Adsorption

Under natural conditions, the adsorption of organic vapors will usually occur

on surfaces containing at least some adsorbed water. Chiou and Shoup (1985)

reported that the magnitude of water, 1,2,4-trichlorobenzene, chlorobenzene, and

benzene adsorption on oven-dry Webster soil was positively correlated to

adsorbate polarity (Figure 1-3a). It should be noted that the relative adsorption

was similar for all adsorbates studied, which suggests that the monolayer

adsorption capacity determined from the BET model accounts for variations in both

adsorbate and adsorbent properties (Figure 1-3b). The fact that adsorbate polarity

enhanced vapor-phase adsorption indicates that water will compete strongly with

organic vapors for adsorption sites. The adsorption of water on mineral surfaces

has been attributed to cation-dipole interactions, hydrogen bonding, and weak

charge transfer, which fall within the extremes of physical and chemical adsorption

(Burchill et al., 1981). Jurinak and Volman (1961b) reported that the enthalpy of

water adsorption on Ca- and Ba-saturated kaolin was approximately -120 kJ/mole,

which corresponded to an enthalpy of cation hydration of approximately -250

kJ/mole. In contrast, Rao et al. (1989) reported that heats of adsorption for

trichloroethene (TCE), toluene, and cyclohexane vapors on oven-dry Oldsmar soil







35

30

25

20
E
15

10

5

0
0


Figure 1-3.


0.2


0.4


0.6


0.8


P/P
0
Adsorption of water, 1,2,4-trichlorobenzene, chlorobenzene, and
benzene on oven-dry Woodburn soil, expressed as (a) amount
adsorbed and (b) relative amount adsorbed, reported by Chiou and
Shoup (1985).


0.2 0.4 0.6 0.8 1


3

2.5

2


E

C)


1.5


0
0
-o


0

"00
S o



-i (b)

I I I _


1

0.5








13
were -23, -37, and -34 kJ/mole. Thus, as the relative humidity or soil moisture

content increases, water will displace organic vapors from adsorbent surfaces

resulting in the suppression of VOC sorption. This finding is supported by infrared

studies, which have demonstrated that p-xylene was immediately displaced from

the surface of montmorillonite when laboratory air was introduced into the sample

cell (C. T. Johnston, 1990, personal communication).

Prior to the attainment of monolayer coverage with water, the adsorption of

organic vapors may proceed, essentially unhindered, on exposed mineral surfaces.

Rhue et al. (1989) reported that p-xylene adsorption on silica gel and kaolin was

not suppressed until the RH was greater than that corresponding to the monolayer

adsorption capacity determined from the BET model (i.e., RH 18%) (Figure 1-4).
In contrast, Call (1957) observed a substantial decrease in ethylene dibromide

adsorption at 5% RH (Figure 1-5). Regardless of the exact point at which

competitive effects become evident, these data indicate that the presence of water

vapor not only reduces organic vapor sorption, but also results in a shift from

Type-II adsorption isotherms to ones that are essentially linear.

In order to predict the competitive adsorption of water and organic vapors

on mineral surfaces a two-component adsorption model must be employed.

Fortunately, the BET equation has been modified by Hill (1946a, 1946b), and more

recently by Rhue et al. (1989), to account for adsorption from two-component

systems. The only additional assumption required to derive the equation of Rhue

et al. (1989) is that each component adsorbs only onto exposed mineral surfaces






















0.2 0.4 0.6


0 0.2 0.4


p-Xylene (P/Po)


Figure 1-4.


The effect of RH on the adsorption of p-xylene vapors on
(a) kaolin and (b) silica gel reported by Rhue et al. (1989).


0)
E
Cl)


2

0


140

120

100


0.8


0)


80

60

40


0.6









15

LO
10



c;

r~
60 0
t:
.0



xO
0, a,
C,








oo




0c

a
0










III I
S0,
a,



















o



0 0 0 0 -


(6/6w) C



C
0I
.u








16
or adsorbed layers of itself. This implies that the two components form immiscible

fluids on the surface, which is reasonable for adsorbates of low mutual solubility,

such as water and a nonpolar organic vapor. The total adsorbed mass of

component "a", Ma (mg/g), can be calculated from the following equation:

Ma = a C, So [Xa/(1-X,) (1-6)

where a. is the mass of component "a" occupying a unit area of surface (mg/m2),

Ca is the BET parameter related to the heat of adsorption determined from single-

component adsorption isotherms, Xa is the relative vapor pressures of component

"a", and So is the area of bare surface per unit mass of adsorbent (m2/g).

Unfortunately, the value of So is unknown in a binary system, and thus the amount

of each component adsorbed could not be expressed on a per-mass-of-adsorbent

basis (Rhue et al.,1989). However, the two-component model was evaluated by

comparing the measured and predicted mass fraction of component "a" (F,) on the

surface using the following equation:

Ma
Fa =. (1-7)
M + Mb

The multi-component BET equation of Hill (1946a, 1946b) is based primarily

on the BET postulate which states that molecules of the second and higher

adsorbed layers possess evaporation-condensation properties of the bulk liquid.

If this assumption is valid, it follows that adsorption and desorption from the

second and succeeding layers of a binary system should approximate the

properties of the liquid mixture. In addition, Hill assumed that area fraction of








17
component "a" (y.) is related to the mole fraction (Na) by the following equation:

Na
Y, = (1-8)
Na + (1-N,) (vdv,)23

where va and Vb are the mole fractions of component "a" and "b", respectively. If

component "a" is assumed to adsorb only onto bare mineral surfaces and an

adsorbed layer of itself, Hill's equation can be reduced to:

S, XJ[C.(1-Xb) + XbCJ
(1-9)
Sm (1-Xa-Xb) [1+X,(C,-1) + Xb(Cb-1)]
where S, is the amount of component "a" adsorbed (mg/g), S,, is the monolayer

adsorption capacity of component "a" (mg/g), X, and Xb are the relative vapor

pressures of component "a" and "b", respectively, and C, and Cb are the BET

parameters related to the heat of adsorption for component "a" and "b",

respectively. The values of Sam, C,, and Cb are determined from single-component

adsorption isotherms. If one of the components is absent (i.e., X, or Xb = 0), Hill's

equation reduces to the single-component BET equation. Although the derivation

referred to here is limited to a two-component system, in theory, the Hill equation

can accommodate an infinite number of components.

Due to the lack of suitable adsorption data, the two-component models of Rhue

et al. (1989) and Hill (1946a, 1946b) have rarely been tested.









Sorption at High Relative Humidity

At RHs approaching saturation (i.e. RH > 90%), the sorption of organic
vapors has been attributed to partitioning into organic carbon (Chiou and Shoup,

1985). This hypothesis is based on (1) the linear nature of benzene and

chlorobenzene vapor adsorption isotherms on Woodburn soil at 90% relative

humidity, and (2) the similarity in the magnitude of sorbate uptake from the

aqueous and vapor phase. However, linear isotherms have been obtained for a

range of sorbents, including those with trace levels of organic carbon (OC), such

as kaolin, silica gel, and Ca-saturated montmorillonite (Call, 1957; Rhue et al.,

1989). In addition, vapor-phase sorption coefficients, normalized for OC (Kc),

calculated for sorbents of low OC content have repeatedly been found to be orders

of magnitude greater than literature values (Rhue et al., 1989; Peterson et al.,

1988). Although these data suggest that other mechanisms may contribute to the

vapor-phase sorption at high RHs, the sorption of organic vapors on hydrated soils

is widely described by dissolution into adsorbed water films and subsequent

partitioning into OC (Baehr, 1987; Glotfelty and Schomburg, 1989; Jury et al.,

1990).

The adsorption of insoluble and sparingly-soluble organic vapors has also

been investigated by gas chromatography (GC). In general, Type-Ill isotherms

have been obtained for the adsorption of nonpolar vapors on hydrated sorbents,

with heats of adsorption that are smaller than heats of vaporization (Dorris and

Gray, 1981; Karger et al., 1971 a, 1971b). These data suggest that the gas-liquid








19
interface of adsorbed water films acts as a low energy surface toward nonpolar

vapors. Once the surface is covered with several monomolecular layers of water

it appears that the sorbent has no effect on vapor-phase adsorption. Karger et al.

(1971a, 1971b) concluded that adsorbed water films between 1.5 and 200 nm in

thickness have properties similar to bulk water. Measurements of the change in

surface tension of bulk water with vapor pressure also indicate that nonpolar

organic vapors are adsorbed at the gas-liquid interface (Blank and Ottewill, 1964;

Cutting and Jones, 1955; Hauxwell and Ottewill, 1968). Due to the large surface

area of adsorbed water films, adsorption at the gas-liquid interface of hydrated

soils may contribute significantly to VOC sorption. In fact, Call (1957) attributed

the sorption of EDB on moist soils to adsorption at the gas-liquid interface and

dissolution into adsorbed water films. It is apparent that a number of mechanisms

may contribute to vapor-phase sorption at high RHs, including partitioning into OC,

adsorption at the gas-liquid interface, and dissolution into adsorbed water films.

In addition, the extent to which sorbate and sorbent properties determine the

importance of each mechanism remains largely unknown.



Research Summary

The purpose of this work was to investigate, from a mechanistic perspective,

the sorption of organic vapors on soils and clay minerals. The study of soil

processes, particularly sorption, is limited by our inability to measure soil

phenomena on a microscopic scale. Thus, a macroscopic approach was







20
employed here, in which experiments were specifically designed to ascertain the

mechanism responsible for sorption under various sorbate-sorbent regimes.

A single volatile organic chemical, p-xylene, was utilized in these studies.

Although this may be viewed as a limitation, it allowed for intensive study of the

factors affecting vapor-phase sorption and for the development of experimental

techniques to study VOC sorption. Relevant physicochemical properties of p-

xylene are presented in Table 1-3. The sorbents used in these studies were

selected to provide a range of physical and chemical properties. In addition, the

OC content and cation saturation of certain sorbents were modified in order to

study the effect of such treatments on vapor-phase adsorption.

In Chapter 2, a flow-equilibration apparatus was utilized to measure the

sorption of p-xylene vapors on soils and mineral surfaces at 0, 67, and 90% RH.

Experiments were designed to determine the amount of p-xylene sorption

attributable to adsorption at the gas-liquid interface, dissolution into adsorbed water

films, and partitioning into OC. Adsorption at the gas-liquid interface of hydrated

sorbents was estimated from measurements of the surface tension of bulk water

exposed to p-xylene vapors using the Gibbs adsorption equation.

Gas chromatography techniques were used to study the sorption of p-xylene

vapors on anhydrous and hydrated quartz sand in Chapter 3. The effect of salt

treatments on vapor-phase sorption, and a comparison of batch and GC data are

also presented. In addition, the advantages and limitations of GC methods for the

study of vapor-phase sorption on soil materials are discussed.









Selected physicochemical properties of p-xylene.


Property


Valuea


Structure
Molecular Weight
Boiling Point
Density
Solubility
Vapor Pressure
Henry's Law Constant


C6H4(CH),2
106.17 g/mole
138.40C
0.86 g/mL (200C)
198 mg/L (250C)
8.14 mm Hg (240C)
7.44 X 10- m3- atm/mole


a Data obtained from Verschueren (1983) and Weast (1987).


Table 1-3.







22
In Chapter 4, the adsorption of p-xylene vapors on Ca-, Na-, and Li-

saturated kaolin was measured using the flow-equilibration method. The effect of

cation saturation on the competitive adsorption of water and p-xylene vapors was

also studied. These data were used to evaluate the two-component BET

adsorption models of Hill (1946a, 1946b) and Rhue et al. (1989).

Li-saturated kaolin was utilized as a reference surface for the study of water

and organic vapor sorption in Chapter 4. However, there has been considerable

debate in the literature as to whether or not Li-kaolin actually represents a surface

free of cation hydration effects. Thus, the mechanism responsible for reduced

water adsorption on Li-kaolin was investigated by gravimetric, spectroscopic, and

ion extraction techniques in Chapter 5.













CHAPTER 2
VAPOR-PHASE SORPTION OF P-XYLENE AND WATER ON
SOIL MATERIALS AT HIGH RELATIVE HUMIDITIES

Introduction

Vapor-phase sorption influences the mobility and distribution of volatile

organic chemicals (VOCs) in the unsaturated zone as well as the atmospheric

transport and deposition of VOCs. Previous studies have demonstrated that oven-

dry soils and clay minerals have a sizable capacity to adsorb organic vapors,

which can be described by the Brunauer-Emmett-Teller (BET) model (Call, 1957;

Chiou and Shoup, 1985; Jurinak and Volman, 1957; Poe et al., 1988; Rao et al.,

1989; Rhue et al., 1988). However, under natural conditions the sorption of

organic vapors usually occurs on surfaces containing at least some adsorbed

water. As the soil moisture content or relative humidity (RH) increases VOCs are

displaced from the surface, resulting in the suppression of VOC sorption (Call,

1957; Chiou and Shoup, 1985; Hollist and Foy, 1971; Rao et al., 1989; Rhue et

al., 1988, 1989; Spencer and Cliath, 1970, 1972, 1974, Wade, 1954). It is

generally agreed that water effectively competes with organic vapors for mineral

surfaces due to the polar nature of water and mineral adsorption sites (Valsaraj

and Thibodeaux, 1988).

At RHs above which the sorbent surface is occupied by at least a

monolayer of water, the specific mechanisms responsible for the sorption of VOCs








24
remain unclear. It has been postulated that the sorption of organic vapors at high

RH can be described by partitioning into organic carbon (OC) (Chiou and Shoup,

1985). This hypothesis was based on the linear nature of benzene and

chlorobenzene vapor sorption isotherms obtained for Woodburn soil (1.9% organic

matter) at 90% RH, and the similarity between the magnitude of solute uptake from

the aqueous and vapor phase (Chiou and Shoup, 1985). However, at 90% RH,

Call (1957) obtained linear isotherms for the sorption of ethylene dibromide (EDB)

vapors on Ca-saturated montmorillonite which contained no detectable OC. Rhue

et al. (1989) also reported linear isotherms for p-xylene vapor sorption on sorbents

with low OC contents; e.g., kaolin (0.65 g OC/kg) and silica gel (0.45 g OC/kg), at

67% relative humidity. In addition, sorption coefficients normalized for OC (K)

calculated from p-xylene sorption data and solubility considerations were 2 to 5

orders of magnitude greater than p-xylene Ko values reported in the literature. A

similar trend was noted by Peterson et al. (1988), who reported that linear sorption

coefficients measured for trichloroethylene (TCE) vapor over a range of

unsaturated conditions were 1 to 4 orders of magnitude greater than values

obtained under saturated conditions. Chiou and Shoup (1985) also found that the

vapor-phase sorption of benzene, m-dichlorobenzene, and 1,2,4-trichlorobenzene

was consistently greater than sorption from aqueous solution, even though the

sorbent surface should have been covered with several monolayers of water at

90% RH. These data suggest that in addition to partitioning into soil organic

carbon, other mechanisms contribute to VOC sorption at high RH.








25
Dissolution into adsorbed water films and adsorption at the gas-liquid

interface were considered by Call (1957) to be the dominant mechanisms

responsible for EDB sorption on moist soils. For sparingly-soluble VOCs, such as

p-xylene, the magnitude of sorption is far greater than dissolution into sorbed

water, based on solubility limits in bulk water (Rhue et al., 1989). However,

adsorption at the interface between the vapor phase and bulk water has been

reported for a number of sparingly-soluble VOCs (Blank and Ottewill, 1964; Cutting

and Jones, 1955; Drozd et al., 1982; Hauxwell and Ottewill, 1968). Due to the

large surface area to volume ratio of adsorbed water films, adsorption at the gas-

liquid interface of hydrated soils could contribute significantly to vapor-phase

sorption.

The experiments reported here were designed to determine the nature of

p-xylene vapor sorption isotherms at high RH and to determine the amount of p-

xylene sorption attributable to adsorption at the gas-liquid interface, dissolution into

adsorbed water films, and partitioning into OC. Adsorption at the gas-liquid

interface was estimated from surface tension measurements of distilled water

exposed to p-xylene vapors using the Gibbs adsorption equation.



Materials and Methods

Sorbents

The sorbents used in this study were selected to provide a range of surface

area and OC content. Colloidal kaolin (K-6, Lot #731063) was obtained from








26
Fisher Scientific Products. The kaolin had a cation exchange capacity (CEC) of

4.23 cmoljkg at pH 5.5 and was predominantly Na-saturated with only trace

amounts of Ca, K, and Mg (Rhue et al., 1989). Silica gel (Syloid 244), average

particle size of 3 pm and a pore volume of 1.4 cm3/g, was obtained from the

Davison Chemical Division, W.R. Grace & Co., Baltimore, MD. The Webster soil,

a silty clay loam (Typic Haplaquoll), was collected from the surface horizon (0-30

cm) of a site in Iowa and ground to pass a 106 pm mesh screen. The Webster
soil had a CEC of 51.11 cmolJkg and was predominantly Ca-saturated. A portion

of the Webster soil (Webster HP) was treated with hydrogen peroxide buffered to

pH 5.0 with acetic acid to remove OC.

Organic carbon content was measured by the Wakley-Black heat-of-dilution

method (Donohoe, 1983). The sorbent surface areas were determined from N2

adsorption data (Advanced Materials Research Center, University of Florida).

Cation exchange capacity was determined by washing the sorbents with 1.0 M

CaCI, 5 times, removing excess salts with 95% ethanol until a negative chloride

test was achieved using AgNO3, and extracting exchangeable Ca with 0.5 M

Mg(NO3)2. The amount of Ca present in the Mg(NO3)2 extract was then measured

by atomic absorption spectroscopy. These and other sorbent properties are

presented in Table 2-1.

Vapor-Phase Adsorption Studies

Vapor-phase sorption of p-xylene was determined on Webster soil and

Webster HP at 0 and 90% RH, and on kaolin and silica gel at 0 and 67% RH. The























I-
0
a-

a)
CD
a)






4.
C

La
0





0



4-











a)
Q-
ci
o
-2



'0









a
cc






a)
a
0





0






-c
a-




ca
I-


0D

E c


0)

CO





a



CO



*C
ODO











x

co
.0
CO


















Wa-
o 2
0















ml)
oc
0o













Wa)











o
00
4-



a )
0 c



(0 -
2(
00




u,


1




E
6)




o
0











E
0




























0)
0
I
O
O
,
:
.


cu




o
CD
















o
0


L0


LO







































4-
an-


co




CM





C4












4-
U)

Bm








28
flow-equilibration apparatus used to measure p-xylene and water vapor sorption

was similar to that described in previous studies (Rhue et al., 1988, 1989).

However, the p-xylene flow stream consisted of two gas washing bottles in series;

the first contained water and the second contained p-xylene and water (Figure 2-

1). This allowed the RH to be maintained at either 67 or 90% while the p-xylene

relative vapor pressure (P/Po) could be varied from 0 to 0.9, where P is the

equilibrium vapor pressure and Po is the saturated vapor pressure. The P, of p-

xylene at 240C is 8.14 mm Hg, which is equivalent to a vapor concentration 46.64

mg/L (Weast, 1987). For sorption experiments conducted at 0% RH, valve V3 was

closed and valves V, and V2 were adjusted to obtain relative vapor pressures of

p-xylene ranging from 0 to 0.9.

The concentration of water and p-xylene vapor in the flow stream was

determined by passing the flow stream through three polyethylene tubes in series.

The three tubes contained magnesium perchlorate, activated charcoal, and a

mixture of activated charcoal and magnesium perchlorate, respectively. The

difference between the initial and final trap weights yielded the total mass of vapor

trapped. The p-xylene vapor concentration was then determined by bubbling the

flow stream through two 40-mL glass centrifuge tubes containing 20 mL of

methanol. P-xylene trapped in these solutions was measured with a Perkin Elmer

Model 320 UV-VIS spectrophotometer. The concentration of water vapor in the

flow stream was determined by subtracting the concentration of p-xylene from the

total vapor concentration.


























I












Ir


o
LI
-j

WI



, -- -
0 I


RI



0 I


!0 I


,)

0
cm
z


C



0)


12
C
0
0




c
0


0
0



3


C
CL
.
cc
0








0


I-
a





-0W
0



oc

'6
04-' [








30
Approximately 1 g of sorbent, which had been oven-dried to 1300C, was

placed in glass centrifuge tubes and capped with teflon-backed septa. Four tubes

containing sorbent, and four blank tubes were placed on the flow stream in series.

The gas flow stream passed through the centrifuge tubes via hypodermic needles

at a rate of approximately 1.0 mL/sec. In general, an exposure time of 24 hours

was sufficient to attain sorption equilibrium.

Adsorbed concentrations of water and p-xylene were measured by

extracting the sorbents with 20 mL of methanol containing CaCI2. The methanol

solution was made by adding 10 mL of CaCI2-saturated methanol per 1 L of

methanol. Water in the methanol extract was measured by Karl Fisher (KF)

titration. The KF reagent was diluted with KF diluent to a strength of approximately

0.5 mL titer per mg of water. The visual endpoint was established by adding titer

to 20 mL of CaCI2-methanol solution until the desired endpoint was obtained. In

a second centrifuge tube, 5 mL of methanol solution was pretitrated to the visual

endpoint and 10 gL of deionized water was injected and titrated to the endpoint to
give the exact strength of the titer. A known volume of the methanol extract was

titrated in a similar manner to determine the amount of adsorbed water.

The concentration of p-xylene in the methanol extract of kaolin and silica gel

was measured using a Perkin Elmer Model 320 UV-VIS spectrophotometer. The

Webster soil and Webster HP released methanol-soluble compounds that

interfered with direct UV spectrophotometric analysis. Therefore, p-xylene extracts

from these sorbents were analyzed by high-performance liquid chromatography








31
(HPLC) techniques. The HPLC system consisted of a Gilson 302 pump, Waters

450 detector, Hewlett Packard 3392A integrator, and a 10-cm Waters RCM C-18

column with a 3-cm Brownlee guard column.

Surface Tension Measurements

The surface tension of deionized water exposed to p-xylene vapors was

measured using the "drop weight" method. The technique is based on Tate's law,

which considers the weight of a drop falling from a small diameter tube to be

proportional to the radius (r) of the tip (cm), and the surface tension (y) of the liquid

(g/s2),

weight per drop = 2 n r y. (2-1)
Tate's law assumes that a spherical drop will form at the tip, but in reality the drop

tends to elongate before it detaches from the tip. Harkins and Brown (1919)

recognized the importance of this discrepancy and developed a correction factor

(CF) based on the ratio of the tip radius to the length of the drop,

CF = f(rN'") (2-2)

where V is the volume of the drop (Table 2-2). In general, the values of rN/V3 were

between 0.45 and 0.50. The following equation was then used to calculate surface

tension:

mg
Y = 2, (2-3)
2 ?rCF

where m is the mass of the drop (g), and g is the acceleration due to gravity

(cm/s2).








32
Table 2-2. Drop-weight surface tension correction factors (CF) adapted from
Harkins and Brown (1919).


rN"3 CF rN/13 CF


0.30 0.7256 0.75 0.6032

0.35 0.7011 0.80 0.6000

0.40 0.6828 0.85 0.5992

0.45 0.6669 0.90 0.5998

0.50 0.6515 0.95 0.6034

0.55 0.6362 1.00 0.6098

0.60 0.6250 1.05 0.6179

0.65 0.6171 1.10 0.6280

0.70 0.6093 1.15 0.6407








33
A 10-mL graduated burette was used forthe surface tension measurements.

After carefully grinding the tip flush, an ocular microscope was used to measure

the diameter of the tip (0.37 cm). Drops of water falling from the tip were collected

in a 40-mL centrifuge tube, capped with a teflon-backed septa. A 0.4-cm diameter

hole was cut in the septa, and the height of the centrifuge tube was adjusted to

achieve a tight seal between the septa and the burette. A total of 18-20 drops, at

a rate of 4-6 drops per minute, were collected in the centrifuge tube. The surface

tension of water was then calculated from the volume and weight of liquid

collected. Solutions of NaCI were used to calibrate the diameter of the tip (0.3724

cm).

p-Xylene vapor, at relative vapor pressures from 0.1 to 0.8, was bubbled

through a 50-mL centrifuge tube capped with teflon-backed septa. The tube

contained approximately 40 mL of deionized water. No detectable change in the

p-xylene concentration was measured after one, two or four days of bubbling.

Therefore, the system was allowed to equilibrate for at least 24 hours. The

surface tension of deionized water exposed to p-xylene vapors was determined in

the same manner as described previously except that the p-xylene vapor was

allowed to flow through the collection tube for at least 2 minutes prior to initiating

the flow of drops.









Results and Discussion

Adsorption at 0% RH

Figures 2-2 and 2-3 show equilibrium isotherms for p-xylene vapor sorption

on silica gel, kaolin, Webster soil, and Webster HP at 240C. Sorption data are

expressed as milligrams of p-xylene sorbed per gram of sorbent (S) versus the p-

xylene relative vapor pressure (P/Po). At 0% RH, the p-xylene isotherms of all four

sorbents conformed to Type-II BET adsorption isotherms. This type of isotherm

is typical of unrestricted monolayer-multilayer adsorption of gases on nonporous

or macroporous (pore width > 0.05 pm) sorbents (Sing et al., 1985). These
sorption data were fit by a least squares procedure to the linear form of the BET

equation,

P/Po 1 (C-1)P/Po
= + (2-4)
S(1-P/Po) SC S,C

where Sm is the nominal monolayer adsorption capacity (mg/g), and C is a

parameter related to the heat of adsorption. Estimated values of S,, C, and the

P/Po associated with monolayer coverage are presented in Table 2-3.

The BET equation is considered to give reliable estimates of Sm for surfaces

exhibiting Type-11 adsorption isotherms. However, the value of C does not provide

a quantitative measure of the heat of adsorption, but does give an indication of the

relative magnitude of sorbent-sorbate interactions (Sing et al., 1985). The values

of C obtained for these systems are indicative of low sorbate-sorbent interactions

associated with physical adsorption. For systems exhibiting low values of C,










180
160
140
0i 120
C 100
80
0C 60
40
20
0


60

50


0 0.2 0.4 0.6 0.8


p-Xylene (P/Po)


Figure 2-2.


Sorption of p-xylene on (a) silica gel and
RH.


(b) kaolin at 0 and 67%


0 0.2 0.4 0.6


0)

E


40

30

20

10

0


1.0























00
cO




oc_

o
d











CM
ac






0


LI o
r-11-


(6/6wu)




























0 0
co a



o o
o 0o





oco
dd
66 V


o

c%
r_
L.




0












0



o













-2
oo
Cu





















0


to T-


U)
0 0
o 0











V- T-











L) 0
4 0
' CM


1. CM
.*t ,*-


C c

". 0





7 CC
c
O 0)


r-
ui





C
0







C/,
0


0n CM
N- T


- c0 CO
T- T- N


co
CD



0
0




0

d
















cr
CM



CO




a-
at
c

0x


0)
c-
0
cc
0






E


0
4-
0

a








38
discrete regions of multilayer sorption (i.e., patches) may form prior to the

attainment of complete monolayer coverage (Jurinak and Volman, 1957; Sing et

al., 1985).

The amount of sorbent surface available for the adsorption of a given

molecule (SA) can be estimated from the Sm value and the area occupied by each

adsorbed molecule. The cross-sectional areas (a) of water and p-xylene were

calculated to be 0.105 and 0.380 nm2, respectively, using the following equation

(Karnaukhov, 1985; McClellan and Harnsberger, 1967),

am = 1.09(MW/tA)m (2-5)

where MW is the molecular weight, I is the liquid density, and A is Avogadro's
number. This equation assumes that the sorbate molecules are oriented in a

hexagonal close packing at a density similar to that of the bulk liquid. The surface

areas occupied by either p-xylene or water molecules at monolayer coverage (S,)

are shown in Table 2-3.

The values of S, for oven-dry kaolin and Webster HP were similar to those

determined from N2 adsorption isotherms. These data are consistent with the

findings of Jurinak and Volman (1957) and Rhue et al. (1989), who concluded that

the N2 surface area provides a reasonable estimate of the area available for the

sorption of organic vapors on predominantly mineral surfaces. It is interesting to

note that the surface area of Webster soil, as determined from N2 and p-xylene

adsorption isotherms, increased following the hydrogen peroxide treatment. These

data suggest that both p-xylene and N2 vapors have a greater affinity for mineral








39
surfaces than for organic matter at 0% RH. The difference between the N2 (2.62

m2/g) and p-xylene/BET surface area (12 m2/g) of Webster soil may have been

due to greater sorption of p-xylene vapor by soil organic matter. This hypothesis

is supported by the work of Chiou and Shoup (1985), who found that the

adsorption of vapors on oven-dry Woodburn soil increased with the polarity of the

sorbate. The discrepancy between the N2 and BET surface area of silica gel has

been discussed in a previous paper (Rhue et al., 1989)

The relative sorption (S/Sm) of p-xylene on oven-dry kaolin, silica gel,

Webster soil, and Webster HP is shown in Figure 2-4. The use of S/S, allows for

the comparison of the adsorptive capacities of various sorbents on a unit-surface-

area basis. At low values of P/Po, the relative sorption of p-xylene on Webster HP

and Webster soil was slightly greater than that on kaolin and silica gel. The

increased sorption corresponds to an increase in the value of C for Webster soil

(C = 38) and Webster HP (C = 73), which suggests that specific sorbate-sorbent

interactions may have occurred. However, the overall similarity in relative sorption

for the sorbents studied here suggests that the adsorption of p-xylene vapors at

0% RH was primarily a function of surface area.

Sorption at High RH

Vapor-phase sorption of p-xylene on silica gel and kaolin decreased

dramatically when the RH was raised to 67% (Figure 2-2). The observed

suppression of vapor-phase sorption at high RH is in agreement with the findings

of others (e.g., Call, 1957; Chiou and Shoup, 1985; Rhue et al., 1989), and lends



































0

CL


c
U)

X
r_


0 L


S/S


0)

0

c,
0
C




I-

0

E



0



E


(0
0


oo


&a.
0(















0- .
ES














4-
CI
4-







co

0
Q.

Cu
0.-








41
further support to the contention that water effectively competes with organic

vapors for mineral surfaces. Sorption of p-xylene vapors on Webster soil and

Webster HP was also reduced at 90% RH (Figure 2-3). In addition, the sorptive

capacity of Webster soil at 90% RH was greater than that of Webster HP, while

the reverse was true at 0% RH. These data suggest that OC contributed to vapor

sorption on Webster soil at high RH, while adsorption on mineral surfaces was the

dominant mechanism at 0% RH.

At both 67 and 90% RH, p-xylene sorption isotherms were linear until the

P/Po reached approximately 0.5, above which, the amount of p-xylene sorbed

increased sharply, resulting in Type-Ill adsorption isotherms. The linear nature of

the sorption isotherms below 0.5 P/Po was consistent with isotherms obtained by

Call (1957) for EDB, and by Chiou and Shoup (1985) for benzene and

chlorobenzenes. Increased sorption at high relative vapor pressures has not been

previously reported for batch adsorption studies. However, researchers studying

sorption of hydrocarbons on hydrated silica and soil materials by gas

chromatography techniques have consistently obtained retention data which yield

Type-III adsorption isotherms (Dorris and Gray, 1981; Karger et al., 1971a;

Okamura and Sawyer, 1973). Therefore, hydrated soils appear to have a sizable

capacity for organic vapor sorption when the relative vapor pressure approaches

one.

The sorption of organic vapors at high RH is commonly described by

dissolution of organic vapors into sorbed water films, using Henry's Law constants








42
(KH), and subsequent solute partitioning into organic carbon, using sorption

coefficients normalized for OC content (KoJ. The justification for such an approach

comes primarily from a single article by Chiou and Shoup (1985). In this work, the

authors conclude that solute partitioning into organic carbon is the dominant

mechanism responsible for organic vapor sorption at high RH based primarily on

two pieces of evidence; (1) the linearity of the sorption isotherms and, (2) the

similarity in sorptive capacity from the aqueous and vapor phase. However, the

data presented here demonstrate that below 0.5 P/Po linear isotherms can be

obtained for sorbents with OC contents ranging from trace levels to 41 g OC/kg.

Thus, the mere existence of a linear isotherm was not sufficient evidence to

conclude that partitioning into organic carbon had occurred. In addition, the

dramatic increase in sorption above 0.5 P/Po was not consistent with partitioning

theory.

In order to compare sorption from the aqueous and vapor phase, Ko values

were estimated from measured p-xylene sorption data for P/Po below 0.5 (linear

portion of the isotherm) and the aqueous concentration of p-xylene determined

using a KH value of 7.44 X 103 m3- atm/mole (Table 2-4). Predicted p-xylene Ko

values for silica gel, kaolin, and Webster HP were 4, 2, and 1 orders-of-magnitude

greater, respectively, than Ko values determined from column studies (105-176

mUg) (Brusseau et al.; Gamerdinger et al., submitted for publication in

Environmental Science and Technology) and estimated from a log octanol-water

partition coefficient of 3.15 (573 mUg) (Karickhoff, 1984). However, the predicted








43

Table 2-4. Sorption coefficients normalized for organic carbon content (K)
calculated from p-xylene sorption data for P/P of 0.06 to 0.50.


Sorbent


Silica Gel


Kaolin


Webster HP


Webster Soil


RH


-(%)--

67


67


90


90


OC Content


---g/kg---

0.45


0.65


2.27


41.36


KOc


-----ml/g-----

2.35 X 106


9.10 X 104


1.53 X 103


2.17 X 102


0.936


0.989


0.967


0.907


---


----








44
p-xylene K. for Webster soil was within the range of literature values. Thus, as

the sorbent OC content increased, the predicted Ko value approached those

reported in the literature. These data suggest that the utility of Ko values for

predicting vapor sorption was limited to sorbents with relatively high OC contents,

at relative vapor pressures less than 0.5.

Adsorption at the Gas-Liquid Interface

Adsorption at the gas-liquid interface was considered as a possible

mechanism to account for the sorption p-xylene vapors on sorbents with low OC

contents and at high relative vapor pressures. The adsorption of insoluble and

sparingly soluble hydrocarbons on water surfaces has been estimated by

measuring the change in surface tension with the partial pressure of the organic

vapor (Baumer and Findenegg, 1982; Blank and Ottewill, 1964; Cutting and Jones,

1955; Hauxwell and Ottewill, 1968; Jho et al., 1978). This approach is based on

the Gibbs adsorption equation,

dy
F = (2-6)
dL
where r is the surface excess (mol/cm2), 7 is the surface tension, and g is the

chemical potential. If the vapor is assumed to obey the ideal gas law, equation (2-

6) can be written as,

P dy
r = (2-7)
RT dP

where P is the partial pressure of the organic vapor, R is the gas constant, and T

is the temperature. The surface tension of distilled water exposed to p-xylene







45
vapor, as determined by the drop-weight method, is shown in Figure 2-5a. These

data were fit by a least squares regression procedure to yield a slope which could

be then used to calculate the surface excess as a function of the partial pressure

using equation (2-7) (Figure 2-5b). The Type-III adsorption isotherm generated

from this procedure were typical of those obtained for other aromatic hydrocarbons

and indicates that water acts as a low energy surface toward the nonpolar vapor

(Cutting and Jones, 1955; Vidal-Madjar et al., 1976). The amount of p-

xylene adsorbed at the gas-liquid interface was estimated from the surface excess

and the N2 surface area of each sorbent (Table 2-5). In addition, the mass of p-

xylene partitioned into organic carbon was predicted using a K. of 200 ml/g and

a KH of 7.44 X 103 m3- atm/mole, and while mass of p-xylene dissolved in

adsorbed water was predicted using the KH value and the measured amount of

water adsorbed. The sum of the estimated values for these adsorption

components represents the total predicted adsorption, which is compared to the

measured adsorption data in Table 2-5. Adsorption on mineral surfaces was not

included in the predicted total because water is generally assumed to displace

organic vapors from mineral surfaces at high RH. However, the appropriateness

of this assumption at 67% RH is discussed.

The predicted data indicated that the gas-liquid interface was the dominant

mechanism responsible for vapor sorption on silica gel and kaolin. Neither

partitioning into organic carbon nor dissolution into sorbed water contributed

significantly to p-xylene sorption, due to the low OC content of these sorbents and














(M

L,


0 1 2 3 4 5 6 7


E


E
0


X
L,


0 1 2 3 4

P (mm Hg)


Figure 2-5.


5 6 7


Surface tension (a) of deionized water exposed to p-xylene vapors
at 240C and surface excess (b) of p-xylene at the gas-liquid
interface calculated using the Gibbs adsorption equation.









Table 2-5.


Predicted and measured p-xylene sorption on Silica Gel, Kaolin,
Webster HP, and Webster Soil at 90% RH.


Sorption by Components Total Sorption
Sorbent P/P, Gas-Liquid Organic Sorbed Predicted Measured
Interface Carbon Water

--------- -------------------mg/g---------------------...----


Silica
Gel





Kaolin







Webster
HP





Webster
Soil


0.081
0.145
0.274
0.282
0.439
0.610

0.069
0.164
0.258
0.286
0.415
0.600
0.896

0.099
0.201
0.206
0.497
0.601
0.777

0.099
0.197
0.206
0.384
0.497
0.610
0.777


1.802
3.921
10.052
10.514
21.522
37.706

0.084
0.267
0.523
0.614
1.120
2.094
18.262

0.324
0.870
0.903
3.677
5.228
14.014

0.026
0.067
0.072
0.190
0.292
0.415
1.113


0.001
0.002
0.004
0.004
0.006
0.004

0.001
0.003
0.005
0.006
0.008
0.012
0.018

0.007
0.014
0.014
0.034
0.043
0.054

0.126
0.251
0.262
0.488
0.632
0.776
0.988


0.001
0.001
0.002
0.003
0.004
0.008

0.000
0.000
0.000
0.000
0.001
0.001
0.001

0.001
0.003
0.003
0.007
0.008
0.009

0.002
0.003
0.003
0.005
0.008
0.008
0.010


1.804
3.924
10.058
10.521
21.532
37.718

0.085
0.270
0.528
0.620
1.129
2.107
18.281

0.332
0.887
0.920
3.71
5.279
14.077

0.154
0.321
0.337
0.683
0.932
1.199
2.111


11.61
20.74
41.95
36.73
80.19
173.97

0.45
1.41
2.28
2.77
3.76
7.71
52.19

0.05
0.08
0.10
0.28
0.91
3.88

0.21
0.26
0.25
0.61
0.63
1.31
4.36








48
the low solubility of p-xylene, respectively. However, the total predicted sorption

of p-xylene on silica gel and kaolin was approximately one-quarter of the measured

amount. This discrepancy may have been due to adsorption of p-xylene vapors

on exposed mineral surfaces. The average amount of water adsorbed on silica

gel and kaolin at 67% RH was 57.9 and 9.3 mg/g, respectively, which is equivalent

to 1.7 and 2.2 monolayers of water, based on BET estimates of S, (Table 2-3).

Due to the low values of C (20 and 18) for these sorbents, it was possible that

patches of water formed on the mineral surface (Jurinak and Volman, 1957; Sing

et al., 1985), thereby allowing for adsorption on exposed mineral surfaces. Even

if monolayer coverage of water was attained, the mineral surface could still have

exerted a surface effect on sorbed water films (Fowkes, 1968), resulting in greater

sorption than would be predicted for bulk water surfaces. These hypotheses are

supported by the work of Dorris and Gray (1981), who reported that the sorption

coefficient for n-heptane on water-coated silica increased significantly at water

contents less than those achieved at 88% RH. Therefore, it is quite possible that

additional adsorption of p-xylene vapors occurred on exposed mineral surfaces

and/or surface-affected water films of silica gel and kaolin.

Predicted p-xylene sorption on Webster HP was considerably greater than

that measured with the flow-equilibration apparatus. Dissolution into sorbed water

films and partitioning into organic carbon contributed very little to the overall

estimate of p-xylene sorption on Webster HP. Thus, the difference between

predicted and measured sorption was primarily the result of the estimate of








49
adsorption at the gas-liquid interface. The surface area would have to be reduced

from 33.8 m2/g to approximately 4 m2/g in order to bring the estimated adsorption

at the gas-liquid interface into agreement with the measured sorption data. In

contrast, the predicted sorption of p-xylene on Webster soil was similar to the

measured values. Partitioning of p-xylene into OC on Webster soil (41 g OC/kg)

accounted for the majority of sorption at relative vapor pressures less that 0.6.

Sorption at the gas-liquid interface of Webster soil was much less than that of

Webster HP because the N2 surface area was only 2.62 m2/g.



Summary

The transport of VOCs in the unsaturated zone is directly influenced by

partitioning of the organic chemical between the liquid, vapor, and solid phase. Of

particular concern is the vapor phase, in which VOC transport may occur at a rate

greater than that in the liquid phases. Thus, it is imperative that the mechanisms

responsible for vapor-phase sorption are correctly identified and incorporated into

VOC models.

For all sorbents studied here, vapor-phase sorption of p-xylene increased

dramatically at relative vapor pressures greater than 0.5, resulting in Type-Ill

adsorption isotherms. Although it is generally accepted that oven-dry sorbents

have sizable sorption capacity for organic vapors, these data suggest that hydrated

soil materials can also sorb significant quantities of organic vapors in regions of

high vapor concentration (e.g., near the contaminant source). In addition, the data








50
presented here indicate that the use of K. values to predict vapor-phase sorption

at high RH appears to be only valid for sorbents with high OC content, at relative

vapor pressures less than 0.5. These findings are particularly important in light of

the fact that most VOC and multi-phase transport models either fail to consider

vapor-phase sorption (Pinder and Abriola, 1986; Sleep and Sykes, 1989) or

describe vapor-phase sorption by dissolution into soil water and partitioning into

OC (Baehr, 1987; Jury et al., 1990).

In order to describe vapor-phase sorption for different sorbate-sorbent

systems over a range of relative vapor pressures, one must consider all

mechanisms which contribute to VOC sorption. The data presented here indicate

that a multi-mechanistic approach should include adsorption on mineral surfaces,

partitioning into OC, dissolution into sorbed water films, and adsorption at the gas-

liquid interface. Surface tension data suggest that adsorption at the gas-liquid

interface could contribute significantly to the sorption of sparingly-soluble VOCs in

the unsaturated zone. Of particular interest is the sizable surface excess

estimated for aromatic hydrocarbons of environmental concern such as toluene,

benzene, and o-xylene (Blank and Ottewill, 1964; Cutting and Jones, 1955;

Hauxwell and Ottewill, 1968; Vidal-Madjar et al., 1976). The task at hand now is

to further define the limits of applicability of each mechanism based on sorbate,

sorbent, and environmental considerations, and to incorporate this knowledge into

current modeling efforts. An initial attempt at this approach has been attempted

by Shoemaker et al. (1990), who described vapor-phase sorption of TCE using an








51
"effective sorption" term that included sorption coefficients for the solid-liquid and

the solid-gas interface.












CHAPTER 3
GAS CHROMATOGRAPHIC STUDIES OF P-XYLENE SORPTION ON
ANHYDROUS AND HYDRATED QUARTZ SAND


Introduction

Gas-liquid chromatography (GLC) is recognized as an efficient and versatile

method for investigating the sorption of volatile organic compounds (VOCs) on

hydrated sorbents. The interpretation of GLC data requires a consideration of

several retention mechanisms including (1) adsorption at the gas-liquid interface,

(2) adsorption at the solid-liquid interface, and (3) partitioning into the liquid phase.

Conder et al. (1969) proposed the following equation to describe the net retention

volume (VN) of a solute at infinite dilution:

VN = KLVL + KA, + KsAs (3-1)

where KL (mUmL), K, (mUm2), and Ks (mLm2) are the distribution coefficients for

the liquid phase, gas-liquid interface, and solid-liquid interface, respectively, VL

(mUg) is the volume of the liquid phase, and A, (m2/g) and A. (m2/g) are the areas

of the gas-liquid interface and solid-liquid interface, respectively. Previous studies

have demonstrated that aliphatic hydrocarbon retention on water-coated supports

is due solely to adsorption at the gas-liquid interface; whereas, aromatic

hydrocarbons and other weakly polar solutes are simultaneously adsorbed at the

gas-liquid interface and partitioned into the liquid phase (Karger et al., 1971a,








53
1971 b; Martin, 1961). At water contents above 3 to 4% by weight, the effect of the

solid support on solute retention appears to vanish, and thus equation (3-1) can

be applied without the KsAs term (Dorris and Gray, 1981; Okamura and Sawyer,

1973). Comparisons of partition coefficients and heats of solution determined by

GLC and static methods indicate that adsorbed water films between 1.5 and 200

nm in thickness have properties similar to those of bulk water (Karger et al.,

1971a, 1971b; Chatterjee et al., 1973). Thus, gas chromatography (GC) appears

to be an ideal method to study vapor-sorption at the gas-liquid interface, and can

be utilized to measure sorption on anhydrous soil materials. A detailed review of

the theoretical and experimental application of GC methods to the study of VOC

sorption has been presented by Rhue and Rao (1990).

The adsorption of insoluble and sparingly-soluble hydrocarbons on water

surfaces has also been estimated from measurements of the change in surface

tension of bulk water with the partial pressure of the vapor, using the Gibbs

adsorption equation. The surface excess of organic vapors calculated in this

manner typically yields Type-Ill adsorption isotherms. In addition, heats of

adsorption for n-hexane and toluene on bulk water were found to be greater than

corresponding heats of vaporization (Hauxwell and Ottewill, 1968). Adamson

(1967) attributed this behavior to the rearrangement of surface water molecules to

accommodate the hydrocarbon, which resulted in larger heats of adsorption.

Although measurements of vapor adsorption on water-coated supports by GLC

yield Type-Ill adsorption isotherms (Dorris and Gray, 1981; Karger et al., 1971b;








54
King et al., 1972), heats of adsorption estimated from GLC data are generally

smaller than heats of vaporization. These findings suggest that the gas-liquid

interface of water acts as a low energy surface toward nonpolar vapors (Chatterjee

et al., 1972; Dorris and Gray, 1981; Hartkopf and Karger, 1973; Karger et al.,

1971a, 1971b). The discrepancy between heats of adsorption obtained from GLC

and surface tension data has been attributed to uncertainty in surface tension

measurements at low surface coverages (Dorris and Gray, 1981; Karger et al.,

1971a, 1971b); whereas, flame-ionization detectors (FID) used in GLC studies

provide accurate measurements of hydrocarbon adsorption.

In addition to high sensitivity, gas chromatography allows for the rapid

collection of sorption data over a range of temperature and moisture content

regimes. Despite the apparent advantages of GC techniques over conventional

batch adsorption methods, relatively few studies have been conducted using soil

material as the solid support phase (Bohn et al., 1980; Okamura and Sawyer,

1973; Rao et al., 1988). Thus, the purpose of this work was to test the utility of

gas chromatography for the study of p-xylene sorption on anhydrous and hydrated

quartz sand. The effect of CaCI2 treatments on p-xylene adsorption was also

investigated by GC, and was compared to adsorption data obtained by flow-

equilibration and surface tension methods.









Materials and Methods

Column Preparation

The solid support material was collected from the Bh horizon of an Oldsmar

soil (Alfic Arenic Haplaquod) located in Collier County, Florida. Mechanical

analysis indicated that the sand-size fraction (diameter > 50 pm) accounted 90%
of the soil sample. The Oldsmar soil sample had a cation exchange capacity of

5.2 cmoljkg and was predominantly Ca-saturated. The N2 surface area was 10.05

m2/g, while the organic carbon content was 10.9 g OC/kg (Rhue et al., 1988). The

soil sample used in the GC experiments was sieved to pass a 250 pm screen and
will be referred to as Oldsmar sand. A portion of this sample was washed 3 times

with 0.1 M CaCIl to test the effect of salt on vapor-phase sorption.

The Oldsmar sand was packed in 6.35 mm o.d. glass columns,

approximately 16 and 90 cm in length. The 90-cm columns were used to measure

sorption on hydrated sorbents; the additional length was necessary to obtain

adequate solute separation. These columns were crafted to form a U-shape which

matched the inlet and outlet ports of the gas chromatograph. As sand was added

to the column, the column was gently vibrated to achieve uniform packing. Glass

wool was placed at the ends of the columns to maintain support integrity.

Gas Chromatoaraphy Experiments

A Tracor 222 gas chromatograph equipped with a FID was used for the

sorption studies. Certified grade p-xylene (99.8% purity) and high purity grade

methane (99.97% purity) were obtained from Fisher Scientific Products. The FID

was calibrated for p-xylene at three N2 flow rates, with air and hydrogen flow rates








56
maintained at 0.65 mL/sec and 5.0 mL/sec, respectively. During calibration the p-

xylene vapor was introduced onto a straight glass column by passing the N2 flow

stream over a thermostated sample of liquid p-xylene. When a constant mV

reading was obtained, the flow stream was bubbled through a 40-mL centrifuge

tube containing 20 mL of methanol. The concentration of p-xylene in the methanol

was measured by UV-VIS spectroscopy or HPLC techniques.

The adsorption of p-xylene on untreated and salt-treated Oldsmar sand was

measured under anhydrous and hydrated conditions at room temperature (= 24C).

For anhydrous experiments, the column was allowed to equilibrate with "dry" N2

for several hours prior to the initiation of p-xylene injections. This was analogous

to the flow-equilibration method in which "dry" N2 was used as the carrier gas. For

hydrated systems, Okamura and Sawyer (1971, 1973) recommend that the desired

water content be reached by desorption of a saturated column in order to attain

uniform water coverages. However, this procedure resulted in the introduction of

excessive quantities of water into the FID and associated column fittings. Dorris

and Gray (1981) obtained reproducible solute retention data at water contents of

0.6, 1.4, and 3.8% by equilibrating the column with carrier gas at 26, 62, and 88%

RH. For the experiments described here, relative humidities of 90 and 98% were

achieved by bubbling the N2 flow stream through a gas-washing bottle containing

deionized water in a manner similar to that described in Chapter 2. The relative

humidity of the N2 flow stream was measured at the column inlet and outlet by

trapping the water vapor in two magnesium perchlorate traps arranged in series.







57
In addition, the back pressure at the column inlet was measured using a pressure

transducer, for which the mV output had been calibrated against pressure heads.

Adsorption isotherms for p-xylene were obtained by the eluted-pulse method

of Dorris and Gray (1981). The retention time of methane (to) and p-xylene (t,)

vapors, which were simultaneously injected on the column, was recorded with a

Hewlett Packard 3390A integrator. The retention time of air injections, which gave

a negative response, were identical to those of methane. These data indicate that

methane was not retained by the stationary phase. Thus, the net retention volume

(VN) of p-xylene was calculated from the difference between t, and to, using the N2

flow rate. Injections volumes ranging from 1 LL to 2 mL of p-xylene vapor were
used to obtain a range of net retention volumes.

If the adsorption of p-xylene is assumed to occur on mineral surfaces for

anhydrous sorbents, and solely by adsorption at the gas-liquid interface of water-

coated supports, the net retention volume (V,) required to elute a solute is given

by,

VN = RT(dF/dP)A = RT(dS/dP)w (3-2)

where R is the gas constant, T is the temperature, r is the surface concentration
(mol/cm2), P is the partial pressure of the vapor, A is the surface area, S is the

amount adsorbed (mg/g), and w is the weight of the column packing (Dorris and

Gray, 1981). Adsorption isotherms can then be obtained by integrating equation

(3-2) as follows:

S= 1/RTw VN(P) dP. (3-3)

The peak-maxima method of Dorris and Gray (1981) was employed to obtain a








58
chromatographic envelope which could be integrated by equation (3-3). The

calibration curve described previously was used to convert mV readings, obtained

from peak height measurements, to partial pressures of p-xylene. However, the

use of equation (3-2) implies that the sorption effect and pressure gradient along

the column were negligible.



Results and Discussion

Adsorption on Anhydrous Oldsmar Sand

Chromatographic peak maxima obtained from injections of p-xylene vapors

on untreated and salt-treated Oldsmar sand are presented in Figure 3-1. Net

retention volumes of p-xylene on untreated Oldsmar sand were larger than those

of salt-treated soil, indicating greater solute retention. Adsorption in the Henry's

Law region, characterized by highly symmetric peaks and net retention volumes

independent of sample size, was not attained for untreated Oldsmar sand, even

at p-xylene partial pressures of 2.5 X 103 mm Hg. In contrast, the salt-treated

Oldsmar sand exhibited Henry's region adsorption at a net retention volume of

approximately 5.2 mL. As greater quantities of p-xylene were injected, the net

retention volume decreased until the peaks became asymmetric, at which point the

net retention volume began to increase. Although not shown here, the position of

the leading edge of the asymmetric peaks was similar, indicating that adsorption

equilibrium was attained (Dorris and Gray, 1981). The connection of peak maxima







7

6

5

14-
E
E3
02-

1

0-
0

4


3

I
E2-
E

1-


0-
0


Figure 3-1.


1 2 3 4 5
VN(mL)


Chromatographic peak maxima at room temperature (-240C) for p-
xylene vapor on (a) untreated Oldsmar soil and (b) salt-treated
Oldsmar soil.








60
formed a chromatographic envelope which was integrated by equation (3-3). The

resulting p-xylene adsorption isotherms are presented in Figure 3-2.

The adsorption of p-xylene on untreated Oldsmar sand yielded a Type-II

isotherm, indicative of multilayer formation. A similar isotherm was obtained for

the salt-treated sand, although the adsorption capacity was reduced. These data

have yet to be confirmed by batch techniques; however, p-xylene adsorption on

250-425 gim Oldsmar sand measured by the GC and flow-equilibration methods
were in close agreement (R. D. Rhue, 1990, personal communication).

The effect of the salt treatments on p-xylene adsorption by Webster soil was

also studied using the flow equilibration apparatus described in Chapter 2 (Figure

3-3). Webster soil and Webster soil treated with hydrogen peroxide (Webster HP)

was extracted with methanol containing CaCI2 to measure water and p-xylene

sorption. Following methanol extraction, the Webster soil and Webster HP

contained 12.01 (0.65) and 15.18 (0.44) mg CaCI2/g, respectively. Subsequent

adsorption experiments indicated that in the presence of salt p-xylene vapor

adsorption was reduced by 6.95 and 5.98 mg/g on Webster HP and Webster soil,

respectively. These data were in agreement with the observed decrease in the

adsorptive capacity of Oldsmar sand following a salt treatment, measured by the

eluted-pulse method. From a mechanistic perspective, the salt may have coated

the adsorbent surface or reduced the surface charge, such that the magnitude of

adsorbate-adsorbent interactions was decreased.









61





CO




-o
0








\.

0
c as 0











I-
c
\ \

C



0



C) 0
.-











0 \ C) 0


(8/CD C
C.s

0.
L -I ----^ i-^ -- ^| o
co m sj i -^ i o 0







0i








20


15

0)
E. 10
C)
5


0


0.2


0.4
p-Xylene


0.6


0.8


(P/Po)


Figure 3-3.


Adsorption of p-xylene vapors on Webster soil and Webster HP at
(a) 0% RH and (b) 90% RH.


0.1 0.2 0.3 0.4


5

4


0)
02
C/)

1

0


0.5


o Webster Soil
*Webster Soil/CaCI 2
0 Webster HP
* Webster HP/CaCI2




(b)
--- 0/
~ "









Adsorption on Hydrated Oldsmar Sand

The net retention volume of p-xylene injected onto 90-cm columns packed

with Oldsmar sand decreased from approximately 297 mL to less than 8 mL when

the RH was increased to 90%. This reduction was indicative of the effect of water

on the retention of p-xylene vapors. Net retention volumes of p-xylene on salt-

treated Oldsmar sand at 90% RH, and on untreated Oldsmar sand at 90 and 98%

RH are presented in Figure 3-4. Henry's region adsorption occurred at smaller

retention volumes, and for greater p-xylene partial pressures, than under

anhydrous conditions. In addition, the value of VN increased continuously, except

in the Henry's Law region, which is characteristic of adsorption yielding Type-III

isotherms (Dorris and Gray, 1981). At N2 flow rates of 0.42 and 0.33 mL/s, the p-

xylene net retention volumes were similar, demonstrating the internal consistency

of the eluted-pulse method. Adsorption isotherms obtained from chromatographic

envelopes of these data are presented in Figure 3-5.

The presence of water not only precipitated a shift from Type-Il to Type-Ill

adsorption isotherms, but also resulted in a substantial reduction in p-xylene

adsorption. These findings are consistent with data reported in Chapter 2 for p-

xylene sorption on silica gel and kaolin at 67% RH, and on Webster soil and

Webster HP at 90% RH. At 98% RH an additional reduction in p-xylene

adsorption on Oldsmar sand was observed. These data suggest that sorbent

surface was not completely covered with water or that the surface continued to

exert an effect on adsorption, even though the RH of the carrier gas at the column





























0
Ol


0
U8
0

0
* 0


If


cP O
0



a 90% RH
0.33 ml/s
o 90% RH
0.42 m/s
* 98% RH
0.31 ml/s


VN (ml)


Figure 3-4.


Chromatographic peak maxima at room temperature (- 240C) for
p-xylene vapor on (a) salt-treated Oldsmar soil at 90% RH and (b)
untreated Oldsmar soil at 90 and 98% RH.


5


4


S3
E
E2

10
1


(a)




90% RH
0.32 ml/s


/_____


41-


I
E
E
(0_


(b)








65



(0




"-n \
'o



6 0
I-
0 6



O 1 c

oo ) V


2 d
00 C0" 0) 0
E E E E ca


\ a)
000 0V 1 .


o)) ) C) V







0 | o o or
.O \
0 0 C 0. 0. x

M It I Lm \ d






c 0 0 co 0 ca \
S 0) 0)) C0) a









C)
Co





)


0)
T-








66
inlet was 90%. Subsequent measurements revealed that inlet relative humidities

of 90 and 98% corresponded to relative humidities at the column outlet of 60 and

70%, respectively. Since the back pressure measured at the column inlet ranged

from only 1.04 to 1.07 atm, it was unlikely that the RH drop was due solely to

pressure gradients. Apparently, the 8-hour equilibration period was not sufficient

to completely hydrate the support. Future experiments will be conducted after

equilibrating the columns for several days at 90% RH.

The presence of salt also reduced p-xylene adsorption on Oldsmar sand,

which was consistent with batch data obtained for the sorption of p-xylene vapors

on Webster soil and Webster HP at 90% RH (Figure 3-3b). Based on water

adsorption data, the concentration of CaCI2 in adsorbed water films of the Webster

soils was approximately 1.0 M. To further investigate the adsorption at the gas-

liquid interface, the surface tension of 1.0 M CaCI2 exposed to p-xylene vapors

was measured by the drop-weight method, as described in Chapter 2. These data

were expressed as surface pressure (n), which is equivalent to the difference
between the surface tension of the pure solution (y) and the film-covered surface

(y) (Figure 3-6). The surface excess (F) can be calculated in the same manner
as described in Chapter 2 by simply replacing y in equation (2-7) with n (Blank and
Ottewill, 1964). However, the data presented in Figure 3-6 indicated that the

surface excess calculated for 1.0 M CaCI2 and deionized water would be identical.

This finding was consistent with the data of Blank and Ottewill (1964), who

reported that the surface excess of benzene, toluene, and o-xylene on 0.1 M NaCI

was similar to that obtained using distilled water. Thus, the surface tension





















4 .


*

4


4.


. I


| .- I


LO) '- CO C-

( s/6) J11


I I


PD


co1



o
E
2



CL
co
0



C
a,

D I
x



0
CV 2
E0



O
Cu
L.
0



N
0


0
'ID
CL


0-
o M

3/ R








68
measurements suggested that the presence of salt would have no effect on the

adsorption of p-xylene at the gas-liquid interface.



Summary

The measurement of vapor-phase adsorption on soil materials by batch

techniques is typically an arduous task, requiring several time-consuming

experiments in order to obtain an adsorption isotherm. In contrast, gas

chromatography can be efficiently employed under a range of temperature and

moisture regimes. Vapor-phase adsorption of p-xylene on Oldsmar sand was

measured by the eluted-pulse method of Dorris and Gray (1981). Type-II

isotherms obtained for p-xylene adsorption on anhydrous Oldsmar sand were in

agreement with preliminary batch data. At high RH, adsorption isotherms shifted

from Type-II to Type-Ill, and the magnitude of p-xylene adsorption was reduced.

A similar effect has been observed for the sorption of several organic vapors on

hydrated soils (Call,1957; Chiou and Shoup, 1985; Rhue et al., 1989). However,

some difficulty was encountered at high RH, and it is recommended that the

columns be equilibrated at 90% RH for several days. Additional experiments will

be conducted at high RH, and batch experiments are planned to further verify GC

data.

Salt treatments resulted in decreased p-xylene adsorption on anhydrous and

hydrated Oldsmar sand. These data were consistent with batch studies of p-

xylene adsorption on Webster soil and Webster HP exposed to CaCIl, and suggest








69
that vapor-phase sorption will be significantly reduced in salt-effected soils. Under

anhydrous conditions, the reduced adsorption capacity of salt-treated Oldsmar

sand may have resulted from the formation of salt coatings on the sorbent surface.

In Chapter 2 it was postulated that sorption on hydrated sorbents occurred by (1)

partitioning into OC, (2) dissolution into adsorbed water films, (3) adsorption at the

gas-liquid interface. Given the low solubility of p-xylene in water and the relatively

low OC content of Oldsmar sand it is unlikely that any alteration of these

components by salt would significantly effect adsorption. Thus, it was postulated

that the salt-treatment reduced the adsorptive capacity of the gas-liquid interface.

However, the surface concentrations of p-xylene on water and 1 M CaCIl

calculated from measurements of the change in surface tension of deionized water

and 1 M CaCl2 exposed to p-xylene vapors were identical. This finding was

somewhat puzzling, and prompted a reformulation of the Gibbs adsorption

equation to account for three components (i.e., p-xylene, CaCI2, and water). If the

surface excess of water is assumed to be constant, the Gibbs equation can be

expressed as:

1 dy dlna2
r, ---- ---- (3-4)
RT dlna, dlna,

where r, and 1, are the surface concentrations of p-xylene and CaCI2 (mol/cm2),

respectively, a, and a2 are the activities of p-xylene and CaCIl, respectively, R is

the gas constant, and T is the temperature. This equation indicates that if CaCI2

moved to the gas-liquid interface, it could compensate for any reduction in the








70
surface tension arising from the accumulation of p-xylene at the gas-liquid

interface. Unfortunately, the surface concentration of CaCI2 (F) was unknown, and

thus it was impossible to calculate the surface concentration of p-xylene. This line

of reasoning may explain why no difference was observed in the change in surface

tension of water and CaClI exposed to p-xylene vapors.

Additional studies indicated that the utility of GC techniques under

anhydrous conditions may be limited to supports of low sorptive capacity. p-

Xylene vapors injected on coated sands and kaolin were strongly adsorbed and

eluted solute peaks were not discernable. Planned experiments will focus on the

dilution of such sorbents, by either adding low-sorptive-capacity materials to the

column or by coating sands with clay films. It should be recognized that batch

studies are difficult to conduct for materials of low sorptive capacity and, thus, GC

techniques are complimentary in this regard.













CHAPTER 4
COMPETITIVE ADSORPTION OF P-XYLENE AND WATER VAPORS
ON CA-, NA-, AND LI-SATURATED KAOLIN


Introduction

Relative humidity (RH) or soil moisture content is one of the most important

factors influencing the sorption of volatile organic chemicals (VOCs) in the

unsaturated zone. Previous studies have demonstrated that water effectively

competes with nonpolar organic vapors for mineral surfaces, resulting in the

suppression of VOC sorption on soils and clay minerals. (Call, 1957; Chiou and

Shoup, 1985; Rhue et al., 1989). This phenomenon has been attributed to the

relatively strong interactions between water and mineral surfaces (Chiou and

Shoup, 1985; Valsaraj and Thibodeaux, 1988), which may result from cation-dipole

interactions, hydrogen bonding, and weak charge transfer interactions (Burchill et

al., 1981). Of particular interest is cation hydration, the energy of which has been

directly related to the degree of water adsorption on kaolinite (Keenan et al., 1951;

Jurinak, 1963). However, the effect of exchangeable cations on the competitive

adsorption of water and organic vapors is largely unknown. In addition, models

capable of predicting vapor-phase adsorption from binary systems have rarely

been tested due, primarily, to the lack of suitable data.







72
Cation saturation has been shown to indirectly effect the competitive

adsorption of water and ethylene dibromide (EDB) vapors by altering the surface

area of montmorillonite. Following exposure to P20s, Jurinak (1957) observed that

water retention by Mg-, Ca-, and Na-saturated montmorillonite was directly related

to the hydration energy of the exchangeable cation. The retained water expanded

the interlayer space, and thus Mg-montmorillonite exhibited the greatest surface

area and EDB adsorption, followed by Ca- and Na-montmorillonite. A similar

phenomenon was noted by Call (1957), who reported that EDB sorption on Ca-

saturated montmorillonite was greater at 5, 10 and 20% relative humidity (RH) than

at 0% RH (Figure 4-1). This effect was attributed to expansion of the clay lattice,

which increased from 3A at 0% RH to 9A at 5-10% RH. Apparently, EDB

molecules were only able to enter the interlayer space after the clay lattice had

expanded to 9A. However, as the number of water molecules continued to

increase, competition between EDB and water became greater, resulting in the

suppression of EDB adsorption.

Although these data clearly demonstrate that cation saturation influenced

EDB adsorption on montmorillonite, the effect of specific interactions between

water and exchangeable cations was obscured by changes in surface area. In

addition, Jurinak (1957) reported that montmorillonite forms porous aggregates or

floccules during dehydration. This process, which has been observed by electron

micrography (Grim, 1953), restricted the adsorption of EDB on Mg-, Ca-, and Na-

montmorillonite (Jurinak, 1957). In contrast, EDB adsorption on kaolinite occurred









73







Ln
C0

0
0


NO C)I
O



oc






o .










Oo o
(L6 0
0 o
o 0



o


0 a






0
E





If)0
0
CL

CL










C\l







ilx







74
on free surfaces or in pores whose size was far greater than that of the EDB

molecule. Thus, kaolin appears to provide a surface absent of surface area and

porosity effects which complicated the interpretation of EDB adsorption on

montmorillonite.

Recently, Rhue et al. (1989) used a methanol extraction procedure to

simultaneously measure water and p-xylene adsorption on predominantly Na-

saturated kaolin. At low RHs and relatively high p-xylene vapors pressures, Rhue

et al. (1989) observed enhanced water adsorption based on comparisons between

measured and predicted data. The predicted values were calculated using a

modified Brunauer, Emmett, and Teller (BET) equation which accounted for two

adsorbate species. The purpose of this study was to determine if the preferential

adsorption of water could be attributed cation hydration effects. Initially, single-

adsorbate isotherms were obtained for p-xylene and water vapor adsorption on

Ca-, Na-, and Li-kaolin. The linear form of BET equation was utilized to obtain the

monolayer adsorption capacity and value of C. These data were then used to

predict competitive adsorption of p-xylene and water vapors based on the two-

component BET equations of Hill (1946a, b) and Rhue et al. (1989).



Materials and Methods

Kaolinite Samples

Colloidal kaolin, obtained from Fisher Scientific Products (K-6, Lot# 731063),

used in this study was identical to that described in Chapter 2. The kaolin had a







75
cation exchange capacity (CEC) of 4.2 cmoljkg at pH 5.5, and was predominantly

Na-saturated with trace amounts of Ca, Mg, and K (Rhue et al., 1989). Prior to

adsorption experiments, the kaolin was washed with 1 M NaAOc buffered to pH

4.11 with acetic acid to remove carbonates. Approximately 2.5 g of kaolin was

placed in individual polyethylene centrifuge tubes, to which 20 mL of 1 M NaAOc

was added. The samples were mixed until the kaolin was completely dispersed,

and separated by centrifugation at 2500 rpm for 5 minutes. When the pH of the

supernatant was less than 5.0, generally after one wash, the kaolin was washed

five times with 1 M NaCI to removed entrained NaAOc. The supernatant was

analyzed for Ca and Mg using a Perkin Elmer model 603 atomic absorption

spectrophotometer. If either Ca or Mg was detected in the supernatant, the

NaAOc treatment was repeated, otherwise the kaolin was saturated with the

desired cation.

Ca-, Na-, and Li-saturated Fisher kaolin was prepared by washing the kaolin

with the appropriate 1 M chloride salt until no other cations could be detected in

the supernatant by atomic absorption spectroscopy. Following cation saturation,

the kaolin was repeatedly washed with 95% ethanol until a negative chloride test

was achieved using AgNO3. The kaolin was air-dried at room temperature and

ground with an agate motar and postal. Prior to adsorption experiments, the kaolin

was oven-dried at approximately 1200C for at least two weeks. The N2 surface

area of Ca, Na, and Li-kaolin was 15.8, 15.6, and 15.5 m2/g, respectively, prior to








76
heating, and 15.5, 15.4, and 15.2 m2/g, respectively, after heating (Advanced

Materials Research Center, University of Florida).

Vapor-Phase Adsorption Experiments

Single and mixed-vapor adsorption experiments were conducted at 240C

using the flow-equilibration apparatus described in Chapter 2. The concentration

of water in the flow stream was determined by Karl Fisher (KF) titration.

Approximately 20 mL of CaCI-saturated methanol was added to two 40 mL glass

centrifuge tubes, and pretitrated to the visual KF endpoint. The tubes were placed

on the flow stream in series, via hypodermic needles, for a measured time period.

The solutions were then removed from the flow stream and immediately retitrated.

A small amount of titer was consistently needed to retitrate the second trap in the

series, which was attributed to loss of volatile compounds from the KF reagent

(Rhue et al., 1988). Therefore, the volume of titer used for the second trap was

subtracted from that of the first trap, and the corrected value was used to calculate

the amount of water trapped in the methanol. p-Xylene vapors were trapped by

bubbling the flow stream through two glass centrifuge tubes containing methanol,

as described in Chapter 2.

Single-adsorbate isotherms were determined for p-xylene and water vapors

at relative vapor pressures ranging from 0.1 to 0.5. The competitive adsorption of

p-xylene and water vapors was measured at 10 and 20% RH. Adsorbed

concentrations of p-xylene and water vapors from single- and binary- sorbate

systems were measured following the procedures described previously.









Preliminary Adsorption Experiment

A preliminary study was conducted to test the effect of cation saturation on

the competitive adsorption of water and p-xylene vapors on kaolin. A portion of

the original Fisher kaolin was saturated with Li by washing the kaolin with 1 M LiCI.

Excess salt was removed by repeatedly washing the kaolin with 95% ethanol until

a negative chloride test was achieved with AgNO3. The adsorption of water and

p-xylene vapors on Na- and Li-saturated kaolin was measured for single- and

binary-sorbate systems as described previously.



Results and Discussion

Preliminary Adsorption Experiment

Water adsorption on Na-kaolin was in agreement with the data obtained by

Rhue et al. (1989), and was significantly greater than that on L-kaolin (Figure 4-

2a). In contrast, p-xylene adsorption on Na- and L-kaolin was similar (Figure 4-

2b), suggesting that exchangeable cations had only a minor effect on p-xylene

adsorption. The adsorption data were fit by a least squares procedure to the linear

form of the BET equation,

P/Po 1 (C-1)P/Po
+ (4-1)
S(1-P/Po) SmC SC

where Sm is the monolayer adsorption capacity (mg/g), and C is a parameter

related to the heat of adsorption. Estimated values of S, and C are presented in

Table 4-1. BET parameters for Na-kaolin were calculated using a combined data











0 (a)


S.... -r Na-Kaolin, Rhue
et al. (1989)
o Na-Kaolin
Li-Kaolin

0.1 0.2 0.3 0.4 0.5 0.6 0.7


Water


(P/Po)


0.1 0.2 0.3


0.4


p-Xylene (P/Po)


Figure 4-2.


Vapor-phase adsorption of (a) water and (b) p-xylene on Na- and
Li-saturated Fisher kaolin at 240C.


E
C)


7

6

5
04
0)
E
3

2

1

0








79
Table 4-1. BET parameters for Na- and Li-kaolin calculated from single-
sorbate isotherm data (Rhue et al., 1989).


P/PO
Sorbent Sorbate Sm C r2 Range Used


-mg/g-

Na-kaolin p-xylene 4.5 14 0.969 0.065-0.424

water 4.2 20 0.988 0.056-0.481


Li-kaolin p-xylene 4.4 9 0.997 0.074-0.365

water 2.6 52 0.997 0.112-0.289







80
set, since the values obtained for water and p-xylene adsorption were similar to

those reported by Rhue et al. (1989).

The monolayer adsorption capacity of water on U-kaolin was considerably

less than that on Na-kaolin. It has been proposed that exchangeable Na on kaolin

hydrates readily; whereas, exchangeable Li does not hydrate, despite the fact that

Li has a slightly greater hydration energy than Na (Keenan et al., 1951).

Apparently, Li ions form inner-sphere complexes or are strongly adsorbed on

kaolin, such that hydration does not occur even at high RHs (Keenan et al., 1951;

Martin, 1959). If the amount of water adsorbed by Li-kaolin is considered to be

independent of cation hydration effects, then the difference between the monolayer

adsorption capacities of Na- and U-kaolin provides an estimate of the amount of

water hydrating Na. Based on this assumption, approximately 1.8 molecules of

water were associated with each exchangeable Na ion, which was consistent with

the range of values (1.5 to 1.8 molecules of water) reported by Keenan et al.

(1951) for Na-, K-, and Rb-saturated kaolinite.

The binary-vapor experiment was conducted at p-xylene and water relative

vapor pressures of 0.395 and 0.095, respectively. The amount of water and p-

xylene adsorbed on Na-kaolin in this experiment was 2.46 (0.00) and 6.56 (0.05)

mg/g, respectively. In contrast, Li-kaolin adsorbed 2.06 (0.01) and 6.04 (0.05)
mg/g of water and p-xylene, respectively. Rhue et al. (1989) modified the BET

equation to account for the competitive adsorption of two sorbate species. The








81
total adsorbed mass of sorbate "a" on the surface (M,, mg/g) can be calculated

using the following equation:

M,a = a C, S, [Xa/(1-Xa) (4-2)

where a is the mass of compound "a" occupying a unit area of surface (mg/m2),

C, is the BET parameter related to heat of adsorption calculated from single-vapor

adsorption isotherm for sorbate "a", X, is the relative vapor pressures of sorbate

"a", and S, is the area of exposed surface area per unit mass of adsorbent (m2/g).

The a values for water and p-xylene were calculated to be 0.31 and 0.50 mg/m2,

respectively, based on the following equation:

a = 1.091(MW/a, A) (4-3)

where MW is the molecular weight, a, is the cross-sectional area of sorbate

determined in Chapter 2, and A is Avogadro's number (Rhue et al., 1989). The

mass of sorbate "b" (M) can be calculated in a similar manner. Unfortunately, the

mass of either adsorbate on the surface cannot be calculated because S, is

unknown in the binary vapor system (Rhue et al., 1989). However, the fraction of

adsorbate "a" (F,) on the surface can be calculated using the following equation:

Ma
Fa = (4-4)
Ma + Mb

The calculated versus the measured fraction of water adsorbed on Na-kaolin (Na)

and Li-kaolin (Li) are presented in Figure 4-3. These data indicate that Na-kaolin

adsorbed considerably more water than was predicted by the two-component BET

equation. The fraction of water adsorbed on Na-kaolin was previously reported by









C
0




mo
>oI

\ 0 o
cI





O
A-
aa









O o
\ .z


\ c
\0 0z





\-- 00

0Z 3



*\ -a


\ o*Co
"-- c




io z 0


as*2 00
*LLL


\ cir



\ 0










uo p l
-a,



UOipoeJd pollnoluO
L.~








83
Rhue et al. (1989), and is denoted by (n) in Figure 4-3. In contrast, the measured

and calculated fractions of water adsorbed on Li-kaolin were almost identical.

These data suggest that the preferential adsorption of water relative to p-xylene

at low water fractions (below 0.4) was due to Na hydration.

One possible explanation for the difference between the measured and

calculated fraction of water adsorbed on Na-kaolin was the similarity in the values

of C estimated from water and p-xylene single-sorbate isotherms. Since the

values of C were essentially the same, the two-component BET equation of Rhue

et al. (1989) did not account for preferential adsorption of water over p-xylene on

Na-kaolin. In contrast, the values of C for water and p-xylene adsorption on Li-

kaolin were 52 and 9, respectively. The large value of C for water adsorption on

Li-kaolin was not anticipated, because Li-kaolin is generally considered to

represent a mineral surface free of cation hydration effects. If a C value of 20 was

used to estimate the mass of water adsorbed on Li-kaolin, then the calculated

fraction of water adsorbed on Li-kaolin would be 0.12 rather than 0.28. Thus, Li-

kaolin would also have exhibited a small degree of preferential water adsorption

if the measured value of C had been in the range expected for water adsorption

on Fisher kaolin.

Vapor-Phase Adsorption on Ca-, Na-, and Li-kaolin

Isotherms for the adsorption of water vapor on Ca-, Na-, and U-kaolin are

presented in Figure 4-4a. Ca-kaolin adsorbed the greatest amount of water at all

RHs studied, followed by Na- and Li-kaolin. The monolayer adsorption capacities








6



.4
0)
E
CO 2



0
0


0.1 0.2 0.3 0.4 0.5
p-Xylene (P/Po)


Figure 4-4.


Vapor-phase adsorption of (a) water and (b)
and Li-saturated Fisher kaolin at 240C.


p-xylene on Ca-, Na-,


0.1 0.2
Water (P/Po)


0)

E
0)


0.3


0.6








85
of water on Ca-, Na-, and Li-kaolin derived from the single-sorbate adsorption data

were 5.0, 3.9, and 2.8 mg/g, respectively (Table 4-2). These data indicate that

cation saturation had a considerable effect on water adsorption, and were similar

to values of Sm obtained for Na- and Li-kaolin in the preliminary study. The value

of C for water adsorption on Li-kaolin (12) was less than that measured previously,

but was now within the range expected for water adsorption on Fisher kaolin.

Thus, the value of C was subject to uncertainty, even when the value of S, derived

from the same adsorption data appeared to give a reasonable estimate of the

monolayer adsorption capacity. The reasons for uncertainty in the value of C are

unclear, but the evaluation of numerous adsorption isotherms indicates that small

differences in adsorption data can result in substantial changes in the value of C,

particularly if the isotherm consists of only a few data points.

In general, Ca-kaolin adsorbed the largest amount of p-xylene, followed by

Na- and Li-kaolin (Figure 4-4b). However, p-xylene adsorption on Na-kaolin was

slightly greater than that on Ca-kaolin at relative vapors pressures below 0.05 and

above 0.5. The p-xylene monolayer adsorption capacities of Ca-, Na-, and U-

kaolin were 6.5, 5.5, and 5.0 mg/g, respectively (Table 4-2). These data indicate

that cation saturation influenced the adsorption of p-xylene vapors, but the

similarity between the values of S, indicates that the effect of cation saturation was

minimal. In order to compare the monolayer adsorption capacities for water and

p-xylene, the value of Sm was expressed as the amount of surface occupied by

sorbate molecules per gram of kaolin (m2/g), as described in Chapter 2 (Table 4-








86
Table 4-2. BET parameters for Ca-, Na- and Li-kaolin calculated from single-
sorbate isotherm data.


Sorbent


Ca-kaolin




Na-kaolin


Sorbate


p-xylene

water


p-xylene

water


Li-kaolin p-xylene

water


C P


Sm

-mg/g-

6.5

5.0


5.5

3.9


5.0

2.8


0.999

0.993


0.998

0.978


0.997

0.994


SA

-m2/g-

14.0

17.6


11.9

13.7


10.8

9.8


P/Po
Range Used


0.045-0.301

0.126-0.245


0.044-0.301

0.126-0.241


0.047-0.303

0.115-0.241







87
2). The BET surface areas determined in this manner indicate that when the

molecular weight and surface packing are taken into consideration, the p-xylene

monolayer adsorption capacities were less than those measured for water. In

addition, the effect of the saturating cation and CEC the BET surface areas were

also smaller than that observed for water.

In order to utilize the method of Keenan et al. (1951) for estimating the

amount of water and p-xylene associated with exchangeable cations, the CEC of

kaolin used in the adsorption experiments was measured. The CEC of oven-dried

Ca-, Na-, and Li-kaolin at pH 4.11 was 3.9, 3.5, and 1.9 cmol/kg, respectively. To

confirm these values, the CEC of the kaolin used in the preliminary adsorption

study was also measured. At pH 5.5, the CEC of oven-dried Na- and Li-kaolin

was 4.23 and 2.19 cmol/kg, respectively. Apparently, the heat-treatment resulted

in a sizable reduction in the CEC of Li-kaolin. These findings suggest that heat-

treated Li-kaolin represents a mineral surface of reduced charge, rather than a

surface free of cation hydration effects as proposed by Keenan et al. (1951) and

Martin (1959). Therefore, the use of Li-kaolin as a reference mineral surface may

not be valid, and could result in incorrect estimates of the amount of water

associated with each exchangeable cation.

Competitive Adsorption of p-Xvlene and Water on Ca-, Na-, and Li-kaolin

Data for the adsorption of p-xylene vapors on Ca-, Na-, and Li-kaolin at 0,

10, and 20% RH are presented in Figure 4-5. An increase in RH from 0% to 10

and 20% had a relatively minor effect on p-xylene adsorption regardless of the












E


E
cl


0
12


E
C/)


p-Xylene (P/Po)


Figure 4-5.


Vapor-phase adsorption of p-xylene on (a) Ca-, (b) Na-, and (c) Li-
saturated Fisher kaolin at 0, 10, and 20% RH.







89
cation saturation. Rhue et al. (1989) reported that sizable reductions in p-xylene

adsorption were not observed until the RH was greater than that required to attain

monolayer water coverage, as estimated from the single-sorbate BET equation.

The RHs corresponding to monolayer coverage of water on Ca-, Na-, and Li-kaolin

were 20, 22, and 22%. Thus, the slightly greater displacement of p-xylene from

Ca-kaolin was consistent with the fact that a lower RH was required to achieve

monolayer coverage on Ca-kaolin than on Na- and Li-kaolin.

The measured fraction of water adsorbed on Ca-, Na-, and Li-kaolin, versus

the fraction calculated from the two-component BET equation of Rhue et al.

(1989), is presented in Figure 4-6a. Below 0.4, enhanced water adsorption was

exhibited by all exchangeable cations studied, but was less for Li-kaolin than Ca-

and Na-kaolin. The degree of preferential water adsorption was consistent with

the CEC values previously reported for oven-dried Ca-, Na-, and Li-kaolin. These

data further support the contention that Li-kaolin represents a surface of reduced

charge.

The fraction of water adsorbed on kaolin was also predicted using the two-

component BET equation proposed by Hill (1946a, 1946b). If the sorbate is

assumed to adsorb only onto the mineral surface or sorbed layers of itself, Hill's

equation can be simplified to:

S, Xa [Ca (1-Xb) + XCJ
= (4-5)
Sam (1 X,- Xb)[1 + X(C,-1)+ Xb(Cb-1)]
where Sa is the amount of sorbate "a" adsorbed (mg/g), Sam is the monolayer









7/

01.


0.8

o

O




0o
50.6

ILL
a2
D 0.4



0




S0.2

0
t0.8
C

!0


(D0.4



(z 0.2


L


0.2


0.2


0.4


0.4


(a)









, (


0.6


0.6


Measured Fraction

Figure 4-6. Measured fraction of water adsorbed on Ca-, Na-, and Li-
saturated Fisher kaolin versus the fraction calculated using the
two-component BET equation of (a) Rhue et al. (1989), and (b)
Hill (1946a, b).


- I/
*
* U


Elm


-


-



^-C
(b) E -




U, ,




/


0.8


0.8


* Ca-kaolin
* Na-kaolin
* Li-kaolin
'







91
adsorption capacity of sorbate "a" (mg/g), Xa and X, are the relative vapor

pressures of sorbate "a" and "b", respectively, and Ca and Cb are the BET

parameters related to the heat of adsorption of sorbate "a" and "b", respectively.

The predicted adsorption of water and p-xylene on Ca-, Na-, and Li-kaolin is

presented in Table 4-3. The adsorption of water and p-xylene on kaolin was well

predicted, regardless of the cation saturation. However, the predicted values for

Li-kaolin were more accurate than those estimated for Ca- and Na-kaolin.

The measured fraction of water adsorbed on Ca-, Na-, and Li-kaolin versus

the fraction predicted using the two-component BET equation of Hill (1946a,

1946b) are presented in Figure 4-6b. The measured and calculated fractions of

water adsorbed on Li-kaolin were similar for all mixed-vapor systems studied. At

fraction less than 0.3, Ca- and Na-kaolin exhibited enhanced water adsorption.

However, the magnitude of the preferential water adsorption observed here was

far less than that obtained using the two-component BET equation of Rhue et al.

(1989). This was primarily due to the fact that Hill's two-component BET equation

incorporates the value of S,, determined from single-sorbate adsorption isotherms.

Thus, the adsorption of water and p-xylene predicted by Hill's equation is based,

in part, on the monolayer adsorption capacity of each sorbent. In contrast, the

equation of Rhue et al. (1989) does not include a monolayer adsorption capacity

term. Therefore, the value of C must be related to the cation hydration energy in

order for the fraction of water calculated using the two-component BET equation

to reflect differences in the monolayer adsorption capacity due to cation saturation.









Table 4-3.


Comparison of measured p-xylene and water adsorption on Ca-,
Na-, and Li-kaolin from mixed-vapor systems with values predicted
using the multi-sorbate BET equation of Hill (1946a, 1946b).


P/Po Measured Predicted
Sorbent Water PX Water PX Water PX

------------------------------------- mg/g ----------.--------------------


Ca-kaolin






Na-kaolin


0.117
0.101
0.112
0.179
0.212
0.184

0.117
0.101
0.112
0.179
0.212
0.218


Li-kaolin 0.117
0.101
0.112
0.179
0.212
0.218


0.093
0.201
0.395
0.096
0.217
0.403

0.093
0.201
0.395
0.096
0.217
0.410

0.093
0.201
0.395
0.096
0.217
0.410


2.64
2.64
3.24
4.13
4.18
3.42

2.31
2.38
2.27
3.56
3.09
3.48

2.02
1.56
1.24
2.93
2.72
2.34


3.58
5.72
8.00
3.22
5.14
7.89

3.40
5.42
7.94
3.32
5.33
7.89

2.57
4.09
6.85
2.39
3.99
6.97


3.06
2.34
2.33
4.07
4.26
3.91

1.93
1.42
1.47
2.71
2.82
3.28

1.56
1.21
1.23
2.13
2.28
2.61


2.51
4.88
9.17
2.28
4.79
9.80

2.75
4.84
8.45
2.54
4.84
9.67

1.91
3.71
7.04
1.77
3.72
8.08




Full Text
A MECHANISTIC INVESTIGATION OF P-XYLENE AND WATER VAPOR
SORPTION ON SOILS AND CLAY MINERALS
By
KURT DAVIS PENNELL
A DISSERTATION PRESENTED TO THE GRADUATE SCHOOL
OF THE UNIVERSITY OF FLORIDA IN PARTIAL FULFILLMENT
OF THE REQUIREMENTS FOR THE DEGREE OF
DOCTOR OF PHILOSOPHY
UNIVERSITY OF FLORIDA
1990

Copyright 1990
by
Kurt Davis Pennell

ACKNOWLEDGEMENTS
I have prospered from the knowledge and compassion of many, and I take
this opportunity to thank those persons. First, I would like to thank my advisory
committee chair, Dr. Arthur Hornsby, who not only convinced me to continue my
studies in soil science, but also provided financial and moral support at critical
junctures in my Ph.D. program. His scientific beliefs and convictions have been
an inspiration, and afforded me the freedom to develop a truly independent
research project. The remainder of my advisory committee, Dr. Dean Rhue, Dr.
Suresh Rao, Dr. Joseph Delfino, and Dr. Ramesh Reddy have all made significant
contributions to my graduate education. In particular, I thank Dean Rhue for
providing laboratory facilities and supplies, but more importantly for instilling in me
the value of solid research. I greatly appreciated the invaluable scientific guidance
and challenges given by Suresh Rao. In his spare time Suresh revived my ego
on the tennis court.
One of the finest attributes of the Soil Science Department is the respect
and professional opportunities offered to graduate students. In this regard, I thank
Dr. Randy Brown, Dr. Willie Harris, and Dr. Peter Nkedi-Kizza for their honesty and
encouragement. I would also like to thank Dr. Brian McNeal, whose support and

humor assured that my tenure as graduate student representative to the faculty
was an enjoyable and enlightening experience.
I thank Bill Reve for his initial tolerance and subsequent respect in the
laboratory, which has fostered a true friendship. Our numerous discussions on a
range of issues removed much of the tedium from my laboratory work. Linda Lee
and Ron Jessup also gave generously of their time and knowledge, for which I am
grateful.
I would like to acknowledge the financial support, in the form of a research
assistantship, provided by the State of Florida via the Soil Science Department,
and additional funding provided by the Florida Department of Environmental
Regulation.
I thank my mother and father for their pride in my accomplishments. Their
accepting nature has given me an appreciation for mutual respect which I could
not have otherwise obtained. Finally, I thank Page whose love has given me the
strength to excel and the tenderness to care.
IV

TABLE OF CONTENTS
ACKNOWLEDGEMENTS iii
ABSTRACT vii
CHAPTERS
1 INTRODUCTION 1
Vapor-Phase Sorption 1
Adsorption on Oven-Dry Sorbents 2
Competitive Adsorption 11
Sorption at High Relative Humidity 17
Research Summary 19
2 VAPOR-PHASE SORPTION OF P-XYLENE AND WATER
ON SOIL MATERIALS AT HIGH RELATIVE HUMIDITIES 23
Introduction 23
Materials and Methods 25
Results and Discussion 34
Summary 49
3 GAS CHROMATOGRAPHIC STUDIES OF P-XYLENE
SORPTION ON ANHYDROUS AND HYDRATED
QUARTZ SAND 52
Introduction 52
Materials and Methods 55
Results and Discussion 58
Summary 68
v

4 COMPETITIVE ADSORPTION OF P-XYLENE AND WATER
VAPORS ON CA-, NA-, AND LI-SATURATED KAOLIN 71
Introduction 71
Materials and Methods 75
Results and Discussion 77
Summary 95
5 THE EFFECT OF HEAT TREATMENTS ON THE TOTAL
CHARGE AND EXCHANGEABLE CATIONS OF CA-, NA-,
AND LI-SATURATED KAOLIN 98
Introduction 98
Materials and Methods 101
Results and Discussion 105
Summary 133
6 SUMMARY AND CONCLUSIONS 135
APPENDICES
A WATER AND P-XYLENE SORPTION DATA 141
B SURFACE TENSION DATA 150
REFERENCES 152
BIOGRAPHICAL SKETCH 159
VI

Abstract of Dissertation Presented to the Graduate School
of the University of Florida in Partial Fulfillment of the
Requirements for the Degree of Doctor of Philosophy
A MECHANISTIC INVESTIGATION OF P-XYLENE AND WATER VAPOR
SORPTION ON SOILS AND CLAY MINERALS
By
Kurt Davis Pennell
December 1990
Chairman: Dr. Arthur G. Hornsby
Major Department: Soil Science
Vapor-phase sorption of p-xylene and water on soils and clay minerals was
studied using a flow-equilibration technique that allowed the amount of sorbed
water and p-xylene to be measured independently. Oven-dry sorbents exhibited
a sizable capacity to adsorb p-xylene vapors which was strongly correlated to
sorbent surface area. Increasing the relative humidity to 67 and 90% resulted in
dramatic reductions in p-xylene sorption and a shift from Type-ll to Type-lll
adsorption isotherms, regardless of the organic carbon content of the sorbent. The
observed increase in p-xylene sorption above relative vapor pressures of 0.6
suggests that hydrated sorbents can sorb significant quantities of organic vapors
near the contaminant source. Similar results were obtained for the sorption of p-
VII

xylene vapors on quartz sand using a gas chromatographic technique, which
provided an efficient and versatile alternative to batch methods.
At relative humidities above which the sorbent surface was covered by at
least a monomolecular layer of water, p-xylene sorption by Webster soil was
primarily attributed to partitioning into organic carbon. However, predictions of the
surface excess based on the Gibbs equation indicated that essentially all p-xylene
sorption on sorbents of low organic carbon content was due to adsorption at the
gas-liquid interface. Therefore, it is recommended that vapor-phase sorption be
described by a multi-mechanistic model that incorporates adsorption onto exposed
mineral surfaces, adsorption at the gas-liquid interface, dissolution into adsorbed
water films, and partitioning into organic carbon.
The effect of cation saturation on the adsorption of water and p-xylene
vapors from single- and binary-vapor systems was also investigated. Water and
p-xylene adsorption on Ca- and Na-saturated kaolin was directly related to the
hydration energy of the exchangeable cation. However, Li-saturated kaolin
exhibited reduced adsorption which was attributed to a decrease in total charge
after heating. Therefore, Li-kaolin is not recommended as a reference surface for
the study of vapor-phase sorption. Predictions of the competitive adsorption of
water and p-xylene vapors using two-component Brunauer, Emmett, and Teller
models indicated that the preferential adsorption of water from p-xylene-water
systems was the result of cation hydration effects.
VIII

CHAPTER 1
INTRODUCTION
Vapor-Phase Sorption
The widespread detection of volatile organic chemicals (VOCs) in
groundwater and soil has prompted intensive study of vapor-phase sorption and
transport in porous media. Contaminants of this nature, such as petroleum-based
solvents, frequently enter the environment as a result of improper disposal
techniques, accidental spills, and loss from storage tanks. The subsequent
distribution and mobility of VOCs in the unsaturated zone can be directly
influenced by vapor-phase sorption. Previous studies have demonstrated that
anhydrous soils and clays have a sizable capacity to adsorb organic vapors, but
this capacity is greatly reduced in the presence of water (Call, 1957; Chiou and
Shoup, 1985; Rhue et al., 1989). However, a comprehensive understanding of the
processes responsible for VOC sorption in the unsaturated zone has yet to be
attained. This is particularly true for soils at high relative humidity (RH), at which
time a number of mechanisms may contribute to organic vapor retention, including
dissolution into adsorbed water films, partitioning into organic carbon (OC), and
adsorption at gas-liquid-solid interfaces.
1

2
Adsorption on Oven-Dry Sorbents
The adsorption of vapors on oven-dry sorbents has been studied in detail,
and provides a basis from which to investigate adsorption in more complex
systems. In his classic treatise on vapor-phase adsorption, Brunauer (1943)
defines adsorption as the accumulation of a chemical species from one bulk phase
at the surface of another bulk phase, without penetrating the structure of the
second phase. Based on the nature of adsorbate-adsorbent interactions,
adsorption can be classified as either physical or chemical (Table 1-1). The
adsorption of nonpolar organic vapors on mineral surfaces is generally considered
to result from nonspecific molecular interactions, such as van der Waals forces,
which are also responsible for vapor condensation and deviations from ideal
behavior. Chemical adsorption of aromatic hydrocarbons has been observed on
Cu-saturated montmorillonite using infrared and ultraviolet-visible spectroscopy
(e.g., Pinnavaia et al., 1974; Pinnavaia and Mortland, 1971). It was postulated that
the chemisorbed species was coordinated with exchangeable Cu(ll) ions via tc
electrons. However, interactions of this nature are typically limited to clay minerals
saturated with certain transition metals under anhydrous conditions.
The equations of Freudlich, Langmuir, and Brunauer, Emmett, and Teller
(BET) are frequently used to interpret gas-solid adsorption data. Although the
Langmuir and BET models can be derived theoretically, the Freudlich adsorption
model is based solely on the following empirical equation:
1/n
S = kP
(1-1)

3
Table 1 -1. Comparison of physical and chemical adsorption of vapors on solids.
Property
Physical Adsorption
Chemical Adsorption
Enthalpy of
Adsorption
< 80 kJ/mole
> 200 kJ/mole
Reversibility
of Adsorption
Reduction In vapor
pressure results in
desorption.
Stronger treatment
required for desorption.
Desorption may result
in chemical alterations.
Adsorbed
Layers
Multilayer formation.
Limited to monolayer.
Adsorption
Rate
Instantaneous. May be
limited by diffusion.
Rapid or slow. May
require activation energy.
Adsorbate-
Adsorbent
Interaction
Nonspecific. Van der
Waals forces.
Specific. Chemical bond
formation.

4
where S is the amount adsorbed (mg/g), P is the equilibrium vapor pressure, and
k and n are constants. The constants k and n are indicative of the extent and
intensity of adsorption, respectively. At low vapor pressures the value of n
frequently approaches one, which results in a linear isotherm. However, the
Freudlich equation rarely fits gas-solid adsorption data over a range of vapor
pressures.
The Langmuir model was the first theoretical treatment of adsorption, and
has been applied with reasonable success to systems exhibiting chemical
adsorption. At equilibrium, Langmuir (1916) considers the rate of evaporation
(desorption) from occupied sites to be equal to the rate of condensation
(adsorption) on the bare surface, which yields the following equation:
S K P
= (1-2)
Sm 1+KP
where S is the amount adsorbed (mg/g), Sm is the monolayer adsorption capacity
(mg/g), P is the equilibrium vapor pressure, and K is the rate of adsorption divided
by the rate of desorption. The Langmuir adsorption isotherm is linear at low vapor
pressures and reaches a limiting value at or above vapor pressures corresponding
to monolayer coverage (Figure 1-1 a).
Implicit in the kinetic derivation of the Langmuir equation are the following
assumptions: (1) the adsorbate behaves as an ideal gas in the bulk phase; (2)
adsorption is limited to monolayer coverage; (3) the energy of adsorption is
constant; (4) no adsorbate-adsorbate interactions occur; (5) adsorption is localized

5
P (mm Hg) P0
Figure 1-1. Gas-solid adsorption isotherms characteristic of the (a) Langmuir
model (Type I) and (b) BET model (Type II).

6
(i.e., site-specific). The assumption of constant adsorption energy and the
absence of adsorbate-adsorbate interactions are rarely valid (Ross and Olivier,
1964). However, the errors associated with these assumptions tend to nullify one
another, and thus the success of the Langmuir equation may be attributed, in part,
to this coincidence.
Brunauer, Emmett, and Teller (BET) extended the Langmuir model to
account for multilayer adsorption by assuming that the Langmuir equation is
applicable to each adsorbed layer (i.e., each layer has a fixed number of
adsorption sites). The first layer is assumed to have a heat of adsorption equal
to Q,, while all successive layers have heats of adsorption equivalent to the heat
of vaporization (Qv). Adsorption and desorption are considered to occur only from
exposed surfaces, and at equilibrium the amount of solute adsorbed on each layer
is at steady state. The BET equation is given as follows:
S C(P/P0)
= (1-3)
Sm (1-P/P0)[1-P/P0+C(P/P0)]
where S is the amount adsorbed (mg/g), Sm is the monolayer adsorption capacity
(mg/g), P is the equilibrium vapor pressure, PQ is the saturated vapor pressure,
and C is a parameter related to the heat of adsorption. The BET equation typically
yields Type-ll adsorption isotherms which are characteristic of multilayer formation
resulting from physical adsorption (Figure 1 -1 b).

7
The values of Sm and C can be obtained from a least squares fit of
adsorption data to the linear form of the BET equation, given as follows:
P/P0 1 (C-1)P/P0
= + . (1-4)
S(1-P/P0) SmC SmC
Estimated values of Sm and C for a range of adsorbate-adsorbent systems are
presented in Table 1-2. In theory, the approximate value of C is given by the
following equation:
(Qr QJ/RT
C = e (1-5)
where R is the gas constant and T is the temperature (°K). Provided the heat of
vaporization (Qv) is known, the heat of adsorption (QJ can be calculated from the
value of C (e.g., Chiou and Shoup, 1985; Jurinak and Volman, 1957). However,
Sing et al. (1985) concluded that the C parameter obtained from the BET model
does not provide a quantitative measure of heats of adsorption, but does indicate
the relative magnitude of adsorbate-adsorbent interactions. In general, the values
of C in Table 1-2 are indicative of the low interactions energies associated with
physical adsorption. The BET equation is considered to yield reliable estimates
of the monolayer adsorption capacity for systems exhibiting Type-ll adsorption
isotherms. The surface area of the adsorbent can then be calculated from the
value of Sm and the cross-sectional area of the adsorbate, typically estimated from
the liquid density. This procedure has become standard practice for the
determination of surface area from N2 adsorption isotherms (Adamson, 1982).

8
Table 1 -2. BET parameters calculated from the adsorption of organic vapors on
anhydrous soil materials.
Adsorbate
Adsorbent
sm
C
Reference3
Benzene
Parsons silt loam
-mg/g-
7.3
1.8
1
Benzene
Weller silty loam
11.3
20.0
1
Benzene
Woodburn silty clay
5.6
13.6
2
Toluene
Bentonite
7.3
10.0
3
Toluene
Kaolin
4.2
27.0
3
Toluene
Silica Gel
65.3
12.0
3
Toluene
Webster silty clay loam
2.3
12.0
3
p-Xylene
Bentonite
7.9
10.0
3
p-Xylene
Kaolin
4.6
18.0
3
p-Xylene
Silica Gel
64.7
17.0
3
p-Xylene
Lula aquifer material
1.8
45.0
3
Ethylbenzene
Bentonite
7.8
17.0
3
Ethylbenzene
Webster silty clay loam
2.6
14.0
3
Dichloropropane
Parsons silt loam
8.2
7.8
1
Dichloropropane
Weller silty loam
12.7
32.7
1
Dichloropropane
Bernow sandy loam
1.2
18.1
1
Dichloropropane
Summit silty loam
8.1
8.1
1
Chlorobenzene
Woodburn silty clay
7.5
22.8
2
m-Chlorobenzene
Woodburn silty clay
7.4
24.4
2
p-Dichlorobenzene
Woodburn silty clay
5.5
78.5
2
1,2,4-trichlorobenzene
Woodburn silty clay
9.5
27.5
2
Ethylene dibromide
Yolo silty clay
35.9
73.4
4
Ethylene dibromide
Yolo loam
18.7
96.2
4
Ethylene dibromide
Salanis clay
23.9
59.9
4
Ethylene dibromide
Meloland clay loam
26.3
41.3
4
Ethylene dibromide
Hanford sandy loam
3.7
15.0
4
Ethylene dibromide
Aiken clay loam
26.9
17.1
4
Ethylene dibromide
Staten peaty muck
11.7
12.6
4
a (1) Poe et al. (1988); (2) Chiou and Shoup (1985); (3) Rhue et al. (1988); (4)
Jurinak and Volman (1957).

9
Rhue et al. (1988) reported that adsorption of p-xylene vapors on oven-dry
silica gel was considerably greater than that on kaolin, bentonite, and Lula aquifer
material (Figure 1-2a). However, when the adsorption data were normalized to the
monolayer adsorption capacity (SJ of each adsorbent, the relative adsorption was
essentially the same for all adsorbents studied (Figure 1-2b). A similar trend was
observed for the adsorption of ethylene dibromide (EDB) on a number of soils
(Jurinak and Volman, 1957). The slight increase in relative adsorption noted for
Lula aquifer material corresponded to a larger value of C, suggesting that specific
adsorbate-adsorbent interactions may have occurred. However, the overall
similarity in relative adsorption is remarkable considering the variation in adsorbent
properties, and indicates that the adsorption of organic vapors on mineral surfaces
is primarily a function of surface area (Jurinak and Volman, 1957; Rhue et al.,
1988).
The significance of the monolayer adsorption capacity obtained from the
BET model has recently come under scrutiny. Rhue et al. (1988) suggested that
for systems exhibiting low values of C, the coverage of the entire surface with a
single monolayer may not occur at any relative vapor pressure. In fact, multilayer
adsorption of EDB on Ca-saturated montmorillonite and kaolinite was observed at
surface coverages of 0.65 and 0.35, respectively (Jurinak and Volman, 1957). The
corresponding values of C for the montmorillonite and kaolinite systems were 24
and 14, respectively. In theory, the onset of multilayer formation prior to
monolayer coverage would result in the formation of discrete adsorbate films or

S/Sm S (mg/g)
p-Xylene (P/F^)
Figure 1-2. Adsorption of p-xylene vapors on oven-dry silica gel, kaolin,
bentonite, and Lula aquifer material, expressed as (a) amount
adsorbed and (b) relative amount adsorbed, reported by Rhue et al.
(1989).

11
"patches" on the adsorbent surface. This scenario appears to be reasonable for
the adsorption of nonpolar organic vapors on mineral surfaces based on the
similarity in their heats of adsorption and condensation (Rao at al., 1989).
Competitive Adsorption
Under natural conditions, the adsorption of organic vapors will usually occur
on surfaces containing at least some adsorbed water. Chiou and Shoup (1985)
reported that the magnitude of water, 1,2,4-trichlorobenzene, chlorobenzene, and
benzene adsorption on oven-dry Webster soil was positively correlated to
adsorbate polarity (Figure 1-3a). It should be noted that the relative adsorption
was similar for all adsorbates studied, which suggests that the monolayer
adsorption capacity determined from the BET model accounts for variations in both
adsorbate and adsorbent properties (Figure 1 -3b). The fact that adsorbate polarity
enhanced vapor-phase adsorption indicates that water will compete strongly with
organic vapors for adsorption sites. The adsorption of water on mineral surfaces
has been attributed to cation-dipole interactions, hydrogen bonding, and weak
charge transfer, which fall within the extremes of physical and chemical adsorption
(Burchill et al., 1981). Jurinak and Volman (1961b) reported that the enthalpy of
water adsorption on Ca- and Ba-saturated kaolin was approximately -120 kJ/mole,
which corresponded to an enthalpy of cation hydration of approximately -250
kJ/mole. In contrast, Rao et al. (1989) reported that heats of adsorption for
trichloroethene (TCE), toluene, and cyclohexane vapors on oven-dry Oldsmar soil

s/sm S (mg/g)
12
Figure 1-3. Adsorption of water, 1,2,4-trichlorobenzene, chlorobenzene, and
benzene on oven-dry Woodburn soil, expressed as (a) amount
adsorbed and (b) relative amount adsorbed, reported by Chiou and
Shoup (1985).

13
were -23, -37, and -34 kJ/mole. Thus, as the relative humidity or soil moisture
content increases, water will displace organic vapors from adsorbent surfaces
resulting in the suppression of VOC sorption. This finding is supported by infrared
studies, which have demonstrated that p-xylene was immediately displaced from
the surface of montmorillonite when laboratory air was introduced into the sample
cell (C. T. Johnston, 1990, personal communication).
Prior to the attainment of monolayer coverage with water, the adsorption of
organic vapors may proceed, essentially unhindered, on exposed mineral surfaces.
Rhue et al. (1989) reported that p-xylene adsorption on silica gel and kaolin was
not suppressed until the RH was greater than that corresponding to the monolayer
adsorption capacity determined from the BET model (i.e., RH « 18%) (Figure 1-4).
In contrast, Call (1957) observed a substantial decrease in ethylene dibromide
adsorption at 5% RH (Figure 1-5). Regardless of the exact point at which
competitive effects become evident, these data indicate that the presence of water
vapor not only reduces organic vapor sorption, but also results in a shift from
Type-ll adsorption isotherms to ones that are essentially linear.
In order to predict the competitive adsorption of water and organic vapors
on mineral surfaces a two-component adsorption model must be employed.
Fortunately, the BET equation has been modified by Hill (1946a, 1946b), and more
recently by Rhue et al. (1989), to account for adsorption from two-component
systems. The only additional assumption required to derive the equation of Rhue
et al. (1989) is that each component adsorbs only onto exposed mineral surfaces

s (mg/g) S (mg/g)
14
p-Xylene (P/f=)
Figure 1-4. The effect of RH on the adsorption of p-xylene vapors on
(a) kaolin and (b) silica gel reported by Rhue et al. (1989).

80
0 0.2 0.4 0.6
EDB (P/P0)
tn
Figure 1-5. The effect of RH on the adsorption of EDB vapors on Whittlesey Black Fen soil reported by Call (1957).

16
or adsorbed layers of itself. This implies that the two components form immiscible
fluids on the surface, which is reasonable for adsorbates of low mutual solubility,
such as water and a nonpolar organic vapor. The total adsorbed mass of
component "a", Ma (mg/g), can be calculated from the following equation:
Ma = aaCaS0[Xa/(1-Xa)2] (1-6)
where aa is the mass of component "a" occupying a unit area of surface (mg/m2),
Ca is the BET parameter related to the heat of adsorption determined from single¬
component adsorption isotherms, Xa is the relative vapor pressures of component
"a", and S0 is the area of bare surface per unit mass of adsorbent (m2/g).
Unfortunately, the value of S0 is unknown in a binary system, and thus the amount
of each component adsorbed could not be expressed on a per-mass-of-adsorbent
basis (Rhue et al.,1989). However, the two-component model was evaluated by
comparing the measured and predicted mass fraction of component "a" (Fa) on the
surface using the following equation:
Ma
Fa - â–  (1-7)
Ma + Mb
The multi-component BET equation of Hill (1946a, 1946b) is based primarily
on the BET postulate which states that molecules of the second and higher
adsorbed layers possess evaporation-condensation properties of the bulk liquid.
If this assumption is valid, it follows that adsorption and desorption from the
second and succeeding layers of a binary system should approximate the
properties of the liquid mixture. In addition, Hill assumed that area fraction of

17
component "a" (ya) is related to the mole fraction (Na) by the following equation:
Na
Ya = (1-8)
Na + (1-Na) (Vb/Var
where va and vb are the mole fractions of component "a" and "b", respectively. If
component "a" is assumed to adsorb only onto bare mineral surfaces and an
adsorbed layer of itself, Hill’s equation can be reduced to:
Sa Xa[Ca(1-Xb) + XbCb]
= (1-9)
Sam (1-Xa-Xb)[1+Xa(Ca-1) + Xb(Cb-1)]
where Sa is the amount of component "a" adsorbed (mg/g), Sam is the monolayer
adsorption capacity of component "a" (mg/g), Xa and \ are the relative vapor
pressures of component "a" and "b", respectively, and Ca and Cb are the BET
parameters related to the heat of adsorption for component "a" and "b",
respectively. The values of Sam, Ca, and Cb are determined from single-component
adsorption isotherms. If one of the components is absent (i.e., Xa or Xb = 0), Hill’s
equation reduces to the single-component BET equation. Although the derivation
referred to here is limited to a two-component system, in theory, the Hill equation
can accommodate an infinite number of components.
Due to the lack of suitable adsorption data, the two-component models of Rhue
et al. (1989) and Hill (1946a, 1946b) have rarely been tested.

18
Sorption at High Relative Humidity
At RHs approaching saturation (i.e. RH > 90%), the sorption of organic
vapors has been attributed to partitioning into organic carbon (Chiou and Shoup,
1985). This hypothesis is based on (1) the linear nature of benzene and
chlorobenzene vapor adsorption isotherms on Woodburn soil at 90% relative
humidity, and (2) the similarity in the magnitude of sórbate uptake from the
aqueous and vapor phase. However, linear isotherms have been obtained for a
range of sorbents, including those with trace levels of organic carbon (OC), such
as kaolin, silica gel, and Ca-saturated montmorillonite (Call, 1957; Rhue et al.,
1989). In addition, vapor-phase sorption coefficients, normalized for OC (K.J,
calculated for sorbents of low OC content have repeatedly been found to be orders
of magnitude greater than literature values (Rhue et al., 1989; Peterson et al.,
1988). Although these data suggest that other mechanisms may contribute to the
vapor-phase sorption at high RHs, the sorption of organic vapors on hydrated soils
is widely described by dissolution into adsorbed water films and subsequent
partitioning into OC (Baehr, 1987; Glotfelty and Schomburg, 1989; Jury et al.,
1990).
The adsorption of insoluble and sparingly-soluble organic vapors has also
been investigated by gas chromatography (GC). In general, Type-lll isotherms
have been obtained for the adsorption of nonpolar vapors on hydrated sorbents,
with heats of adsorption that are smaller than heats of vaporization (Dorris and
Gray, 1981; Karger et al., 1971a, 1971b). These data suggest that the gas-liquid

19
interface of adsorbed water films acts as a low energy surface toward nonpolar
vapors. Once the surface is covered with several monomolecular layers of water
it appears that the sorbent has no effect on vapor-phase adsorption. Karger et al.
(1971a, 1971b) concluded that adsorbed water films between 1.5 and 200 nm in
thickness have properties similar to bulk water. Measurements of the change in
surface tension of bulk water with vapor pressure also indicate that nonpolar
organic vapors are adsorbed at the gas-liquid interface (Blank and Ottewill, 1964;
Cutting and Jones, 1955; Hauxwell and Ottewill, 1968). Due to the large surface
area of adsorbed water films, adsorption at the gas-liquid interface of hydrated
soils may contribute significantly to VOC sorption. In fact, Call (1957) attributed
the sorption of EDB on moist soils to adsorption at the gas-liquid interface and
dissolution into adsorbed water films. It is apparent that a number of mechanisms
may contribute to vapor-phase sorption at high RHs, including partitioning into OC,
adsorption at the gas-liquid interface, and dissolution into adsorbed water films.
In addition, the extent to which sórbate and sorbent properties determine the
importance of each mechanism remains largely unknown.
Research Summary
The purpose of this work was to investigate, from a mechanistic perspective,
the sorption of organic vapors on soils and clay minerals. The study of soil
processes, particularly sorption, is limited by our inability to measure soil
phenomena on a microscopic scale. Thus, a macroscopic approach was

20
employed here, in which experiments were specifically designed to ascertain the
mechanism responsible for sorption under various sorbate-sorbent regimes.
A single volatile organic chemical, p-xylene, was utilized in these studies.
Although this may be viewed as a limitation, it allowed for intensive study of the
factors affecting vapor-phase sorption and for the development of experimental
techniques to study VOC sorption. Relevant physicochemical properties of p-
xylene are presented in Table 1-3. The sorbents used in these studies were
selected to provide a range of physical and chemical properties. In addition, the
OC content and cation saturation of certain sorbents were modified in order to
study the effect of such treatments on vapor-phase adsorption.
In Chapter 2, a flow-equilibration apparatus was utilized to measure the
sorption of p-xylene vapors on soils and mineral surfaces at 0, 67, and 90% RH.
Experiments were designed to determine the amount of p-xylene sorption
attributable to adsorption at the gas-liquid interface, dissolution into adsorbed water
films, and partitioning into OC. Adsorption at the gas-liquid interface of hydrated
sorbents was estimated from measurements of the surface tension of bulk water
exposed to p-xylene vapors using the Gibbs adsorption equation.
Gas chromatography techniques were used to study the sorption of p-xylene
vapors on anhydrous and hydrated quartz sand in Chapter 3. The effect of salt
treatments on vapor-phase sorption, and a comparison of batch and GC data are
also presented. In addition, the advantages and limitations of GC methods for the
study of vapor-phase sorption on soil materials are discussed.

21
Table 1-3. Selected physicochemical properties of p-xylene.
Property
Value3
Structure
Molecular Weight
Boiling Point
Density
Solubility
Vapor Pressure
Henry’s Law Constant
C6H4(CH3)2
106.17 g/mole
138.4°C
0.86 g/mL (20°C)
198 mg/L (25°C)
8.14 mm Hg (24°C)
7.44 X 10'3 m3- atm/mole
a Data obtained from Verschueren (1983) and Weast (1987).

22
In Chapter 4, the adsorption of p-xylene vapors on Ca-, Na-, and Li-
saturated kaolin was measured using the flow-equilibration method. The effect of
cation saturation on the competitive adsorption of water and p-xylene vapors was
also studied. These data were used to evaluate the two-component BET
adsorption models of Hill (1946a, 1946b) and Rhue et al. (1989).
Li-saturated kaolin was utilized as a reference surface for the study of water
and organic vapor sorption in Chapter 4. However, there has been considerable
debate in the literature as to whether or not Li-kaolin actually represents a surface
free of cation hydration effects. Thus, the mechanism responsible for reduced
water adsorption on Li-kaolin was investigated by gravimetric, spectroscopic, and
ion extraction techniques in Chapter 5.

CHAPTER 2
VAPOR-PHASE SORPTION OF P-XYLENE AND WATER ON
SOIL MATERIALS AT HIGH RELATIVE HUMIDITIES
Introduction
Vapor-phase sorption influences the mobility and distribution of volatile
organic chemicals (VOCs) in the unsaturated zone as well as the atmospheric
transport and deposition of VOCs. Previous studies have demonstrated that oven-
dry soils and clay minerals have a sizable capacity to adsorb organic vapors,
which can be described by the Brunauer-Emmett-Teller (BET) model (Call, 1957;
Chiou and Shoup, 1985; Jurinak and Volman, 1957; Poe et al., 1988; Rao et al.,
1989; Rhue et al., 1988). However, under natural conditions the sorption of
organic vapors usually occurs on surfaces containing at least some adsorbed
water. As the soil moisture content or relative humidity (RH) increases VOCs are
displaced from the surface, resulting in the suppression of VOC sorption (Call,
1957; Chiou and Shoup, 1985; Hollist and Foy, 1971; Rao et al., 1989; Rhue et
al., 1988, 1989; Spencer and Cliath, 1970, 1972, 1974, Wade, 1954). It is
generally agreed that water effectively competes with organic vapors for mineral
surfaces due to the polar nature of water and mineral adsorption sites (Valsaraj
and Thibodeaux, 1988).
At RHs above which the sorbent surface is occupied by at least a
monolayer of water, the specific mechanisms responsible for the sorption of VOCs
23

24
remain unclear. It has been postulated that the sorption of organic vapors at high
RH can be described by partitioning into organic carbon (OC) (Chiou and Shoup,
1985). This hypothesis was based on the linear nature of benzene and
chlorobenzene vapor sorption isotherms obtained for Woodburn soil (1.9% organic
matter) at 90% RH, and the similarity between the magnitude of solute uptake from
the aqueous and vapor phase (Chiou and Shoup, 1985). However, at 90% RH,
Call (1957) obtained linear isotherms for the sorption of ethylene dibromide (EDB)
vapors on Ca-saturated montmorillonite which contained no detectable OC. Rhue
et al. (1989) also reported linear isotherms for p-xylene vapor sorption on sorbents
with low OC contents; e.g., kaolin (0.65 g OC/kg) and silica gel (0.45 g OC/kg), at
67% relative humidity. In addition, sorption coefficients normalized for OC (K^)
calculated from p-xylene sorption data and solubility considerations were 2 to 5
orders of magnitude greater than p-xylene values reported in the literature. A
similar trend was noted by Peterson et al. (1988), who reported that linear sorption
coefficients measured for trichloroethylene (TCE) vapor over a range of
unsaturated conditions were 1 to 4 orders of magnitude greater than values
obtained under saturated conditions. Chiou and Shoup (1985) also found that the
vapor-phase sorption of benzene, m-dichlorobenzene, and 1,2,4-trichlorobenzene
was consistently greater than sorption from aqueous solution, even though the
sorbent surface should have been covered with several monolayers of water at
90% RH. These data suggest that in addition to partitioning into soil organic
carbon, other mechanisms contribute to VOC sorption at high RH.

25
Dissolution into adsorbed water films and adsorption at the gas-liquid
interface were considered by Call (1957) to be the dominant mechanisms
responsible for EDB sorption on moist soils. For sparingly-soluble VOCs, such as
p-xylene, the magnitude of sorption is far greater than dissolution into sorbed
water, based on solubility limits in bulk water (Rhue et al., 1989). However,
adsorption at the interface between the vapor phase and bulk water has been
reported for a number of sparingly-soluble VOCs (Blank and Ottewill, 1964; Cutting
and Jones, 1955; Drozd et al., 1982; Hauxwell and Ottewill, 1968). Due to the
large surface area to volume ratio of adsorbed water films, adsorption at the gas-
liquid interface of hydrated soils could contribute significantly to vapor-phase
sorption.
The experiments reported here were designed to determine the nature of
p-xylene vapor sorption isotherms at high RH and to determine the amount of p-
xylene sorption attributable to adsorption at the gas-liquid interface, dissolution into
adsorbed water films, and partitioning into OC. Adsorption at the gas-liquid
interface was estimated from surface tension measurements of distilled water
exposed to p-xylene vapors using the Gibbs adsorption equation.
Materials and Methods
Sorbents
The sorbents used in this study were selected to provide a range of surface
area and OC content. Colloidal kaolin (K-6, Lot #731063) was obtained from

26
Fisher Scientific Products. The kaolin had a cation exchange capacity (CEC) of
4.23 cmolj/kg at pH 5.5 and was predominantly Na-saturated with only trace
amounts of Ca, K, and Mg (Rhue et al., 1989). Silica gel (Syloid 244), average
particle size of 3 pm and a pore volume of 1.4 cm3/g, was obtained from the
Davison Chemical Division, W.R. Grace & Co., Baltimore, MD. The Webster soil,
a silty clay loam (Typic Haplaquoll), was collected from the surface horizon (0-30
cm) of a site in Iowa and ground to pass a 106 pm mesh screen. The Webster
soil had a CEC of 51.11 cmolj/kg and was predominantly Ca-saturated. A portion
of the Webster soil (Webster HP) was treated with hydrogen peroxide buffered to
pH 5.0 with acetic acid to remove OC.
Organic carbon content was measured by the Wakley-Black heat-of-dilution
method (Donohoe, 1983). The sorbent surface areas were determined from N2
adsorption data (Advanced Materials Research Center, University of Florida).
Cation exchange capacity was determined by washing the sorbents with 1.0 M
CaCI2 5 times, removing excess salts with 95% ethanol until a negative chloride
test was achieved using AgN03, and extracting exchangeable Ca with 0.5 M
Mg(N03)2. The amount of Ca present in the Mg(N03)2 extract was then measured
by atomic absorption spectroscopy. These and other sorbent properties are
presented in Table 2-1.
Vapor-Phase Adsorption Studies
Vapor-phase sorption of p-xylene was determined on Webster soil and
Webster HP at 0 and 90% RH, and on kaolin and silica gel at 0 and 67% RH. The

Table 2-1. Physical and chemical properties of sorbents used to study sorption of p-xylene vapors.
Sorbent
Organic
Carbon
N2 Surface
Area
Cation Exchange
Capacity
Particle Size
Sand Silt Clay
Clay
Mineralogy
—-g OC/kg—-
-m2/g-
cmol^kg-—
g/kg—
Kaolin3
0.65 (±0.02)
13.6
4.23 (±0.03)
0 150 850
kaolinite
Silica Gel3
0.45 (±0.08)
238.0
amorphous
Webster
Soil
41.36 (±0.23)
2.6
51.11 (±0.53)
550 200 250
smectite,
kaolinite,
mica
Webster
HP
2.27 (±0.09)
33.0
31.89 (±0.12)
550 200 250
smectite,
kaolinite,
mica
a Adapted from Rhue et al. (1989).
ro
-j

28
flow-equilibration apparatus used to measure p-xylene and water vapor sorption
was similar to that described in previous studies (Rhue et al., 1988, 1989).
However, the p-xylene flow stream consisted of two gas washing bottles in series;
the first contained water and the second contained p-xylene and water (Figure 2-
1). This allowed the RH to be maintained at either 67 or 90% while the p-xylene
relative vapor pressure (P/PJ could be varied from 0 to 0.9, where P is the
equilibrium vapor pressure and PQ is the saturated vapor pressure. The PG of p-
xylene at 24°C is 8.14 mm Hg, which is equivalent to a vapor concentration 46.64
mg/L (Weast, 1987). For sorption experiments conducted at 0% RH, valve V3 was
closed and valves V, and V2 were adjusted to obtain relative vapor pressures of
p-xylene ranging from 0 to 0.9.
The concentration of water and p-xylene vapor in the flow stream was
determined by passing the flow stream through three polyethylene tubes in series.
The three tubes contained magnesium perchlorate, activated charcoal, and a
mixture of activated charcoal and magnesium perchlorate, respectively. The
difference between the initial and final trap weights yielded the total mass of vapor
trapped. The p-xylene vapor concentration was then determined by bubbling the
flow stream through two 40-mL glass centrifuge tubes containing 20 mL of
methanol. P-xylene trapped in these solutions was measured with a Perkin Elmer
Model 320 UV-VIS spectrophotometer. The concentration of water vapor in the
flow stream was determined by subtracting the concentration of p-xylene from the
total vapor concentration.

ISOTHERMAL CHAMBER
n2gas
Figure 2-1.
\
Flow-equilibration apparatus used to study sorption of p-xylene and water vapors on silica gel, kaolin,
Webster soil, and Webster HP.
NJ
CO

30
Approximately 1 g of sorbent, which had been oven-dried to 130°C, was
placed in glass centrifuge tubes and capped with teflon-backed septa. Four tubes
containing sorbent, and four blank tubes were placed on the flow stream in series.
The gas flow stream passed through the centrifuge tubes via hypodermic needles
at a rate of approximately 1.0 mL/sec. In general, an exposure time of 24 hours
was sufficient to attain sorption equilibrium.
Adsorbed concentrations of water and p-xylene were measured by
extracting the sorbents with 20 ml_ of methanol containing CaCI2. The methanol
solution was made by adding 10 mL of CaCI2-saturated methanol per 1 L of
methanol. Water in the methanol extract was measured by Karl Fisher (KF)
titration. The KF reagent was diluted with KF diluent to a strength of approximately
0.5 mL titer per mg of water. The visual endpoint was established by adding titer
to 20 mL of CaCI2-methanol solution until the desired endpoint was obtained. In
a second centrifuge tube, 5 mL of methanol solution was pretitrated to the visual
endpoint and 10 pL of deionized water was injected and titrated to the endpoint to
give the exact strength of the titer. A known volume of the methanol extract was
titrated in a similar manner to determine the amount of adsorbed water.
The concentration of p-xylene in the methanol extract of kaolin and silica gel
was measured using a Perkin Elmer Model 320 UV-VIS spectrophotometer. The
Webster soil and Webster HP released methanol-soluble compounds that
interfered with direct UV spectrophotometric analysis. Therefore, p-xylene extracts
from these sorbents were analyzed by high-performance liquid chromatography

31
(HPLC) techniques. The HPLC system consisted of a Gilson 302 pump, Waters
450 detector, Hewlett Packard 3392A integrator, and a 10-cm Waters RCM C-18
column with a 3-cm Brownlee guard column.
Surface Tension Measurements
The surface tension of deionized water exposed to p-xylene vapors was
measured using the "drop weight" method. The technique is based on Tate’s law,
which considers the weight of a drop falling from a small diameter tube to be
proportional to the radius (r) of the tip (cm), and the surface tension (y) of the liquid
(g/s2),
weight per drop = 2 n r y. (2-1)
Tate’s law assumes that a spherical drop will form at the tip, but in reality the drop
tends to elongate before it detaches from the tip. Harkins and Brown (1919)
recognized the importance of this discrepancy and developed a correction factor
(CF) based on the ratio of the tip radius to the length of the drop,
CF = /(r/V1/3) (2-2)
where V is the volume of the drop (Table 2-2). In general, the values of r/V1/3 were
between 0.45 and 0.50. The following equation was then used to calculate surface
tension:
m g
Y =
2 n rCF
(2-3)
where m is the mass of the drop (g), and g is the acceleration due to gravity
(cm/s2).

32
Table 2-2.
Drop-weight surface tension correction factors (CF) adapted from
Harkins and Brown (1919).
r/V1/3
CF
rNm
CF
0.30
0.7256
0.75
0.6032
0.35
0.7011
0.80
0.6000
0.40
0.6828
0.85
0.5992
0.45
0.6669
0.90
0.5998
0.50
0.6515
0.95
0.6034
0.55
0.6362
1.00
0.6098
0.60
0.6250
1.05
0.6179
0.65
0.6171
1.10
0.6280
0.70
0.6093
1.15
0.6407

33
A 10-mL graduated burette was used for the surface tension measurements.
After carefully grinding the tip flush, an ocular microscope was used to measure
the diameter of the tip (0.37 cm). Drops of water falling from the tip were collected
in a 40-mL centrifuge tube, capped with a teflon-backed septa. A 0.4-cm diameter
hole was cut in the septa, and the height of the centrifuge tube was adjusted to
achieve a tight seal between the septa and the burette. A total of 18-20 drops, at
a rate of 4-6 drops per minute, were collected in the centrifuge tube. The surface
tension of water was then calculated from the volume and weight of liquid
collected. Solutions of NaCI were used to calibrate the diameter of the tip (0.3724
cm).
p-Xylene vapor, at relative vapor pressures from 0.1 to 0.8, was bubbled
through a 50-mL centrifuge tube capped with teflon-backed septa. The tube
contained approximately 40 mL of deionized water. No detectable change in the
p-xylene concentration was measured after one, two or four days of bubbling.
Therefore, the system was allowed to equilibrate for at least 24 hours. The
surface tension of deionized water exposed to p-xylene vapors was determined in
the same manner as described previously except that the p-xylene vapor was
allowed to flow through the collection tube for at least 2 minutes prior to initiating
the flow of drops.

34
Results and Discussion
Adsorption at 0% RH
Figures 2-2 and 2-3 show equilibrium isotherms for p-xylene vapor sorption
on silica gel, kaolin, Webster soil, and Webster HP at 24°C. Sorption data are
expressed as milligrams of p-xylene sorbed per gram of sorbent (S) versus the p-
xylene relative vapor pressure (P/PJ. At 0% RH, the p-xylene isotherms of all four
sorbents conformed to Type-ll BET adsorption isotherms. This type of isotherm
is typical of unrestricted monolayer-multilayer adsorption of gases on nonporous
or macroporous (pore width > 0.05 pm) sorbents (Sing et al., 1985). These
sorption data were fit by a least squares procedure to the linear form of the BET
equation,
P/P0 1 (C-1)P/P0
= + (2-4)
S(1 -P/P 0) SmC SmC
where Sm is the nominal monolayer adsorption capacity (mg/g), and C is a
parameter related to the heat of adsorption. Estimated values of Sm, C, and the
P/P0 associated with monolayer coverage are presented in Table 2-3.
The BET equation is considered to give reliable estimates of Sm for surfaces
exhibiting Type-ll adsorption isotherms. However, the value of C does not provide
a quantitative measure of the heat of adsorption, but does give an indication of the
relative magnitude of sorbent-sorbate interactions (Sing et al., 1985). The values
of C obtained for these systems are indicative of low sorbate-sorbent interactions
associated with physical adsorption. For systems exhibiting low values of C,

s (mg/g) S (mg/g)
35
Figure 2-2. Sorption of p-xylene on (a) silica gel and (b) kaolin at 0 and 67%
RH.

Figure 2-3. Sorption of p-xylene vapors on Webster soil and Webster HP at 0 and 90% RH.

Table 2-3. BET parameters calculated from single-sorbate adsorption isotherms.
Sorbent
Sórbate
sm
C
BET
Surface Area
P/P0
monolayer
P/P0
Range Used
Kaolin3
p-xylene
4.5
14
15
0.21
0.065-0.424
water
4.2
20
10
0.18
0.056-0.481
Silica Gel3
p-xylene
64.7
17
139
0.20
0.003-0.387
water
33.8
18
19
0.18
0.027-0.348
Webster
Soil
p-xylene
5.7
48
12
0.13
0.061-0.264
Webster
HP
p-xylene
12.3
73
27
0.10
0.061-0.262
a Adapted from Rhue et al. (1989).

38
discrete regions of multilayer sorption (i.e., patches) may form prior to the
attainment of complete monolayer coverage (Jurinak and Volman, 1957; Sing et
al., 1985).
The amount of sorbent surface available for the adsorption of a given
molecule (SmA) can be estimated from the Sm value and the area occupied by each
adsorbed molecule. The cross-sectional areas (aj of water and p-xylene were
calculated to be 0.105 and 0.380 nm2, respectively, using the following equation
(Karnaukhov, 1985; McClellan and Harnsberger, 1967),
aâ„¢ = I.COiMW/xA)273 (2-5)
where MW is the molecular weight, x is the liquid density, and A is Avogadro’s
number. This equation assumes that the sórbate molecules are oriented in a
hexagonal close packing at a density similar to that of the bulk liquid. The surface
areas occupied by either p-xylene or water molecules at monolayer coverage (SmA)
are shown in Table 2-3.
The values of SmA for oven-dry kaolin and Webster HP were similar to those
determined from N2 adsorption isotherms. These data are consistent with the
findings of Jurinak and Volman (1957) and Rhue et al. (1989), who concluded that
the N2 surface area provides a reasonable estimate of the area available for the
sorption of organic vapors on predominantly mineral surfaces. It is interesting to
note that the surface area of Webster soil, as determined from N2 and p-xylene
adsorption isotherms, increased following the hydrogen peroxide treatment. These
data suggest that both p-xylene and N2 vapors have a greater affinity for mineral

39
surfaces than for organic matter at 0% RH. The difference between the N2 (2.62
m2/g) and p-xylene/BET surface area (12 m2/g) of Webster soil may have been
due to greater sorption of p-xylene vapor by soil organic matter. This hypothesis
is supported by the work of Chiou and Shoup (1985), who found that the
adsorption of vapors on oven-dry Woodburn soil increased with the polarity of the
sórbate. The discrepancy between the N2 and BET surface area of silica gel has
been discussed in a previous paper (Rhue et al., 1989)
The relative sorption (S/SJ of p-xylene on oven-dry kaolin, silica gel,
Webster soil, and Webster HP is shown in Figure 2-4. The use of S/Sm allows for
the comparison of the adsorptive capacities of various sorbents on a unit-surface-
area basis. At low values of P/P0, the relative sorption of p-xylene on Webster HP
and Webster soil was slightly greater than that on kaolin and silica gel. The
increased sorption corresponds to an increase in the value of C for Webster soil
(C = 38) and Webster HP (C = 73), which suggests that specific sorbate-sorbent
interactions may have occurred. However, the overall similarity in relative sorption
for the sorbents studied here suggests that the adsorption of p-xylene vapors at
0% RH was primarily a function of surface area.
Sorption at High RH
Vapor-phase sorption of p-xylene on silica gel and kaolin decreased
dramatically when the RH was raised to 67% (Figure 2-2). The observed
suppression of vapor-phase sorption at high RH is in agreement with the findings
of others (e.g., Call, 1957; Chiou and Shoup, 1985; Rhue et al., 1989), and lends

s/s
2.0
1.5
E
1.0
0.5
0
0 0.2 0.4 0.6
p-Xylene (P/PQ)
. 5|C
*
*
* Kaolin
• Silica Gel
â–  Webster HP
^ Webster Soil
Figure 2-4. Sorption of p-xylene vapors normalized to values of Sm determined from the BET equation for silica gel,
kaolin, Webster soil, and Webster HP at 0% RH.
-p*
o

41
further support to the contention that water effectively competes with organic
vapors for mineral surfaces. Sorption of p-xylene vapors on Webster soil and
Webster HP was also reduced at 90% RH (Figure 2-3). In addition, the sorptive
capacity of Webster soil at 90% RH was greater than that of Webster HP, while
the reverse was true at 0% RH. These data suggest that OC contributed to vapor
sorption on Webster soil at high RH, while adsorption on mineral surfaces was the
dominant mechanism at 0% RH.
At both 67 and 90% RH, p-xylene sorption isotherms were linear until the
P/P0 reached approximately 0.5, above which, the amount of p-xylene sorbed
increased sharply, resulting in Type-lll adsorption isotherms. The linear nature of
the sorption isotherms below 0.5 P/P0 was consistent with isotherms obtained by
Call (1957) for EDB, and by Chiou and Shoup (1985) for benzene and
chlorobenzenes. Increased sorption at high relative vapor pressures has not been
previously reported for batch adsorption studies. However, researchers studying
sorption of hydrocarbons on hydrated silica and soil materials by gas
chromatography techniques have consistently obtained retention data which yield
Type-lll adsorption isotherms (Dorris and Gray, 1981; Karger et al., 1971a;
Okamura and Sawyer, 1973). Therefore, hydrated soils appear to have a sizable
capacity for organic vapor sorption when the relative vapor pressure approaches
one.
The sorption of organic vapors at high RH is commonly described by
dissolution of organic vapors into sorbed water films, using Henry’s Law constants

42
(Kh), and subsequent solute partitioning into organic carbon, using sorption
coefficients normalized for OC content (K.J. The justification for such an approach
comes primarily from a single article by Chiou and Shoup (1985). In this work, the
authors conclude that solute partitioning into organic carbon is the dominant
mechanism responsible for organic vapor sorption at high RH based primarily on
two pieces of evidence; (1) the linearity of the sorption isotherms and, (2) the
similarity in sorptive capacity from the aqueous and vapor phase. However, the
data presented here demonstrate that below 0.5 P/P0 linear isotherms can be
obtained for sorbents with OC contents ranging from trace levels to 41 g OC/kg.
Thus, the mere existence of a linear isotherm was not sufficient evidence to
conclude that partitioning into organic carbon had occurred. In addition, the
dramatic increase in sorption above 0.5 P/P0 was not consistent with partitioning
theory.
In order to compare sorption from the aqueous and vapor phase, values
were estimated from measured p-xylene sorption data for P/P0 below 0.5 (linear
portion of the isotherm) and the aqueous concentration of p-xylene determined
using a KH value of 7.44 X 10'3 m3- atm/mole (Table 2-4). Predicted p-xylene
values for silica gel, kaolin, and Webster HP were 4, 2, and 1 orders-of-magnitude
greater, respectively, than values determined from column studies (105-176
mL/g) (Brusseau et al.; Gamerdinger et al., submitted for publication in
Environmental Science and Technology) and estimated from a log octanol-water
partition coefficient of 3.15 (573 mUg) (Karickhoff, 1984). However, the predicted

43
Table 2-4. Sorption coefficients normalized for organic carbon content (K^)
calculated from p-xylene sorption data for P/P° of 0.06 to 0.50.
Sorbent
RH
OC Content
Koc
r2
-(%)-"
—g/kg—
—ml/g—
Silica Gel
67
0.45
2.35 X 106
0.936
Kaolin
67
0.65
9.10 X 104
0.989
Webster HP
90
2.27
1.53 X 103
0.967
Webster Soil
90
41.36
2.17 X 102
0.907

44
p-xylene for Webster soil was within the range of literature values. Thus, as
the sorbent OC content increased, the predicted value approached those
reported in the literature. These data suggest that the utility of values for
predicting vapor sorption was limited to sorbents with relatively high OC contents,
at relative vapor pressures less than 0.5.
Adsorption at the Gas-Liquid Interface
Adsorption at the gas-liquid interface was considered as a possible
mechanism to account for the sorption p-xylene vapors on sorbents with low OC
contents and at high relative vapor pressures. The adsorption of insoluble and
sparingly soluble hydrocarbons on water surfaces has been estimated by
measuring the change in surface tension with the partial pressure of the organic
vapor (Baumer and Findenegg, 1982; Blank and Ottewill, 1964; Cutting and Jones,
1955; Hauxwell and Ottewill, 1968; Jho et al., 1978). This approach is based on
the Gibbs adsorption equation,
dy
T = (2-6)
dp
where T is the surface excess (mol/cm2), y is the surface tension, and p is the
chemical potential. If the vapor is assumed to obey the ideal gas law, equation (2-
6) can be written as,
P dy
r
RT dP
(2-7)
where P is the partial pressure of the organic vapor, R is the gas constant, and T
is the temperature. The surface tension of distilled water exposed to p-xylene

45
vapor, as determined by the drop-weight method, is shown in Figure 2-5a. These
data were fit by a least squares regression procedure to yield a slope which could
be then used to calculate the surface excess as a function of the partial pressure
using equation (2-7) (Figure 2-5b). The Type-Ill adsorption isotherm generated
from this procedure were typical of those obtained for other aromatic hydrocarbons
and indicates that water acts as a low energy surface toward the nonpolar vapor
(Cutting and Jones, 1955; Vidal-Madjar et al., 1976). The amount of p-
xylene adsorbed at the gas-liquid interface was estimated from the surface excess
and the N2 surface area of each sorbent (Table 2-5). In addition, the mass of p-
xylene partitioned into organic carbon was predicted using a of 200 mL/g and
a Kh of 7.44 X 10'3 m3- atm/mole, and while mass of p-xylene dissolved in
adsorbed water was predicted using the KH value and the measured amount of
water adsorbed. The sum of the estimated values for these adsorption
components represents the total predicted adsorption, which is compared to the
measured adsorption data in Table 2-5. Adsorption on mineral surfaces was not
included in the predicted total because water is generally assumed to displace
organic vapors from mineral surfaces at high RH. However, the appropriateness
of this assumption at 67% RH is discussed.
The predicted data indicated that the gas-liquid interface was the dominant
mechanism responsible for vapor sorption on silica gel and kaolin. Neither
partitioning into organic carbon nor dissolution into sorbed water contributed
significantly to p-xylene sorption, due to the low OC content of these sorbents and

r X 10 10 (mol/cm2) # (g/s2)
46
P (mm Hg)
Figure 2-5. Surface tension (a) of deionized water exposed to p-xylene vapors
at 24°C and surface excess (b) of p-xylene at the gas-liquid
interface calculated using the Gibbs adsorption equation.

47
Table 2-5. Predicted and measured p-xylene sorption on Silica Gel, Kaolin,
Webster HP, and Webster Soil at 90% RH.
Sorption bv Components Total Sorption
Sorbent
P/P0
Gas-Liquid
Interface
Organic
Carbon
Sorbed
Water
Predicted
Measured
iiiy/y---
Silica
0.081
1.802
0.001
0.001
1.804
11.61
Gel
0.145
3.921
0.002
0.001
3.924
20.74
0.274
10.052
0.004
0.002
10.058
41.95
0.282
10.514
0.004
0.003
10.521
36.73
0.439
21.522
0.006
0.004
21.532
80.19
0.610
37.706
0.004
0.008
37.718
173.97
Kaolin
0.069
0.084
0.001
0.000
0.085
0.45
0.164
0.267
0.003
0.000
0.270
1.41
0.258
0.523
0.005
0.000
0.528
2.28
0.286
0.614
0.006
0.000
0.620
2.77
0.415
1.120
0.008
0.001
1.129
3.76
0.600
2.094
0.012
0.001
2.107
7.71
0.896
18.262
0.018
0.001
18.281
52.19
Webster
0.099
0.324
0.007
0.001
0.332
0.05
HP
0.201
0.870
0.014
0.003
0.887
0.08
0.206
0.903
0.014
0.003
0.920
0.10
0.497
3.677
0.034
0.007
3.718
0.28
0.601
5.228
0.043
0.008
5.279
0.91
0.777
14.014
0.054
0.009
14.077
3.88
Webster
0.099
0.026
0.126
0.002
0.154
0.21
Soil
0.197
0.067
0.251
0.003
0.321
0.26
0.206
0.072
0.262
0.003
0.337
0.25
0.384
0.190
0.488
0.005
0.683
0.61
0.497
0.292
0.632
0.008
0.932
0.63
0.610
0.415
0.776
0.008
1.199
1.31
0.777
1.113
0.988
0.010
2.111
4.36

48
the low solubility of p-xylene, respectively. However, the total predicted sorption
of p-xylene on silica gel and kaolin was approximately one-quarter of the measured
amount. This discrepancy may have been due to adsorption of p-xylene vapors
on exposed mineral surfaces. The average amount of water adsorbed on silica
gel and kaolin at 67% RH was 57.9 and 9.3 mg/g, respectively, which is equivalent
to 1.7 and 2.2 monolayers of water, based on BET estimates of Sm (Table 2-3).
Due to the low values of C (20 and 18) for these sorbents, it was possible that
patches of water formed on the mineral surface (Jurinak and Volman, 1957; Sing
et al., 1985), thereby allowing for adsorption on exposed mineral surfaces. Even
if monolayer coverage of water was attained, the mineral surface could still have
exerted a surface effect on sorbed water films (Fowkes, 1968), resulting in greater
sorption than would be predicted for bulk water surfaces. These hypotheses are
supported by the work of Dorris and Gray (1981), who reported that the sorption
coefficient for n-heptane on water-coated silica increased significantly at water
contents less than those achieved at 88% RH. Therefore, it is quite possible that
additional adsorption of p-xylene vapors occurred on exposed mineral surfaces
and/or surface-affected water films of silica gel and kaolin.
Predicted p-xylene sorption on Webster HP was considerably greater than
that measured with the flow-equilibration apparatus. Dissolution into sorbed water
films and partitioning into organic carbon contributed very little to the overall
estimate of p-xylene sorption on Webster HP. Thus, the difference between
predicted and measured sorption was primarily the result of the estimate of

49
adsorption at the gas-liquid interface. The surface area would have to be reduced
from 33.8 m2/g to approximately 4 m2/g in order to bring the estimated adsorption
at the gas-liquid interface into agreement with the measured sorption data. In
contrast, the predicted sorption of p-xylene on Webster soil was similar to the
measured values. Partitioning of p-xylene into OC on Webster soil (41 g OC/kg)
accounted for the majority of sorption at relative vapor pressures less that 0.6.
Sorption at the gas-liquid interface of Webster soil was much less than that of
Webster HP because the N2 surface area was only 2.62 m2/g.
Summary
The transport of VOCs in the unsaturated zone is directly influenced by
partitioning of the organic chemical between the liquid, vapor, and solid phase. Of
particular concern is the vapor phase, in which VOC transport may occur at a rate
greater than that in the liquid phases. Thus, it is imperative that the mechanisms
responsible for vapor-phase sorption are correctly identified and incorporated into
VOC models.
For all sorbents studied here, vapor-phase sorption of p-xylene increased
dramatically at relative vapor pressures greater than 0.5, resulting in Type-Ill
adsorption isotherms. Although it is generally accepted that oven-dry sorbents
have sizable sorption capacity for organic vapors, these data suggest that hydrated
soil materials can also sorb significant quantities of organic vapors in regions of
high vapor concentration (e.g., near the contaminant source). In addition, the data

50
presented here indicate that the use of values to predict vapor-phase sorption
at high RH appears to be only valid for sorbents with high OC content, at relative
vapor pressures less than 0.5. These findings are particularly important in light of
the fact that most VOC and multi-phase transport models either fail to consider
vapor-phase sorption (Pinder and Abrióla, 1986; Sleep and Sykes, 1989) or
describe vapor-phase sorption by dissolution into soil water and partitioning into
OC (Baehr, 1987; Jury et al., 1990).
In order to describe vapor-phase sorption for different sorbate-sorbent
systems over a range of relative vapor pressures, one must consider all
mechanisms which contribute to VOC sorption. The data presented here indicate
that a multi-mechanistic approach should include adsorption on mineral surfaces,
partitioning into OC, dissolution into sorbed water films, and adsorption at the gas-
liquid interface. Surface tension data suggest that adsorption at the gas-liquid
interface could contribute significantly to the sorption of sparingly-soluble VOCs in
the unsaturated zone. Of particular interest is the sizable surface excess
estimated for aromatic hydrocarbons of environmental concern such as toluene,
benzene, and o-xylene (Blank and Ottewill, 1964; Cutting and Jones, 1955;
Hauxwell and Ottewill, 1968; Vidal-Madjar et al., 1976). The task at hand now is
to further define the limits of applicability of each mechanism based on sórbate,
sorbent, and environmental considerations, and to incorporate this knowledge into
current modeling efforts. An initial attempt at this approach has been attempted
by Shoemaker et al. (1990), who described vapor-phase sorption of TCE using an

51
"effective sorption" term that included sorption coefficients for the solid-liquid and
the solid-gas interface.

CHAPTER 3
GAS CHROMATOGRAPHIC STUDIES OF P-XYLENE SORPTION ON
ANHYDROUS AND HYDRATED QUARTZ SAND
Introduction
Gas-liquid chromatography (GLC) is recognized as an efficient and versatile
method for investigating the sorption of volatile organic compounds (VOCs) on
hydrated sorbents. The interpretation of GLC data requires a consideration of
several retention mechanisms including (1) adsorption at the gas-liquid interface,
(2) adsorption at the solid-liquid interface, and (3) partitioning into the liquid phase.
Conder et al. (1969) proposed the following equation to describe the net retention
volume (VN) of a solute at infinite dilution:
VN = KlVl + K,A, + KSAS (3-1)
where KL (mL/mL), K, (mL/m2), and Ks (mL/m2) are the distribution coefficients for
the liquid phase, gas-liquid interface, and solid-liquid interface, respectively, VL
(mLVg) is the volume of the liquid phase, and A, (m2/g) and As (m2/g) are the areas
of the gas-liquid interface and solid-liquid interface, respectively. Previous studies
have demonstrated that aliphatic hydrocarbon retention on water-coated supports
is due solely to adsorption at the gas-liquid interface: whereas, aromatic
hydrocarbons and other weakly polar solutes are simultaneously adsorbed at the
gas-liquid interface and partitioned into the liquid phase (Karger et al., 1971a,
52

53
1971 b; Martin, 1961). At water contents above 3 to 4% by weight, the effect of the
solid support on solute retention appears to vanish, and thus equation (3-1) can
be applied without the KSAS term (Dorris and Gray, 1981; Okamura and Sawyer,
1973). Comparisons of partition coefficients and heats of solution determined by
GLC and static methods indicate that adsorbed water films between 1.5 and 200
nm in thickness have properties similar to those of bulk water (Karger et al.,
1971a, 1971b; Chatterjee et al., 1973). Thus, gas chromatography (GC) appears
to be an ideal method to study vapor-sorption at the gas-liquid interface, and can
be utilized to measure sorption on anhydrous soil materials. A detailed review of
the theoretical and experimental application of GC methods to the study of VOC
sorption has been presented by Rhue and Rao (1990).
The adsorption of insoluble and sparingly-soluble hydrocarbons on water
surfaces has also been estimated from measurements of the change in surface
tension of bulk water with the partial pressure of the vapor, using the Gibbs
adsorption equation. The surface excess of organic vapors calculated in this
manner typically yields Type-lll adsorption isotherms. In addition, heats of
adsorption for n-hexane and toluene on bulk water were found to be greater than
corresponding heats of vaporization (Hauxwell and Ottewill, 1968). Adamson
(1967) attributed this behavior to the rearrangement of surface water molecules to
accommodate the hydrocarbon, which resulted in larger heats of adsorption.
Although measurements of vapor adsorption on water-coated supports by GLC
yield Type-Ill adsorption isotherms (Dorris and Gray, 1981; Karger et al., 1971b;

54
King et al., 1972), heats of adsorption estimated from GLC data are generally
smaller than heats of vaporization. These findings suggest that the gas-liquid
interface of water acts as a low energy surface toward nonpolar vapors (Chatterjee
et al., 1972; Dorris and Gray, 1981; Hartkopf and Karger, 1973; Karger et al.,
1971 a, 1971b). The discrepancy between heats of adsorption obtained from GLC
and surface tension data has been attributed to uncertainty in surface tension
measurements at low surface coverages (Dorris and Gray, 1981; Karger et al.,
1971a, 1971b); whereas, flame-ionization detectors (FID) used in GLC studies
provide accurate measurements of hydrocarbon adsorption.
In addition to high sensitivity, gas chromatography allows for the rapid
collection of sorption data over a range of temperature and moisture content
regimes. Despite the apparent advantages of GC techniques over conventional
batch adsorption methods, relatively few studies have been conducted using soil
material as the solid support phase (Bohn et al., 1980; Okamura and Sawyer,
1973; Rao et al., 1988). Thus, the purpose of this work was to test the utility of
gas chromatography for the study of p-xylene sorption on anhydrous and hydrated
quartz sand. The effect of CaCI2 treatments on p-xylene adsorption was also
investigated by GC, and was compared to adsorption data obtained by flow-
equilibration and surface tension methods.

55
Materials and Methods
Column Preparation
The solid support material was collected from the Bh horizon of an Oldsmar
soil (Alfic Arenic Haplaquod) located in Collier County, Florida. Mechanical
analysis indicated that the sand-size fraction (diameter > 50 jim) accounted 90%
of the soil sample. The Oldsmar soil sample had a cation exchange capacity of
5.2 cmol^kg and was predominantly Ca-saturated. The N2 surface area was 10.05
m2/g, while the organic carbon content was 10.9 g OC/kg (Rhue et al., 1988). The
soil sample used in the GC experiments was sieved to pass a 250 pm screen and
will be referred to as Oldsmar sand. A portion of this sample was washed 3 times
with 0.1 M CaCI2 to test the effect of salt on vapor-phase sorption.
The Oldsmar sand was packed in 6.35 mm o.d. glass columns,
approximately 16 and 90 cm in length. The 90-cm columns were used to measure
sorption on hydrated sorbents; the additional length was necessary to obtain
adequate solute separation. These columns were crafted to form a U-shape which
matched the inlet and outlet ports of the gas chromatograph. As sand was added
to the column, the column was gently vibrated to achieve uniform packing. Glass
wool was placed at the ends of the columns to maintain support integrity.
Gas Chromatography Experiments
A Tracor 222 gas chromatograph equipped with a FID was used for the
sorption studies. Certified grade p-xylene (99.8% purity) and high purity grade
methane (99.97% purity) were obtained from Fisher Scientific Products. The FID
was calibrated for p-xylene at three N2 flow rates, with air and hydrogen flow rates

56
maintained at 0.65 mL/sec and 5.0 mL/sec, respectively. During calibration the p-
xylene vapor was introduced onto a straight glass column by passing the N2 flow
stream over a thermostated sample of liquid p-xylene. When a constant mV
reading was obtained, the flow stream was bubbled through a 40-mL centrifuge
tube containing 20 mL of methanol. The concentration of p-xylene in the methanol
was measured by UV-VIS spectroscopy or HPLC techniques.
The adsorption of p-xylene on untreated and salt-treated Oldsmar sand was
measured under anhydrous and hydrated conditions at room temperature (= 24°C).
For anhydrous experiments, the column was allowed to equilibrate with "dry" N2
for several hours prior to the initiation of p-xylene injections. This was analogous
to the flow-equilibration method in which "dry" N2 was used as the carrier gas. For
hydrated systems, Okamura and Sawyer (1971,1973) recommend that the desired
water content be reached by desorption of a saturated column in order to attain
uniform water coverages. However, this procedure resulted in the introduction of
excessive quantities of water into the FID and associated column fittings. Dorris
and Gray (1981) obtained reproducible solute retention data at water contents of
0.6, 1.4, and 3.8% by equilibrating the column with carrier gas at 26, 62, and 88%
RH. For the experiments described here, relative humidities of 90 and 98% were
achieved by bubbling the N2 flow stream through a gas-washing bottle containing
deionized water in a manner similar to that described in Chapter 2. The relative
humidity of the N2 flow stream was measured at the column inlet and outlet by
trapping the water vapor in two magnesium perchlorate traps arranged in series.

57
In addition, the back pressure at the column inlet was measured using a pressure
transducer, for which the mV output had been calibrated against pressure heads.
Adsorption isotherms forp-xylene were obtained by the eluted-pulse method
of Dorris and Gray (1981). The retention time of methane (tc) and p-xylene (tr)
vapors, which were simultaneously injected on the column, was recorded with a
Hewlett Packard 3390A integrator. The retention time of air injections, which gave
a negative response, were identical to those of methane. These data indicate that
methane was not retained by the stationary phase. Thus, the net retention volume
(VN) of p-xylene was calculated from the difference between tr and t0, using the N2
flow rate. Injections volumes ranging from 1 pl_ to 2 mL of p-xylene vapor were
used to obtain a range of net retention volumes.
If the adsorption of p-xylene is assumed to occur on mineral surfaces for
anhydrous sorbents, and solely by adsorption at the gas-liquid interface of water-
coated supports, the net retention volume (VN) required to elute a solute is given
by,
VN = RT(dT/dP)A = RT(dS/dP)w (3-2)
where R is the gas constant, T is the temperature, T is the surface concentration
(mol/cm2), P is the partial pressure of the vapor, A is the surface area, S is the
amount adsorbed (mg/g), and w is the weight of the column packing (Dorris and
Gray, 1981). Adsorption isotherms can then be obtained by integrating equation
(3-2) as follows:
S = 1/RTwJ VN(P) dP. (3-3)
The peak-maxima method of Dorris and Gray (1981) was employed to obtain a

58
chromatographic envelope which could be integrated by equation (3-3). The
calibration curve described previously was used to convert mV readings, obtained
from peak height measurements, to partial pressures of p-xylene. However, the
use of equation (3-2) implies that the sorption effect and pressure gradient along
the column were negligible.
Results and Discussion
Adsorption on Anhydrous Oldsmar Sand
Chromatographic peak maxima obtained from injections of p-xylene vapors
on untreated and salt-treated Oldsmar sand are presented in Figure 3-1. Net
retention volumes of p-xylene on untreated Oldsmar sand were larger than those
of salt-treated soil, indicating greater solute retention. Adsorption in the Henry’s
Law region, characterized by highly symmetric peaks and net retention volumes
independent of sample size, was not attained for untreated Oldsmar sand, even
at p-xylene partial pressures of 2.5 X 10'3 mm Hg. In contrast, the salt-treated
Oldsmar sand exhibited Henry’s region adsorption at a net retention volume of
approximately 5.2 mL. As greater quantities of p-xylene were injected, the net
retention volume decreased until the peaks became asymmetric, at which point the
net retention volume began to increase. Although not shown here, the position of
the leading edge of the asymmetric peaks was similar, indicating that adsorption
equilibrium was attained (Dorris and Gray, 1981). The connection of peak maxima

P (mm Hg) P (mm Hg)
7
59
Figure 3-1. Chromatographic peak maxima at room temperature (=24°C) for p-
xylene vapor on (a) untreated Oldsmar soil and (b) salt-treated
Oldsmar soil.

60
formed a chromatographic envelope which was integrated by equation (3-3). The
resulting p-xylene adsorption isotherms are presented in Figure 3-2.
The adsorption of p-xylene on untreated Oldsmar sand yielded a Type-ll
isotherm, indicative of multilayer formation. A similar isotherm was obtained for
the salt-treated sand, although the adsorption capacity was reduced. These data
have yet to be confirmed by batch techniques; however, p-xylene adsorption on
250-425 pm Oldsmar sand measured by the GC and flow-equilibration methods
were in close agreement (R. D. Rhue, 1990, personal communication).
The effect of the salt treatments on p-xylene adsorption by Webster soil was
also studied using the flow equilibration apparatus described in Chapter 2 (Figure
3-3). Webster soil and Webster soil treated with hydrogen peroxide (Webster HP)
was extracted with methanol containing CaCI2 to measure water and p-xylene
sorption. Following methanol extraction, the Webster soil and Webster HP
contained 12.01 (±0.65) and 15.18 (±0.44) mg CaCl^g, respectively. Subsequent
adsorption experiments indicated that in the presence of salt p-xylene vapor
adsorption was reduced by 6.95 and 5.98 mg/g on Webster HP and Webster soil,
respectively. These data were in aggreement with the observed decrease in the
adsorptive capacity of Oldsmar sand following a salt treatment, measured by the
eluted-pulse method. From a mechanistic perspective, the salt may have coated
the adsorbent surface or reduced the surface charge, such that the magnitude of
adsorbate-adsorbent interactions was decreased.

0.01
0.005
0
â–  untreated
A salt-treated
0.2 0.3 0.4
p-Xylene (P/P0)
0.5
0.6
Figure 3-2. Adsorption isotherms for p-xylene vapor on untreated and salt-treated Oldsmar soil.

S (mg/g) S (mg/g)
62
"W i 1 - ... i 1 i I _ i
0 0.2 0.4 0.6 0.8 1
p-Xylene (P/F^,)
Figure 3-3. Adsorption of p-xylene vapors on Webster soil and Webster HP at
(a) 0% RH and (b) 90% RH.

63
Adsorption on Hydrated Oldsmar Sand
The net retention volume of p-xylene injected onto 90-cm columns packed
with Oldsmar sand decreased from approximately 297 mL to less than 8 mL when
the RH was increased to 90%. This reduction was indicative of the effect of water
on the retention of p-xylene vapors. Net retention volumes of p-xylene on salt-
treated Oldsmar sand at 90% RH, and on untreated Oldsmar sand at 90 and 98%
RH are presented in Figure 3-4. Henry’s region adsorption occurred at smaller
retention volumes, and for greater p-xylene partial pressures, than under
anhydrous conditions. In addition, the value of VN increased continuously, except
in the Henry’s Law region, which is characteristic of adsorption yielding Type-lll
isotherms (Dorris and Gray, 1981). At N2 flow rates of 0.42 and 0.33 ml_/s, the p-
xylene net retention volumes were similar, demonstrating the internal consistency
of the eluted-pulse method. Adsorption isotherms obtained from chromatographic
envelopes of these data are presented in Figure 3-5.
The presence of water not only precipitated a shift from Type-ll to Type-Ill
adsorption isotherms, but also resulted in a substantial reduction in p-xylene
adsorption. These findings are consistent with data reported in Chapter 2 for p-
xylene sorption on silica gel and kaolin at 67% RH, and on Webster soil and
Webster HP at 90% RH. At 98% RH an additional reduction in p-xylene
adsorption on Oldsmar sand was observed. These data suggest that sorbent
surface was not completely covered with water or that the surface continued to
exert an effect on adsorption, even though the RH of the carrier gas at the column

P (mm Hg) P (mm Hg)
64
5
4
3
2
0
4 6
VN (ml)
8
10
Figure 3-4. Chromatographic peak maxima at room temperature (= 24°C) for
p-xylene vapor on (a) salt-treated Oldsmar soil at 90% RH and (b)
untreated Oldsmar soil at 90 and 98% RH.

S (mg/g)
Figure 3-5. Adsorption isotherm for p-xylene vapor on salt-treated Oldsmar soil at 90% RH, and salt-treated Oldsmar
soil at 90 and 98% RH.
U1

66
inlet was 90%. Subsequent measurements revealed that inlet relative humidities
of 90 and 98% corresponded to relative humidities at the column outlet of 60 and
70%, respectively. Since the back pressure measured at the column inlet ranged
from only 1.04 to 1.07 atm, it was unlikely that the RH drop was due solely to
pressure gradients. Apparently, the 8-hour equilibration period was not sufficient
to completely hydrate the support. Future experiments will be conducted after
equilibrating the columns for several days at 90% RH.
The presence of salt also reduced p-xylene adsorption on Oldsmar sand,
which was consistent with batch data obtained for the sorption of p-xylene vapors
on Webster soil and Webster HP at 90% RH (Figure 3-3b). Based on water
adsorption data, the concentration of CaCI2 in adsorbed water films of the Webster
soils was approximately 1.0 M. To further investigate the adsorption at the gas-
liquid interface, the surface tension of 1.0 M CaCI2 exposed to p-xylene vapors
was measured by the drop-weight method, as described in Chapter 2. These data
were expressed as surface pressure (7t), which is equivalent to the difference
between the surface tension of the pure solution (y0) and the film-covered surface
(y) (Figure 3-6). The surface excess (T) can be calculated in the same manner
as described in Chapter 2 by simply replacing yin equation (2-7) with n (Blank and
Ottewill, 1964). However, the data presented in Figure 3-6 indicated that the
surface excess calculated for 1.0 M CaCI2 and deionized water would be identical.
This finding was consistent with the data of Blank and Ottewill (1964), who
reported that the surface excess of benzene, toluene, and o-xylene on 0.1 M NaCI
was similar to that obtained using distilled water. Thus, the surface tension

6
â–  DI Water
A 1.0MCaCI2
A
3 4 5
P (mm Hg)
J I
6 7 8
Figure 3-6. Surface pressure of deionized water and 1.0 M CaCI2 exposed to p-xylene vapors at room temperature
(=24°C).
O)
-n!

68
measurements suggested that the presence of salt would have no effect on the
adsorption of p-xylene at the gas-liquid interface.
Summary
The measurement of vapor-phase adsorption on soil materials by batch
techniques is typically an arduous task, requiring several time-consuming
experiments in order to obtain an adsorption isotherm. In contrast, gas
chromatography can be efficiently employed under a range of temperature and
moisture regimes. Vapor-phase adsorption of p-xylene on Oldsmar sand was
measured by the eluted-pulse method of Dorris and Gray (1981). Type-ll
isotherms obtained for p-xylene adsorption on anhydrous Oldsmar sand were in
agreement with preliminary batch data. At high RH, adsorption isotherms shifted
from Type-ll to Type-Ill, and the magnitude of p-xylene adsorption was reduced.
A similar effect has been observed for the sorption of several organic vapors on
hydrated soils (Call, 1957; Chiou and Shoup, 1985; Rhue et al., 1989). However,
some difficulty was encountered at high RH, and it is recommended that the
columns be equilibrated at 90% RH for several days. Additional experiments will
be conducted at high RH, and batch experiments are planned to further verify GC
data.
Salt treatments resulted in decreased p-xylene adsorption on anhydrous and
hydrated Oldsmar sand. These data were consistent with batch studies of p-
xylene adsorption on Webster soil and Webster HP exposed to CaCI2, and suggest

69
that vapor-phase sorption will be significantly reduced in salt-effected soils. Under
anhydrous conditions, the reduced adsorption capacity of salt-treated Oldsmar
sand may have resulted from the formation of salt coatings on the sorbent surface.
In Chapter 2 it was postulated that sorption on hydrated sorbents occurred by (1)
partitioning into OC, (2) dissolution into adsorbed water films, (3) adsorption at the
gas-liquid interface. Given the low solubility of p-xylene in water and the relatively
low OC content of Oldsmar sand it is unlikely that any alteration of these
components by salt would significantly effect adsorption. Thus, it was postulated
that the salt-treatment reduced the adsorptive capacity of the gas-liquid interface.
However, the surface concentrations of p-xylene on water and 1 M CaCI2
calculated from measurements of the change in surface tension of deionized water
and 1 M CaCI2 exposed to p-xylene vapors were identical. This finding was
somewhat puzzling, and prompted a reformulation of the Gibbs adsorption
equation to account for three components (i.e., p-xylene, CaCI2, and water). If the
surface excess of water is assumed to be constant, the Gibbs equation can be
expressed as:
1 dy dlna2
r, = r2 (3-4)
RT dina! dina,
where T, and r2 are the surface concentrations of p-xylene and CaCI2 (mol/cm2),
respectively, a, and a2 are the activities of p-xylene and CaCI2, respectively, R is
the gas constant, and T is the temperature. This equation indicates that if CaCI2
moved to the gas-liquid interface, it could compensate for any reduction in the

70
surface tension arising from the accumulation of p-xylene at the gas-liquid
interface. Unfortunately, the surface concentration of CaCI2 (r2) was unknown, and
thus it was impossible to calculate the surface concentration of p-xylene. This line
of reasoning may explain why no difference was observed in the change in surface
tension of water and CaCI2 exposed to p-xylene vapors.
Additional studies indicated that the utility of GC techniques under
anhydrous conditions may be limited to supports of low sorptive capacity, p-
Xylene vapors injected on coated sands and kaolin were strongly adsorbed and
eluted solute peaks were not discernable. Planned experiments will focus on the
dilution of such sorbents, by either adding low-sorptive-capacity materials to the
column or by coating sands with clay films. It should be recognized that batch
studies are difficult to conduct for materials of low sorptive capacity and, thus, GC
techniques are complimentary in this regard.

CHAPTER 4
COMPETITIVE ADSORPTION OF P-XYLENE AND WATER VAPORS
ON CA-, NA-, AND LI-SATURATED KAOLIN
Introduction
Relative humidity (RH) or soil moisture content is one of the most important
factors influencing the sorption of volatile organic chemicals (VOCs) in the
unsaturated zone. Previous studies have demonstrated that water effectively
competes with nonpolar organic vapors for mineral surfaces, resulting in the
suppression of VOC sorption on soils and clay minerals. (Call, 1957; Chiou and
Shoup, 1985; Rhue et al., 1989). This phenomenon has been attributed to the
relatively strong interactions between water and mineral surfaces (Chiou and
Shoup, 1985; Valsaraj and Thibodeaux, 1988), which may result from cation-dipole
interactions, hydrogen bonding, and weak charge transfer interactions (Burchill et
al., 1981). Of particular interest is cation hydration, the energy of which has been
directly related to the degree of water adsorption on kaolinite (Keenan et al., 1951;
Jurinak, 1963). However, the effect of exchangeable cations on the competitive
adsorption of water and organic vapors is largely unknown. In addition, models
capable of predicting vapor-phase adsorption from binary systems have rarely
been tested due, primarily, to the lack of suitable data.
71

72
Cation saturation has been shown to indirectly effect the competitive
adsorption of water and ethylene dibromide (EDB) vapors by altering the surface
area of montmorillonite. Following exposure to P205, Jurinak (1957) observed that
water retention by Mg-, Ca-, and Na-saturated montmorillonite was directly related
to the hydration energy of the exchangeable cation. The retained water expanded
the interlayer space, and thus Mg-montmorillonite exhibited the greatest surface
area and EDB adsorption, followed by Ca- and Na-montmorillonite. A similar
phenomenon was noted by Call (1957), who reported that EDB sorption on Ca-
saturated montmorillonite was greater at 5,10 and 20% relative humidity (RH) than
at 0% RH (Figure 4-1). This effect was attributed to expansion of the clay lattice,
which increased from 3Á at 0% RH to 9Á at 5-10% RH. Apparently, EDB
molecules were only able to enter the interlayer space after the clay lattice had
expanded to 9Á. However, as the number of water molecules continued to
increase, competition between EDB and water became greater, resulting in the
suppression of EDB adsorption.
Although these data clearly demonstrate that cation saturation influenced
EDB adsorption on montmorillonite, the effect of specific interactions between
water and exchangeable cations was obscured by changes in surface area. In
addition, Jurinak (1957) reported that montmorillonite forms porous aggregates or
floccules during dehydration. This process, which has been observed by electron
micrography (Grim, 1953), restricted the adsorption of EDB on Mg-, Ca-, and Na-
montmorillonite (Jurinak, 1957). In contrast, EDB adsorption on kaolinite occurred

S (mg/g)
0 0.2 0.4
EDB (P/PQ)
0.6
Figure 4-1. Vapor-phase adsorption of EDB on Ca-saturated montmorillonite at various RH (Call, 1957).
"J
CO

74
on free surfaces or in pores whose size was far greater than that of the EDB
molecule. Thus, kaolin appears to provide a surface absent of surface area and
porosity effects which complicated the interpretation of EDB adsorption on
montmorillonite.
Recently, Rhue et al. (1989) used a methanol extraction procedure to
simultaneously measure water and p-xylene adsorption on predominantly Na-
saturated kaolin. At low RHs and relatively high p-xylene vapors pressures, Rhue
et al. (1989) observed enhanced water adsorption based on comparisons between
measured and predicted data. The predicted values were calculated using a
modified Brunauer, Emmett, and Teller (BET) equation which accounted for two
adsorbate species. The purpose of this study was to determine if the preferential
adsorption of water could be attributed cation hydration effects. Initially, single¬
adsorbate isotherms were obtained for p-xylene and water vapor adsorption on
Ca-, Na-, and Li-kaolin. The linear form of BET equation was utilized to obtain the
monolayer adsorption capacity and value of C. These data were then used to
predict competitive adsorption of p-xylene and water vapors based on the two-
component BET equations of Hill (1946a, b) and Rhue et al. (1989).
Materials and Methods
Kaolinite Samples
Colloidal kaolin, obtained from Fisher Scientific Products (K-6, Lot# 731063),
used in this study was identical to that described in Chapter 2. The kaolin had a

75
cation exchange capacity (CEC) of 4.2 cmolc/kg at pH 5.5, and was predominantly
Na-saturated with trace amounts of Ca, Mg, and K (Rhue et al., 1989). Prior to
adsorption experiments, the kaolin was washed with 1 M NaAOc buffered to pH
4.11 with acetic acid to remove carbonates. Approximately 2.5 g of kaolin was
placed in individual polyethylene centrifuge tubes, to which 20 mL of 1 M NaAOc
was added. The samples were mixed until the kaolin was completely dispersed,
and separated by centrifugation at 2500 rpm for 5 minutes. When the pH of the
supernatant was less than 5.0, generally after one wash, the kaolin was washed
five times with 1 M NaCI to removed entrained NaAOc. The supernatant was
analyzed for Ca and Mg using a Perkin Elmer model 603 atomic absorption
spectrophotometer. If either Ca or Mg was detected in the supernatant, the
NaAOc treatment was repeated, otherwise the kaolin was saturated with the
desired cation.
Ca-, Na-, and Li-saturated Fisher kaolin was prepared by washing the kaolin
with the appropriate 1 M chloride salt until no other cations could be detected in
the supernatant by atomic absorption spectroscopy. Following cation saturation,
the kaolin was repeatedly washed with 95% ethanol until a negative chloride test
was achieved using AgN03. The kaolin was air-dried at room temperature and
ground with an agate motar and pestal. Prior to adsorption experiments, the kaolin
was oven-dried at approximately 120°C for at least two weeks. The N2 surface
area of Ca, Na, and Li-kaolin was 15.8, 15.6, and 15.5 m2/g, respectively, prior to

76
heating, and 15.5, 15.4, and 15.2 m2/g, respectively, after heating (Advanced
Materials Research Center, University of Florida).
Vapor-Phase Adsorption Experiments
Single and mixed-vapor adsorption experiments were conducted at 24°C
using the flow-equilibration apparatus described in Chapter 2. The concentration
of water in the flow stream was determined by Karl Fisher (KF) titration.
Approximately 20 mL of CaCI2-saturated methanol was added to two 40 mL glass
centrifuge tubes, and pretitrated to the visual KF endpoint. The tubes were placed
on the flow stream in series, via hypodermic needles, for a measured time period.
The solutions were then removed from the flow stream and immediately retitrated.
A small amount of titer was consistently needed to retitrate the second trap in the
series, which was attributed to loss of volatile compounds from the KF reagent
(Rhue et al., 1988). Therefore, the volume of titer used for the second trap was
subtracted from that of the first trap, and the corrected value was used to calculate
the amount of water trapped in the methanol. p-Xylene vapors were trapped by
bubbling the flow stream through two glass centrifuge tubes containing methanol,
as described in Chapter 2.
Single-adsorbate isotherms were determined for p-xylene and water vapors
at relative vapor pressures ranging from 0.1 to 0.5. The competitive adsorption of
p-xylene and water vapors was measured at 10 and 20% RH. Adsorbed
concentrations of p-xylene and water vapors from single- and binary- sórbate
systems were measured following the procedures described previously.

77
Preliminary Adsorption Experiment
A preliminary study was conducted to test the effect of cation saturation on
the competitive adsorption of water and p-xylene vapors on kaolin. A portion of
the original Fisher kaolin was saturated with Li by washing the kaolin with 1 M LiCI.
Excess salt was removed by repeatedly washing the kaolin with 95% ethanol until
a negative chloride test was achieved with AgN03. The adsorption of water and
p-xylene vapors on Na- and Li-saturated kaolin was measured for single- and
binary-sorbate systems as described previously.
Results and Discussion
Preliminary Adsorption Experiment
Water adsorption on Na-kaolin was in agreement with the data obtained by
Rhue et al. (1989), and was significantly greater than that on Li-kaolin (Figure 4-
2a). In contrast, p-xylene adsorption on Na- and Li-kaolin was similar (Figure 4-
2b), suggesting that exchangeable cations had only a minor effect on p-xylene
adsorption. The adsorption data were fit by a least squares procedure to the linear
form of the BET equation,
P/P0 1 (C-1)P/P0
= + (4-1)
S(1-P/P0) SmC SmC
where Sm is the monolayer adsorption capacity (mg/g), and C is a parameter
related to the heat of adsorption. Estimated values of Sm and C are presented in
Table 4-1. BET parameters for Na-kaolin were calculated using a combined data

S (mg/g) S (mg/g)
Water (P/P0)
p-Xylene (P/P0)
Figure 4-2. Vapor-phase adsorption of (a) water and (b) p-xylene on Na- and
Li-saturated Fisher kaolin at 24°C.

79
Table 4-1. BET parameters for Na- and Li-kaolin calculated from single-
sorbate isotherm data (Rhue et al., 1989).
Sorbent
Sórbate
sm
C
r2
P/P0
Range Used
-mg/g-
Na-kaolin
p-xylene
4.5
14
0.969
0.065-0.424
water
4.2
20
0.988
0.056-0.481
Li-kaolin
p-xylene
4.4
9
0.997
0.074-0.365
water
2.6
52
0.997
0.112-0.289

80
set, since the values obtained for water and p-xylene adsorption were similar to
those reported by Rhue et al. (1989).
The monolayer adsorption capacity of water on Li-kaolin was considerably
less than that on Na-kaolin. It has been proposed that exchangeable Na on kaolin
hydrates readily; whereas, exchangeable Li does not hydrate, despite the fact that
Li has a slightly greater hydration energy than Na (Keenan et al., 1951).
Apparently, Li ions form inner-sphere complexes or are strongly adsorbed on
kaolin, such that hydration does not occur even at high RHs (Keenan et al., 1951;
Martin, 1959). If the amount of water adsorbed by Li-kaolin is considered to be
independent of cation hydration effects, then the difference between the monolayer
adsorption capacities of Na- and Li-kaolin provides an estimate of the amount of
water hydrating Na. Based on this assumption, approximately 1.8 molecules of
water were associated with each exchangeable Na ion, which was consistent with
the range of values (1.5 to 1.8 molecules of water) reported by Keenan et al.
(1951) for Na-, K-, and Rb-saturated kaolinite.
The binary-vapor experiment was conducted at p-xylene and water relative
vapor pressures of 0.395 and 0.095, respectively. The amount of water and p-
xylene adsorbed on Na-kaolin in this experiment was 2.46 (±0.00) and 6.56 (±0.05)
mg/g, respectively. In contrast, Li-kaolin adsorbed 2.06 (±0.01) and 6.04 (±0.05)
mg/g of water and p-xylene, respectively. Rhue et al. (1989) modified the BET
equation to account for the competitive adsorption of two sórbate species. The

81
total adsorbed mass of sórbate "a" on the surface (Ma, mg/g) can be calculated
using the following equation:
Ma = oaCaS0[Xa/(1-Xa)2] (4-2)
where a is the mass of compound "a" occupying a unit area of surface (mg/m2),
Ca is the BET parameter related to heat of adsorption calculated from single-vapor
adsorption isotherm for sórbate "a", Xa is the relative vapor pressures of sórbate
"a", and S0 is the area of exposed surface area per unit mass of adsorbent (m2/g).
The a values for water and p-xylene were calculated to be 0.31 and 0.50 mg/m2,
respectively, based on the following equation:
a = 1.091 (MW/am A) (4-3)
where MW is the molecular weight, am is the cross-sectional area of sórbate
determined in Chapter 2, and A is Avogadro’s number (Rhue et al., 1989). The
mass of sórbate "b" (Mb) can be calculated in a similar manner. Unfortunately, the
mass of either adsorbate on the surface cannot be calculated because S0 is
unknown in the binary vapor system (Rhue et al., 1989). However, the fraction of
adsorbate "a" (Fa) on the surface can be calculated using the following equation:
Ma
Fa = • (4-4)
Ma + Mb
The calculated versus the measured fraction of water adsorbed on Na-kaolin (Na)
and Li-kaolin (Li) are presented in Figure 4-3. These data indicate that Na-kaolin
adsorbed considerably more water than was predicted by the two-component BET
equation. The fraction of water adsorbed on Na-kaolin was previously reported by

Calculated Fraction
1.0
0.8
0.6
0.4
0.2
0
0 0.2 0.4 0.6 0.8 1.0
Measured Fraction
/i
/
/
/
/
/
/
/
/
Na-kaolin, Rhue
et al. (1989)
/
/
/
/
Na
Figure 4-3. Measured fraction of water adsorbed on Na- (Na) and Li-saturated (Li) Fisher kaolin versus the fraction
predicted using the multi-sorbate BET equation of Rhue et al. (1989).
CD
ro

83
Rhue et al. (1989), and is denoted by (â– ) in Figure 4-3. In contrast, the measured
and calculated fractions of water adsorbed on Li-kaolin were almost identical.
These data suggest that the preferential adsorption of water relative to p-xylene
at low water fractions (below 0.4) was due to Na hydration.
One possible explanation for the difference between the measured and
calculated fraction of water adsorbed on Na-kaolin was the similarity in the values
of C estimated from water and p-xylene single-sorbate isotherms. Since the
values of C were essentially the same, the two-component BET equation of Rhue
et al. (1989) did not account for preferential adsorption of water over p-xylene on
Na-kaolin. In contrast, the values of C for water and p-xylene adsorption on Li-
kaolin were 52 and 9, respectively. The large value of C for water adsorption on
Li-kaolin was not anticipated, because Li-kaolin is generally considered to
represent a mineral surface free of cation hydration effects. If a C value of 20 was
used to estimate the mass of water adsorbed on Li-kaolin, then the calculated
fraction of water adsorbed on Li-kaolin would be 0.12 rather than 0.28. Thus, Li-
kaolin would also have exhibited a small degree of preferential water adsorption
if the measured value of C had been in the range expected for water adsorption
on Fisher kaolin.
Vapor-Phase Adsorption on Ca-, Na-, and Li-kaolin
Isotherms for the adsorption of water vapor on Ca-, Na-, and Li-kaolin are
presented in Figure 4-4a. Ca-kaolin adsorbed the greatest amount of water at all
RHs studied, followed by Na- and Li-kaolin. The monolayer adsorption capacities

S (mg/g) S (mg/g)
84
Figure 4-4. Vapor-phase adsorption of (a) water and (b) p-xylene on Ca-, Na-,
and Li-saturated Fisher kaolin at 24°C.

85
of water on Ca-, Na-, and Li-kaolin derived from the single-sórbate adsorption data
were 5.0, 3.9, and 2.8 mg/g, respectively (Table 4-2). These data indicate that
cation saturation had a considerable effect on water adsorption, and were similar
to values of Sm obtained for Na- and Li-kaolin in the preliminary study. The value
of C for water adsorption on Li-kaolin (12) was less than that measured previously,
but was now within the range expected for water adsorption on Fisher kaolin.
Thus, the value of C was subject to uncertainty, even when the value of Sm derived
from the same adsorption data appeared to give a reasonable estimate of the
monolayer adsorption capacity. The reasons for uncertainty in the value of C are
unclear, but the evaluation of numerous adsorption isotherms indicates that small
differences in adsorption data can result in substantial changes in the value of C,
particularly if the isotherm consists of only a few data points.
In general, Ca-kaolin adsorbed the largest amount of p-xylene, followed by
Na- and Li-kaolin (Figure 4-4b). However, p-xylene adsorption on Na-kaolin was
slightly greater than that on Ca-kaolin at relative vapors pressures below 0.05 and
above 0.5. The p-xylene monolayer adsorption capacities of Ca-, Na-, and Li-
kaolin were 6.5, 5.5, and 5.0 mg/g, respectively (Table 4-2). These data indicate
that cation saturation influenced the adsorption of p-xylene vapors, but the
similarity between the values of Sm indicates that the effect of cation saturation was
minimal. In order to compare the monolayer adsorption capacities for water and
p-xylene, the value of Sm was expressed as the amount of surface occupied by
sórbate molecules per gram of kaolin (m2/g), as described in Chapter 2 (Table 4-

86
Table 4-2. BET parameters for Ca-, Na- and Li-kaolin calculated from single-
sórbate isotherm data.
P/P0
Sorbent
Sórbate
sm
C
r2
SmA
Range Used
-mg/g-
-m2/g-
Ca-kaolin
p-xylene
6.5
12
0.999
14.0
0.045-0.301
water
5.0
17
0.993
17.6
0.126-0.245
Na-kaolin
p-xylene
5.5
16
0.998
11.9
0.044-0.301
water
3.9
12
0.978
13.7
0.126-0.241
Li-kaolin
p-xylene
5.0
10
0.997
10.8
0.047-0.303
water
2.8
12
0.994
9.8
0.115-0.241

87
2). The BET surface areas determined in this manner indicate that when the
molecular weight and surface packing are taken into consideration, the p-xylene
monolayer adsorption capacities were less than those measured for water. In
addition, the effect of the saturating cation and CEC the BET surface areas were
also smaller than that observed for water.
In order to utilize the method of Keenan et al. (1951) for estimating the
amount of water and p-xylene associated with exchangeable cations, the CEC of
kaolin used in the adsorption experiments was measured. The CEC of oven-dried
Ca-, Na-, and Li-kaolin at pH 4.11 was 3.9, 3.5, and 1.9 cmolj/kg, respectively. To
confirm these values, the CEC of the kaolin used in the preliminary adsorption
study was also measured. At pH 5.5, the CEC of oven-dried Na- and Li-kaolin
was 4.23 and 2.19 cmolj/kg, respectively. Apparently, the heat-treatment resulted
in a sizable reduction in the CEC of Li-kaolin. These findings suggest that heat-
treated Li-kaolin represents a mineral surface of reduced charge, rather than a
surface free of cation hydration effects as proposed by Keenan et al. (1951) and
Martin (1959). Therefore, the use of Li-kaolin as a reference mineral surface may
not be valid, and could result in incorrect estimates of the amount of water
associated with each exchangeable cation.
Competitive Adsorption of p-Xylene and Water on Ca-, Na-, and Li-kaolin
Data for the adsorption of p-xylene vapors on Ca-, Na-, and Li-kaolin at 0,
10, and 20% RH are presented in Figure 4-5. An increase in RH from 0% to 10
and 20% had a relatively minor effect on p-xylene adsorption regardless of the

S (mg/g) S (mg/g) S (mg/g)
Figure 4-5. Vapor-phase adsorption of p-xylene on (a) Ca-, (b) Na-, and (c) Li-
saturated Fisher kaolin at 0, 10, and 20% RH.

89
cation saturation. Rhue et al. (1989) reported that sizable reductions in p-xylene
adsorption were not observed until the RH was greater than that required to attain
monolayer water coverage, as estimated from the single-sórbate BET equation.
The RHs corresponding to monolayer coverage of water on Ca-, Na-, and Li-kaolin
were 20, 22, and 22%. Thus, the slightly greater displacement of p-xylene from
Ca-kaolin was consistent with the fact that a lower RH was required to achieve
monolayer coverage on Ca-kaolin than on Na- and Li-kaolin.
The measured fraction of water adsorbed on Ca-, Na-, and Li-kaolin, versus
the fraction calculated from the two-component BET equation of Rhue et al.
(1989), is presented in Figure 4-6a. Below 0.4, enhanced water adsorption was
exhibited by all exchangeable cations studied, but was less for Li-kaolin than Ca-
and Na-kaolin. The degree of preferential water adsorption was consistent with
the CEC values previously reported for oven-dried Ca-, Na-, and Li-kaolin. These
data further support the contention that Li-kaolin represents a surface of reduced
charge.
The fraction of water adsorbed on kaolin was also predicted using the two-
component BET equation proposed by Hill (1946a, 1946b). If the sórbate is
assumed to adsorb only onto the mineral surface or sorbed layers of itself, Hill’s
equation can be simplified to:
Sa Xa[Ca(1-Xb) + XbCJ
Sam (1 -Xa-Xb)[1 +Xa(Ca-1) + Xb(Cb-1)]
(4-5)
where Sa is the amount of sórbate "a" adsorbed (mg/g), Sam is the monolayer

Calculated Fraction Calculated Fraction
90
0.2 0.4 0.6
Measured Fraction
Figure 4-6. Measured fraction of water adsorbed on Ca-, Na-, and Li-
saturated Fisher kaolin versus the fraction calculated using the
two-component BET equation of (a) Rhue et al. (1989), and (b)
Hill (1946a, b).

91
adsorption capacity of sórbate "a" (mg/g), Xa and Xb are the relative vapor
pressures of sórbate "a" and "b", respectively, and Ca and Cb are the BET
parameters related to the heat of adsorption of sórbate "a" and "b”, respectively.
The predicted adsorption of water and p-xylene on Ca-, Na-, and Li-kaolin is
presented in Table 4-3. The adsorption of water and p-xylene on kaolin was well
predicted, regardless of the cation saturation. However, the predicted values for
Li-kaolin were more accurate than those estimated for Ca- and Na-kaolin.
The measured fraction of water adsorbed on Ca-, Na-, and Li-kaolin versus
the fraction predicted using the two-component BET equation of Hill (1946a,
1946b) are presented in Figure 4-6b. The measured and calculated fractions of
water adsorbed on Li-kaolin were similar for all mixed-vapor systems studied. At
fraction less than 0.3, Ca- and Na-kaolin exhibited enhanced water adsorption.
However, the magnitude of the preferential water adsorption observed here was
far less than that obtained using the two-component BET equation of Rhue et al.
(1989). This was primarily due to the fact that Hill’s two-component BET equation
incorporates the value of Sm, determined from single-sórbate adsorption isotherms.
Thus, the adsorption of water and p-xylene predicted by Hill’s equation is based,
in part, on the monolayer adsorption capacity of each sorbent. In contrast, the
equation of Rhue et al. (1989) does not include a monolayer adsorption capacity
term. Therefore, the value of C must be related to the cation hydration energy in
order for the fraction of water calculated using the two-component BET equation
to reflect differences in the monolayer adsorption capacity due to cation saturation.

92
Table 4-3. Comparison of measured p-xylene and water adsorption on Ca-,
Na-, and Li-kaolin from mixed-vapor systems with values predicted
using the multi-sorbate BET equation of Hill (1946a, 1946b).
P/Po Measured Predicted
Sorbent Water PX Water PX Water PX
mg/g
Ca-kaolin
Na-kaolin
Li-kaolin
0.117
0.093
2.64
0.101
0.201
2.64
0.112
0.395
3.24
0.179
0.096
4.13
0.212
0.217
4.18
0.184
0.403
3.42
0.117
0.093
2.31
0.101
0.201
2.38
0.112
0.395
2.27
0.179
0.096
3.56
0.212
0.217
3.09
0.218
0.410
3.48
0.117
0.093
2.02
0.101
0.201
1.56
0.112
0.395
1.24
0.179
0.096
2.93
0.212
0.217
2.72
0.218
0.410
2.34
3.58
3.06
2.51
5.72
2.34
4.88
8.00
2.33
9.17
3.22
4.07
2.28
5.14
4.26
4.79
7.89
3.91
9.80
3.40
1.93
2.75
5.42
1.42
4.84
7.94
1.47
8.45
3.32
2.71
2.54
5.33
2.82
4.84
7.89
3.28
9.67
2.57
1.56
1.91
4.09
1.21
3.71
6.85
1.23
7.04
2.39
2.13
1.77
3.99
2.28
3.72
6.97
2.61
8.08

93
However, Keenan et al. (1951) noted that the value of C, estimated from water
adsorption on a series of alkali-saturated kaolin samples, ranged from 10 to 40 and
showed no correlation with the properties of the exchange cation.
The utility of the two-component BET equation of Rhue et al. (1989) was
also limited by uncertainty in the value of C. As noted previously, the C parameter
obtained for Li-kaolin varied considerably even though the value of Sm appeared
to be reasonable. This type of behavior was also observed for Na-kaolin. The
calculated fraction of water adsorbed on Na-kaolin using the two-component BET
equation of Rhue et al. (1989) at different values of C for water (CJ is presented
in Figure 4-7. For a p-xylene C value (Cpx) of 16, the calculated fraction of water
become larger as the value of Cw was increased. The value of Cw (12) determined
from the single-sorbate isotherm was consistent with the value required for the
calculated and measured fractions of water to agree for fractions greater than 0.4.
When the value of Cpx was decreased, the calculated fraction of water shifted to
larger values, and separation between the curves increased (Figure 4-7b). These
data indicate that the calculated fraction of adsorbed water predicted by the two-
component BET equation of Rhue et al. (1989) was extremely sensitive to changes
in the value of C for both water and p-xylene.
Summary
The data presented here indicate that vapor-phase adsorption of water on
kaolin was a function of both the saturating cation and CEC of the kaolin. The

Calculated Fraction Calculated Fraction
94
Figure 4-7. The effect of different values of C for water (CJ on the fraction of
water adsorbed on Na-kaolin using the two-component BET
equation of Rhue et al. (1989) at values of C for p-xylene of (a)
16, and (b) 10.

95
amount of water adsorbed on Ca- and Na-kaolin was directly related to the
hydration energy of the exchangeable cation. In contrast, Li-kaolin adsorbed
considerably less water than Na-kaolin even though the hydration energy of Li is
slightly greater than that of Na. This phenomenon has been reported previously,
and was attributed to the absence of Li hydration (Keenan et al., 1951; Martin,
1959). However, Li-kaolin exhibited a 50% reduction in CEC after drying at 120°C,
suggesting that the reduced water adsorption observed for Li-kaolin was due to a
decrease in CEC. Thus, Li-kaolin may represent a surface of reduced charge,
rather than a reference surface, free of cation hydration effects. The specific
mechanisms responsible for charge reduction, and its effect on the hydration
properties of Li-kaolin will be addressed in Chapter 5.
The effect of the saturating cation and CEC of kaolin on p-xylene adsorption
were similar, but to a lesser extent, than that observed for water. These data
suggest that specific interactions occurred between p-xylene molecules and
exchangeable cations, which has not been reported previously. It was
hypothesized that vapor-phase adsorption of p-xylene on kaolin can be
characterized by weak interactions at cation exchange sites and physical
adsorption (e.g., dipole-dipole interactions) on the remaining mineral surface.
Since the energy of adsorption would be similar at these locations, p-xylene
adsorption may approach "theoretical" monolayer coverage prior to the onset of
multilayer formation. In contrast, water adsorption at low RHs is likely to be
concentrated at cation exchange sites, resulting in the formation of discrete

96
patches of water. As the RH increases, multilayer formation would occur on
hydrated cations along with adsorption on the remaining exposed mineral surface.
Increasing the RH from 0% to 10 and 20% resulted in small but successive
decreases in p-xylene adsorption on Ca-, Na-, and Li-kaolin. Although competition
between p-xylene and water vapors was evident at low RHs, kaolin exhibited a
sizable capacity to adsorb p-xylene. These data suggest that exposed mineral
surfaces were available for p-xylene adsorption, even at RHs approaching those
required to attain monolayer water coverages. This rationale is consistent with the
proposed existence of discrete regions of multilayer water adsorption and exposed
mineral surfaces on kaolin at low surface coverages. Measured fractions of water
adsorbed on Ca-, Na-, and Li-kaolin deviated from those calculated by the two-
component BET equation of Rhue et al. (1989) at fractions less than 0.4. The
observed difference could be attributed, in part, to the similarity in the values of C
determined from p-xylene and water adsorption isotherms. In addition, uncertainty
in the value of C limited the utility of the two-component BET equation of Rhue et
al. (1989). In contrast, the two-component BET equation of Hill (1946a, b)
incorporates both the Sm and C parameters determined from single-sorbate
adsorption isotherms using the BET equation. Nevertheless, a small degree of
preferential water adsorption was observed on Ca- and Na-kaolin at water fractions
less than 0.3, indicating that at low RH and relatively high p-xylene vapor pressure
the adsorption of water was greater than could be accounted for based on single-
sorbate adsorption isotherms. Water and p-xylene adsorption on Ca-, Na-, and Li-

97
kaolin predicted from Hill’s multi-sorbate BET equation deviated, on the average,
by a factor of 0.25 from the measured adsorption. These data suggest that the
two-component equation of Hill (1946a, 1946b) warrants further investigation as
a tool to predict the competitive adsorption of water and organic vapors at low
surface coverages.

CHAPTER 5
THE EFFECT OF HEAT TREATMENTS ON THE TOTAL CHARGE AND
EXCHANGEABLE CATIONS OF CA-, NA-, AND LI-SATURATED KAOLIN
Introduction
The effect of exchangeable Ions on the adsorption and desorption of water
vapor by kaolin has been studied in great detail (Jurinak, 1961, 1963; Jurinak and
Volman, 1961a, 1961b; Keenan et al., 1951; Martin, 1959). Of particular interest
is the Li ion, which has been shown to have no apparent effect on water
adsorption. Martin (1959) reported that Li-saturated kaolin did not exhibit
hysteresis due to cation hydration effects at relative humidities below 80%;
whereas, Ca-, Mg-, and Na-saturated kaolin yielded hysteretic adsorption-
desorption isotherms. In addition, kaolin saturated with Li has been found to
adsorb less water than kaolin saturated with Na, despite the fact that Li has a
slightly greater hydration energy than Na (Keenan et al., 1951). Based on these
data, Li-saturated kaolin is generally considered to represent a mineral surface
independent of cation hydration effects and has frequently been utilized as a
reference surface in the study of water and organic vapor sorption on kaolin
(Jurinak, 1963; Jurinak and Volman, 1961a; Rhue et al., 1989).
Although published data present strong evidence for the absence of Li
hydration, the mechanisms responsible for such behavior have not been clearly
98

99
identified. Keenan et al. (1951) hypothesized that Li ions fit into the tetrahedral
layer of kaolin such that hydration is sterically hindered by the outer oxygen atoms.
In contrast, Martin (1959) postulated that the hydration energy of Li was not
sufficient to overcome the specific adsorption energy of the ion for the clay
surface, and thus true ionic hydration did not occur. In both of these studies the
kaolin was dried at 70°C in a vacuum, which has been shown to be equivalent to
air-drying at 115°C (Keenan et al., 1951), prior to the adsorption experiments.
The effect of heating on the cation exchange capacity (CEC) of kaolin
saturated with Ca, Mg, Na, and Li was studied by Greene-Kelly (1955).
Interestingly, the CEC of Li-kaolin, as determined from NH4 exchange, was 50%
of the original level after heating to 100°C. The heat treatment had no apparent
effect on the CEC of Ca-, Mg-, and Na-kaolin. A reduction in NH4 exchange by
Li-kaolin after heating to 300°C was also reported by Cashen (1959). These data
suggest that the reason water adsorption on Li-saturated kaolin was less than that
of Na-saturated kaolin was actually due to a reduction in CEC. Jurinak (1961),
Keenan et al. (1951), and Martin (1959) failed to report the CEC of kaolin following
cation saturation and heat treatments, and were apparently unaware of possible
charge reductions upon heating.
Greene-Kelly (1955) also reported that heating substantially decreased the
the amount of Li that could be extracted from Li-kaolin using 1 N NH4AOc.
These data suggest that a portion of the Li ions were fixed within the kaolinite
structure. A similar phenomenon, the migration of Li ions into the clay lattice, has

100
been observed for montmorillonite and is commonly referred to as the Hofmann-
Klemen effect (Brindley and Ertem, 1971; Calvet and Prost, 1971; Glaser and
Mering, 1971; Greene-Kelly; 1953; Hofmann and Klemen, 1950; Jaynes and
Bigham, 1987; Lim and Jackson, 1986; Luca and Cardile, 1989; Luca et al., 1989;
Sposito et al., 1986). Two positions have been proposed for the location of
nonexchangeable Li ions in montmorillonite: (1) the bottom of the
pseudohexagonal cavities of the basal surface; and (2) vacant octahedral sites.
Calvet and Prost (1971), using infrared (IR) spectroscopy, found that only a
fraction of the nonexchangeable Li resides within the octahedral layer, the
remainder being located in the hexagonal cavities. These data were supported by
Luca and Cardile (1989), who reported that Fe+3 migrates into the
pseudohexagonal cavities, but not the vacant octahedral sites of dehydrated
montmorillonite based on electron spin resonance techniques. Although there
remains some controversy over the exact location of nonexchangeable Li ions, it
is clear that upon heating Li migrates into the montmorillonite structure.
The purpose of this study was to determine the effect of heating on the total
charge and exchangeable cations of Ca-, Na-, and Li-saturated kaolin. It was
hypothesized that Li migrates into kaolin upon heating, in a manner similar to that
reported for montmorillonite (i.e., the Hofmann-Klemen effect). Infrared
spectroscopy was utilized to infer the location of Li ions in heat-treated kaolin.
The effect of heat and vacuum treatments on the adsorption and desorption of
water vapor by kaolin was also studied.

101
Materials and Methods
Kaolinite Samples
The kaolinite samples studied were colloidal kaolin (K-6, Lot #731063),
obtained from Fisher Scientific Products, and KGa-1 kaolinite from Washington
County, Georgia, obtained from the Source Clays Repository of The Clay Minerals
Society. The reported CEC values for KGa-1 kaolinite range from 1.7 to 2.4
cmolc/kg (van Olphen and Fripiat, 1979). The KGa-1 kaolinite was considered to
be well-crystallized, with a N2 surface area of 10.05 ± 0.02 m2/g. The Fisher kaolin
had a slightly larger CEC (3.3 cmol^kg at pH 4.0) and was predominantly Na-
saturated with trace amounts of exchangeable Ca, Mg, and K (Rhue and Reve,
1990). Additional physical and chemical characteristics of Fisher kaolin are given
in Chapter 2.
X-Ray Diffraction Studies
Due to the lack of mineralogical data for Fisher kaolin, x-ray diffraction
(XRD) studies were undertaken to provide a preliminary mineralogical
characterization and to determine the relative degree of order in the mineral
structure. Oriented mounts of Fisher kaolin were prepared for XRD analysis by
depositing approximately 300 mg of kaolin from suspension onto a ceramic tile
under suction. The kaolin mounts were treated with 1 M MgClz and KCI, and
washed free of salts with deionized water. A 30% glycerol solution was applied
to the Mg-saturated samples. All mounts were scanned with a computer-controlled
XRD system operated at 2.0° 20 per minute using CuKa radiation. The XRD

102
analyses were performed at room temperature (= 24°C) and after overnight heating
at 110, 300, and 550°C.
Cation Exchange Capacity Experiments
Prior to cation saturation, Fisher kaolin was treated with 1 M NaAOc
buffered to pH 4.11 with acetic acid to remove carbonates. Homoionic samples
of Ca-, Na-, and Li-saturated Fisher kaolin were prepared following the procedure
described in Chapter 4. With the exception of the NaAOc treatment, the same
procedure was followed to saturate the KGa-1 kaolin with Ca, Na, and Li.
A preliminary experiment was conducted to determine the effect of heating
(130°C) on the CEC of Fisher kaolin saturated with Ca, Na, and Li. The amount
of saturating cation which remained exchangeable after 0, 2, 7, and 15 days of
exposure to heat was measured using a Mg(N03)2 extraction procedure.
Approximately 0.5 g of kaolin was placed in a 50 mL polyethylene centrifuge tube.
To each tube 10 mL of 0.5 M Mg(N03)2 was added, which was mixed until the
kaolin was completely dispersed, and separated by centrifugation at 2500 rpm for
5 minutes. The supernatant from five Mg(N03)2 washes was collected in a 100 mL
volumetric flask, which was brought to volume with deionized water. The
concentration of the appropriate cation (i.e., Ca, Na, Li) in the Mg(N03)2 extract
was measured by atomic absorption spectroscopy and expressed as cmolc/kg.
Aluminum was also measured in the Mg(N03)2 extracts of Na- and Li-saturated
kaolin on day 15.

103
After seven days of heating, the total charge of the Ca-, Na-, and Li-
saturated Fisher kaolin was determined by Ca-exchange. An additional 0.5 g
sample of kaolin was placed in a 50 mL polyethylene centrifuge tube. The kaolin
was washed five times with 20 mL of 1 M CaCI2, and excess salt was removed by
repeatedly washing the kaolin with 95% ethanol until a negative chloride test was
achieved using AgN03. Calcium was extracted with 0.5 M Mg(N03)2, following the
same procedure as described previously.
A second, more extensive study was initiated to determine the effect of
heating at 110°C on the total charge and exchangeable cations of Ca-, Na-, and
â–¡-saturated Fisher and KGa-1 kaolin. Approximately 0.5 g of kaolin was placed
in individual 50 mL polyethylene centrifuge tubes. The samples were washed with
20 mL of 1 M NH4CI to extract exchangeable Ca, Na, Li, Mg, and Al. The total
charge of the kaolin was then determined by Ca-exchange, as described
previously. The Na- and Li-saturated kaolin samples were also treated with 0.1
M HCI for 30 minutes to extract additional Na, Li, and Al. All extractions described
here were replicated four times.
Hysteresis Experiments
Thermal-gravimetric analysis (TGA) of Ca- and Li-saturated Fisher and KGa-
1 kaolin was conducted to determine the effect of heating on water vapor
adsorption and desorption. Approximately 15 mg of kaolin was placed in the
sample pan of a computer-controlled thermal-gravimetric analyzer. The samples
were equilibrated with a high RH (=90-95%) air flow stream for 2 hours at 24°C,

104
heated to 150°C (at a rate of 20°C per minute) for 48 hours, and allowed to
reequilibrate with the high RH flow stream at 24°C for approximately 20 hours. A
second treatment sequence consisted of exposure to the high RH flow stream with
the temperature alternating between 24°C and 150°C every 2 hours.
A Cahn® electrobalance was used to study the effect of exposure to a
vacuum on the adsorption and desorption of water vapor by Ca- and Li-saturated
Fisher kaolin. Approximately 25 mg of kaolin was placed on a hanging sample
pan (loop A) which was counterbalanced by an empty hanging pan (loop C). A
glass tube containing water was placed over loop A in order to expose the kaolin
to water vapor. The kaolin was then allowed to equilibrate until the sample weight
was constant, approximately 2 hours. The glass tube was then replaced by one
containing no water and a vacuum of approximately 0.18 torr was applied to the
system. The kaolin was allowed to equilibrate for approximately 8 hours, after
which time the system was returned to atmospheric pressure and the empty glass
tube was replaced with one containing water. The weight of kaolin was recorded
by an IBM-AT compatible computer that was connected to the Cahn®
microprocessor via a RS-232 cable.
Infrared Spectroscopy Experiments
Suspensions of Fisher kaolin were made by placing approximately 1.5 g of
kaolin in 10 mL of deionized water. A sample from the suspension was air-dried
onto a small piece of a 25 mm X 2 mm ZnSe disk. The ZnSe was positioned on
a standard KBr mount in a sample compartment evacuated to 0.05 torr in order to

105
eliminate interferences from atmospheric C02 and water vapors. Infrared spectra
were collected using a Bomem DA3.10 Fourier-transform IR spectrometer. The
DA3.10 spectrometer was equipped with a Michelson interferometer containing a
KBr beamsplitter positioned at a 30° angle to the optical axis. A mercury-
cadmium-telluride (MCT) detector with a D* value of 3.13 X 109 cmHz0 5 and a low
frequency cutoff of 400 cm'1 (25 m) was used in this study. The Bomem DA3.10
spectrometer was controlled by a DEC Vaxstation-ll computer via an IEEE-488
interface. An optical resolution of 2.0 wavenumbers was used for the collection
of the reported IR spectra.
Results and Discussion
X-Ray Diffraction Studies
The K-saturated sample exhibited strong peaks at 0.72 and 0.36 nm, which
are characteristic of 001 and 002 peaks for kaolinite (Figure 5-1). A very small
peak, located at 1.42 nm, was investigated in more detail to determine if the kaolin
was contaminated with smectite. Heating the sample to 110 and 300°C had no
discernable effect on the 1.42 nm peak; however, all peaks were eliminated at
550°C (Figure 5-2). The Mg-saturation and glycerol treatment did not result in a
shift of the 1.42 nm peak (Figure 5-3b). These data indicate that the 1.42 nm
peak was not due to smectite contamination, but was probably attributable to a
chlorite of low thermal stability.

106
0.72 nm
Figure 5-1. XRD patterns of K-saturated Fisher Kaolin after overnight
exposure to the specified temperatures.

107
29
Figure 5-2. Effect of overnight exposure to the specified temperatures on
the 1.42 nm peak of K-saturated Fisher kaolin.

108
0.72 nm
Figure 5-3. XRD pattern of Mg-saturated and glycerol treated (a) clay
fraction and (b) unfractionated Fisher kaolin.

109
The kaolin sample was separated into silt (50-2 pm) and clay (< 2 pm)
fractions to determine if the contaminant could be isolated. Separation of the
kaolin was achieved by repeated dispersion, centrifugation, and collection of the
supernatant. Prior to each centrifugation, pH 10 water was added to the kaolin
sample. Centrifugation proceeded as follows: (1) 2000 rpm for 5 minutes, (2) 1500
rpm for 10 minutes, and (3) 1000 rpm for 2 minutes. Step 3 was repeated until the
supernatant was essentially clear, after approximately five additional treatments.
The supernatant collected after each centrifugation step was considered to be the
clay fraction, while the residual in centrifugation tube was the silt fraction.
Oriented clay mounts of the silt and clay fractions were made following the
procedure described previously. The Mg-saturation and glycerol treatment of the
clay fraction yielded essentially the same peaks that were obtained for the whole
clay sample (Figure 5-3a). The K-saturated silt fraction was identical to that of the
whole clay, indicating that the 1.42 nm peak exists in both fractions. However, the
small peak at 9.93 nm was attributed to mica (Figure 5-4). A faint peak was also
observed in the whole clay sample at approximately 9.9 nm. The contamination
noted here was likely to have little effect on the CEC and surface area of the
kaolin because it appeared to be attributable to non-expandable phyllosilicate
minerals of low surface charge.
Semi-random powder mounts of the Fisher kaolin were prepared by gently
packing air-dry kaolin into the sample reservoir of a plastic mount. A powder
mount allows all crystal planes (h,k,l) to be detected by XRD analysis. As the

110
0.72 nm
Figure 5-4. XRD pattern of K-saturated silt fraction of Fisher kaolin.

111
order of the kaolin decreases, the 001 peak will tend to broaden and the 020,110,
111, 111, 021, and 021 peaks will lose resolution. A comparison of the XRD
diffraction patterns of Fisher kaolin, well-crystallized Ga kaolin, and poorly-
crystallized Ga kaolin are shown in Figure 5-5. The 020, 110, 111, 111,021, and
021 peaks were clearly identifiable in the Fisher kaolin and well-crystallized kaolin,
but were not readily discernable in the poorly-crystallized kaolin. These data
suggest that the Fisher kaolin approached the order of the well-crystallized kaolin,
and thus was considered to be medium- to well-crystallized.
Cation Exchange Capacity
The results of the preliminary CEC experiment are presented in Table 5-1.
After seven days of heating at 130°C, the amount of Ca extracted from Ca-
saturated Fisher kaolin had not changed, whereas extractable Na and Li was 81
and 10%, respectively, of the original level. The total charge of Ca- and Na-kaolin,
as determined by Ca exchange, was not affected by the heat treatment, but
decreased by approximately 50% for Li-kaolin. The disparity between the charge
attributable to the saturating cation and that determined by Ca exchange for Na-
and Li-kaolin suggests that other ions were involved in the exchange process. To
test this hypothesis, the Mg(N03)2 extracts of Na- and Li-kaolin were analyzed for
Al on day 15. Aluminum was not detected in the Na-kaolin extract, but was
present in the Li-kaolin extract, suggesting that Li displaced Al from the kaolin
lattice. It should also be noted that the color of the Li-kaolin changed from nearly
white to gray upon heating. The color of Ca-kaolin was not affected the heat

112
29
Figure 5-5. XRD patterns from powder mounts of (a) well-crystallized Ga
kaolin, (b) Fisher kaolin, and (c) poorly-crystallized Ga kaolin.

113
Table 5-1. Results of preliminary experiment to determine the effect of
heating at 130°C on the CEC of Ca-, Na-, and Li-saturated Fisher
kaolin.
Elapsed Extraction Ca-kaolin
Days Method
Na-kaolin Li-kaolin
0 Mg(N03)2a 4.107 ±0.005
—cmolc/kg
3.547 ± 0.056 3.809 ± 0.039
2 Mg(N03)2 3.951 ±0.018
3.034 ±0.057 0.598 ±0.014
7 Mg(N03)2 3.981 ± 0.031
CaCI2b 3.709 ± 0.032
2.862 ± 0.066 0.391 ± 0.027
3.523 ±0.022 1.985 ±0.009
15 Mg(N03)2
Mg(N03)2/Alc
2.283 ± 0.022 0.209 ± 0.007
0.000 ±0.000 0.819 ±0.015
a Mg(N03)2 extraction of saturating cation.
b CaCI2 wash, 95% ethanol rinse, and Mg(N03)2 extraction of Ca.
c Mg(N03)2 extraction of Al.

114
treatment, while that of Na-kaolin became slightly darker. A similar color change
has been reported for Li-saturated montmorillonite subject to heat treatments
(Jaynes and Bigham, 1987).
To substantiate the findings of the preliminary experiment, a second study
was conducted to determine the effect of heating on the CEC and extractable
cations of kaolin. The total charge, as determined by Ca exchange, of Fisher and
KGa-1 kaolin air-dried at 110°C is presented in Tables 5-2 and 5-3, respectively.
After seven days of heating, the total charge of Ca-, Na-, and Li-saturated Fisher
kaolin was 87, 82, and 51%, respectively, of the charge prior to heating. The
KGa-1 kaolins exhibited a similar trend after 18 days of heating, although the
decrease in charge of Ca- and Li-kaolin was less than that of the corresponding
Fisher kaolin. The reduction in total charge or CEC of Li-kaolin was consistent
with the findings of Greene-Kelly (1955) and Cashen (1959). In addition, no
chloride was detected in the Mg(N03)2 extracts, indicating that positive charge did
not develop as a result of heating.
The effect of heating on the amount of Ca, Na, Li, Mg, and Al extracted
from Fisher and KGa-1 kaolins is presented in Tables 5-4 and 5-5, respectively.
A slight decrease in the extractable Ca was observed for Ca-kaolin, along with
trace amounts of Na, Mg, and occasionally Al. In contrast, Li-kaolin exhibited a
dramatic decrease in exchangeable Li upon heating, with a corresponding increase
in Al. The retention of Li ions after heating has also been reported for Li-
saturated Peerless No. 2, English Clays, and Merck kaolin (Greene-Kelly, 1955).

115
Table 5-2.
Total charge of Ca-, Na-, and Li-saturated Fisher kaolin, as
determined by Ca exchange, air-dried at 110°C.
Elapsed
Days
Ca-kaolin Na-kaolin Li-kaolin
Cation Exchange Capacity
0
cmolc/kg
3.938 ± 0.050 4.272 ± 0.041 3.789 ± 0.005
2
3.597 ± 0.016 3.667 ± 0.022 2.450 ± 0.058
7
3.445 ± 0.054 3.485 ± 0.025 1.947 ± 0.019

116
Table 5-3. Total charge of Ca, Na, and Li-saturated KGa-1 kaolin, as
determined by Ca exchange, air-dried at 110°C.
Elapsed
Days
Ca-kaolin
Na-kaolin
Cation Exchange Capacity
Li-kaolin
i njijVrvy
0
2.443 ±0.011
2.453 ± 0.032
2.149 ±0.025
2
2.434 ± 0.009
2.306 ± 0.025
1.766 ± 0.072
8
2.075 ± 0.027
1.803 ±0.019
1.291 ± 0.020
18
2.301 ± 0.003
1.951 ± 0.005
1.450 ± 0.029

117
Table 5-4. Charge attributable to Ca, Na, Li, Mg, and Al extracted from Ca-,
Na-, and Li-saturated Fisher kaolin air-dried at 110°C.
Elapsed
Days
Cation
Ca-kaolin
Na-kaolin
Li-kaolin
i lui^rvy
Ca
3.845 ± 0.038
0.075 ± 0.002
0.010 ±0.002
Na
0.052 ±0.010
3.671 ± 0.039
0.062 ± 0.004
0
Li
3.597 ± 0.023
Al
0.000 ±
0.000 ±
0.000 ±
Mg
0.025 ± 0.001
0.031 ±0.001
0.024 ± 0.001
Ca
3.684 ± 0.023
0.048 ± 0.000
0.000 ±
Na
0.110 ±0.002
3.013 ±0.037
0.114 ± 0.006
2
Li
1.163 ± 0.076
Al
0.097 ± 0.034
0.164 ±0.039
0.601 ± 0.024
Mg
0.027 ± 0.002
0.029 ± 0.002
0.020 ± 0.001
Ca
3.623 ±0.018
0.053 ± 0.005
0.000 ±
Na
0.157 ± 0.006
2.828 ± 0.031
0.153 ± 0.002
7
Li
0.315 ±0.004
Al
0.102 ±0.007
0.142 ±0.010
0.977 ± 0.085
Mg
0.025 ± 0.001
0.027 ± 0.000
0.011 ±0.001
Ca
3.512 ±0.018
0.044 ± 0.009
0.000 ±
Na
0.173 ± 0.002
2.737 ± 0.022
0.195 ± 0.015
15
Li
0.245 ± 0.007
Al
0.000 ±
0.157 ±0.056
1.198 ±0.066
Mg
0.030 ± 0.001
0.020 ± 0.000
0.004 ± 0.002
Ca
3.554 ± 0.015
0.039 ± 0.003
0.000 ±
Na
0.191 ± 0.003
2.624 ± 0.058
0.183 ±0.006
40
Li
0.205 ± 0.005
Al
0.000 ±
0.187 ± 0.032
0.905 ± 0.019
Mg
0.026 ± 0.003
0.022 ± 0.001
0.007 ± 0.004

118
Table 5-5. Charge attributable to Ca, Na, LI, Mg, and Al extracted from Ca-,
Na-, and Li-saturated KGa-1 kaolin air-dried at 110°C.
Elapsed NH4CI Ca-kaolin Na-kaolin Li-kaolin
Days Extract
cmolj/kg
Ca 2.199 + 0.012 0.000 ± 0.000 ±
Na 0.044 ± 0.007 2.000 ± 0.022 0.047 ± 0.004
0 Li 1.719 ±0.014
Al 0.000 ± 0.000 ± 0.000 ±
Mg 0.043 ± 0.001 0.019 ± 0.002 0.011 ± 0.002
Ca 2.164 ±0.012 0.000 ± 0.000 ±
Na 0.124 ± 0.007 1.522±0.035 0.131 ±0.006
2 Li 0.417 ±0.012
Al 0.064 ±0.038 0.144 ±0.013 0.460 ± 0.044
Mg 0.045 ±0.001 0.028 ± 0.001 0.025 ± 0.003
Ca 2.038 ±0.021 0.000 ± 0.000 ±
Na 0.151 ± 0.003 1.324 ± 0.023 0.147 ± 0.003
8 Li 0.125 ±0.001
Al 0.000 ± 0.067 ±0.067 0.569 ±0.019
Mg 0.031 ±0.001 0.023 ± 0.008 0.013 ±0.001
Ca 2.101 ±0.014 0.000 ± 0.000 ±
Na 0.149 ±0.004 1.334 ±0.017 0.152 ±0.007
18 Li 0.113 ±0.005
Al 0.085 ± 0.056 0.092 ± 0.031 0.524 ± 0.049
Mg 0.038 ± 0.002 0.024 ± 0.001 0.023 ± 0.003

119
A similar trend was observed for Na-kaolin, but to a much lesser degree than that
of Li-kaolin. It should be noted that the Fisher and KGa-1 kaolin exhibited an
almost identical decrease in the percentage of Li ions extracted with 1 M NH4CI.
However, the initial reduction (day 2) in extractable Li was less than that measured
at 130°C, which suggests that temperature influenced the rate of Li retention. The
data presented here clearly demonstrate that heating Li-saturated kaolin results in
Li retention and a decrease in total charge or CEC.
The sum of charge attributable to Ca, Na, Mg, and Al extracted from Ca-
saturated Fisher and KGa-1 kaolin remained essentially constant over the
treatment periods (Figures 5-6a and 5-7a). These data were in agreement with
the total charge measured by Ca-exchange. In contrast, the sum of cation
charges for Na-kaolin decreased slightly, while that of Li-kaolin decreased
substantially as a result of heating. Figures 5-6c and 5-7c clearly indicate that
exchangeable Al contributed significantly to the charge of Li-kaolin after heating,
and suggest that a portion of the Li retained by the kaolin displaced Al from the
clay lattice. These data are contrary to those reported by Greene-Kelly (1955),
who extracted only trace amounts of Al from Li-kaolin before and after heating,
using a 0.001 M HCI and 1 M NH4CI extraction procedure. However, Greene-Kelly
(1955) apparently washed the kaolin with 1 M NH4AOc (pH 7) prior to extracting
Li ions. This treatment may have precipitated exchangeable Al, which was then
not extractable with the weak acid and NH4CI.

120
Figure 5-6. The sum of Ca, Na, Li, Mg, and Al extracted from (a) Ca-, (b) Na-,
and (c) Li-saturated Fisher kaolin.

3
2
1
O
2
1
O
2
1
O
121
Elapsed Days
of Ca, Na,
-saturated
Li,
Mg, and Al extracted from (a) Ca-, (b) Na-, and
a-1 kaolin.

122
Even though Al contributed to the charge of Na- and Li- kaolin, a
considerable difference remained between the total charge determined by Ca
exchange and that determined from the sum of extractable Ca, Na, Li, Mg, and Al.
This discrepancy suggests that other cations contributed to the total charge of the
kaolin. Interestingly, Cashen (1958) reported that heated samples of Na- and Li-
saturated Peerless No. 2 kaolin were far more acid than untreated samples. Thus,
the heating of Li-kaolin and subsequent retention of Li ions may also have caused
the displacement of H ions from the clay lattice. This hypothesis is supported by
Farmer and Russell (1967), who proposed that a portion of the Li ions that migrate
into montmorillonite react with interlayer water or structural hydroxyls to liberate
protons. Although the inclusion of H ions may bring the charge determined from
the sum of extractable cations into agreement with the value obtained by Ca-
exchange, the fact remains that the heat treatment reduced the total charge of Na-
and Li-kaolin.
In an attempt to extract non-exchangeable Na and Li from the heat-treated
Fisher kaolin, the kaolin was washed with 0.1 M HCI for successive 15 minute
intervals. However, only a small amount of Li and trace levels of Na were
recovered (Table 5-6). A total elemental analysis of the heat-treated kaolin would
be likely to recover all the retained Li; however, the exact quantity of Li involved
in charge reduction would still be difficult to ascertain. After the original heat
treatment, Greene-Kelly (1955) reported that Peerless kaolin was capable of fixing
an additional 11 cmol^kg of Li, after nine LiCI washes and heat treatments, with

123
Table 5-6. Amount of Li, Na, and Al extracted from Na- and Li-saturated
Fisher kaolin air-dried at 110°C using 0.1 M HCI.
Elapsed HCI Na Kaolin Li Kaolin
Days Trt. Na Al Li Al
-min. cmolc/kg
0 15
30
0.000 ± 1.040 ±0.009
0.000 ± 0.295 ±0.011
2 15 0.011 ±0.001 1.577 ±0.022 0.007 ± 0.000 0.995 ± 0.051
30 0.005 ±0.000 0.443 ±0.014 0.000 ± 0.478 ± 0.045
7
15
0.014 ± 0.001
1.519 ±0.013
0.025 ± 0.002
1.169 ±0.020
30
0.002 ± 0.000
0.699 ±0.021
0.008 ± 0.001
0.721 ± 0.062
15
15
0.014 ± 0.013
1.531 ± 0.443
0.019 ±0.001
1.046 ±0.026
30
0.001 ± 0.001
0.395 ± 0.021
0.006 ± 0.002
0.356 ±0.012
40 15 0.000 ± 1.758 ±0.049 0.042 ± 0.062 1.344 ±0.042
30 0.000 ± 0.356 ±0.016 0.010 ±0.001 0.345 ± 0.024

124
a further reduction in total charge of only 0.5 cmolc/kg. These data, although
somewhat puzzling at first, suggest that only a portion of the retained Li was
actually involved in charge reduction, while the remainder displaced Al and H ions,
which were then exchangeable.
Adsorption and Desorption of Water Vapor
The adsorption and desorption of water following heating of Ca- and Li-
saturated Fisher kaolin, measured by TGA, are presented in Figures 5-8, 5-9, and
5-10. Figures 5-8 and 5-9 are representative of the weight change recorded for
kaolin samples exposed to an air flow stream at =90-95% RH, subject to the
following sequence of heat treatments: (1) room temperature for two hours, (2)
150°C for 48 hours, and (3) room temperature for approximately 24 hours. The
Ca- and Li-kaolin regained an average of 98.9 ± 1.8% and 46.3 ± 1.3%,
respectively, of their original weight lost due to the 150°C heat treatment. The
degree of hysteresis exhibited by Li-kaolin was consistent with the 50% reduction
in the total charge measured for Li-kaolin after seven days at 110 and 130°C, and
after long-term exposure to heat as reported in Chapter 4. The absence of
hysteresis observed for Ca-kaolin was in agreement with the stability of the total
charge of Ca-kaolin upon heating. The KGa-1 kaolin also exhibited hysteresis.
Ca- and Li-saturated KGa-1 kaolin regained 84.8 ± 5.2% and 57 ± 5.0%,
respectively, of the original weight lost after heating. The total charge reduction
of Ca- and Li-kaolin was 94 and 67%, respectively, of the level prior to heating.
This discrepancy may have been due to particle coalescence of the well-
crystallized KGa-1 kaolin during heat treatments. However, the overall similarity

125
Figure 5-8. Adsorption and desorption of water by (a) Ca-saturated, and
(b) Li-saturated Fisher kaolin measured by TGA.

126
Figure 5-9. Adsorption and desorption of water by (a) Ca-saturated, and
(b) Li-saturated KGa-1 kaolin measured by TGA.

Tima (Min)
Figure 5-10. Adsorption and desorption of water by (a) Ca-saturated and
(b) Li-saturated Fisher kaolin exposed to repeated 150°C
treatments.

128
between the magnitude of hysteresis and reduction in total charge of kaolin upon
heating suggests that reducted water adsorption observed for Li-kaolin was simply
due to the reduction in the total charge or CEC of the Li-kaolin.
The percentage of weight regained by Li- (55.5 ± 3.5%) and Ca-saturated
(97 ± 2.5%) Fisher kaolin subject to temperatures of 24 and 150°C for alternating
two hour intervals was essentially the same as that measured after 48 hours at
150°C (Figure 5-10). These data indicate that the 2 hour treatment at 150°C was
sufficient to reduce water adsorption to the extent of charge reduction observed
after 7 days at 110 and 130°C. This finding was consistent with the increased rate
of Li retention observed at 130°C versus 110°C, and indicates that temperature
influenced the rate of Li retention and CEC reduction.
Similar experiments were conducted to determine if exposure to a vacuum
would induce hysteresis by Li-saturated Fisher kaolin. After equilibration in a high
RH atmosphere, Ca- and Li-kaolin regained 67 ± 6.0 % and 54 ± 1.0% of the
weight lost following exposure to the vacuum (Figure 5-11). The considerable
hysteresis observed for Ca-kaolin suggests that the actual effect of the vacuum on
water adsorption by Li-kaolin was minimal. It is quite plausible that the vacuum
resulted in considerable particle coalescence. Thus, even though the results of
these experiments suggest the vacuum treatment induced a slight reduction in the
water adsorption capacity of Li-kaolin, the utility of such a technique is limited by
coincidental hysteresis effects.

WEIGHT (mg) WEIGHT (mg)
129
TIME (hrs)
Figure 5-11. Adsorption and desorption of water by (a) Ca-saturated, and
(b) Li-saturated Fisher kaolin exposed to a vacuum.

130
Location of Nonexchangable Li
The location of exchangeable cations on kaolin is considered to be limited
to the basal plane of the tetrahedral layer; in response to permanent charge arising
from the substitution of Al+3 for Si+4 in the outer tetrahedral sheet (Bolland et al.,
1976; Follet, 1965; Weiss and Russow, 1963) (Figure 5-12). However, a portion
of the negative charge may still be the result of pH dependent charges. Reduced
water adsorption on Li-kaolin led Keenan et al. (1951) to propose that Li occupied
a position in the tetrahedral layer from which hydration was sterically hindered by
outer oxygen atoms. However, other cations, although small enough to fit between
oxygen atoms of the tetrahedral layer, were readily hydrated. Greene-Kelly (1955),
aware of the fact that Li retention and CEC reductions occurred after heating Li-
kaolin, proposed that Li ions migrate into vacant octahedral coordination sites, as
has been suggested to explain a similar phenomenon in montmorillonite. This
hypothesis would more readily explain the displacement of Al and H from the
octahedral layer. The inner hydroxyls of kaolin, which are oriented toward the
octahedral cavity, yield an IR spectra band at 3620 cm'1. It was hypothesized that
the migration of Li into the vacant octahedral site would alter the orientation of
inner hydroxyls, resulting in a shift in the 3620 cm'1 band or the creation of several
unresolved bands.
The IR spectra obtained from air-dry Na- and Li-kaolin, and heated-treated
Li-kaolin are shown in Figure 5-13. A subtraction procedure indicated that the
inner hydroxyl stretching band of Na-kaolin and heat-treated Li-kaolin were not the

131
Figure 5-12. Projection of kaolinite structure onto the 100 plane.

132
Figure 5-13. IR spectra of (a) heated Na-saturated, (b) heated Li-saturated, and
(c) air-dried Li-saturated Fisher kaolin in the inner hydroxyl
stretching region.

133
same. To substantiate this finding a deconvolution program was used to
quantitatively determine the position, width, and intensity of each band (Johnston
et al., 1985). Air-dry Na-kaolin yielded a single peak at 3620 cm'1, whereas heat-
treated Li-kaolin exhibited peaks at 3615 and 3620 cm'1. The existance of a
second peak at a lower wave number suggests that Li displaced a portion of the
Al from the kaolin structure upon heating (C. T. Johnston, 1990, personal
communication). This finding was consistent with the displacement of Al measured
by ion extraction, and indicated that Li migration into the kaolin structure was
directly responsible for the reduced charge of heat-treated Li-kaolin.
Summary
In a number of vapor-phase adsorption studies Li-saturated kaolin has been
utilized as a reference mineral surface; considered to be independent of cation
hydration effects. However, the data presented here indicate that the heating of
Li-kaolin, and to a lesser extent Na-kaolin, results in a decrease in the total charge
or CEC of kaolin. This effect was manifested in measurements of water adsorption
following heating, which were directly related the magnitude of CEC reduction
determined by Ca-exchange. These findings suggest that reduced water
adsorption observed for Li-kaolin in previous studies was actually the result of a
decrease in the CEC of heated Li-kaolin samples. Therefore, heat-treated Li-kaolin
represents a surface of reduced charge, rather than a surface free of cation
hydration effects.

134
Extraction of Li-kaolin with NH4CI revealed that only 6% of the Li ions
remained exchangeable after heat treatment. A considerable amount of Al was
extracted from the Li-kaolin, and yet the sum of Al, Li, Mg, Na, and Ca accounted
for only 75% of the reduced CEC. Based on previous reports of increased acidity
following heating, it appears likely that H contributed to the residual charge. Thus,
the remaining exchange capacity of the heated Li-kaolin was satisfied by Li, Al,
and possibly H.
The Li ions rendered nonexchangeable by heating apparently acted to (1)
to reduce the total charge, and (2) to displace Al and H from the clay lattice. The
fact that an additional 11 cmol^kg of Li could be introduced to kaolin with only a
0.5 cmolc/kg reduction in total charge, suggests that the magnitude of total charge
reduction is fixed or limited, whereas, a considerable quantity of Al and H can be
displaced from the lattice, the location of Li ions could not be definitively
ascertained by IR spectroscopy. These data demonstrate that heat-treated Li-
kaolin cannot be treated as a reference surface, In particular, the assumption that
Li-kaolin is free of cation hydration effects may lead to erroneous estimates of the
number of water molecules associated with each exchangeable cation (e.g.,
Keenan et al., 1951).

CHAPTER 6
SUMMARY AND CONCLUSIONS
Antecedent moisture content or relative humidity (RH) is arguably the most
important factor influencing vapor-phase sorption in the unsaturated zone. In
Chapter 2, the effect of RH on the sorption of p-xylene vapors in the unsaturated
zone was investigated at a mechanistic level. Soils and clay minerals exhibited a
sizable capacity to adsorb organic vapors at low RH which was characterized by
Type-ll adsorption isotherms. When the RH was increased to 67 and 90%, p-
xylene sorption decreased dramatically and isotherms shifted from Type-ll to Type-
111 regardless of the organic carbon (OC) content. Increased sorption at relative
vapor pressures above 0.6 has not been reported previously, and indicates that
hydrated soils may adsorb significant quantities of organic vapors near the
contaminant source.
The adsorption of p-xylene vapors on anhydrous sorbents was strongly
correlated to mineral surface area determined from N2 adsorption isotherms. In
contrast, greater sorption was observed for untreated than hydrogen peroxide
treated Webster soil at 90% RH. These data suggest that soil organic matter
functions as a partitioning medium for organic vapors following hydration. In
addition, the use of values to predict vapor-phase sorption at high RH was only
applicable to sorbents of high OC content at p-xylene relative vapors less than 0.5.
135

136
Predictions of the surface excess based on the Gibbs adsorption equation suggest
that adsorption at the gas-liquid interface was the dominant mechanism
responsible for p-xylene sorption on kaolin and silica gel.
Vapor-phase sorption was also studied by gas chromatography, which offers
an efficient and versatile alternative to conventional batch techniques (Chapter 3).
Data for the sorption of p-xylene, obtained by the eluted-pulse method, on
anhydrous and hydrated Oldsmar sand conformed to Type-ll and Type-lll
isotherms, respectively. The salt treatment of Oldsmar soil resulted in decreased
p-xylene sorption, which was consistent with sorption data obtained for Webster
soil. At high RH, this phenomenon was attributed to a reduction in sorptive
capacity at the gas-liquid interface of salt-treated soils. However, predictions of
the surface excess failed to support this hypothesis, even though salt solutions
exhibited a significantly greater surface tension than deionized water. Regardless
of the mechanism, these data suggest that vapor-phase sorption of volatile organic
chemicals (VOCs) will be significantly reduced in salt-affected soils.
In Chapter 4, the adsorption of water and p-xylene vapors on Ca-, Na-, and
â–¡-saturated kaolin was investigated for single and mixed-vapor systems. The
amount of water adsorbed on Ca- and Na-kaolin was directly related to the
hydration energy of the cation. In contrast, Li-kaolin exhibited less adsorption than
Na-kaolin even though the hydration energy of Li is slightly greater than that of Na.
A similar effect was observed for p-xylene vapors, which suggests that weak
interactions occurred between exchangeable cations and p-xylene molecules.

137
When the RH was increased to 10 and 20%, p-xylene adsorption decreased
successively. Enhanced water adsorption exhibited at high p-xylene relative vapor
pressures was attributed to cation hydration effects. In addition, the competitive
adsorption of water and p-xylene was well predicted by the two-component model
of Hill (1946a, 1946b).
Reduced water adsorption on Li-kaolin has been attributed to the lack of Li
hydration due to steric hindrance effects (Keenan et al., 1951). However,
measurements of cation exchange capacity (CEC) indicated that the total charge
of Li-kaolin was reduced by 50% after heating to 120°C. The reduction in CEC
and water adsorption for Li-kaolin was confirmed by extraction techniques and
gravimetric analysis in Chapter 5. Extractions with NH4CI revealed that only 6%
of the Li remained exchangeable after heating; whereas, Al and H were released
from the kaolin. Thus, non-exchangeable Li ions not only reduced the total charge
on kaolin but also displaced Al and H from the clay lattice. Although the location
of non-exchangeable Li was not ascertained by infrared spectroscopy, it appears
that Li acted as a weak acid to dissolve the clay structure. These data clearly
demonstrate that heated Li-kaolin represents a surface of reduced charge, rather
than a surface free of cation hydration effects. Therefore, it is recommended that
Li-kaolin not be used as a reference for the study of vapor-phase sorption, and
conclusions based on such an assumption appear to have no theoretical basis.

138
The effect of RH on vapor-phase sorption of VOCs by soil materials is
summarized in Figure 6-1. In order to account for the dramatic change in sorptive
capacity as a function of RH, it is recommended that vapor-phase sorption be
described by a multi-mechanistic approach which includes (1) adsorption on
exposed mineral surfaces, (2) partitioning into organic carbon, (3) dissolution into
adsorbed water films and, (4) adsorption at the gas-liquid interface. The original
BET equation and two-component BET equation of Hill (1946a, b) provided
accurate predictions of p-xylene adsorption under anhydrous and low RH
conditions, respectively. At RHs above which the sórbate surface is covered by
at least a monomolecular layer of water, sorption may result from dissolution into
adsorbed water films, partitioning into OC, and adsorption at the gas-liquid
interface. The importance of each mechanism will be governed by sórbate
properties, such as solubility and hydrophobicity, and sorbent properties, such as
OC content.

05
g
E
-£=
05
|d
2 g
•4- <5
° E
TS E
£ jg
® o
05 X3
¡c tz
I— «J
co
I
.05
U.
SorPtion

APPENDIX A
WATER AND P-XYLENE SORPTION DATA

Table A-1. Sorption of water and p-xylene vapors on Webster soil from single
and mixed-vapor systems.
P/Po
Sorbed
System
p-xylene water
p-xylene water
p-xylene
0.061 (±0.003)
mg/g
4.63 (±0.15)
0.264 (±0.001)
7.37 (±0.05)
0.441 (±0.005)
9.01 (±0.00)
+ CaCI2
0.441 (±0.005)
3.03 (±0.10)
p-xylene
0.099 (±0.001)
0.886 (—-
--)
0.21 (±0.00)
115.50 (±1.61)
and
0.197 (±0.002)
0.890 (—-
-*)
0.26 (±0.01)
93.31 (±1.70)
water
0.206 (±0.000)
0.897 (—-
0.25 (±0.01)
99.91 (±1.68)
0.384 (±0.005)
0.899 (—-
0.61 (±0.01)
86.68 (±1.49)
0.497 (±0.000)
0.889 (—-
0.63 (±0.00)
102.38 (±0.60)
0.610 (±0.002)
0.890 (—-
1.35 (±0.03)
86.91 (±0.11)
0.610 (±0.002)
0.890 (—-
1.21 (±0.01)
89.34 (±0.40)
0.610 (±0.002)
0.890 (—-
1.37 (±0.05)
87.63(±0.87)
0.777 (±0.000)
0.900 (—-
4.36 (±0.06)
87.07(±0.15)
+ CaCI2
0.610 (±0.002)
0.890 (—-
0.62 (±0.01)
116.52 (±1.84)
141

142
Table A-2. Sorption of water and p-xylene vapors on Webster HP from single and
mixed-vapor systems.
System
P/Po
Sorbed
p-xylene
water
p-xylene
water
mg/g
p-xylene
0.061 (±0.003)
10.80 (±0.06)
0.262 (±0.002)
16.01 (±0.18)
0.459 (±0.006)
18.79 (±0.17)
+ OaCI2
0.459(±0.006)
11.83(±0.15)
p-xylene
0.099 (±0.001)
0.886 (—-
--")
0.05 (±0.00)
96.19 (±1.20)
and
0.201 (±0.001)
0.917 (-—
-â„¢)
0.08 (±0.01)
109.34 (±1.35)
water
0.206 (±0.000)
0.897 (-—
0.10 (±0.01)
89.02 (±0.72)
0.497 (±0.000)
0.889
-*)
0.28 (±0.01)
91.80 (±0.85)
0.610(±0.002)
0.890 (—-
0.91 (±0.04)
79.51 (±0.22)
0.777(±0.000)
0.900 (—-
3.88 (±0.12)
79.28 (±1.42)
+ CaOI2
0.610 (±0.002)
0.890 (—-
0.18 (±0.03)
132.61 (±1.52)
0.777 (±0.000)
0.900 (---
0.43 (±0.00)
111.34 (±0.00)

143
Table A-3. Sorption of water and p-xylene vapors on Fisher kaolin from single and
mixed-vapor systems.
P/Po
Sorbed
System
p-xylene
water p-xylene
water
mg/g
p-xylene
0.074 (±0.001)
0.151 (±0.001)
0.217 (±0.001)
0.365 (±0.005)
2.48 (±0.06)
3.42 (±0.05)
4.24 (±0.06)
6.56 (±0.06)
water
0.113 (±0.003)
0.136 (±0.001)
0.219 (±0.001)
0.289 (±0.001)
3.36 (±0.01)
3.58 (±0.28)
4.57 (±0.20)
5.13 (±0.26)
p-xylene
0.095 (±0.003)
0.379 (±0.004) 2.46 (±0.00)
6.56 (±0.05)
and
0.258 (±0.003)
0.663 (±0.009) 2.28 (±0.02)
10.48 (±0.04)
water
0.415 (±0.007)
0.676 (±0.008) 3.76 (±0.02)
8.68 (±0.10)
0.600 (±0.008)
0.708 (±0.008) 7.71 (±0.10)
8.73 (±0.16)
0.896 (±0.008)
0.732 (±0.009) 52.19 (±1.23)
9.22 (±0.24)

144
Table A-4. Preliminary data for the sorption of water and p-xylene vapors on Li-
saturated Fisher kaolin from single and mixed-vapor systems.
P/Po
Sorbed
System
p-xylene water
p-xylene water
p-xylene
0.074 (±0.001)
mg/g
2.15 (±0.05)
0.151 (±0.001)
3.26 (±0.01)
0.217 (±0.001)
3.98 (±0.03)
0.365 (±0.005)
5.99 (±0.05)
water
0.113 (±0.003)
2.45 (±0.13)
0.136 (±0.001)
2.79 (±0.04)
0.219 (±0.001)
3.11 (±0.06)
0.289 (±0.001)
3.48 (±0.07)
p-xylene 0.095 (±0.003)
and
0.379 (±0.004) 2.06 (±0.01)
6.04 (±0.05)
water

145
Table A-5. Sorption of water and p-xylene vapors on silica gel from mixed-vapor
systems.
P/Po
System p-xylene water
Sorbed
p-xylene water
mg/g
p-xylene 0.274 (±0.003)
and 0.439 (±0.011)
water 0.610 (±0.002
0.669 (±0.009)
0.725 (±0.037)
0.688 (±0.005)
41.95 (±0.55) 54.89 (±0.45)
80.19 (±0.59) 52.01 (±0.19)
173.97 (±2.68) 45.73 (±0.58)

146
Table A-6. Sorption of water and p-xylene vapors on Li-saturated Fisher kaolin
from single and mixed-vapor systems.
System
P/Po
Sorbed
p-xylene
water
p-xylene
water
mg/g
p-xylene
0.047 (±0.001)
1.67 (±0.004)
0.048 (±0.001)
1.79 (±0.02)
0.162 (±0.002)
3.77 (±0.01)
0.303 (±0.002)
5.83 (±0.01)
0.484 (±0.010)
9.06 (±0.06)
water
0.115 (±0.003)
1.87 (±0.17)
0.126 (±0.003)
2.08 (±——)
0.186 (±0.006)
2.85 (±0.17)
0.241 (±0.024)
2.92 (+ )
0.245 (±0.020)
2.74 (±0.02)
p-xylene
0.093
(±0.001)
0.117
(±0.005)
2.57
(±0.02)
2.02
(±0.11)
and
0.201
(±0.001)
0.101
(±0.003)
4.09
(±0.03)
1.56
(±0.06)
water
0.395
(±0.002)
0.117
(±0.004)
6.85
(±0.02)
1.24
(±0.09)
0.096
(±0.001)
0.179
(±0.009)
2.39
(±0.01)
2.93
(±0.11)
0.217
(±0.003)
0.211
(±0.009)
4.00
(±0.03)
2.72
(±0.02)
0.410
(±0.003)
0.218
(±0.008)
6.70
(±0.06)
2.34
(±0.14)

147
Table A-7. Sorption of water and p-xylene vapors on Na-saturated Fisher kaolin
from single and mixed-vapor systems.
System
P/Po
Sorbed
p-xylene
water
p-xylene
water
mg/g
p-xylene
0.044 (±0.000)
2.61 (±0.02)
0.048 (±0.001)
2.57 (±0.00)
0.072 (±0.001)
3.24 (±0.00)
0.165 (±0.001)
4.91 (±0.03)
0.301 (±0.001)
6.97 (±0.07)
0.475 (±0.011)
10.04 (±0.04)
0.512 (±0.004)
10.58 (±0.12)
water
0.126 (±0.003)
2.86 (±0.02)
0.186 (±0.006)
3.46 (±0.10)
0.241 (±0.024)
4.11 (±0.11)
p-xylene
0.093 (±0.001)
0.117 (±0.005)
7.94 (±0.05)
2.27 (±0.15)
and
0.201 (±0.001)
0.101 (±0.003)
5.42 (±0.07)
2.38 (±0.14)
water
0.395 (±0.002)
0.112 (±0.004)
3.40 (±0.02)
2.31 (±0.04)
0.096 (±0.001)
0.179 (±0.009)
3.32 (±0.02)
3.56 (±0.06)
0.217 (±0.003)
0.211 (±0.009)
5.33 (±0.04)
3.09 (±0.00)
0.410 (±0.003)
0.218 (±0.008)
7.89 (±0.02)
3.48 (±0.19)

148
Table A-8. Sorption of water and p-xylene vapors on Ca-saturated Fisher kaolin
from single and mixed-vapor systems.
System
P/Po
water
Adsorbed
p-xylene
p-xylene
water
mg/g
p-xylene
0.045(±0.003)
2.42(±0.02)
0.072(±0.001)
3.42(±0.02)
0.165(±0.002)
5.55(±0.03)
0.301 (±0.001)
7.75(±0.03)
0.477(±0.011)
9.71 (±0.05)
water
0.126 (±0.003)
3.94 (±0.03)
0.186 (±0.006)
4.93 (±0.16)
0.245 (±0.020)
5.48 (±0.05)
p-xylene
0.093 (±0.001)
0.112 (±0.004)
3.58 (±0.02)
3.42 (±0.20)
and
0.201 (±0.001)
0.101 (±0.003)
5.72 (±0.01)
2.64 (±0.06)
water
0.395 (±0.002)
0.117 (±0.004)
8.00 (±0.01)
3.24 (±0.10)
0.096 (±0.001)
0.179 (±0.009)
3.22 (±0.01)
4.13 (±0.07)
0.217 (±0.007)
0.211 (±0.009)
5.14 (±0.02)
4.18 (±0.03)
0.403 (±0.004)
0.184 (±0.002)
7.88 (±0.02)
3.42 (±0.20)

APPENDIX B
SURFACE TENSION DATA

Table B-1. Surface tension of deionized water exposed ot p-xylene (PX) vapors.
Pressure
(mm Hg)
Surface Tension
PX/Water
(g/s2)
Dl Water
(g/s2)
0.693 (±0.002)
71.980 (±0.196)
72.160 (±0.070)
1.357 (±0.026)
71.785 (±0.067)
72.323 (±0.053)
1.378 (±0.025)
71.749 (±0.047)
72.427 (±0.309)
2.013 (±0.004)
71.539 (±0.247)
72.447 (±0.143)
2.915 (±0.006)
71.233 (±0.024)
72.475 (±0.144)
4.190 (±0.009)
70.493 (±0.115)
72.371 (±0.203)
5.541 (±0.077)
69.589 (±0.061)
72.303 (±0.297)
6.451 (±0.052)
68.578 (±0.023)
72.489 (±0.075)
6.781 (±0.001)
66.851 (±0.150)
72.287 (±0.064)
150

151
Table B-2. Surface tension of 1.0 M CaCI2 exposed to p-xylene (PX) vapors.
Pressure
(mm Hg)
Surface Tension
PX/1.0 M CaCI2
(g/s2)
1.0 M CaCI2
(g/s2)
0.709 (±0.001)
75.575 (±0.127)
75.957 ( )
1.993 (±0.032)
75.021 (±0.044)
75.621 (±0.102)
3.739 (±0.055)
74.411 (±0.151)
( )
5.116 (±0.081)
73.767 (±0.399)
75.740 (±0.131)
5.824 (±0.204)
72.947 (±0.175)
75.809 (±0.166)
6.577 (±0.010)
71.333 (±0.219)
74.800 (±0.109)
6.705 (±0.001)
70.588 (±0.197)
75.590 (±0.153)

REFERENCES
Adamson, A.W. 1982. Physical chemistry of surfaces. 2nd ed. John Wiley &
Sons, New York.
Adamson, A.W., L. Dormant, and M.W. Orem. 1967. J. Colloid Interface Sci.
25:206-217.
Baehr, A.L. 1987. Selective transport of hydrocarbons in the unsaturated zone
due to aqueous and vapor phase partitioning. Water Resour. Res.
23:1926-1938.
Baumer, D. and G.H. Findenegg. 1982. Adsorption of hydrophobic vapors on the
surface of water. J. Colloid Interface Sci. 85:118-127.
Blank, M. and R.H. Ottewill. 1964. The adsorption of aromatic vapors on water
surfaces. J. Phys. Chem. 68:2206-2211.
Bohn, H.L., G.K. Prososki, and J.G. Eckhardt. 1980. Hydrocarbon adsorption by
soils as the stationary phase of gas-solid chromatography. J. Environ.
Qual. 9:563-565.
Bolland, M.D., A.M. Ponser, and J.P. Quirk. 1976. Surface charge of kaolinites in
aqueous suspension. Aust. J. Soil Res. 14:197-216.
Brindley, G.W. and G. Ertem. 1971. Preparation and solvation properties of
some variable charge montmorillonites. Clays and Clay Minerals. 19:399-
404.
Brunauer, S. 1943. The adsorption of gas and vapors. Vol. 1. Physical
adsorption. Princeton Univ. Press, London.
Burchill, S., M. Hayes, and D.J. Greenland. 1981. Adsorption. In D.J. Greenland
and M. Hayes (ed.) Chemistry of soil processes. John Wiley & Sons,
New York.
Call, F. 1957. The mechanism of sorption of ethylene dibromide on moist soils. J
Sci. Agrie. 8:630-639.
152

153
Calvet, R. and R. Prost. 1971. Cation migration into empty octahedral sites and
surface properties of clays. Clays and Clay Minerals. 19:175-186.
Cashen, G.H. 1959. Electric charges of kaolin. Faraday Soc. Trans. 55:477-
486.
Chatterjee, A.K., J.W. King, and B.L. Karger. 1972. Adsorption and solution of
weakly polar vapors with thin layers of water as studied by gas-liquid
chromatography. J. Colloid Interface Sci. 41:71-76.
Chiou, C.T. and T.D. Shoup. 1985. Soil sorption on organic vapors and effects of
humidity on sorptive mechanism and capacity. Environ. Sci. Technol.
19:1196-1200.
Conder, J.R., D.C. Locke, and J.H. Purnell. 1969. Concurrent solution and
adsorption phenomena in chromatography. I. General considerations. J.
Phys. Chem. 73:700-708.
Cutting, C.L. and D.C. Jones. 1955. Adsorption of insoluble vapors on water
surfaces. Part 1. J. Chem. Soc., London. 4067-4075.
Donohoe, S.J. (ed.) 1983. Reference soil test methods for the southern region of
the United States. Southern Coop. Ser. Bull. 289. Univ. of Georgia, Athens,
GA.
Dorris, G.M. and D. G. Gray. 1981. Adsorption of hydrocarbons on silica-
supported water surfaces. J. Phys. Chem. 85:3628-3635.
Drozd, J., J. Vejrosta, and J. Novak. 1982. Spurious adsorption effects in
headspace-gas determination of hydrocarbons in water. J.
Chromatography. 245:185-192.
Farmer, V.C. and J.D. Russell. 1967. Infrared absorption spectroscopy in clay
studies. Clays and Clay Minerals. 15:121-142.
Follet, E.A.C. 1965. The retention of amorphous colloidal "ferric hydroxide" by
kaolinites. J. Soil Sci. 16:334-341.
Fowkes, F.M. 1968. Calculation of work of adhesion by pair potential
summation. J. Colloid Interface Sci. 28:493-505.
Glaser, R. and J. Mering. 1971. Migration des cations Li dans les smectites di-
octaedriques (effect Hofmann-Klemen). C.R. Acad. Sci., Serie D.
273:2399-2402.

154
Glotfelty, D.E. and C.J. Schomburg. 1989. Volatilization of pesticides from soil.
pp.181-207. In B.L. Sawhney and K. Brown (ed.) Reactions and
movement of organic chemicals in soils. ASA Spec. Publ. 22. ASA,
CSSA, and SSSA, Madison, Wl.
Greene-Kelly, R. 1953. Irreversible dehydration in montmorillonite. Part II. Clay
Minerals Bull. 2:52-56.
Greene-Kelly, R. 1955. Lithium absorption by kaolin minerals. J. Phys. Chem.
59:1151-1152.
Grim, R.E. 1953. Clay mineralogy. McGraw-Hill, New York.
Harkins, W.D. and F.E. Brown. 1919. The determination of surface tension (free
surface energy), and the weight of falling drops: The surface tension on
water and benzene by the capillary height method. J. Am. Chem. Soc.
41:499-524.
Hartkopf, A. and B.L. Karger. 1973. Study of the interfacial properties of water by
gas chromatography. Acc. Chem. Res. 6:209-216.
Hauxwell, F. and R.H. Ottewill. 1968. The adsorption of toluene vapor on water
surfaces. J. Colloid Interface Sci. 28:514-521.
Hill, T.L. 1946a. Theory of multimolecular adsorption from a mixture of gases. J.
Phys. Chem. 14:46-47.
Hill, T.L. 1946b. Theory of multimolecular adsorption from a mixture of gases. J.
Phys. Chem. 14:268-275.
Hofmann, V.U. and R. Klemen. 1950. Verlust der austauschfahigkeit von
lithiumionen an bentonit durch erhitzung. Z. Anorg. Allg. Chem. 262:95-99.
Hollist, R.L. and C.L. Foy. 1971. Trifluralin interactions with soil constituents.
Weed Sci. 19:11-16.
Jaynes, W.F. and J.M. Bigham. 1987. Charge reduction, octahedral charge, and
lithium retention in heated, Li-saturated smectites. Clays and Clay
Minerals. 35:440-448.
Jho, C., D. Nealon, S. Shogbola, and A.D. King, Jr. 1978. Effect of pressure on the
surface tension of water: Adsorption of hydrocarbon gases and carbon
dioxide on water at temperatures between 0 and 50°C. J. Colloid Interface
Sci. 65:141-154.

155
Johnston, C.T., G. Sposito, and R.R. Birge. 1985. Raman spectroscopic study of
kaolinite in aqueous suspension. Clays and Clay Minerals. 33:483-489.
Jurinak, J.J. 1957. The effect of clay minerals and exchangeable cations on the
adsorption of ethylene dibromide. Soil Sci. Soc. Am. Proc. 21:599-602.
Jurinak, J.J. 1961. The effect of pretreatment on the adsorption and desorption
of water vapor by lithium and calcium kaolinite. J. Phys. Chem. 65:62-64.
Jurinak, J.J. 1963. Multilayer adsorption of water by kaolinite. Soil Sci. Soc. Am.
Proc. 27:269-272.
Jurinak, J.J. and D.H. Volman. 1957. Application of the Brunauer, Emmett, and
Teller equation to ethylene dibromide adsorption by soils. Soil Sci.
33:487-496.
Jurinak, J.J. and D.H. Volman. 1961a. Thermodynamics of water and n-butane
adsorption by Li-kaolinite at low coverages. J. Phys. Chem. 65:150-152.
Jurinak, J.J. and D.H. Volman. 1961b. Cation hydration effects on the
thermodynamics of water adsorption by kaolonite. J. Phys. Chem.
65:1853-1856.
Jury, W.A., D. Russo, G. Streile, and H. El Abd. 1990. Evaluation of
volatilization by organic chemicals residing below the soil surface. Water
Resour. Res. 26:13-20.
Karger, B.L., R.C. Castells, P.A. Sewell, and A. Hartkopf. 1971a. Study of the
adsorption of insoluble and sparingly soluble vapors at the gas-liquid
interface of water by gas chromatography. J. Phys. Chem. 75:3870-3879.
Karger, B.L., P.A. Sewell, R.C. Castells, and A. Hartkopf. 1971b. Gas
chromatographic study of the adsorption of insoluble vapors on water. J.
Colloid Interface Sci. 35:328-339.
Karickhoff, S.W. 1984. Organic pollutant sorption in aquatic systems. J. Hydraulic
Eng. 110:707-735.
Karnaukhov, A.P. 1985. Improvement of methods for surface area determinations.
J. Colloid Interface Sci. 103:311-320.
Keenan, A.G., R.W. Mooney, and L.A. Wood. 1951. The relation between
exchangeable ions and water adsorption on kaolinite. J. Phys. Chem.
55:1462-1474.

156
King, J.W., A. Chatterjee, and B.L. Karger. 1972. Adsorption isotherms and
equations of state of insoluble vapors at the water-gas interface as
studied by gas chromatography. J. Phys. Chem. 2769-2777.
Langmuir, I. 1916. The constitution and fundamental properties of solids and
liquids. Part 1. Solids. J. Am. Chem. Soc. 38:2221-2295.
Lim, C.H. and M.L. Jackson. 1986. Expandable phyllosilicate reactions with
lithium on heating. Clays and Clay Minerals. 34:346-352.
Luca, V. and C.M. Cardile. 1989. Cation migration in smectite minerals: Electron
spin resonance of exchanged Fe+ probes. Clays and Clay Minerals.
37:325-332.
Luca, V., C.M. Cardile, and R.H. Meinhold. 1989. High-resolution multinuclear
NMR study of cation migration in montmorillonite. Clay Minerals. 24:115-
119.
Maes, A. and A. Cremers. 1977. Charge density effects in ion exchange. Part 1.
Heterovalent exchange equilibria. J. Chem. Soc. Faraday I. 73:1807-1814.
Martin, R.L. 1961. Adsorption on the liquid phase in gas chromatography. Anal.
Chem. 33:347-352.
Martin, R.T. 1959. Water-vapor sorption on kaolinite: Hysteresis, pp. 259-278. In
A. Swineford (ed.) Clays and Clay Minerals monograph No. 2., Proc. Sixth
National Conf., Berkeley, CA.
McClellan, A.L. and H.F. Harnsberger. 1967. Cross-sectional areas of molecules
adsorbed on solid surfaces. J. Colloid Interface Sci. 23:577-599.
Okamura, J.P. and D.T. Sawyer. 1971. Adsorption as a function of molecular
parameters in gas-solid chromatography. Anal. Chem. 43:1730-1733.
Okamura, J. P. and D.T. Sawyer. 1973. Gas chromatographic studies of the
sorptive interactions on normal and halogenated hydrocarbons with
water-modified soil, silica, and chromosorb W. Anal. Chem. 45:80-84.
Peterson, M.S., L.W. Lion, and C.A. Shoemaker. 1988. Influence of vapor-phase
sorption on the fate of trichloroethylene in an unsaturated aquifer system.
Environ. Sci. Technol. 22:571-578.

157
Pinder, G.F. and L.M. Abrióla. 1986. On the simulation of non-aqueous phase
organic compounds in the subsurface. Water Resour. Res. 22:109S-
119S.
Pinnavaia, T.J., P.L. Hall, S.C. Cady, and M.M. Mortland. 1974. Aromatic
radical cation formation on the intracrystal surfaces of transition metal
layer lattice silicates. J. Phys. Chem. 78:994-999.
Pinnavaia, T.J. and M.M. Mortland. 1971. Interlamellar metal complexes on
layer silicates. I. Copper (ll)-arene complexes on montmorillonite. J.
Phys. Chem. 75:3957-3962.
Poe, S.H., K.T. Valsaraj, L.J. Thibodeaux, and C. Springer. 1988. Equilibrium
vapor phase adsorption of volatile organic chemicals on dry soils. J.
Hazardous. Mater. 19:17-32.
Rao, P.S.C., R.A. Ogwada, and R.D. Rhue. 1989. Adsorption of volatile organic
compounds on anhydrous and hydrated sorbents: Equilibrium adsorption
and energetics. Chemosphere. 18:2177-2191.
Rhue, R.D., K.D. Pennell, P.S.C. Rao and W. H. Reve. 1989. Competitive
adsorption of alkylbenzene and water vapors on predominantly mineral
surfaces. Chemosphere. 18:1971-1986.
Rhue, R.D. and P.S.C. Rao. 1990. Application of gas chromatography
techniques for characterizing vapor sorption on soils: A review.
Chemosphere (in press).
Rhue, R.D., P.S.C. Rao, and R.E. Smith. 1988. Vapor-phase adsorption of
alkylbenzenes and water on soils and clays. Chemosphere. 17:727-741.
Rhue, R.D. and W.H. Reve. 1990. Effect of chlorite and perchlorate anions on
CEC of several soil and clay materials. Soil Sci. Soc. Am. J. 54:705-708.
Ross, S. and J. Olivier. 1964. On physical adsorption. John Wiley & Sons, New
York.
Shoemaker, C.A., T.B. Culver, L.W. Lion, and M.G. Peterson. 1990. Analytical
models of the impact of two-phase sorption on subsurface transport of
volatile chemicals. Water Resour. Res. 26:745-758.
Sing, K.S.W., D.H. Everett, R.A.W. Haul, L. Moscou, R.A. Pierotti, J. Rouquerol,
and T. Siemieniewska. 1985. Reporting physisorption data for gas/solid
systems. Pure Appl. Chem. 57:603-619.

158
Sleep, B.E. and J.F. Sykes. 1989. Modeling the transport of volatile organics in
variably saturated media. Water Resour. Res. 25:81-92.
Spencer, W.F. and M.M. Cliath. 1970. Desorption of lindane from soil as related
to vapor density. Soil Sci. Soc. Amer. Proc. 34:574-578.
Spencer, W.F. and M.M. Cliath. 1972. Volatility of DDT and related compounds.
J. Agr. Food Chem. 20:645-649.
Spencer, W.F. and M.M. Cliath. 1974. Factors affecting vapor loss of trifluralin
from soil. J. Agr. Food Chem. 22:987-991.
Sposito, G., R. Prost, and J.-P. Gaultier. 1983. Infrared spectroscopic study of
adsorbed water on reduced-charge Na/Li-montmorillonites. Clays and
Clay Minerals. 31:9-16.
Valsaraj, K.T. and L.J. Thibodeaux. 1988. Equilibrium adsorption of chemical
vapors on surface soils, landfills, and land farms-A review. J. Hazardous
Mater. 19:79-99.
van Olphen, H. and J.J. Fripiat. 1979. Data handbook for clay materials and
other non-metallic minerals. Pergamon Press, New York.
Verschueren, K. 1983. Handbook of environmental data on organic chemicals.
2nd ed. Van Nostrand Reinhold, New York.
Vidal-Madjar, C., G. Gulochon, and B.L. Karger. 1976. Adsorption potential of
hydrocarbons at the gas-liquid interface of water. J. Phys. Chem. 80:394-
402.
Wade, P. 1954. Soil fumigation. I. The sorption of ethylene dibromide by soils. J.
Sci. Food Agrie. 5:184-192.
Weast, R.C. (ed.) 1987. Handbook of chemistry and physics. 67th ed. CRC
Press. Cleveland, OH.
Weiss, A. and J. Russow. 1963. The location of exchangeable cations on
kaolinites. pp. 203-213. In Proc. Int. Clay Conf. Vol. 1., Stockholm.

BIOGRAPHICAL SKETCH
Kurt Davis Pennell was born in Boston, Massachusetts, on July 25, 1962,
to John and Caroline Pennell. He grew up in Harvard, Massachusetts, not to be
confused with Cambridge, where he attended The Bromfield School. He obtained
a B.S. degree in Forestry with high distinction from the University of Maine in May
of 1984. While at Maine he played varsity tennis and remains a loyal, albeit
distant, Black Bear fan. In July of 1984 he embarked on graduate studies at North
Carolina State University, from which he received a M.S. degree in Forestry with
a minor in Soil Science in December of 1986. He began a Ph.D. program in Soil
Physics at the University of Florida in August of 1986. Over the past four years
he has acquired an appreciation of science, academia, and the questioning of
paradigms. He has accepted a post-doctoral research associate position with the
Environmental and Water Resources Engineering program at The University of
Michigan.
159

I certify that I have read this study and that in my opinion it conforms to
acceptable standards of scholarly presentation and is fully adequate, in scope and
quality, as a dissertation for the degree of Doctor of Philosophy.
Ujl¿Lufb k
Arthur G. Horns
by, Chair
Professor of Soil Science
I certify that I have read this study and that in my opinion it conforms to
acceptable standards of scholarly presentation and is fully adequate, in scope and
quality, as a dissertation for the degree of Doctor of Philosophy.
7^x0?^
R. Dean Rhue
Associate Professor of Soil
Science
I certify that I have read this study and that in my opinion it conforms to
acceptable standards of scholarly presentation and is fully adequate, in scope and
quality, as a dissertation for the degree of Doctor of Philosophy.
Professor of Soil Science
I certify that I have read this study and that in my opinion it conforms to
acceptable standards of scholarly presentation and is fully adequate, in scope and
quality, as a dissertation for the degree of Doctor of Philosophy.
Professor of Environmental
Engineering Sciences

I certify that I have read this study and that in my opinion it conforms to
acceptable standards of scholarly presentation and is fully adequate, in scope and
quality, as a dissertation for the degree of Doctor of Philosophy.
K. Ramesh Reddy
Professor of Soil Science
This dissertation was submitted to the Graduate Faculty of the College of
Agriculture and to the Graduate School and was accepted as partial fulfillment of
the requirements for the degree of Doctor of Philosophy.
December, 1990
'(ZcA^.
allege of Agriodti
Dean,
tture
Dean, Graduate School
l

3 1262 08556 9811



xml version 1.0 encoding UTF-8
REPORT xmlns http:www.fcla.edudlsmddaitss xmlns:xsi http:www.w3.org2001XMLSchema-instance xsi:schemaLocation http:www.fcla.edudlsmddaitssdaitssReport.xsd
INGEST IEID EVJI81E6L_M5202E INGEST_TIME 2011-10-06T21:24:00Z PACKAGE AA00004767_00001
AGREEMENT_INFO ACCOUNT UF PROJECT UFDC
FILES



PAGE 1

$ 0(&+$1,67,& ,19(67,*$7,21 2) 3;
PAGE 2

&RS\ULJKW E\ .XUW 'DYLV 3HQQHOO

PAGE 3

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

PAGE 4

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

PAGE 5

7$%/( 2) &217(176 $&.12:/('*(0(176 LLL $%675$&7 YLL &+$37(56 ,1752'8&7,21 9DSRU3KDVH 6RUSWLRQ $GVRUSWLRQ RQ 2YHQ'U\ 6RUEHQWV &RPSHWLWLYH $GVRUSWLRQ 6RUSWLRQ DW +LJK 5HODWLYH +XPLGLW\ 5HVHDUFK 6XPPDU\ 9$3253+$6( 62537,21 2) 3;
PAGE 6

&203(7,7,9( $'62537,21 2) 3;
PAGE 7

$EVWUDFW RI 'LVVHUWDWLRQ 3UHVHQWHG WR WKH *UDGXDWH 6FKRRO RI WKH 8QLYHUVLW\ RI )ORULGD LQ 3DUWLDO )XOILOOPHQW RI WKH 5HTXLUHPHQWV IRU WKH 'HJUHH RI 'RFWRU RI 3KLORVRSK\ $ 0(&+$1,67,& ,19(67,*$7,21 2) 3;
PAGE 8

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

PAGE 9

&+$37(5 ,1752'8&7,21 9DSRU3KDVH 6RUSWLRQ 7KH ZLGHVSUHDG GHWHFWLRQ RI YRODWLOH RUJDQLF FKHPLFDOV 92&Vf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f +RZHYHU D FRPSUHKHQVLYH XQGHUVWDQGLQJ RI WKH SURFHVVHV UHVSRQVLEOH IRU 92& VRUSWLRQ LQ WKH XQVDWXUDWHG ]RQH KDV \HW WR EH DWWDLQHG 7KLV LV SDUWLFXODUO\ WUXH IRU VRLOV DW KLJK UHODWLYH KXPLGLW\ 5+f DW ZKLFK WLPH D QXPEHU RI PHFKDQLVPV PD\ FRQWULEXWH WR RUJDQLF YDSRU UHWHQWLRQ LQFOXGLQJ GLVVROXWLRQ LQWR DGVRUEHG ZDWHU ILOPV SDUWLWLRQLQJ LQWR RUJDQLF FDUERQ 2&f DQG DGVRUSWLRQ DW JDVOLTXLGVROLG LQWHUIDFHV

PAGE 10

$GVRUSWLRQ RQ 2YHQ'U\ 6RUEHQWV 7KH DGVRUSWLRQ RI YDSRUV RQ RYHQGU\ VRUEHQWV KDV EHHQ VWXGLHG LQ GHWDLO DQG SURYLGHV D EDVLV IURP ZKLFK WR LQYHVWLJDWH DGVRUSWLRQ LQ PRUH FRPSOH[ V\VWHPV ,Q KLV FODVVLF WUHDWLVH RQ YDSRUSKDVH DGVRUSWLRQ %UXQDXHU f GHILQHV DGVRUSWLRQ DV WKH DFFXPXODWLRQ RI D FKHPLFDO VSHFLHV IURP RQH EXON SKDVH DW WKH VXUIDFH RI DQRWKHU EXON SKDVH ZLWKRXW SHQHWUDWLQJ WKH VWUXFWXUH RI WKH VHFRQG SKDVH %DVHG RQ WKH QDWXUH RI DGVRUEDWHDGVRUEHQW LQWHUDFWLRQV DGVRUSWLRQ FDQ EH FODVVLILHG DV HLWKHU SK\VLFDO RU FKHPLFDO 7DEOH f 7KH DGVRUSWLRQ RI QRQSRODU RUJDQLF YDSRUV RQ PLQHUDO VXUIDFHV LV JHQHUDOO\ FRQVLGHUHG WR UHVXOW IURP QRQVSHFLILF PROHFXODU LQWHUDFWLRQV VXFK DV YDQ GHU :DDOV IRUFHV ZKLFK DUH DOVR UHVSRQVLEOH IRU YDSRU FRQGHQVDWLRQ DQG GHYLDWLRQV IURP LGHDO EHKDYLRU &KHPLFDO DGVRUSWLRQ RI DURPDWLF K\GURFDUERQV KDV EHHQ REVHUYHG RQ &XVDWXUDWHG PRQWPRULOORQLWH XVLQJ LQIUDUHG DQG XOWUDYLROHWYLVLEOH VSHFWURVFRS\ HJ 3LQQDYDLD HW DO 3LQQDYDLD DQG 0RUWODQG f ,W ZDV SRVWXODWHG WKDW WKH FKHPLVRUEHG VSHFLHV ZDV FRRUGLQDWHG ZLWK H[FKDQJHDEOH &XOOf LRQV YLD WF HOHFWURQV +RZHYHU LQWHUDFWLRQV RI WKLV QDWXUH DUH W\SLFDOO\ OLPLWHG WR FOD\ PLQHUDOV VDWXUDWHG ZLWK FHUWDLQ WUDQVLWLRQ PHWDOV XQGHU DQK\GURXV FRQGLWLRQV 7KH HTXDWLRQV RI )UHXGOLFK /DQJPXLU DQG %UXQDXHU (PPHWW DQG 7HOOHU %(7f DUH IUHTXHQWO\ XVHG WR LQWHUSUHW JDVVROLG DGVRUSWLRQ GDWD $OWKRXJK WKH /DQJPXLU DQG %(7 PRGHOV FDQ EH GHULYHG WKHRUHWLFDOO\ WKH )UHXGOLFK DGVRUSWLRQ PRGHO LV EDVHG VROHO\ RQ WKH IROORZLQJ HPSLULFDO HTXDWLRQ Q 6 N3 f

PAGE 11

7DEOH &RPSDULVRQ RI SK\VLFDO DQG FKHPLFDO DGVRUSWLRQ RI YDSRUV RQ VROLGV 3URSHUW\ 3K\VLFDO $GVRUSWLRQ &KHPLFDO $GVRUSWLRQ (QWKDOS\ RI $GVRUSWLRQ N-PROH N-PROH 5HYHUVLELOLW\ RI $GVRUSWLRQ 5HGXFWLRQ ,Q YDSRU SUHVVXUH UHVXOWV LQ GHVRUSWLRQ 6WURQJHU WUHDWPHQW UHTXLUHG IRU GHVRUSWLRQ 'HVRUSWLRQ PD\ UHVXOW LQ FKHPLFDO DOWHUDWLRQV $GVRUEHG /D\HUV 0XOWLOD\HU IRUPDWLRQ /LPLWHG WR PRQROD\HU $GVRUSWLRQ 5DWH ,QVWDQWDQHRXV 0D\ EH OLPLWHG E\ GLIIXVLRQ 5DSLG RU VORZ 0D\ UHTXLUH DFWLYDWLRQ HQHUJ\ $GVRUEDWH $GVRUEHQW ,QWHUDFWLRQ 1RQVSHFLILF 9DQ GHU :DDOV IRUFHV 6SHFLILF &KHPLFDO ERQG IRUPDWLRQ

PAGE 12

ZKHUH 6 LV WKH DPRXQW DGVRUEHG PJJf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f FRQVLGHUV WKH UDWH RI HYDSRUDWLRQ GHVRUSWLRQf IURP RFFXSLHG VLWHV WR EH HTXDO WR WKH UDWH RI FRQGHQVDWLRQ DGVRUSWLRQf RQ WKH EDUH VXUIDFH ZKLFK \LHOGV WKH IROORZLQJ HTXDWLRQ 6 3 f 6P .3 ZKHUH 6 LV WKH DPRXQW DGVRUEHG PJJf 6P LV WKH PRQROD\HU DGVRUSWLRQ FDSDFLW\ PJJf 3 LV WKH HTXLOLEULXP YDSRU SUHVVXUH DQG LV WKH UDWH RI DGVRUSWLRQ GLYLGHG E\ WKH UDWH RI GHVRUSWLRQ 7KH /DQJPXLU DGVRUSWLRQ LVRWKHUP LV OLQHDU DW ORZ YDSRU SUHVVXUHV DQG UHDFKHV D OLPLWLQJ YDOXH DW RU DERYH YDSRU SUHVVXUHV FRUUHVSRQGLQJ WR PRQROD\HU FRYHUDJH )LJXUH Df ,PSOLFLW LQ WKH NLQHWLF GHULYDWLRQ RI WKH /DQJPXLU HTXDWLRQ DUH WKH IROORZLQJ DVVXPSWLRQV f WKH DGVRUEDWH EHKDYHV DV DQ LGHDO JDV LQ WKH EXON SKDVH f DGVRUSWLRQ LV OLPLWHG WR PRQROD\HU FRYHUDJH f WKH HQHUJ\ RI DGVRUSWLRQ LV FRQVWDQW f QR DGVRUEDWHDGVRUEDWH LQWHUDFWLRQV RFFXU f DGVRUSWLRQ LV ORFDOL]HG

PAGE 13

3 PP +Jf 3 )LJXUH *DVVROLG DGVRUSWLRQ LVRWKHUPV FKDUDFWHULVWLF RI WKH Df /DQJPXLU PRGHO 7\SH ,f DQG Ef %(7 PRGHO 7\SH ,,f

PAGE 14

LH VLWHVSHFLILFf 7KH DVVXPSWLRQ RI FRQVWDQW DGVRUSWLRQ HQHUJ\ DQG WKH DEVHQFH RI DGVRUEDWHDGVRUEDWH LQWHUDFWLRQV DUH UDUHO\ YDOLG 5RVV DQG 2OLYLHU f +RZHYHU WKH HUURUV DVVRFLDWHG ZLWK WKHVH DVVXPSWLRQV WHQG WR QXOOLI\ RQH DQRWKHU DQG WKXV WKH VXFFHVV RI WKH /DQJPXLU HTXDWLRQ PD\ EH DWWULEXWHG LQ SDUW WR WKLV FRLQFLGHQFH %UXQDXHU (PPHWW DQG 7HOOHU %(7f H[WHQGHG WKH /DQJPXLU PRGHO WR DFFRXQW IRU PXOWLOD\HU DGVRUSWLRQ E\ DVVXPLQJ WKDW WKH /DQJPXLU HTXDWLRQ LV DSSOLFDEOH WR HDFK DGVRUEHG OD\HU LH HDFK OD\HU KDV D IL[HG QXPEHU RI DGVRUSWLRQ VLWHVf 7KH ILUVW OD\HU LV DVVXPHG WR KDYH D KHDW RI DGVRUSWLRQ HTXDO WR 4 ZKLOH DOO VXFFHVVLYH OD\HUV KDYH KHDWV RI DGVRUSWLRQ HTXLYDOHQW WR WKH KHDW RI YDSRUL]DWLRQ 4Yf $GVRUSWLRQ DQG GHVRUSWLRQ DUH FRQVLGHUHG WR RFFXU RQO\ IURP H[SRVHG VXUIDFHV DQG DW HTXLOLEULXP WKH DPRXQW RI VROXWH DGVRUEHG RQ HDFK OD\HU LV DW VWHDG\ VWDWH 7KH %(7 HTXDWLRQ LV JLYHQ DV IROORZV 6 &33f f 6P 33f>33&33f@ ZKHUH 6 LV WKH DPRXQW DGVRUEHG PJJf 6P LV WKH PRQROD\HU DGVRUSWLRQ FDSDFLW\ PJJf 3 LV WKH HTXLOLEULXP YDSRU SUHVVXUH 34 LV WKH VDWXUDWHG YDSRU SUHVVXUH DQG & LV D SDUDPHWHU UHODWHG WR WKH KHDW RI DGVRUSWLRQ 7KH %(7 HTXDWLRQ W\SLFDOO\ \LHOGV 7\SHOO DGVRUSWLRQ LVRWKHUPV ZKLFK DUH FKDUDFWHULVWLF RI PXOWLOD\HU IRUPDWLRQ UHVXOWLQJ IURP SK\VLFDO DGVRUSWLRQ )LJXUH Ef

PAGE 15

7KH YDOXHV RI 6P DQG & FDQ EH REWDLQHG IURP D OHDVW VTXDUHV ILW RI DGVRUSWLRQ GDWD WR WKH OLQHDU IRUP RI WKH %(7 HTXDWLRQ JLYHQ DV IROORZV 33 &f33 f 633f 6P& 6P& (VWLPDWHG YDOXHV RI 6P DQG & IRU D UDQJH RI DGVRUEDWHDGVRUEHQW V\VWHPV DUH SUHVHQWHG LQ 7DEOH ,Q WKHRU\ WKH DSSUR[LPDWH YDOXH RI & LV JLYHQ E\ WKH IROORZLQJ HTXDWLRQ 2U 4-57 & H f ZKHUH 5 LV WKH JDV FRQVWDQW DQG 7 LV WKH WHPSHUDWXUH r.f 3URYLGHG WKH KHDW RI YDSRUL]DWLRQ 4Yf LV NQRZQ WKH KHDW RI DGVRUSWLRQ 4FDQ EH FDOFXODWHG IURP WKH YDOXH RI & HJ &KLRX DQG 6KRXS -XULQDN DQG 9ROPDQ f +RZHYHU 6LQJ HW DO f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f

PAGE 16

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
PAGE 17

5KXH HW DO f UHSRUWHG WKDW DGVRUSWLRQ RI S[\OHQH YDSRUV RQ RYHQGU\ VLOLFD JHO ZDV FRQVLGHUDEO\ JUHDWHU WKDQ WKDW RQ NDROLQ EHQWRQLWH DQG /XOD DTXLIHU PDWHULDO )LJXUH Df +RZHYHU ZKHQ WKH DGVRUSWLRQ GDWD ZHUH QRUPDOL]HG WR WKH PRQROD\HU DGVRUSWLRQ FDSDFLW\ 6RI HDFK DGVRUEHQW WKH UHODWLYH DGVRUSWLRQ ZDV HVVHQWLDOO\ WKH VDPH IRU DOO DGVRUEHQWV VWXGLHG )LJXUH Ef $ VLPLODU WUHQG ZDV REVHUYHG IRU WKH DGVRUSWLRQ RI HWK\OHQH GLEURPLGH ('%f RQ D QXPEHU RI VRLOV -XULQDN DQG 9ROPDQ f 7KH VOLJKW LQFUHDVH LQ UHODWLYH DGVRUSWLRQ QRWHG IRU /XOD DTXLIHU PDWHULDO FRUUHVSRQGHG WR D ODUJHU YDOXH RI & VXJJHVWLQJ WKDW VSHFLILF DGVRUEDWHDGVRUEHQW LQWHUDFWLRQV PD\ KDYH RFFXUUHG +RZHYHU WKH RYHUDOO VLPLODULW\ LQ UHODWLYH DGVRUSWLRQ LV UHPDUNDEOH FRQVLGHULQJ WKH YDULDWLRQ LQ DGVRUEHQW SURSHUWLHV DQG LQGLFDWHV WKDW WKH DGVRUSWLRQ RI RUJDQLF YDSRUV RQ PLQHUDO VXUIDFHV LV SULPDULO\ D IXQFWLRQ RI VXUIDFH DUHD -XULQDN DQG 9ROPDQ 5KXH HW DO f 7KH VLJQLILFDQFH RI WKH PRQROD\HU DGVRUSWLRQ FDSDFLW\ REWDLQHG IURP WKH %(7 PRGHO KDV UHFHQWO\ FRPH XQGHU VFUXWLQ\ 5KXH HW DO f VXJJHVWHG WKDW IRU V\VWHPV H[KLELWLQJ ORZ YDOXHV RI & WKH FRYHUDJH RI WKH HQWLUH VXUIDFH ZLWK D VLQJOH PRQROD\HU PD\ QRW RFFXU DW DQ\ UHODWLYH YDSRU SUHVVXUH ,Q IDFW PXOWLOD\HU DGVRUSWLRQ RI ('% RQ &DVDWXUDWHG PRQWPRULOORQLWH DQG NDROLQLWH ZDV REVHUYHG DW VXUIDFH FRYHUDJHV RI DQG UHVSHFWLYHO\ -XULQDN DQG 9ROPDQ f 7KH FRUUHVSRQGLQJ YDOXHV RI & IRU WKH PRQWPRULOORQLWH DQG NDROLQLWH V\VWHPV ZHUH DQG UHVSHFWLYHO\ ,Q WKHRU\ WKH RQVHW RI PXOWLOD\HU IRUPDWLRQ SULRU WR PRQROD\HU FRYHUDJH ZRXOG UHVXOW LQ WKH IRUPDWLRQ RI GLVFUHWH DGVRUEDWH ILOPV RU

PAGE 18

66P 6 PJJf S;\OHQH 3)Af )LJXUH $GVRUSWLRQ RI S[\OHQH YDSRUV RQ RYHQGU\ VLOLFD JHO NDROLQ EHQWRQLWH DQG /XOD DTXLIHU PDWHULDO H[SUHVVHG DV Df DPRXQW DGVRUEHG DQG Ef UHODWLYH DPRXQW DGVRUEHG UHSRUWHG E\ 5KXH HW DO f

PAGE 19

SDWFKHV RQ WKH DGVRUEHQW VXUIDFH 7KLV VFHQDULR DSSHDUV WR EH UHDVRQDEOH IRU WKH DGVRUSWLRQ RI QRQSRODU RUJDQLF YDSRUV RQ PLQHUDO VXUIDFHV EDVHG RQ WKH VLPLODULW\ LQ WKHLU KHDWV RI DGVRUSWLRQ DQG FRQGHQVDWLRQ 5DR DW DO f &RPSHWLWLYH $GVRUSWLRQ 8QGHU QDWXUDO FRQGLWLRQV WKH DGVRUSWLRQ RI RUJDQLF YDSRUV ZLOO XVXDOO\ RFFXU RQ VXUIDFHV FRQWDLQLQJ DW OHDVW VRPH DGVRUEHG ZDWHU &KLRX DQG 6KRXS f UHSRUWHG WKDW WKH PDJQLWXGH RI ZDWHU WULFKORUREHQ]HQH FKORUREHQ]HQH DQG EHQ]HQH DGVRUSWLRQ RQ RYHQGU\ :HEVWHU VRLO ZDV SRVLWLYHO\ FRUUHODWHG WR DGVRUEDWH SRODULW\ )LJXUH Df ,W VKRXOG EH QRWHG WKDW WKH UHODWLYH DGVRUSWLRQ ZDV VLPLODU IRU DOO DGVRUEDWHV VWXGLHG ZKLFK VXJJHVWV WKDW WKH PRQROD\HU DGVRUSWLRQ FDSDFLW\ GHWHUPLQHG IURP WKH %(7 PRGHO DFFRXQWV IRU YDULDWLRQV LQ ERWK DGVRUEDWH DQG DGVRUEHQW SURSHUWLHV )LJXUH Ef 7KH IDFW WKDW DGVRUEDWH SRODULW\ HQKDQFHG YDSRUSKDVH DGVRUSWLRQ LQGLFDWHV WKDW ZDWHU ZLOO FRPSHWH VWURQJO\ ZLWK RUJDQLF YDSRUV IRU DGVRUSWLRQ VLWHV 7KH DGVRUSWLRQ RI ZDWHU RQ PLQHUDO VXUIDFHV KDV EHHQ DWWULEXWHG WR FDWLRQGLSROH LQWHUDFWLRQV K\GURJHQ ERQGLQJ DQG ZHDN FKDUJH WUDQVIHU ZKLFK IDOO ZLWKLQ WKH H[WUHPHV RI SK\VLFDO DQG FKHPLFDO DGVRUSWLRQ %XUFKLOO HW DO f -XULQDN DQG 9ROPDQ Ef UHSRUWHG WKDW WKH HQWKDOS\ RI ZDWHU DGVRUSWLRQ RQ &D DQG %DVDWXUDWHG NDROLQ ZDV DSSUR[LPDWHO\ N-PROH ZKLFK FRUUHVSRQGHG WR DQ HQWKDOS\ RI FDWLRQ K\GUDWLRQ RI DSSUR[LPDWHO\ N-PROH ,Q FRQWUDVW 5DR HW DO f UHSRUWHG WKDW KHDWV RI DGVRUSWLRQ IRU WULFKORURHWKHQH 7&(f WROXHQH DQG F\FORKH[DQH YDSRUV RQ RYHQGU\ 2OGVPDU VRLO

PAGE 20

VVP 6 PJJf )LJXUH $GVRUSWLRQ RI ZDWHU WULFKORUREHQ]HQH FKORUREHQ]HQH DQG EHQ]HQH RQ RYHQGU\ :RRGEXUQ VRLO H[SUHVVHG DV Df DPRXQW DGVRUEHG DQG Ef UHODWLYH DPRXQW DGVRUEHG UHSRUWHG E\ &KLRX DQG 6KRXS f

PAGE 21

ZHUH DQG N-PROH 7KXV DV WKH UHODWLYH KXPLGLW\ RU VRLO PRLVWXUH FRQWHQW LQFUHDVHV ZDWHU ZLOO GLVSODFH RUJDQLF YDSRUV IURP DGVRUEHQW VXUIDFHV UHVXOWLQJ LQ WKH VXSSUHVVLRQ RI 92& VRUSWLRQ 7KLV ILQGLQJ LV VXSSRUWHG E\ LQIUDUHG VWXGLHV ZKLFK KDYH GHPRQVWUDWHG WKDW S[\OHQH ZDV LPPHGLDWHO\ GLVSODFHG IURP WKH VXUIDFH RI PRQWPRULOORQLWH ZKHQ ODERUDWRU\ DLU ZDV LQWURGXFHG LQWR WKH VDPSOH FHOO & 7 -RKQVWRQ SHUVRQDO FRPPXQLFDWLRQf 3ULRU WR WKH DWWDLQPHQW RI PRQROD\HU FRYHUDJH ZLWK ZDWHU WKH DGVRUSWLRQ RI RUJDQLF YDSRUV PD\ SURFHHG HVVHQWLDOO\ XQKLQGHUHG RQ H[SRVHG PLQHUDO VXUIDFHV 5KXH HW DO f UHSRUWHG WKDW S[\OHQH DGVRUSWLRQ RQ VLOLFD JHO DQG NDROLQ ZDV QRW VXSSUHVVHG XQWLO WKH 5+ ZDV JUHDWHU WKDQ WKDW FRUUHVSRQGLQJ WR WKH PRQROD\HU DGVRUSWLRQ FDSDFLW\ GHWHUPLQHG IURP WKH %(7 PRGHO LH 5+ bf )LJXUH f ,Q FRQWUDVW &DOO f REVHUYHG D VXEVWDQWLDO GHFUHDVH LQ HWK\OHQH GLEURPLGH DGVRUSWLRQ DW b 5+ )LJXUH f 5HJDUGOHVV RI WKH H[DFW SRLQW DW ZKLFK FRPSHWLWLYH HIIHFWV EHFRPH HYLGHQW WKHVH GDWD LQGLFDWH WKDW WKH SUHVHQFH RI ZDWHU YDSRU QRW RQO\ UHGXFHV RUJDQLF YDSRU VRUSWLRQ EXW DOVR UHVXOWV LQ D VKLIW IURP 7\SHOO DGVRUSWLRQ LVRWKHUPV WR RQHV WKDW DUH HVVHQWLDOO\ OLQHDU ,Q RUGHU WR SUHGLFW WKH FRPSHWLWLYH DGVRUSWLRQ RI ZDWHU DQG RUJDQLF YDSRUV RQ PLQHUDO VXUIDFHV D WZRFRPSRQHQW DGVRUSWLRQ PRGHO PXVW EH HPSOR\HG )RUWXQDWHO\ WKH %(7 HTXDWLRQ KDV EHHQ PRGLILHG E\ +LOO D Ef DQG PRUH UHFHQWO\ E\ 5KXH HW DO f WR DFFRXQW IRU DGVRUSWLRQ IURP WZRFRPSRQHQW V\VWHPV 7KH RQO\ DGGLWLRQDO DVVXPSWLRQ UHTXLUHG WR GHULYH WKH HTXDWLRQ RI 5KXH HW DO f LV WKDW HDFK FRPSRQHQW DGVRUEV RQO\ RQWR H[SRVHG PLQHUDO VXUIDFHV

PAGE 22

V PJJf 6 PJJf S;\OHQH 3I f )LJXUH 7KH HIIHFW RI 5+ RQ WKH DGVRUSWLRQ RI S[\OHQH YDSRUV RQ Df NDROLQ DQG Ef VLOLFD JHO UHSRUWHG E\ 5KXH HW DO f

PAGE 23

('% 33f FQ )LJXUH 7KH HIIHFW RI 5+ RQ WKH DGVRUSWLRQ RI ('% YDSRUV RQ :KLWWOHVH\ %ODFN )HQ VRLO UHSRUWHG E\ &DOO f

PAGE 24

RU DGVRUEHG OD\HUV RI LWVHOI 7KLV LPSOLHV WKDW WKH WZR FRPSRQHQWV IRUP LPPLVFLEOH IOXLGV RQ WKH VXUIDFH ZKLFK LV UHDVRQDEOH IRU DGVRUEDWHV RI ORZ PXWXDO VROXELOLW\ VXFK DV ZDWHU DQG D QRQSRODU RUJDQLF YDSRU 7KH WRWDO DGVRUEHG PDVV RI FRPSRQHQW D 0D PJJf FDQ EH FDOFXODWHG IURP WKH IROORZLQJ HTXDWLRQ 0D DD&D6>;D;Df@ f ZKHUH DD LV WKH PDVV RI FRPSRQHQW D RFFXS\LQJ D XQLW DUHD RI VXUIDFH PJPf &D LV WKH %(7 SDUDPHWHU UHODWHG WR WKH KHDW RI DGVRUSWLRQ GHWHUPLQHG IURP VLQJOHn FRPSRQHQW DGVRUSWLRQ LVRWKHUPV ;D LV WKH UHODWLYH YDSRU SUHVVXUHV RI FRPSRQHQW D DQG 6 LV WKH DUHD RI EDUH VXUIDFH SHU XQLW PDVV RI DGVRUEHQW PJf 8QIRUWXQDWHO\ WKH YDOXH RI 6 LV XQNQRZQ LQ D ELQDU\ V\VWHP DQG WKXV WKH DPRXQW RI HDFK FRPSRQHQW DGVRUEHG FRXOG QRW EH H[SUHVVHG RQ D SHUPDVVRIDGVRUEHQW EDVLV 5KXH HW DOf +RZHYHU WKH WZRFRPSRQHQW PRGHO ZDV HYDOXDWHG E\ FRPSDULQJ WKH PHDVXUHG DQG SUHGLFWHG PDVV IUDFWLRQ RI FRPSRQHQW D )Df RQ WKH VXUIDFH XVLQJ WKH IROORZLQJ HTXDWLRQ 0D )D ‘ f 0D 0E 7KH PXOWLFRPSRQHQW %(7 HTXDWLRQ RI +LOO D Ef LV EDVHG SULPDULO\ RQ WKH %(7 SRVWXODWH ZKLFK VWDWHV WKDW PROHFXOHV RI WKH VHFRQG DQG KLJKHU DGVRUEHG OD\HUV SRVVHVV HYDSRUDWLRQFRQGHQVDWLRQ SURSHUWLHV RI WKH EXON OLTXLG ,I WKLV DVVXPSWLRQ LV YDOLG LW IROORZV WKDW DGVRUSWLRQ DQG GHVRUSWLRQ IURP WKH VHFRQG DQG VXFFHHGLQJ OD\HUV RI D ELQDU\ V\VWHP VKRXOG DSSUR[LPDWH WKH SURSHUWLHV RI WKH OLTXLG PL[WXUH ,Q DGGLWLRQ +LOO DVVXPHG WKDW DUHD IUDFWLRQ RI

PAGE 25

FRPSRQHQW D \Df LV UHODWHG WR WKH PROH IUDFWLRQ 1Df E\ WKH IROORZLQJ HTXDWLRQ 1D &D;Ef ;E&E@ f 6DP ;D;Ef>;D&Df ;E&Ef@ ZKHUH 6D LV WKH DPRXQW RI FRPSRQHQW D DGVRUEHG PJJf 6DP LV WKH PRQROD\HU DGVRUSWLRQ FDSDFLW\ RI FRPSRQHQW D PJJf ;D DQG ? DUH WKH UHODWLYH YDSRU SUHVVXUHV RI FRPSRQHQW D DQG E UHVSHFWLYHO\ DQG &D DQG &E DUH WKH %(7 SDUDPHWHUV UHODWHG WR WKH KHDW RI DGVRUSWLRQ IRU FRPSRQHQW D DQG E UHVSHFWLYHO\ 7KH YDOXHV RI 6DP &D DQG &E DUH GHWHUPLQHG IURP VLQJOHFRPSRQHQW DGVRUSWLRQ LVRWKHUPV ,I RQH RI WKH FRPSRQHQWV LV DEVHQW LH ;D RU ;E f +LOOfV HTXDWLRQ UHGXFHV WR WKH VLQJOHFRPSRQHQW %(7 HTXDWLRQ $OWKRXJK WKH GHULYDWLRQ UHIHUUHG WR KHUH LV OLPLWHG WR D WZRFRPSRQHQW V\VWHP LQ WKHRU\ WKH +LOO HTXDWLRQ FDQ DFFRPPRGDWH DQ LQILQLWH QXPEHU RI FRPSRQHQWV 'XH WR WKH ODFN RI VXLWDEOH DGVRUSWLRQ GDWD WKH WZRFRPSRQHQW PRGHOV RI 5KXH HW DO f DQG +LOO D Ef KDYH UDUHO\ EHHQ WHVWHG

PAGE 26

6RUSWLRQ DW +LJK 5HODWLYH +XPLGLW\ $W 5+V DSSURDFKLQJ VDWXUDWLRQ LH 5+ bf WKH VRUSWLRQ RI RUJDQLF YDSRUV KDV EHHQ DWWULEXWHG WR SDUWLWLRQLQJ LQWR RUJDQLF FDUERQ &KLRX DQG 6KRXS f 7KLV K\SRWKHVLV LV EDVHG RQ f WKH OLQHDU QDWXUH RI EHQ]HQH DQG FKORUREHQ]HQH YDSRU DGVRUSWLRQ LVRWKHUPV RQ :RRGEXUQ VRLO DW b UHODWLYH KXPLGLW\ DQG f WKH VLPLODULW\ LQ WKH PDJQLWXGH RI VUEDWH XSWDNH IURP WKH DTXHRXV DQG YDSRU SKDVH +RZHYHU OLQHDU LVRWKHUPV KDYH EHHQ REWDLQHG IRU D UDQJH RI VRUEHQWV LQFOXGLQJ WKRVH ZLWK WUDFH OHYHOV RI RUJDQLF FDUERQ 2&f VXFK DV NDROLQ VLOLFD JHO DQG &DVDWXUDWHG PRQWPRULOORQLWH &DOO 5KXH HW DO f ,Q DGGLWLRQ YDSRUSKDVH VRUSWLRQ FRHIILFLHQWV QRUPDOL]HG IRU 2& .FDOFXODWHG IRU VRUEHQWV RI ORZ 2& FRQWHQW KDYH UHSHDWHGO\ EHHQ IRXQG WR EH RUGHUV RI PDJQLWXGH JUHDWHU WKDQ OLWHUDWXUH YDOXHV 5KXH HW DO 3HWHUVRQ HW DO f $OWKRXJK WKHVH GDWD VXJJHVW WKDW RWKHU PHFKDQLVPV PD\ FRQWULEXWH WR WKH YDSRUSKDVH VRUSWLRQ DW KLJK 5+V WKH VRUSWLRQ RI RUJDQLF YDSRUV RQ K\GUDWHG VRLOV LV ZLGHO\ GHVFULEHG E\ GLVVROXWLRQ LQWR DGVRUEHG ZDWHU ILOPV DQG VXEVHTXHQW SDUWLWLRQLQJ LQWR 2& %DHKU *ORWIHOW\ DQG 6FKRPEXUJ -XU\ HW DO f 7KH DGVRUSWLRQ RI LQVROXEOH DQG VSDULQJO\VROXEOH RUJDQLF YDSRUV KDV DOVR EHHQ LQYHVWLJDWHG E\ JDV FKURPDWRJUDSK\ *&f ,Q JHQHUDO 7\SHOOO LVRWKHUPV KDYH EHHQ REWDLQHG IRU WKH DGVRUSWLRQ RI QRQSRODU YDSRUV RQ K\GUDWHG VRUEHQWV ZLWK KHDWV RI DGVRUSWLRQ WKDW DUH VPDOOHU WKDQ KHDWV RI YDSRUL]DWLRQ 'RUULV DQG *UD\ .DUJHU HW DO D Ef 7KHVH GDWD VXJJHVW WKDW WKH JDVOLTXLG

PAGE 27

LQWHUIDFH RI DGVRUEHG ZDWHU ILOPV DFWV DV D ORZ HQHUJ\ VXUIDFH WRZDUG QRQSRODU YDSRUV 2QFH WKH VXUIDFH LV FRYHUHG ZLWK VHYHUDO PRQRPROHFXODU OD\HUV RI ZDWHU LW DSSHDUV WKDW WKH VRUEHQW KDV QR HIIHFW RQ YDSRUSKDVH DGVRUSWLRQ .DUJHU HW DO D Ef FRQFOXGHG WKDW DGVRUEHG ZDWHU ILOPV EHWZHHQ DQG QP LQ WKLFNQHVV KDYH SURSHUWLHV VLPLODU WR EXON ZDWHU 0HDVXUHPHQWV RI WKH FKDQJH LQ VXUIDFH WHQVLRQ RI EXON ZDWHU ZLWK YDSRU SUHVVXUH DOVR LQGLFDWH WKDW QRQSRODU RUJDQLF YDSRUV DUH DGVRUEHG DW WKH JDVOLTXLG LQWHUIDFH %ODQN DQG 2WWHZLOO &XWWLQJ DQG -RQHV +DX[ZHOO DQG 2WWHZLOO f 'XH WR WKH ODUJH VXUIDFH DUHD RI DGVRUEHG ZDWHU ILOPV DGVRUSWLRQ DW WKH JDVOLTXLG LQWHUIDFH RI K\GUDWHG VRLOV PD\ FRQWULEXWH VLJQLILFDQWO\ WR 92& VRUSWLRQ ,Q IDFW &DOO f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

PAGE 28

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b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

PAGE 29

7DEOH 6HOHFWHG SK\VLFRFKHPLFDO SURSHUWLHV RI S[\OHQH 3URSHUW\ 9DOXH 6WUXFWXUH 0ROHFXODU :HLJKW %RLOLQJ 3RLQW 'HQVLW\ 6ROXELOLW\ 9DSRU 3UHVVXUH +HQU\fV /DZ &RQVWDQW &+&+f JPROH r& JP/ r&f PJ/ r&f PP +J r&f ; n P DWPPROH D 'DWD REWDLQHG IURP 9HUVFKXHUHQ f DQG :HDVW f

PAGE 30

,Q &KDSWHU WKH DGVRUSWLRQ RI S[\OHQH YDSRUV RQ &D 1D DQG /L VDWXUDWHG NDROLQ ZDV PHDVXUHG XVLQJ WKH IORZHTXLOLEUDWLRQ PHWKRG 7KH HIIHFW RI FDWLRQ VDWXUDWLRQ RQ WKH FRPSHWLWLYH DGVRUSWLRQ RI ZDWHU DQG S[\OHQH YDSRUV ZDV DOVR VWXGLHG 7KHVH GDWD ZHUH XVHG WR HYDOXDWH WKH WZRFRPSRQHQW %(7 DGVRUSWLRQ PRGHOV RI +LOO D Ef DQG 5KXH HW DO f /LVDWXUDWHG NDROLQ ZDV XWLOL]HG DV D UHIHUHQFH VXUIDFH IRU WKH VWXG\ RI ZDWHU DQG RUJDQLF YDSRU VRUSWLRQ LQ &KDSWHU +RZHYHU WKHUH KDV EHHQ FRQVLGHUDEOH GHEDWH LQ WKH OLWHUDWXUH DV WR ZKHWKHU RU QRW /LNDROLQ DFWXDOO\ UHSUHVHQWV D VXUIDFH IUHH RI FDWLRQ K\GUDWLRQ HIIHFWV 7KXV WKH PHFKDQLVP UHVSRQVLEOH IRU UHGXFHG ZDWHU DGVRUSWLRQ RQ /LNDROLQ ZDV LQYHVWLJDWHG E\ JUDYLPHWULF VSHFWURVFRSLF DQG LRQ H[WUDFWLRQ WHFKQLTXHV LQ &KDSWHU

PAGE 31

&+$37(5 9$3253+$6( 62537,21 2) 3;
PAGE 32

UHPDLQ XQFOHDU ,W KDV EHHQ SRVWXODWHG WKDW WKH VRUSWLRQ RI RUJDQLF YDSRUV DW KLJK 5+ FDQ EH GHVFULEHG E\ SDUWLWLRQLQJ LQWR RUJDQLF FDUERQ 2&f &KLRX DQG 6KRXS f 7KLV K\SRWKHVLV ZDV EDVHG RQ WKH OLQHDU QDWXUH RI EHQ]HQH DQG FKORUREHQ]HQH YDSRU VRUSWLRQ LVRWKHUPV REWDLQHG IRU :RRGEXUQ VRLO b RUJDQLF PDWWHUf DW b 5+ DQG WKH VLPLODULW\ EHWZHHQ WKH PDJQLWXGH RI VROXWH XSWDNH IURP WKH DTXHRXV DQG YDSRU SKDVH &KLRX DQG 6KRXS f +RZHYHU DW b 5+ &DOO f REWDLQHG OLQHDU LVRWKHUPV IRU WKH VRUSWLRQ RI HWK\OHQH GLEURPLGH ('%f YDSRUV RQ &DVDWXUDWHG PRQWPRULOORQLWH ZKLFK FRQWDLQHG QR GHWHFWDEOH 2& 5KXH HW DO f DOVR UHSRUWHG OLQHDU LVRWKHUPV IRU S[\OHQH YDSRU VRUSWLRQ RQ VRUEHQWV ZLWK ORZ 2& FRQWHQWV HJ NDROLQ J 2&NJf DQG VLOLFD JHO J 2&NJf DW b UHODWLYH KXPLGLW\ ,Q DGGLWLRQ VRUSWLRQ FRHIILFLHQWV QRUPDOL]HG IRU 2& .Af FDOFXODWHG IURP S[\OHQH VRUSWLRQ GDWD DQG VROXELOLW\ FRQVLGHUDWLRQV ZHUH WR RUGHUV RI PDJQLWXGH JUHDWHU WKDQ S[\OHQH YDOXHV UHSRUWHG LQ WKH OLWHUDWXUH $ VLPLODU WUHQG ZDV QRWHG E\ 3HWHUVRQ HW DO f ZKR UHSRUWHG WKDW OLQHDU VRUSWLRQ FRHIILFLHQWV PHDVXUHG IRU WULFKORURHWK\OHQH 7&(f YDSRU RYHU D UDQJH RI XQVDWXUDWHG FRQGLWLRQV ZHUH WR RUGHUV RI PDJQLWXGH JUHDWHU WKDQ YDOXHV REWDLQHG XQGHU VDWXUDWHG FRQGLWLRQV &KLRX DQG 6KRXS f DOVR IRXQG WKDW WKH YDSRUSKDVH VRUSWLRQ RI EHQ]HQH PGLFKORUREHQ]HQH DQG WULFKORUREHQ]HQH ZDV FRQVLVWHQWO\ JUHDWHU WKDQ VRUSWLRQ IURP DTXHRXV VROXWLRQ HYHQ WKRXJK WKH VRUEHQW VXUIDFH VKRXOG KDYH EHHQ FRYHUHG ZLWK VHYHUDO PRQROD\HUV RI ZDWHU DW b 5+ 7KHVH GDWD VXJJHVW WKDW LQ DGGLWLRQ WR SDUWLWLRQLQJ LQWR VRLO RUJDQLF FDUERQ RWKHU PHFKDQLVPV FRQWULEXWH WR 92& VRUSWLRQ DW KLJK 5+

PAGE 33

'LVVROXWLRQ LQWR DGVRUEHG ZDWHU ILOPV DQG DGVRUSWLRQ DW WKH JDVOLTXLG LQWHUIDFH ZHUH FRQVLGHUHG E\ &DOO f WR EH WKH GRPLQDQW PHFKDQLVPV UHVSRQVLEOH IRU ('% VRUSWLRQ RQ PRLVW VRLOV )RU VSDULQJO\VROXEOH 92&V VXFK DV S[\OHQH WKH PDJQLWXGH RI VRUSWLRQ LV IDU JUHDWHU WKDQ GLVVROXWLRQ LQWR VRUEHG ZDWHU EDVHG RQ VROXELOLW\ OLPLWV LQ EXON ZDWHU 5KXH HW DO f +RZHYHU DGVRUSWLRQ DW WKH LQWHUIDFH EHWZHHQ WKH YDSRU SKDVH DQG EXON ZDWHU KDV EHHQ UHSRUWHG IRU D QXPEHU RI VSDULQJO\VROXEOH 92&V %ODQN DQG 2WWHZLOO &XWWLQJ DQG -RQHV 'UR]G HW DO +DX[ZHOO DQG 2WWHZLOO f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f ZDV REWDLQHG IURP

PAGE 34

)LVKHU 6FLHQWLILF 3URGXFWV 7KH NDROLQ KDG D FDWLRQ H[FKDQJH FDSDFLW\ &(&f RI FPROMNJ DW S+ DQG ZDV SUHGRPLQDQWO\ 1DVDWXUDWHG ZLWK RQO\ WUDFH DPRXQWV RI &D DQG 0J 5KXH HW DO f 6LOLFD JHO 6\ORLG f DYHUDJH SDUWLFOH VL]H RI SP DQG D SRUH YROXPH RI FPJ ZDV REWDLQHG IURP WKH 'DYLVRQ &KHPLFDO 'LYLVLRQ :5 *UDFH t &R %DOWLPRUH 0' 7KH :HEVWHU VRLO D VLOW\ FOD\ ORDP 7\SLF +DSODTXROOf ZDV FROOHFWHG IURP WKH VXUIDFH KRUL]RQ FPf RI D VLWH LQ ,RZD DQG JURXQG WR SDVV D SP PHVK VFUHHQ 7KH :HEVWHU VRLO KDG D &(& RI FPROMNJ DQG ZDV SUHGRPLQDQWO\ &DVDWXUDWHG $ SRUWLRQ RI WKH :HEVWHU VRLO :HEVWHU +3f ZDV WUHDWHG ZLWK K\GURJHQ SHUR[LGH EXIIHUHG WR S+ ZLWK DFHWLF DFLG WR UHPRYH 2& 2UJDQLF FDUERQ FRQWHQW ZDV PHDVXUHG E\ WKH :DNOH\%ODFN KHDWRIGLOXWLRQ PHWKRG 'RQRKRH f 7KH VRUEHQW VXUIDFH DUHDV ZHUH GHWHUPLQHG IURP 1 DGVRUSWLRQ GDWD $GYDQFHG 0DWHULDOV 5HVHDUFK &HQWHU 8QLYHUVLW\ RI )ORULGDf &DWLRQ H[FKDQJH FDSDFLW\ ZDV GHWHUPLQHG E\ ZDVKLQJ WKH VRUEHQWV ZLWK 0 &D&, WLPHV UHPRYLQJ H[FHVV VDOWV ZLWK b HWKDQRO XQWLO D QHJDWLYH FKORULGH WHVW ZDV DFKLHYHG XVLQJ $J1 DQG H[WUDFWLQJ H[FKDQJHDEOH &D ZLWK 0 0J1f 7KH DPRXQW RI &D SUHVHQW LQ WKH 0J1f H[WUDFW ZDV WKHQ PHDVXUHG E\ DWRPLF DEVRUSWLRQ VSHFWURVFRS\ 7KHVH DQG RWKHU VRUEHQW SURSHUWLHV DUH SUHVHQWHG LQ 7DEOH 9DSRU3KDVH $GVRUSWLRQ 6WXGLHV 9DSRUSKDVH VRUSWLRQ RI S[\OHQH ZDV GHWHUPLQHG RQ :HEVWHU VRLO DQG :HEVWHU +3 DW DQG b 5+ DQG RQ NDROLQ DQG VLOLFD JHO DW DQG b 5+ 7KH

PAGE 35

7DEOH 3K\VLFDO DQG FKHPLFDO SURSHUWLHV RI VRUEHQWV XVHG WR VWXG\ VRUSWLRQ RI S[\OHQH YDSRUV 6RUEHQW 2UJDQLF &DUERQ 1 6XUIDFH $UHD &DWLRQ ([FKDQJH &DSDFLW\ 3DUWLFOH 6L]H 6DQG 6LOW &OD\ &OD\ 0LQHUDORJ\ f§J 2&NJf§ PJa FPROANJf§ JNJf§ .DROLQ sf sf NDROLQLWH 6LOLFD *HO sf DPRUSKRXV :HEVWHU 6RLO sf sf VPHFWLWH NDROLQLWH PLFD :HEVWHU +3 sf sf VPHFWLWH NDROLQLWH PLFD D $GDSWHG IURP 5KXH HW DO f UR M

PAGE 36

IORZHTXLOLEUDWLRQ DSSDUDWXV XVHG WR PHDVXUH S[\OHQH DQG ZDWHU YDSRU VRUSWLRQ ZDV VLPLODU WR WKDW GHVFULEHG LQ SUHYLRXV VWXGLHV 5KXH HW DO f +RZHYHU WKH S[\OHQH IORZ VWUHDP FRQVLVWHG RI WZR JDV ZDVKLQJ ERWWOHV LQ VHULHV WKH ILUVW FRQWDLQHG ZDWHU DQG WKH VHFRQG FRQWDLQHG S[\OHQH DQG ZDWHU )LJXUH f 7KLV DOORZHG WKH 5+ WR EH PDLQWDLQHG DW HLWKHU RU b ZKLOH WKH S[\OHQH UHODWLYH YDSRU SUHVVXUH 33FRXOG EH YDULHG IURP WR ZKHUH 3 LV WKH HTXLOLEULXP YDSRU SUHVVXUH DQG 34 LV WKH VDWXUDWHG YDSRU SUHVVXUH 7KH 3* RI S [\OHQH DW r& LV PP +J ZKLFK LV HTXLYDOHQW WR D YDSRU FRQFHQWUDWLRQ PJ/ :HDVW f )RU VRUSWLRQ H[SHULPHQWV FRQGXFWHG DW b 5+ YDOYH 9 ZDV FORVHG DQG YDOYHV 9 DQG 9 ZHUH DGMXVWHG WR REWDLQ UHODWLYH YDSRU SUHVVXUHV RI S[\OHQH UDQJLQJ IURP WR 7KH FRQFHQWUDWLRQ RI ZDWHU DQG S[\OHQH YDSRU LQ WKH IORZ VWUHDP ZDV GHWHUPLQHG E\ SDVVLQJ WKH IORZ VWUHDP WKURXJK WKUHH SRO\HWK\OHQH WXEHV LQ VHULHV 7KH WKUHH WXEHV FRQWDLQHG PDJQHVLXP SHUFKORUDWH DFWLYDWHG FKDUFRDO DQG D PL[WXUH RI DFWLYDWHG FKDUFRDO DQG PDJQHVLXP SHUFKORUDWH UHVSHFWLYHO\ 7KH GLIIHUHQFH EHWZHHQ WKH LQLWLDO DQG ILQDO WUDS ZHLJKWV \LHOGHG WKH WRWDO PDVV RI YDSRU WUDSSHG 7KH S[\OHQH YDSRU FRQFHQWUDWLRQ ZDV WKHQ GHWHUPLQHG E\ EXEEOLQJ WKH IORZ VWUHDP WKURXJK WZR P/ JODVV FHQWULIXJH WXEHV FRQWDLQLQJ P/ RI PHWKDQRO 3[\OHQH WUDSSHG LQ WKHVH VROXWLRQV ZDV PHDVXUHG ZLWK D 3HUNLQ (OPHU 0RGHO 899,6 VSHFWURSKRWRPHWHU 7KH FRQFHQWUDWLRQ RI ZDWHU YDSRU LQ WKH IORZ VWUHDP ZDV GHWHUPLQHG E\ VXEWUDFWLQJ WKH FRQFHQWUDWLRQ RI S[\OHQH IURP WKH WRWDO YDSRU FRQFHQWUDWLRQ

PAGE 37

,627+(50$/ &+$0%(5 QJDV )LJXUH ? )ORZHTXLOLEUDWLRQ DSSDUDWXV XVHG WR VWXG\ VRUSWLRQ RI S[\OHQH DQG ZDWHU YDSRUV RQ VLOLFD JHO NDROLQ :HEVWHU VRLO DQG :HEVWHU +3 U?M FR

PAGE 38

$SSUR[LPDWHO\ J RI VRUEHQW ZKLFK KDG EHHQ RYHQGULHG WR r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f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

PAGE 39

+3/&f WHFKQLTXHV 7KH +3/& V\VWHP FRQVLVWHG RI D *LOVRQ SXPS :DWHUV GHWHFWRU +HZOHWW 3DFNDUG $ LQWHJUDWRU DQG D FP :DWHUV 5&0 & FROXPQ ZLWK D FP %URZQOHH JXDUG FROXPQ 6XUIDFH 7HQVLRQ 0HDVXUHPHQWV 7KH VXUIDFH WHQVLRQ RI GHLRQL]HG ZDWHU H[SRVHG WR S[\OHQH YDSRUV ZDV PHDVXUHG XVLQJ WKH GURS ZHLJKW PHWKRG 7KH WHFKQLTXH LV EDVHG RQ 7DWHfV ODZ ZKLFK FRQVLGHUV WKH ZHLJKW RI D GURS IDOOLQJ IURP D VPDOO GLDPHWHU WXEH WR EH SURSRUWLRQDO WR WKH UDGLXV Uf RI WKH WLS FPf DQG WKH VXUIDFH WHQVLRQ \f RI WKH OLTXLG JVf ZHLJKW SHU GURS Q U \ f 7DWHfV ODZ DVVXPHV WKDW D VSKHULFDO GURS ZLOO IRUP DW WKH WLS EXW LQ UHDOLW\ WKH GURS WHQGV WR HORQJDWH EHIRUH LW GHWDFKHV IURP WKH WLS +DUNLQV DQG %URZQ f UHFRJQL]HG WKH LPSRUWDQFH RI WKLV GLVFUHSDQF\ DQG GHYHORSHG D FRUUHFWLRQ IDFWRU &)f EDVHG RQ WKH UDWLR RI WKH WLS UDGLXV WR WKH OHQJWK RI WKH GURS &) U9f f ZKHUH 9 LV WKH YROXPH RI WKH GURS 7DEOH f ,Q JHQHUDO WKH YDOXHV RI U9 ZHUH EHWZHHQ DQG 7KH IROORZLQJ HTXDWLRQ ZDV WKHQ XVHG WR FDOFXODWH VXUIDFH WHQVLRQ P J < Q U&) f ZKHUH P LV WKH PDVV RI WKH GURS Jf DQG J LV WKH DFFHOHUDWLRQ GXH WR JUDYLW\ FPVf

PAGE 40

7DEOH 'URSZHLJKW VXUIDFH WHQVLRQ FRUUHFWLRQ IDFWRUV &)f DGDSWHG IURP +DUNLQV DQG %URZQ f U9 &) U1P &)

PAGE 41

$ P/ JUDGXDWHG EXUHWWH ZDV XVHG IRU WKH VXUIDFH WHQVLRQ PHDVXUHPHQWV $IWHU FDUHIXOO\ JULQGLQJ WKH WLS IOXVK DQ RFXODU PLFURVFRSH ZDV XVHG WR PHDVXUH WKH GLDPHWHU RI WKH WLS FPf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f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

PAGE 42

5HVXOWV DQG 'LVFXVVLRQ $GVRUSWLRQ DW b 5+ )LJXUHV DQG VKRZ HTXLOLEULXP LVRWKHUPV IRU S[\OHQH YDSRU VRUSWLRQ RQ VLOLFD JHO NDROLQ :HEVWHU VRLO DQG :HEVWHU +3 DW r& 6RUSWLRQ GDWD DUH H[SUHVVHG DV PLOOLJUDPV RI S[\OHQH VRUEHG SHU JUDP RI VRUEHQW 6f YHUVXV WKH S [\OHQH UHODWLYH YDSRU SUHVVXUH 33$W b 5+ WKH S[\OHQH LVRWKHUPV RI DOO IRXU VRUEHQWV FRQIRUPHG WR 7\SHOO %(7 DGVRUSWLRQ LVRWKHUPV 7KLV W\SH RI LVRWKHUP LV W\SLFDO RI XQUHVWULFWHG PRQROD\HUPXOWLOD\HU DGVRUSWLRQ RI JDVHV RQ QRQSRURXV RU PDFURSRURXV SRUH ZLGWK SPf VRUEHQWV 6LQJ HW DO f 7KHVH VRUSWLRQ GDWD ZHUH ILW E\ D OHDVW VTXDUHV SURFHGXUH WR WKH OLQHDU IRUP RI WKH %(7 HTXDWLRQ 33 &f33 f 6 33 f 6P& 6P& ZKHUH 6P LV WKH QRPLQDO PRQROD\HU DGVRUSWLRQ FDSDFLW\ PJJf DQG & LV D SDUDPHWHU UHODWHG WR WKH KHDW RI DGVRUSWLRQ (VWLPDWHG YDOXHV RI 6P & DQG WKH 33 DVVRFLDWHG ZLWK PRQROD\HU FRYHUDJH DUH SUHVHQWHG LQ 7DEOH 7KH %(7 HTXDWLRQ LV FRQVLGHUHG WR JLYH UHOLDEOH HVWLPDWHV RI 6P IRU VXUIDFHV H[KLELWLQJ 7\SHOO DGVRUSWLRQ LVRWKHUPV +RZHYHU WKH YDOXH RI & GRHV QRW SURYLGH D TXDQWLWDWLYH PHDVXUH RI WKH KHDW RI DGVRUSWLRQ EXW GRHV JLYH DQ LQGLFDWLRQ RI WKH UHODWLYH PDJQLWXGH RI VRUEHQWVRUEDWH LQWHUDFWLRQV 6LQJ HW DO f 7KH YDOXHV RI & REWDLQHG IRU WKHVH V\VWHPV DUH LQGLFDWLYH RI ORZ VRUEDWHVRUEHQW LQWHUDFWLRQV DVVRFLDWHG ZLWK SK\VLFDO DGVRUSWLRQ )RU V\VWHPV H[KLELWLQJ ORZ YDOXHV RI &

PAGE 43

V PJJf 6 PJJf )LJXUH 6RUSWLRQ RI S[\OHQH RQ Df VLOLFD JHO DQG Ef NDROLQ DW DQG b 5+

PAGE 44

)LJXUH 6RUSWLRQ RI S[\OHQH YDSRUV RQ :HEVWHU VRLO DQG :HEVWHU +3 DW DQG b 5+

PAGE 45

7DEOH %(7 SDUDPHWHUV FDOFXODWHG IURP VLQJOHVRUEDWH DGVRUSWLRQ LVRWKHUPV 6RUEHQW 6UEDWH VP & %(7 6XUIDFH $UHD 33 PRQROD\HU 33 5DQJH 8VHG .DROLQ S[\OHQH ZDWHU 6LOLFD *HO S[\OHQH ZDWHU :HEVWHU 6RLO S[\OHQH :HEVWHU +3 S[\OHQH D $GDSWHG IURP 5KXH HW DO f

PAGE 46

GLVFUHWH UHJLRQV RI PXOWLOD\HU VRUSWLRQ LH SDWFKHVf PD\ IRUP SULRU WR WKH DWWDLQPHQW RI FRPSOHWH PRQROD\HU FRYHUDJH -XULQDN DQG 9ROPDQ 6LQJ HW DO f 7KH DPRXQW RI VRUEHQW VXUIDFH DYDLODEOH IRU WKH DGVRUSWLRQ RI D JLYHQ PROHFXOH 6P$f FDQ EH HVWLPDWHG IURP WKH 6P YDOXH DQG WKH DUHD RFFXSLHG E\ HDFK DGVRUEHG PROHFXOH 7KH FURVVVHFWLRQDO DUHDV DM RI ZDWHU DQG S[\OHQH ZHUH FDOFXODWHG WR EH DQG QP UHVSHFWLYHO\ XVLQJ WKH IROORZLQJ HTXDWLRQ .DUQDXNKRY 0F&OHOODQ DQG +DUQVEHUJHU f Dr1 ,&A0:[$f f ZKHUH 0: LV WKH PROHFXODU ZHLJKW [ LV WKH OLTXLG GHQVLW\ DQG $ LV $YRJDGURfV QXPEHU 7KLV HTXDWLRQ DVVXPHV WKDW WKH VUEDWH PROHFXOHV DUH RULHQWHG LQ D KH[DJRQDO FORVH SDFNLQJ DW D GHQVLW\ VLPLODU WR WKDW RI WKH EXON OLTXLG 7KH VXUIDFH DUHDV RFFXSLHG E\ HLWKHU S[\OHQH RU ZDWHU PROHFXOHV DW PRQROD\HU FRYHUDJH 6P$f DUH VKRZQ LQ 7DEOH 7KH YDOXHV RI 6P$ IRU RYHQGU\ NDROLQ DQG :HEVWHU +3 ZHUH VLPLODU WR WKRVH GHWHUPLQHG IURP 1 DGVRUSWLRQ LVRWKHUPV 7KHVH GDWD DUH FRQVLVWHQW ZLWK WKH ILQGLQJV RI -XULQDN DQG 9ROPDQ f DQG 5KXH HW DO f ZKR FRQFOXGHG WKDW WKH 1 VXUIDFH DUHD SURYLGHV D UHDVRQDEOH HVWLPDWH RI WKH DUHD DYDLODEOH IRU WKH VRUSWLRQ RI RUJDQLF YDSRUV RQ SUHGRPLQDQWO\ PLQHUDO VXUIDFHV ,W LV LQWHUHVWLQJ WR QRWH WKDW WKH VXUIDFH DUHD RI :HEVWHU VRLO DV GHWHUPLQHG IURP 1 DQG S[\OHQH DGVRUSWLRQ LVRWKHUPV LQFUHDVHG IROORZLQJ WKH K\GURJHQ SHUR[LGH WUHDWPHQW 7KHVH GDWD VXJJHVW WKDW ERWK S[\OHQH DQG 1 YDSRUV KDYH D JUHDWHU DIILQLW\ IRU PLQHUDO

PAGE 47

VXUIDFHV WKDQ IRU RUJDQLF PDWWHU DW b 5+ 7KH GLIIHUHQFH EHWZHHQ WKH 1 PJf DQG S[\OHQH%(7 VXUIDFH DUHD PJf RI :HEVWHU VRLO PD\ KDYH EHHQ GXH WR JUHDWHU VRUSWLRQ RI S[\OHQH YDSRU E\ VRLO RUJDQLF PDWWHU 7KLV K\SRWKHVLV LV VXSSRUWHG E\ WKH ZRUN RI &KLRX DQG 6KRXS f ZKR IRXQG WKDW WKH DGVRUSWLRQ RI YDSRUV RQ RYHQGU\ :RRGEXUQ VRLO LQFUHDVHG ZLWK WKH SRODULW\ RI WKH VUEDWH 7KH GLVFUHSDQF\ EHWZHHQ WKH 1 DQG %(7 VXUIDFH DUHD RI VLOLFD JHO KDV EHHQ GLVFXVVHG LQ D SUHYLRXV SDSHU 5KXH HW DO f 7KH UHODWLYH VRUSWLRQ 66RI S[\OHQH RQ RYHQGU\ NDROLQ VLOLFD JHO :HEVWHU VRLO DQG :HEVWHU +3 LV VKRZQ LQ )LJXUH 7KH XVH RI 66P DOORZV IRU WKH FRPSDULVRQ RI WKH DGVRUSWLYH FDSDFLWLHV RI YDULRXV VRUEHQWV RQ D XQLWVXUIDFH DUHD EDVLV $W ORZ YDOXHV RI 33 WKH UHODWLYH VRUSWLRQ RI S[\OHQH RQ :HEVWHU +3 DQG :HEVWHU VRLO ZDV VOLJKWO\ JUHDWHU WKDQ WKDW RQ NDROLQ DQG VLOLFD JHO 7KH LQFUHDVHG VRUSWLRQ FRUUHVSRQGV WR DQ LQFUHDVH LQ WKH YDOXH RI & IRU :HEVWHU VRLO & f DQG :HEVWHU +3 & f ZKLFK VXJJHVWV WKDW VSHFLILF VRUEDWHVRUEHQW LQWHUDFWLRQV PD\ KDYH RFFXUUHG +RZHYHU WKH RYHUDOO VLPLODULW\ LQ UHODWLYH VRUSWLRQ IRU WKH VRUEHQWV VWXGLHG KHUH VXJJHVWV WKDW WKH DGVRUSWLRQ RI S[\OHQH YDSRUV DW b 5+ ZDV SULPDULO\ D IXQFWLRQ RI VXUIDFH DUHD 6RUSWLRQ DW +LJK 5+ 9DSRUSKDVH VRUSWLRQ RI S[\OHQH RQ VLOLFD JHO DQG NDROLQ GHFUHDVHG GUDPDWLFDOO\ ZKHQ WKH 5+ ZDV UDLVHG WR b )LJXUH f 7KH REVHUYHG VXSSUHVVLRQ RI YDSRUSKDVH VRUSWLRQ DW KLJK 5+ LV LQ DJUHHPHQW ZLWK WKH ILQGLQJV RI RWKHUV HJ &DOO &KLRX DQG 6KRXS 5KXH HW DO f DQG OHQGV

PAGE 48

VV ( S;\OHQH 334f LI r r r .DROLQ f 6LOLFD *HO ‘ :HEVWHU +3 A :HEVWHU 6RLO )LJXUH 6RUSWLRQ RI S[\OHQH YDSRUV QRUPDOL]HG WR YDOXHV RI 6P GHWHUPLQHG IURP WKH %(7 HTXDWLRQ IRU VLOLFD JHO NDROLQ :HEVWHU VRLO DQG :HEVWHU +3 DW b 5+ Hr R

PAGE 49

IXUWKHU VXSSRUW WR WKH FRQWHQWLRQ WKDW ZDWHU HIIHFWLYHO\ FRPSHWHV ZLWK RUJDQLF YDSRUV IRU PLQHUDO VXUIDFHV 6RUSWLRQ RI S[\OHQH YDSRUV RQ :HEVWHU VRLO DQG :HEVWHU +3 ZDV DOVR UHGXFHG DW b 5+ )LJXUH f ,Q DGGLWLRQ WKH VRUSWLYH FDSDFLW\ RI :HEVWHU VRLO DW b 5+ ZDV JUHDWHU WKDQ WKDW RI :HEVWHU +3 ZKLOH WKH UHYHUVH ZDV WUXH DW b 5+ 7KHVH GDWD VXJJHVW WKDW 2& FRQWULEXWHG WR YDSRU VRUSWLRQ RQ :HEVWHU VRLO DW KLJK 5+ ZKLOH DGVRUSWLRQ RQ PLQHUDO VXUIDFHV ZDV WKH GRPLQDQW PHFKDQLVP DW b 5+ $W ERWK DQG b 5+ S[\OHQH VRUSWLRQ LVRWKHUPV ZHUH OLQHDU XQWLO WKH 33 UHDFKHG DSSUR[LPDWHO\ DERYH ZKLFK WKH DPRXQW RI S[\OHQH VRUEHG LQFUHDVHG VKDUSO\ UHVXOWLQJ LQ 7\SHOOO DGVRUSWLRQ LVRWKHUPV 7KH OLQHDU QDWXUH RI WKH VRUSWLRQ LVRWKHUPV EHORZ 33 ZDV FRQVLVWHQW ZLWK LVRWKHUPV REWDLQHG E\ &DOO f IRU ('% DQG E\ &KLRX DQG 6KRXS f IRU EHQ]HQH DQG FKORUREHQ]HQHV ,QFUHDVHG VRUSWLRQ DW KLJK UHODWLYH YDSRU SUHVVXUHV KDV QRW EHHQ SUHYLRXVO\ UHSRUWHG IRU EDWFK DGVRUSWLRQ VWXGLHV +RZHYHU UHVHDUFKHUV VWXG\LQJ VRUSWLRQ RI K\GURFDUERQV RQ K\GUDWHG VLOLFD DQG VRLO PDWHULDOV E\ JDV FKURPDWRJUDSK\ WHFKQLTXHV KDYH FRQVLVWHQWO\ REWDLQHG UHWHQWLRQ GDWD ZKLFK \LHOG 7\SHOOO DGVRUSWLRQ LVRWKHUPV 'RUULV DQG *UD\ .DUJHU HW DO D 2NDPXUD DQG 6DZ\HU f 7KHUHIRUH K\GUDWHG VRLOV DSSHDU WR KDYH D VL]DEOH FDSDFLW\ IRU RUJDQLF YDSRU VRUSWLRQ ZKHQ WKH UHODWLYH YDSRU SUHVVXUH DSSURDFKHV RQH 7KH VRUSWLRQ RI RUJDQLF YDSRUV DW KLJK 5+ LV FRPPRQO\ GHVFULEHG E\ GLVVROXWLRQ RI RUJDQLF YDSRUV LQWR VRUEHG ZDWHU ILOPV XVLQJ +HQU\fV /DZ FRQVWDQWV

PAGE 50

.Kf DQG VXEVHTXHQW VROXWH SDUWLWLRQLQJ LQWR RUJDQLF FDUERQ XVLQJ VRUSWLRQ FRHIILFLHQWV QRUPDOL]HG IRU 2& FRQWHQW .7KH MXVWLILFDWLRQ IRU VXFK DQ DSSURDFK FRPHV SULPDULO\ IURP D VLQJOH DUWLFOH E\ &KLRX DQG 6KRXS f ,Q WKLV ZRUN WKH DXWKRUV FRQFOXGH WKDW VROXWH SDUWLWLRQLQJ LQWR RUJDQLF FDUERQ LV WKH GRPLQDQW PHFKDQLVP UHVSRQVLEOH IRU RUJDQLF YDSRU VRUSWLRQ DW KLJK 5+ EDVHG SULPDULO\ RQ WZR SLHFHV RI HYLGHQFH f WKH OLQHDULW\ RI WKH VRUSWLRQ LVRWKHUPV DQG f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f DQG WKH DTXHRXV FRQFHQWUDWLRQ RI S[\OHQH GHWHUPLQHG XVLQJ D .+ YDOXH RI ; n P DWPPROH 7DEOH f 3UHGLFWHG S[\OHQH YDOXHV IRU VLOLFD JHO NDROLQ DQG :HEVWHU +3 ZHUH DQG RUGHUVRIPDJQLWXGH JUHDWHU UHVSHFWLYHO\ WKDQ YDOXHV GHWHUPLQHG IURP FROXPQ VWXGLHV P/Jf %UXVVHDX HW DO *DPHUGLQJHU HW DO VXEPLWWHG IRU SXEOLFDWLRQ LQ (QYLURQPHQWDO 6FLHQFH DQG 7HFKQRORJ\f DQG HVWLPDWHG IURP D ORJ RFWDQROZDWHU SDUWLWLRQ FRHIILFLHQW RI P8Jf .DULFNKRII f +RZHYHU WKH SUHGLFWHG

PAGE 51

7DEOH 6RUSWLRQ FRHIILFLHQWV QRUPDOL]HG IRU RUJDQLF FDUERQ FRQWHQW .Af FDOFXODWHG IURP S[\OHQH VRUSWLRQ GDWD IRU 33r RI WR 6RUEHQW 5+ 2& &RQWHQW .RF U bff f§JNJf§ f§POJf§ 6LOLFD *HO ; .DROLQ ; :HEVWHU +3 ; :HEVWHU 6RLO ;

PAGE 52

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f 7KLV DSSURDFK LV EDVHG RQ WKH *LEEV DGVRUSWLRQ HTXDWLRQ G\ 7 f GS ZKHUH 9 LV WKH VXUIDFH H[FHVV PROFPf \ LV WKH VXUIDFH WHQVLRQ DQG S LV WKH FKHPLFDO SRWHQWLDO ,I WKH YDSRU LV DVVXPHG WR REH\ WKH LGHDO JDV ODZ HTXDWLRQ f FDQ EH ZULWWHQ DV 3 G\ U 57 G3 f ZKHUH 3 LV WKH SDUWLDO SUHVVXUH RI WKH RUJDQLF YDSRU 5 LV WKH JDV FRQVWDQW DQG 7 LV WKH WHPSHUDWXUH 7KH VXUIDFH WHQVLRQ RI GLVWLOOHG ZDWHU H[SRVHG WR S[\OHQH

PAGE 53

YDSRU DV GHWHUPLQHG E\ WKH GURSZHLJKW PHWKRG LV VKRZQ LQ )LJXUH D 7KHVH GDWD ZHUH ILW E\ D OHDVW VTXDUHV UHJUHVVLRQ SURFHGXUH WR \LHOG D VORSH ZKLFK FRXOG EH WKHQ XVHG WR FDOFXODWH WKH VXUIDFH H[FHVV DV D IXQFWLRQ RI WKH SDUWLDO SUHVVXUH XVLQJ HTXDWLRQ f )LJXUH Ef 7KH 7\SHOOO DGVRUSWLRQ LVRWKHUP JHQHUDWHG IURP WKLV SURFHGXUH ZHUH W\SLFDO RI WKRVH REWDLQHG IRU RWKHU DURPDWLF K\GURFDUERQV DQG LQGLFDWHV WKDW ZDWHU DFWV DV D ORZ HQHUJ\ VXUIDFH WRZDUG WKH QRQSRODU YDSRU &XWWLQJ DQG -RQHV 9LGDO0DGMDU HW DO f 7KH DPRXQW RI S [\OHQH DGVRUEHG DW WKH JDVOLTXLG LQWHUIDFH ZDV HVWLPDWHG IURP WKH VXUIDFH H[FHVV DQG WKH 1 VXUIDFH DUHD RI HDFK VRUEHQW 7DEOH f ,Q DGGLWLRQ WKH PDVV RI S [\OHQH SDUWLWLRQHG LQWR RUJDQLF FDUERQ ZDV SUHGLFWHG XVLQJ D RI P/J DQG D .K RI ; n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b 5+ LV GLVFXVVHG 7KH SUHGLFWHG GDWD LQGLFDWHG WKDW WKH JDVOLTXLG LQWHUIDFH ZDV WKH GRPLQDQW PHFKDQLVP UHVSRQVLEOH IRU YDSRU VRUSWLRQ RQ VLOLFD JHO DQG NDROLQ 1HLWKHU SDUWLWLRQLQJ LQWR RUJDQLF FDUERQ QRU GLVVROXWLRQ LQWR VRUEHG ZDWHU FRQWULEXWHG VLJQLILFDQWO\ WR S[\OHQH VRUSWLRQ GXH WR WKH ORZ 2& FRQWHQW RI WKHVH VRUEHQWV DQG

PAGE 54

U ; PROFPf JVf 3 PP +Jf )LJXUH 6XUIDFH WHQVLRQ Df RI GHLRQL]HG ZDWHU H[SRVHG WR S[\OHQH YDSRUV DW r& DQG VXUIDFH H[FHVV Ef RI S[\OHQH DW WKH JDVOLTXLG LQWHUIDFH FDOFXODWHG XVLQJ WKH *LEEV DGVRUSWLRQ HTXDWLRQ

PAGE 55

7DEOH 3UHGLFWHG DQG PHDVXUHG S[\OHQH VRUSWLRQ RQ 6LOLFD *HO .DROLQ :HEVWHU +3 DQG :HEVWHU 6RLO DW b 5+ 6RUSWLRQ EY &RPSRQHQWV 7RWDO 6RUSWLRQ 6RUEHQW 33 *DV/LTXLG ,QWHUIDFH 2UJDQLF &DUERQ 6RUEHG :DWHU 3UHGLFWHG 0HDVXUHG QL\\ 6LOLFD *HO .DROLQ :HEVWHU +3 :HEVWHU 6RLO

PAGE 56

WKH ORZ VROXELOLW\ RI S[\OHQH UHVSHFWLYHO\ +RZHYHU WKH WRWDO SUHGLFWHG VRUSWLRQ RI S[\OHQH RQ VLOLFD JHO DQG NDROLQ ZDV DSSUR[LPDWHO\ RQHTXDUWHU RI WKH PHDVXUHG DPRXQW 7KLV GLVFUHSDQF\ PD\ KDYH EHHQ GXH WR DGVRUSWLRQ RI S[\OHQH YDSRUV RQ H[SRVHG PLQHUDO VXUIDFHV 7KH DYHUDJH DPRXQW RI ZDWHU DGVRUEHG RQ VLOLFD JHO DQG NDROLQ DW b 5+ ZDV DQG PJJ UHVSHFWLYHO\ ZKLFK LV HTXLYDOHQW WR DQG PRQROD\HUV RI ZDWHU EDVHG RQ %(7 HVWLPDWHV RI 6P 7DEOH f 'XH WR WKH ORZ YDOXHV RI & DQG f IRU WKHVH VRUEHQWV LW ZDV SRVVLEOH WKDW SDWFKHV RI ZDWHU IRUPHG RQ WKH PLQHUDO VXUIDFH -XULQDN DQG 9ROPDQ 6LQJ HW DO f WKHUHE\ DOORZLQJ IRU DGVRUSWLRQ RQ H[SRVHG PLQHUDO VXUIDFHV (YHQ LI PRQROD\HU FRYHUDJH RI ZDWHU ZDV DWWDLQHG WKH PLQHUDO VXUIDFH FRXOG VWLOO KDYH H[HUWHG D VXUIDFH HIIHFW RQ VRUEHG ZDWHU ILOPV )RZNHV f UHVXOWLQJ LQ JUHDWHU VRUSWLRQ WKDQ ZRXOG EH SUHGLFWHG IRU EXON ZDWHU VXUIDFHV 7KHVH K\SRWKHVHV DUH VXSSRUWHG E\ WKH ZRUN RI 'RUULV DQG *UD\ f ZKR UHSRUWHG WKDW WKH VRUSWLRQ FRHIILFLHQW IRU QKHSWDQH RQ ZDWHUFRDWHG VLOLFD LQFUHDVHG VLJQLILFDQWO\ DW ZDWHU FRQWHQWV OHVV WKDQ WKRVH DFKLHYHG DW b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

PAGE 57

DGVRUSWLRQ DW WKH JDVOLTXLG LQWHUIDFH 7KH VXUIDFH DUHD ZRXOG KDYH WR EH UHGXFHG IURP PJ WR DSSUR[LPDWHO\ PJ LQ RUGHU WR EULQJ WKH HVWLPDWHG DGVRUSWLRQ DW WKH JDVOLTXLG LQWHUIDFH LQWR DJUHHPHQW ZLWK WKH PHDVXUHG VRUSWLRQ GDWD ,Q FRQWUDVW WKH SUHGLFWHG VRUSWLRQ RI S[\OHQH RQ :HEVWHU VRLO ZDV VLPLODU WR WKH PHDVXUHG YDOXHV 3DUWLWLRQLQJ RI S[\OHQH LQWR 2& RQ :HEVWHU VRLO J 2&NJf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f ,Q DGGLWLRQ WKH GDWD

PAGE 58

SUHVHQWHG KHUH LQGLFDWH WKDW WKH XVH RI YDOXHV WR SUHGLFW YDSRUSKDVH VRUSWLRQ DW KLJK 5+ DSSHDUV WR EH RQO\ YDOLG IRU VRUEHQWV ZLWK KLJK 2& FRQWHQW DW UHODWLYH YDSRU SUHVVXUHV OHVV WKDQ 7KHVH ILQGLQJV DUH SDUWLFXODUO\ LPSRUWDQW LQ OLJKW RI WKH IDFW WKDW PRVW 92& DQG PXOWLSKDVH WUDQVSRUW PRGHOV HLWKHU IDLO WR FRQVLGHU YDSRUSKDVH VRUSWLRQ 3LQGHU DQG $EULOD 6OHHS DQG 6\NHV f RU GHVFULEH YDSRUSKDVH VRUSWLRQ E\ GLVVROXWLRQ LQWR VRLO ZDWHU DQG SDUWLWLRQLQJ LQWR 2& %DHKU -XU\ HW DO f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f 7KH WDVN DW KDQG QRZ LV WR IXUWKHU GHILQH WKH OLPLWV RI DSSOLFDELOLW\ RI HDFK PHFKDQLVP EDVHG RQ VUEDWH VRUEHQW DQG HQYLURQPHQWDO FRQVLGHUDWLRQV DQG WR LQFRUSRUDWH WKLV NQRZOHGJH LQWR FXUUHQW PRGHOLQJ HIIRUWV $Q LQLWLDO DWWHPSW DW WKLV DSSURDFK KDV EHHQ DWWHPSWHG E\ 6KRHPDNHU HW DO f ZKR GHVFULEHG YDSRUSKDVH VRUSWLRQ RI 7&( XVLQJ DQ

PAGE 59

HIIHFWLYH VRUSWLRQ WHUP WKDW LQFOXGHG VRUSWLRQ FRHIILFLHQWV IRU WKH VROLGOLTXLG DQG WKH VROLGJDV LQWHUIDFH

PAGE 60

&+$37(5 *$6 &+520$72*5$3+,& 678',(6 2) 3;
PAGE 61

E 0DUWLQ f $W ZDWHU FRQWHQWV DERYH WR b E\ ZHLJKW WKH HIIHFW RI WKH VROLG VXSSRUW RQ VROXWH UHWHQWLRQ DSSHDUV WR YDQLVK DQG WKXV HTXDWLRQ f FDQ EH DSSOLHG ZLWKRXW WKH .6$6 WHUP 'RUULV DQG *UD\ 2NDPXUD DQG 6DZ\HU f &RPSDULVRQV RI SDUWLWLRQ FRHIILFLHQWV DQG KHDWV RI VROXWLRQ GHWHUPLQHG E\ */& DQG VWDWLF PHWKRGV LQGLFDWH WKDW DGVRUEHG ZDWHU ILOPV EHWZHHQ DQG QP LQ WKLFNQHVV KDYH SURSHUWLHV VLPLODU WR WKRVH RI EXON ZDWHU .DUJHU HW DO D E &KDWWHUMHH HW DO f 7KXV JDV FKURPDWRJUDSK\ *&f DSSHDUV WR EH DQ LGHDO PHWKRG WR VWXG\ YDSRUVRUSWLRQ DW WKH JDVOLTXLG LQWHUIDFH DQG FDQ EH XWLOL]HG WR PHDVXUH VRUSWLRQ RQ DQK\GURXV VRLO PDWHULDOV $ GHWDLOHG UHYLHZ RI WKH WKHRUHWLFDO DQG H[SHULPHQWDO DSSOLFDWLRQ RI *& PHWKRGV WR WKH VWXG\ RI 92& VRUSWLRQ KDV EHHQ SUHVHQWHG E\ 5KXH DQG 5DR f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f $GDPVRQ f DWWULEXWHG WKLV EHKDYLRU WR WKH UHDUUDQJHPHQW RI VXUIDFH ZDWHU PROHFXOHV WR DFFRPPRGDWH WKH K\GURFDUERQ ZKLFK UHVXOWHG LQ ODUJHU KHDWV RI DGVRUSWLRQ $OWKRXJK PHDVXUHPHQWV RI YDSRU DGVRUSWLRQ RQ ZDWHUFRDWHG VXSSRUWV E\ */& \LHOG 7\SH,OO DGVRUSWLRQ LVRWKHUPV 'RUULV DQG *UD\ .DUJHU HW DO E

PAGE 62

.LQJ HW DO f KHDWV RI DGVRUSWLRQ HVWLPDWHG IURP */& GDWD DUH JHQHUDOO\ VPDOOHU WKDQ KHDWV RI YDSRUL]DWLRQ 7KHVH ILQGLQJV VXJJHVW WKDW WKH JDVOLTXLG LQWHUIDFH RI ZDWHU DFWV DV D ORZ HQHUJ\ VXUIDFH WRZDUG QRQSRODU YDSRUV &KDWWHUMHH HW DO 'RUULV DQG *UD\ +DUWNRSI DQG .DUJHU .DUJHU HW DO D Ef 7KH GLVFUHSDQF\ EHWZHHQ KHDWV RI DGVRUSWLRQ REWDLQHG IURP */& DQG VXUIDFH WHQVLRQ GDWD KDV EHHQ DWWULEXWHG WR XQFHUWDLQW\ LQ VXUIDFH WHQVLRQ PHDVXUHPHQWV DW ORZ VXUIDFH FRYHUDJHV 'RUULV DQG *UD\ .DUJHU HW DO D Ef ZKHUHDV IODPHLRQL]DWLRQ GHWHFWRUV ),'f XVHG LQ */& VWXGLHV SURYLGH DFFXUDWH PHDVXUHPHQWV RI K\GURFDUERQ DGVRUSWLRQ ,Q DGGLWLRQ WR KLJK VHQVLWLYLW\ JDV FKURPDWRJUDSK\ DOORZV IRU WKH UDSLG FROOHFWLRQ RI VRUSWLRQ GDWD RYHU D UDQJH RI WHPSHUDWXUH DQG PRLVWXUH FRQWHQW UHJLPHV 'HVSLWH WKH DSSDUHQW DGYDQWDJHV RI *& WHFKQLTXHV RYHU FRQYHQWLRQDO EDWFK DGVRUSWLRQ PHWKRGV UHODWLYHO\ IHZ VWXGLHV KDYH EHHQ FRQGXFWHG XVLQJ VRLO PDWHULDO DV WKH VROLG VXSSRUW SKDVH %RKQ HW DO 2NDPXUD DQG 6DZ\HU 5DR HW DO f 7KXV WKH SXUSRVH RI WKLV ZRUN ZDV WR WHVW WKH XWLOLW\ RI JDV FKURPDWRJUDSK\ IRU WKH VWXG\ RI S[\OHQH VRUSWLRQ RQ DQK\GURXV DQG K\GUDWHG TXDUW] VDQG 7KH HIIHFW RI &D&, WUHDWPHQWV RQ S[\OHQH DGVRUSWLRQ ZDV DOVR LQYHVWLJDWHG E\ *& DQG ZDV FRPSDUHG WR DGVRUSWLRQ GDWD REWDLQHG E\ IORZ HTXLOLEUDWLRQ DQG VXUIDFH WHQVLRQ PHWKRGV

PAGE 63

0DWHULDOV DQG 0HWKRGV &ROXPQ 3UHSDUDWLRQ 7KH VROLG VXSSRUW PDWHULDO ZDV FROOHFWHG IURP WKH %K KRUL]RQ RI DQ 2OGVPDU VRLO $OILF $UHQLF +DSODTXRGf ORFDWHG LQ &ROOLHU &RXQW\ )ORULGD 0HFKDQLFDO DQDO\VLV LQGLFDWHG WKDW WKH VDQGVL]H IUDFWLRQ GLDPHWHU MLPf DFFRXQWHG b RI WKH VRLO VDPSOH 7KH 2OGVPDU VRLO VDPSOH KDG D FDWLRQ H[FKDQJH FDSDFLW\ RI FPROANJ DQG ZDV SUHGRPLQDQWO\ &DVDWXUDWHG 7KH 1 VXUIDFH DUHD ZDV PJ ZKLOH WKH RUJDQLF FDUERQ FRQWHQW ZDV J 2&NJ 5KXH HW DO f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b SXULW\f DQG KLJK SXULW\ JUDGH PHWKDQH b SXULW\f ZHUH REWDLQHG IURP )LVKHU 6FLHQWLILF 3URGXFWV 7KH ),' ZDV FDOLEUDWHG IRU S[\OHQH DW WKUHH 1 IORZ UDWHV ZLWK DLU DQG K\GURJHQ IORZ UDWHV

PAGE 64

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r&f )RU DQK\GURXV H[SHULPHQWV WKH FROXPQ ZDV DOORZHG WR HTXLOLEUDWH ZLWK GU\ 1 IRU VHYHUDO KRXUV SULRU WR WKH LQLWLDWLRQ RI S[\OHQH LQMHFWLRQV 7KLV ZDV DQDORJRXV WR WKH IORZHTXLOLEUDWLRQ PHWKRG LQ ZKLFK GU\ 1 ZDV XVHG DV WKH FDUULHU JDV )RU K\GUDWHG V\VWHPV 2NDPXUD DQG 6DZ\HU f UHFRPPHQG WKDW WKH GHVLUHG ZDWHU FRQWHQW EH UHDFKHG E\ GHVRUSWLRQ RI D VDWXUDWHG FROXPQ LQ RUGHU WR DWWDLQ XQLIRUP ZDWHU FRYHUDJHV +RZHYHU WKLV SURFHGXUH UHVXOWHG LQ WKH LQWURGXFWLRQ RI H[FHVVLYH TXDQWLWLHV RI ZDWHU LQWR WKH ),' DQG DVVRFLDWHG FROXPQ ILWWLQJV 'RUULV DQG *UD\ f REWDLQHG UHSURGXFLEOH VROXWH UHWHQWLRQ GDWD DW ZDWHU FRQWHQWV RI DQG b E\ HTXLOLEUDWLQJ WKH FROXPQ ZLWK FDUULHU JDV DW DQG b 5+ )RU WKH H[SHULPHQWV GHVFULEHG KHUH UHODWLYH KXPLGLWLHV RI DQG b ZHUH DFKLHYHG E\ EXEEOLQJ WKH 1 IORZ VWUHDP WKURXJK D JDVZDVKLQJ ERWWOH FRQWDLQLQJ GHLRQL]HG ZDWHU LQ D PDQQHU VLPLODU WR WKDW GHVFULEHG LQ &KDSWHU 7KH UHODWLYH KXPLGLW\ RI WKH 1 IORZ VWUHDP ZDV PHDVXUHG DW WKH FROXPQ LQOHW DQG RXWOHW E\ WUDSSLQJ WKH ZDWHU YDSRU LQ WZR PDJQHVLXP SHUFKORUDWH WUDSV DUUDQJHG LQ VHULHV

PAGE 65

,Q DGGLWLRQ WKH EDFN SUHVVXUH DW WKH FROXPQ LQOHW ZDV PHDVXUHG XVLQJ D SUHVVXUH WUDQVGXFHU IRU ZKLFK WKH P9 RXWSXW KDG EHHQ FDOLEUDWHG DJDLQVW SUHVVXUH KHDGV $GVRUSWLRQ LVRWKHUPV IRU S[\OHQH ZHUH REWDLQHG E\ WKH HOXWHGSXOVH PHWKRG RI 'RUULV DQG *UD\ f 7KH UHWHQWLRQ WLPH RI PHWKDQH WM DQG S[\OHQH WUf YDSRUV ZKLFK ZHUH VLPXOWDQHRXVO\ LQMHFWHG RQ WKH FROXPQ ZDV UHFRUGHG ZLWK D +HZOHWW 3DFNDUG $ LQWHJUDWRU 7KH UHWHQWLRQ WLPH RI DLU LQMHFWLRQV ZKLFK JDYH D QHJDWLYH UHVSRQVH ZHUH LGHQWLFDO WR WKRVH RI PHWKDQH 7KHVH GDWD LQGLFDWH WKDW PHWKDQH ZDV QRW UHWDLQHG E\ WKH VWDWLRQDU\ SKDVH 7KXV WKH QHW UHWHQWLRQ YROXPH 91f RI S[\OHQH ZDV FDOFXODWHG IURP WKH GLIIHUHQFH EHWZHHQ WU DQG W2, XVLQJ WKH 1 IORZ UDWH ,QMHFWLRQV YROXPHV UDQJLQJ IURP SOB WR POB RI S[\OHQH YDSRU ZHUH XVHG WR REWDLQ D UDQJH RI QHW UHWHQWLRQ YROXPHV ,I WKH DGVRUSWLRQ RI S[\OHQH LV DVVXPHG WR RFFXU RQ PLQHUDO VXUIDFHV IRU DQK\GURXV VRUEHQWV DQG VROHO\ E\ DGVRUSWLRQ DW WKH JDVOLTXLG LQWHUIDFH RI ZDWHU FRDWHG VXSSRUWV WKH QHW UHWHQWLRQ YROXPH 91f UHTXLUHG WR HOXWH D VROXWH LV JLYHQ E\ 91 57GUG3f$ 57G6G3fZ f ZKHUH 5 LV WKH JDV FRQVWDQW 7 LV WKH WHPSHUDWXUH 7 LV WKH VXUIDFH FRQFHQWUDWLRQ PROFPf 3 LV WKH SDUWLDO SUHVVXUH RI WKH YDSRU $ LV WKH VXUIDFH DUHD 6 LV WKH DPRXQW DGVRUEHG PJJf DQG Z LV WKH ZHLJKW RI WKH FROXPQ SDFNLQJ 'RUULV DQG *UD\ f $GVRUSWLRQ LVRWKHUPV FDQ WKHQ EH REWDLQHG E\ LQWHJUDWLQJ HTXDWLRQ f DV IROORZV 6 57Z913f G3 f 7KH SHDNPD[LPD PHWKRG RI 'RUULV DQG *UD\ f ZDV HPSOR\HG WR REWDLQ D

PAGE 66

FKURPDWRJUDSKLF HQYHORSH ZKLFK FRXOG EH LQWHJUDWHG E\ HTXDWLRQ f 7KH FDOLEUDWLRQ FXUYH GHVFULEHG SUHYLRXVO\ ZDV XVHG WR FRQYHUW P9 UHDGLQJV REWDLQHG IURP SHDN KHLJKW PHDVXUHPHQWV WR SDUWLDO SUHVVXUHV RI S[\OHQH +RZHYHU WKH XVH RI HTXDWLRQ f LPSOLHV WKDW WKH VRUSWLRQ HIIHFW DQG SUHVVXUH JUDGLHQW DORQJ WKH FROXPQ ZHUH QHJOLJLEOH 5HVXOWV DQG 'LVFXVVLRQ $GVRUSWLRQ RQ $QK\GURXV 2OGVPDU 6DQG &KURPDWRJUDSKLF SHDN PD[LPD REWDLQHG IURP LQMHFWLRQV RI S[\OHQH YDSRUV RQ XQWUHDWHG DQG VDOWWUHDWHG 2OGVPDU VDQG DUH SUHVHQWHG LQ )LJXUH 1HW UHWHQWLRQ YROXPHV RI S[\OHQH RQ XQWUHDWHG 2OGVPDU VDQG ZHUH ODUJHU WKDQ WKRVH RI VDOWWUHDWHG VRLO LQGLFDWLQJ JUHDWHU VROXWH UHWHQWLRQ $GVRUSWLRQ LQ WKH +HQU\fV /DZ UHJLRQ FKDUDFWHUL]HG E\ KLJKO\ V\PPHWULF SHDNV DQG QHW UHWHQWLRQ YROXPHV LQGHSHQGHQW RI VDPSOH VL]H ZDV QRW DWWDLQHG IRU XQWUHDWHG 2OGVPDU VDQG HYHQ DW S[\OHQH SDUWLDO SUHVVXUHV RI ; n PP +J ,Q FRQWUDVW WKH VDOWWUHDWHG 2OGVPDU VDQG H[KLELWHG +HQU\fV UHJLRQ DGVRUSWLRQ DW D QHW UHWHQWLRQ YROXPH RI DSSUR[LPDWHO\ P/ $V JUHDWHU TXDQWLWLHV RI S[\OHQH ZHUH LQMHFWHG WKH QHW UHWHQWLRQ YROXPH GHFUHDVHG XQWLO WKH SHDNV EHFDPH DV\PPHWULF DW ZKLFK SRLQW WKH QHW UHWHQWLRQ YROXPH EHJDQ WR LQFUHDVH $OWKRXJK QRW VKRZQ KHUH WKH SRVLWLRQ RI WKH OHDGLQJ HGJH RI WKH DV\PPHWULF SHDNV ZDV VLPLODU LQGLFDWLQJ WKDW DGVRUSWLRQ HTXLOLEULXP ZDV DWWDLQHG 'RUULV DQG *UD\ f 7KH FRQQHFWLRQ RI SHDN PD[LPD

PAGE 67

3 PP +Jf 3 PP +Jf )LJXUH &KURPDWRJUDSKLF SHDN PD[LPD DW URRP WHPSHUDWXUH r&f IRU S [\OHQH YDSRU RQ Df XQWUHDWHG 2OGVPDU VRLO DQG Ef VDOWWUHDWHG 2OGVPDU VRLO

PAGE 68

IRUPHG D FKURPDWRJUDSKLF HQYHORSH ZKLFK ZDV LQWHJUDWHG E\ HTXDWLRQ f 7KH UHVXOWLQJ S[\OHQH DGVRUSWLRQ LVRWKHUPV DUH SUHVHQWHG LQ )LJXUH 7KH DGVRUSWLRQ RI S[\OHQH RQ XQWUHDWHG 2OGVPDU VDQG \LHOGHG D 7\SHOO LVRWKHUP LQGLFDWLYH RI PXOWLOD\HU IRUPDWLRQ $ VLPLODU LVRWKHUP ZDV REWDLQHG IRU WKH VDOWWUHDWHG VDQG DOWKRXJK WKH DGVRUSWLRQ FDSDFLW\ ZDV UHGXFHG 7KHVH GDWD KDYH \HW WR EH FRQILUPHG E\ EDWFK WHFKQLTXHV KRZHYHU S[\OHQH DGVRUSWLRQ RQ SP 2OGVPDU VDQG PHDVXUHG E\ WKH *& DQG IORZHTXLOLEUDWLRQ PHWKRGV ZHUH LQ FORVH DJUHHPHQW 5 5KXH SHUVRQDO FRPPXQLFDWLRQf 7KH HIIHFW RI WKH VDOW WUHDWPHQWV RQ S[\OHQH DGVRUSWLRQ E\ :HEVWHU VRLO ZDV DOVR VWXGLHG XVLQJ WKH IORZ HTXLOLEUDWLRQ DSSDUDWXV GHVFULEHG LQ &KDSWHU )LJXUH f :HEVWHU VRLO DQG :HEVWHU VRLO WUHDWHG ZLWK K\GURJHQ SHUR[LGH :HEVWHU +3f ZDV H[WUDFWHG ZLWK PHWKDQRO FRQWDLQLQJ &D&, WR PHDVXUH ZDWHU DQG S[\OHQH VRUSWLRQ )ROORZLQJ PHWKDQRO H[WUDFWLRQ WKH :HEVWHU VRLO DQG :HEVWHU +3 FRQWDLQHG sf DQG sf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

PAGE 69

‘ XQWUHDWHG $ VDOWWUHDWHG S;\OHQH 33f )LJXUH $GVRUSWLRQ LVRWKHUPV IRU S[\OHQH YDSRU RQ XQWUHDWHG DQG VDOWWUHDWHG 2OGVPDU VRLO

PAGE 70

6 PJJf 6 PJJf Z L L L B L S;\OHQH 3)Af )LJXUH $GVRUSWLRQ RI S[\OHQH YDSRUV RQ :HEVWHU VRLO DQG :HEVWHU +3 DW Df b 5+ DQG Ef b 5+

PAGE 71

$GVRUSWLRQ RQ +\GUDWHG 2OGVPDU 6DQG 7KH QHW UHWHQWLRQ YROXPH RI S[\OHQH LQMHFWHG RQWR FP FROXPQV SDFNHG ZLWK 2OGVPDU VDQG GHFUHDVHG IURP DSSUR[LPDWHO\ P/ WR OHVV WKDQ P/ ZKHQ WKH 5+ ZDV LQFUHDVHG WR b 7KLV UHGXFWLRQ ZDV LQGLFDWLYH RI WKH HIIHFW RI ZDWHU RQ WKH UHWHQWLRQ RI S[\OHQH YDSRUV 1HW UHWHQWLRQ YROXPHV RI S[\OHQH RQ VDOW WUHDWHG 2OGVPDU VDQG DW b 5+ DQG RQ XQWUHDWHG 2OGVPDU VDQG DW DQG b 5+ DUH SUHVHQWHG LQ )LJXUH +HQU\fV UHJLRQ DGVRUSWLRQ RFFXUUHG DW VPDOOHU UHWHQWLRQ YROXPHV DQG IRU JUHDWHU S[\OHQH SDUWLDO SUHVVXUHV WKDQ XQGHU DQK\GURXV FRQGLWLRQV ,Q DGGLWLRQ WKH YDOXH RI 91 LQFUHDVHG FRQWLQXRXVO\ H[FHSW LQ WKH +HQU\fV /DZ UHJLRQ ZKLFK LV FKDUDFWHULVWLF RI DGVRUSWLRQ \LHOGLQJ 7\SHOOO LVRWKHUPV 'RUULV DQG *UD\ f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b 5+ DQG RQ :HEVWHU VRLO DQG :HEVWHU +3 DW b 5+ $W b 5+ DQ DGGLWLRQDO UHGXFWLRQ LQ S[\OHQH DGVRUSWLRQ RQ 2OGVPDU VDQG ZDV REVHUYHG 7KHVH GDWD VXJJHVW WKDW VRUEHQW VXUIDFH ZDV QRW FRPSOHWHO\ FRYHUHG ZLWK ZDWHU RU WKDW WKH VXUIDFH FRQWLQXHG WR H[HUW DQ HIIHFW RQ DGVRUSWLRQ HYHQ WKRXJK WKH 5+ RI WKH FDUULHU JDV DW WKH FROXPQ

PAGE 72

3 PP +Jf 3 PP +Jf 91 POf )LJXUH &KURPDWRJUDSKLF SHDN PD[LPD DW URRP WHPSHUDWXUH r&f IRU S[\OHQH YDSRU RQ Df VDOWWUHDWHG 2OGVPDU VRLO DW b 5+ DQG Ef XQWUHDWHG 2OGVPDU VRLO DW DQG b 5+

PAGE 73

6 PJJf )LJXUH $GVRUSWLRQ LVRWKHUP IRU S[\OHQH YDSRU RQ VDOWWUHDWHG 2OGVPDU VRLO DW b 5+ DQG VDOWWUHDWHG 2OGVPDU VRLO DW DQG b 5+ 8

PAGE 74

LQOHW ZDV b 6XEVHTXHQW PHDVXUHPHQWV UHYHDOHG WKDW LQOHW UHODWLYH KXPLGLWLHV RI DQG b FRUUHVSRQGHG WR UHODWLYH KXPLGLWLHV DW WKH FROXPQ RXWOHW RI DQG b UHVSHFWLYHO\ 6LQFH WKH EDFN SUHVVXUH PHDVXUHG DW WKH FROXPQ LQOHW UDQJHG IURP RQO\ WR DWP LW ZDV XQOLNHO\ WKDW WKH 5+ GURS ZDV GXH VROHO\ WR SUHVVXUH JUDGLHQWV $SSDUHQWO\ WKH KRXU HTXLOLEUDWLRQ SHULRG ZDV QRW VXIILFLHQW WR FRPSOHWHO\ K\GUDWH WKH VXSSRUW )XWXUH H[SHULPHQWV ZLOO EH FRQGXFWHG DIWHU HTXLOLEUDWLQJ WKH FROXPQV IRU VHYHUDO GD\V DW b 5+ 7KH SUHVHQFH RI VDOW DOVR UHGXFHG S[\OHQH DGVRUSWLRQ RQ 2OGVPDU VDQG ZKLFK ZDV FRQVLVWHQW ZLWK EDWFK GDWD REWDLQHG IRU WKH VRUSWLRQ RI S[\OHQH YDSRUV RQ :HEVWHU VRLO DQG :HEVWHU +3 DW b 5+ )LJXUH Ef %DVHG RQ ZDWHU DGVRUSWLRQ GDWD WKH FRQFHQWUDWLRQ RI &D&, LQ DGVRUEHG ZDWHU ILOPV RI WKH :HEVWHU VRLOV ZDV DSSUR[LPDWHO\ 0 7R IXUWKHU LQYHVWLJDWH WKH DGVRUSWLRQ DW WKH JDV OLTXLG LQWHUIDFH WKH VXUIDFH WHQVLRQ RI 0 &D&, H[SRVHG WR S[\OHQH YDSRUV ZDV PHDVXUHG E\ WKH GURSZHLJKW PHWKRG DV GHVFULEHG LQ &KDSWHU 7KHVH GDWD ZHUH H[SUHVVHG DV VXUIDFH SUHVVXUH ^Qf ZKLFK LV HTXLYDOHQW WR WKH GLIIHUHQFH EHWZHHQ WKH VXUIDFH WHQVLRQ RI WKH SXUH VROXWLRQ \f DQG WKH ILOPFRYHUHG VXUIDFH \f )LJXUH f 7KH VXUIDFH H[FHVV 7f FDQ EH FDOFXODWHG LQ WKH VDPH PDQQHU DV GHVFULEHG LQ &KDSWHU E\ VLPSO\ UHSODFLQJ \LQ HTXDWLRQ f ZLWK Q %ODQN DQG 2WWHZLOO f +RZHYHU WKH GDWD SUHVHQWHG LQ )LJXUH LQGLFDWHG WKDW WKH VXUIDFH H[FHVV FDOFXODWHG IRU 0 &D&, DQG GHLRQL]HG ZDWHU ZRXOG EH LGHQWLFDO 7KLV ILQGLQJ ZDV FRQVLVWHQW ZLWK WKH GDWD RI %ODQN DQG 2WWHZLOO f ZKR UHSRUWHG WKDW WKH VXUIDFH H[FHVV RI EHQ]HQH WROXHQH DQG R[\OHQH RQ 0 1D&, ZDV VLPLODU WR WKDW REWDLQHG XVLQJ GLVWLOOHG ZDWHU 7KXV WKH VXUIDFH WHQVLRQ

PAGE 75

FU Lf V 6XUIDL }r ‘ 'O :DWHU $ 0 &D&, $ 3 PP +Jf SUHVVXUH RI GHLRQL]HG ZDWHU DQG 0 &D&, H[SRVHG WR S[\OHQH YDSRUV DW URRP WHPSHUDWXUH 2f aQ,

PAGE 76

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f 7\SHOO LVRWKHUPV REWDLQHG IRU S[\OHQH DGVRUSWLRQ RQ DQK\GURXV 2OGVPDU VDQG ZHUH LQ DJUHHPHQW ZLWK SUHOLPLQDU\ EDWFK GDWD $W KLJK 5+ DGVRUSWLRQ LVRWKHUPV VKLIWHG IURP 7\SHOO WR 7\SH,OO DQG WKH PDJQLWXGH RI S[\OHQH DGVRUSWLRQ ZDV UHGXFHG $ VLPLODU HIIHFW KDV EHHQ REVHUYHG IRU WKH VRUSWLRQ RI VHYHUDO RUJDQLF YDSRUV RQ K\GUDWHG VRLOV &DOO &KLRX DQG 6KRXS 5KXH HW DO f +RZHYHU VRPH GLIILFXOW\ ZDV HQFRXQWHUHG DW KLJK 5+ DQG LW LV UHFRPPHQGHG WKDW WKH FROXPQV EH HTXLOLEUDWHG DW b 5+ IRU VHYHUDO GD\V $GGLWLRQDO H[SHULPHQWV ZLOO EH FRQGXFWHG DW KLJK 5+ DQG EDWFK H[SHULPHQWV DUH SODQQHG WR IXUWKHU YHULI\ *& GDWD 6DOW WUHDWPHQWV UHVXOWHG LQ GHFUHDVHG S[\OHQH DGVRUSWLRQ RQ DQK\GURXV DQG K\GUDWHG 2OGVPDU VDQG 7KHVH GDWD ZHUH FRQVLVWHQW ZLWK EDWFK VWXGLHV RI S [\OHQH DGVRUSWLRQ RQ :HEVWHU VRLO DQG :HEVWHU +3 H[SRVHG WR &D&, DQG VXJJHVW

PAGE 77

WKDW YDSRUSKDVH VRUSWLRQ ZLOO EH VLJQLILFDQWO\ UHGXFHG LQ VDOWHIIHFWHG VRLOV 8QGHU DQK\GURXV FRQGLWLRQV WKH UHGXFHG DGVRUSWLRQ FDSDFLW\ RI VDOWWUHDWHG 2OGVPDU VDQG PD\ KDYH UHVXOWHG IURP WKH IRUPDWLRQ RI VDOW FRDWLQJV RQ WKH VRUEHQW VXUIDFH ,Q &KDSWHU LW ZDV SRVWXODWHG WKDW VRUSWLRQ RQ K\GUDWHG VRUEHQWV RFFXUUHG E\ f SDUWLWLRQLQJ LQWR 2& f GLVVROXWLRQ LQWR DGVRUEHG ZDWHU ILOPV f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f ,I WKH VXUIDFH H[FHVV RI ZDWHU LV DVVXPHG WR EH FRQVWDQW WKH *LEEV HTXDWLRQ FDQ EH H[SUHVVHG DV G\ GOQD U U f 57 GLQD GLQD ZKHUH 7 DQG U DUH WKH VXUIDFH FRQFHQWUDWLRQV RI S[\OHQH DQG &D&, PROFPf UHVSHFWLYHO\ D DQG D DUH WKH DFWLYLWLHV RI S[\OHQH DQG &D&, UHVSHFWLYHO\ 5 LV WKH JDV FRQVWDQW DQG 7 LV WKH WHPSHUDWXUH 7KLV HTXDWLRQ LQGLFDWHV WKDW LI &D&, PRYHG WR WKH JDVOLTXLG LQWHUIDFH LW FRXOG FRPSHQVDWH IRU DQ\ UHGXFWLRQ LQ WKH

PAGE 78

VXUIDFH WHQVLRQ DULVLQJ IURP WKH DFFXPXODWLRQ RI S[\OHQH DW WKH JDVOLTXLG LQWHUIDFH 8QIRUWXQDWHO\ WKH VXUIDFH FRQFHQWUDWLRQ RI &D&, Uf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

PAGE 79

&+$37(5 &203(7,7,9( $'62537,21 2) 3;
PAGE 80

&DWLRQ VDWXUDWLRQ KDV EHHQ VKRZQ WR LQGLUHFWO\ HIIHFW WKH FRPSHWLWLYH DGVRUSWLRQ RI ZDWHU DQG HWK\OHQH GLEURPLGH ('%f YDSRUV E\ DOWHULQJ WKH VXUIDFH DUHD RI PRQWPRULOORQLWH )ROORZLQJ H[SRVXUH WR 3 -XULQDN f REVHUYHG WKDW ZDWHU UHWHQWLRQ E\ 0J &D DQG 1DVDWXUDWHG PRQWPRULOORQLWH ZDV GLUHFWO\ UHODWHG WR WKH K\GUDWLRQ HQHUJ\ RI WKH H[FKDQJHDEOH FDWLRQ 7KH UHWDLQHG ZDWHU H[SDQGHG WKH LQWHUOD\HU VSDFH DQG WKXV 0JPRQWPRULOORQLWH H[KLELWHG WKH JUHDWHVW VXUIDFH DUHD DQG ('% DGVRUSWLRQ IROORZHG E\ &D DQG 1DPRQWPRULOORQLWH $ VLPLODU SKHQRPHQRQ ZDV QRWHG E\ &DOO f ZKR UHSRUWHG WKDW ('% VRUSWLRQ RQ &D VDWXUDWHG PRQWPRULOORQLWH ZDV JUHDWHU DW DQG b UHODWLYH KXPLGLW\ 5+f WKDQ DW b 5+ )LJXUH f 7KLV HIIHFW ZDV DWWULEXWHG WR H[SDQVLRQ RI WKH FOD\ ODWWLFH ZKLFK LQFUHDVHG IURP ƒ DW b 5+ WR ƒ DW b 5+ $SSDUHQWO\ ('% PROHFXOHV ZHUH RQO\ DEOH WR HQWHU WKH LQWHUOD\HU VSDFH DIWHU WKH FOD\ ODWWLFH KDG H[SDQGHG WR ƒ +RZHYHU DV WKH QXPEHU RI ZDWHU PROHFXOHV FRQWLQXHG WR LQFUHDVH FRPSHWLWLRQ EHWZHHQ ('% DQG ZDWHU EHFDPH JUHDWHU UHVXOWLQJ LQ WKH VXSSUHVVLRQ RI ('% DGVRUSWLRQ $OWKRXJK WKHVH GDWD FOHDUO\ GHPRQVWUDWH WKDW FDWLRQ VDWXUDWLRQ LQIOXHQFHG ('% DGVRUSWLRQ RQ PRQWPRULOORQLWH WKH HIIHFW RI VSHFLILF LQWHUDFWLRQV EHWZHHQ ZDWHU DQG H[FKDQJHDEOH FDWLRQV ZDV REVFXUHG E\ FKDQJHV LQ VXUIDFH DUHD ,Q DGGLWLRQ -XULQDN f UHSRUWHG WKDW PRQWPRULOORQLWH IRUPV SRURXV DJJUHJDWHV RU IORFFXOHV GXULQJ GHK\GUDWLRQ 7KLV SURFHVV ZKLFK KDV EHHQ REVHUYHG E\ HOHFWURQ PLFURJUDSK\ *ULP f UHVWULFWHG WKH DGVRUSWLRQ RI ('% RQ 0J &D DQG 1D PRQWPRULOORQLWH -XULQDN f ,Q FRQWUDVW ('% DGVRUSWLRQ RQ NDROLQLWH RFFXUUHG

PAGE 81

6 PJJf ('% 33f )LJXUH 9DSRUSKDVH DGVRUSWLRQ RI ('% RQ &DVDWXUDWHG PRQWPRULOORQLWH DW YDULRXV 5+ &DOO f 1O &2

PAGE 82

RQ IUHH VXUIDFHV RU LQ SRUHV ZKRVH VL]H ZDV IDU JUHDWHU WKDQ WKDW RI WKH ('% PROHFXOH 7KXV NDROLQ DSSHDUV WR SURYLGH D VXUIDFH DEVHQW RI VXUIDFH DUHD DQG SRURVLW\ HIIHFWV ZKLFK FRPSOLFDWHG WKH LQWHUSUHWDWLRQ RI ('% DGVRUSWLRQ RQ PRQWPRULOORQLWH 5HFHQWO\ 5KXH HW DO f XVHG D PHWKDQRO H[WUDFWLRQ SURFHGXUH WR VLPXOWDQHRXVO\ PHDVXUH ZDWHU DQG S[\OHQH DGVRUSWLRQ RQ SUHGRPLQDQWO\ 1D VDWXUDWHG NDROLQ $W ORZ 5+V DQG UHODWLYHO\ KLJK S[\OHQH YDSRUV SUHVVXUHV 5KXH HW DO f REVHUYHG HQKDQFHG ZDWHU DGVRUSWLRQ EDVHG RQ FRPSDULVRQV EHWZHHQ PHDVXUHG DQG SUHGLFWHG GDWD 7KH SUHGLFWHG YDOXHV ZHUH FDOFXODWHG XVLQJ D PRGLILHG %UXQDXHU (PPHWW DQG 7HOOHU %(7f HTXDWLRQ ZKLFK DFFRXQWHG IRU WZR DGVRUEDWH VSHFLHV 7KH SXUSRVH RI WKLV VWXG\ ZDV WR GHWHUPLQH LI WKH SUHIHUHQWLDO DGVRUSWLRQ RI ZDWHU FRXOG EH DWWULEXWHG FDWLRQ K\GUDWLRQ HIIHFWV ,QLWLDOO\ VLQJOHn DGVRUEDWH LVRWKHUPV ZHUH REWDLQHG IRU S[\OHQH DQG ZDWHU YDSRU DGVRUSWLRQ RQ &D 1D DQG /LNDROLQ 7KH OLQHDU IRUP RI %(7 HTXDWLRQ ZDV XWLOL]HG WR REWDLQ WKH PRQROD\HU DGVRUSWLRQ FDSDFLW\ DQG YDOXH RI & 7KHVH GDWD ZHUH WKHQ XVHG WR SUHGLFW FRPSHWLWLYH DGVRUSWLRQ RI S[\OHQH DQG ZDWHU YDSRUV EDVHG RQ WKH WZR FRPSRQHQW %(7 HTXDWLRQV RI +LOO D Ef DQG 5KXH HW DO f 0DWHULDOV DQG 0HWKRGV .DROLQLWH 6DPSOHV &ROORLGDO NDROLQ REWDLQHG IURP )LVKHU 6FLHQWLILF 3URGXFWV /RW f XVHG LQ WKLV VWXG\ ZDV LGHQWLFDO WR WKDW GHVFULEHG LQ &KDSWHU 7KH NDROLQ KDG D

PAGE 83

FDWLRQ H[FKDQJH FDSDFLW\ &(&f RI FPROFNJ DW S+ DQG ZDV SUHGRPLQDQWO\ 1DVDWXUDWHG ZLWK WUDFH DPRXQWV RI &D 0J DQG 5KXH HW DO f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b HWKDQRO XQWLO D QHJDWLYH FKORULGH WHVW ZDV DFKLHYHG XVLQJ $J1 7KH NDROLQ ZDV DLUGULHG DW URRP WHPSHUDWXUH DQG JURXQG ZLWK DQ DJDWH PRWDU DQG SHVWDO 3ULRU WR DGVRUSWLRQ H[SHULPHQWV WKH NDROLQ ZDV RYHQGULHG DW DSSUR[LPDWHO\ r& IRU DW OHDVW WZR ZHHNV 7KH 1 VXUIDFH DUHD RI &D 1D DQG /LNDROLQ ZDV DQG PJ UHVSHFWLYHO\ SULRU WR

PAGE 84

KHDWLQJ DQG DQG PJ UHVSHFWLYHO\ DIWHU KHDWLQJ $GYDQFHG 0DWHULDOV 5HVHDUFK &HQWHU 8QLYHUVLW\ RI )ORULGDf 9DSRU3KDVH $GVRUSWLRQ ([SHULPHQWV 6LQJOH DQG PL[HGYDSRU DGVRUSWLRQ H[SHULPHQWV ZHUH FRQGXFWHG DW r& XVLQJ WKH IORZHTXLOLEUDWLRQ DSSDUDWXV GHVFULEHG LQ &KDSWHU 7KH FRQFHQWUDWLRQ RI ZDWHU LQ WKH IORZ VWUHDP ZDV GHWHUPLQHG E\ .DUO )LVKHU .)f WLWUDWLRQ $SSUR[LPDWHO\ P/ RI &D&,VDWXUDWHG PHWKDQRO ZDV DGGHG WR WZR P/ JODVV FHQWULIXJH WXEHV DQG SUHWLWUDWHG WR WKH YLVXDO .) HQGSRLQW 7KH WXEHV ZHUH SODFHG RQ WKH IORZ VWUHDP LQ VHULHV YLD K\SRGHUPLF QHHGOHV IRU D PHDVXUHG WLPH SHULRG 7KH VROXWLRQV ZHUH WKHQ UHPRYHG IURP WKH IORZ VWUHDP DQG LPPHGLDWHO\ UHWLWUDWHG $ VPDOO DPRXQW RI WLWHU ZDV FRQVLVWHQWO\ QHHGHG WR UHWLWUDWH WKH VHFRQG WUDS LQ WKH VHULHV ZKLFK ZDV DWWULEXWHG WR ORVV RI YRODWLOH FRPSRXQGV IURP WKH .) UHDJHQW 5KXH HW DO f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b 5+ $GVRUEHG FRQFHQWUDWLRQV RI S[\OHQH DQG ZDWHU YDSRUV IURP VLQJOH DQG ELQDU\ VUEDWH V\VWHPV ZHUH PHDVXUHG IROORZLQJ WKH SURFHGXUHV GHVFULEHG SUHYLRXVO\

PAGE 85

3UHOLPLQDU\ $GVRUSWLRQ ([SHULPHQW $ SUHOLPLQDU\ VWXG\ ZDV FRQGXFWHG WR WHVW WKH HIIHFW RI FDWLRQ VDWXUDWLRQ RQ WKH FRPSHWLWLYH DGVRUSWLRQ RI ZDWHU DQG S[\OHQH YDSRUV RQ NDROLQ $ SRUWLRQ RI WKH RULJLQDO )LVKHU NDROLQ ZDV VDWXUDWHG ZLWK /L E\ ZDVKLQJ WKH NDROLQ ZLWK 0 /L&, ([FHVV VDOW ZDV UHPRYHG E\ UHSHDWHGO\ ZDVKLQJ WKH NDROLQ ZLWK b HWKDQRO XQWLO D QHJDWLYH FKORULGH WHVW ZDV DFKLHYHG ZLWK $J1 7KH DGVRUSWLRQ RI ZDWHU DQG S[\OHQH YDSRUV RQ 1D DQG /LVDWXUDWHG NDROLQ ZDV PHDVXUHG IRU VLQJOH DQG ELQDU\VRUEDWH V\VWHPV DV GHVFULEHG SUHYLRXVO\ 5HVXOWV DQG 'LVFXVVLRQ 3UHOLPLQDU\ $GVRUSWLRQ ([SHULPHQW :DWHU DGVRUSWLRQ RQ 1DNDROLQ ZDV LQ DJUHHPHQW ZLWK WKH GDWD REWDLQHG E\ 5KXH HW DO f DQG ZDV VLJQLILFDQWO\ JUHDWHU WKDQ WKDW RQ /LNDROLQ )LJXUH Df ,Q FRQWUDVW S[\OHQH DGVRUSWLRQ RQ 1D DQG /LNDROLQ ZDV VLPLODU )LJXUH Ef VXJJHVWLQJ WKDW H[FKDQJHDEOH FDWLRQV KDG RQO\ D PLQRU HIIHFW RQ S[\OHQH DGVRUSWLRQ 7KH DGVRUSWLRQ GDWD ZHUH ILW E\ D OHDVW VTXDUHV SURFHGXUH WR WKH OLQHDU IRUP RI WKH %(7 HTXDWLRQ 33 &f33 f 633f 6P& 6P& ZKHUH 6P LV WKH PRQROD\HU DGVRUSWLRQ FDSDFLW\ PJJf DQG & LV D SDUDPHWHU UHODWHG WR WKH KHDW RI DGVRUSWLRQ (VWLPDWHG YDOXHV RI 6P DQG & DUH SUHVHQWHG LQ 7DEOH %(7 SDUDPHWHUV IRU 1DNDROLQ ZHUH FDOFXODWHG XVLQJ D FRPELQHG GDWD

PAGE 86

6 PJJf 6 PJJf :DWHU 33f S;\OHQH 33f )LJXUH 9DSRUSKDVH DGVRUSWLRQ RI Df ZDWHU DQG Ef S[\OHQH RQ 1D DQG /LVDWXUDWHG )LVKHU NDROLQ DW r&

PAGE 87

7DEOH %(7 SDUDPHWHUV IRU 1D DQG /LNDROLQ FDOFXODWHG IURP VLQJOH VUEDWH LVRWKHUP GDWD 5KXH HW DO f 6RUEHQW 6UEDWH VP & U 33 5DQJH 8VHG PJJ 1DNDROLQ S[\OHQH ZDWHU /LNDROLQ S[\OHQH ZDWHU

PAGE 88

VHW VLQFH WKH YDOXHV REWDLQHG IRU ZDWHU DQG S[\OHQH DGVRUSWLRQ ZHUH VLPLODU WR WKRVH UHSRUWHG E\ 5KXH HW DO f 7KH PRQROD\HU DGVRUSWLRQ FDSDFLW\ RI ZDWHU RQ /LNDROLQ ZDV FRQVLGHUDEO\ OHVV WKDQ WKDW RQ 1DNDROLQ ,W KDV EHHQ SURSRVHG WKDW H[FKDQJHDEOH 1D RQ NDROLQ K\GUDWHV UHDGLO\ ZKHUHDV H[FKDQJHDEOH /L GRHV QRW K\GUDWH GHVSLWH WKH IDFW WKDW /L KDV D VOLJKWO\ JUHDWHU K\GUDWLRQ HQHUJ\ WKDQ 1D .HHQDQ HW DO f $SSDUHQWO\ /L LRQV IRUP LQQHUVSKHUH FRPSOH[HV RU DUH VWURQJO\ DGVRUEHG RQ NDROLQ VXFK WKDW K\GUDWLRQ GRHV QRW RFFXU HYHQ DW KLJK 5+V .HHQDQ HW DO 0DUWLQ f ,I WKH DPRXQW RI ZDWHU DGVRUEHG E\ /LNDROLQ LV FRQVLGHUHG WR EH LQGHSHQGHQW RI FDWLRQ K\GUDWLRQ HIIHFWV WKHQ WKH GLIIHUHQFH EHWZHHQ WKH PRQROD\HU DGVRUSWLRQ FDSDFLWLHV RI 1D DQG /LNDROLQ SURYLGHV DQ HVWLPDWH RI WKH DPRXQW RI ZDWHU K\GUDWLQJ 1D %DVHG RQ WKLV DVVXPSWLRQ DSSUR[LPDWHO\ PROHFXOHV RI ZDWHU ZHUH DVVRFLDWHG ZLWK HDFK H[FKDQJHDEOH 1D LRQ ZKLFK ZDV FRQVLVWHQW ZLWK WKH UDQJH RI YDOXHV WR PROHFXOHV RI ZDWHUf UHSRUWHG E\ .HHQDQ HW DO f IRU 1D DQG 5EVDWXUDWHG NDROLQLWH 7KH ELQDU\YDSRU H[SHULPHQW ZDV FRQGXFWHG DW S[\OHQH DQG ZDWHU UHODWLYH YDSRU SUHVVXUHV RI DQG UHVSHFWLYHO\ 7KH DPRXQW RI ZDWHU DQG S [\OHQH DGVRUEHG RQ 1DNDROLQ LQ WKLV H[SHULPHQW ZDV sf DQG sf PJJ UHVSHFWLYHO\ ,Q FRQWUDVW /LNDROLQ DGVRUEHG sf DQG sf PJJ RI ZDWHU DQG S[\OHQH UHVSHFWLYHO\ 5KXH HW DO f PRGLILHG WKH %(7 HTXDWLRQ WR DFFRXQW IRU WKH FRPSHWLWLYH DGVRUSWLRQ RI WZR VUEDWH VSHFLHV 7KH

PAGE 89

WRWDO DGVRUEHG PDVV RI VUEDWH D RQ WKH VXUIDFH 0D PJJf FDQ EH FDOFXODWHG XVLQJ WKH IROORZLQJ HTXDWLRQ 0D RD&D6>;D;Df@ f ZKHUH D LV WKH PDVV RI FRPSRXQG D RFFXS\LQJ D XQLW DUHD RI VXUIDFH PJPf &D LV WKH %(7 SDUDPHWHU UHODWHG WR KHDW RI DGVRUSWLRQ FDOFXODWHG IURP VLQJOHYDSRU DGVRUSWLRQ LVRWKHUP IRU VUEDWH D ;D LV WKH UHODWLYH YDSRU SUHVVXUHV RI VUEDWH D DQG 6 LV WKH DUHD RI H[SRVHG VXUIDFH DUHD SHU XQLW PDVV RI DGVRUEHQW PJf 7KH D YDOXHV IRU ZDWHU DQG S[\OHQH ZHUH FDOFXODWHG WR EH DQG PJP UHVSHFWLYHO\ EDVHG RQ WKH IROORZLQJ HTXDWLRQ D 0:DP $f f ZKHUH 0: LV WKH PROHFXODU ZHLJKW DP LV WKH FURVVVHFWLRQDO DUHD RI VUEDWH GHWHUPLQHG LQ &KDSWHU DQG $ LV $YRJDGURfV QXPEHU 5KXH HW DO f 7KH PDVV RI VUEDWH E 0Ef FDQ EH FDOFXODWHG LQ D VLPLODU PDQQHU 8QIRUWXQDWHO\ WKH PDVV RI HLWKHU DGVRUEDWH RQ WKH VXUIDFH FDQQRW EH FDOFXODWHG EHFDXVH 6 LV XQNQRZQ LQ WKH ELQDU\ YDSRU V\VWHP 5KXH HW DO f +RZHYHU WKH IUDFWLRQ RI DGVRUEDWH D )Df RQ WKH VXUIDFH FDQ EH FDOFXODWHG XVLQJ WKH IROORZLQJ HTXDWLRQ 0D )D f f 0D 0E 7KH FDOFXODWHG YHUVXV WKH PHDVXUHG IUDFWLRQ RI ZDWHU DGVRUEHG RQ 1DNDROLQ 1Df DQG /LNDROLQ /Lf DUH SUHVHQWHG LQ )LJXUH 7KHVH GDWD LQGLFDWH WKDW 1DNDROLQ DGVRUEHG FRQVLGHUDEO\ PRUH ZDWHU WKDQ ZDV SUHGLFWHG E\ WKH WZRFRPSRQHQW %(7 HTXDWLRQ 7KH IUDFWLRQ RI ZDWHU DGVRUEHG RQ 1DNDROLQ ZDV SUHYLRXVO\ UHSRUWHG E\

PAGE 90

&DOFXODWHG )UDFWLRQ 0HDVXUHG )UDFWLRQ V? 1DNDROLQ 5KXH HW DO f 1D )LJXUH 0HDVXUHG IUDFWLRQ RI ZDWHU DGVRUEHG RQ 1D 1Df DQG /LVDWXUDWHG /Lf )LVKHU NDROLQ YHUVXV WKH IUDFWLRQ SUHGLFWHG XVLQJ WKH PXOWLVRUEDWH %(7 HTXDWLRQ RI 5KXH HW DO f UR

PAGE 91

5KXH HW DO f DQG LV GHQRWHG E\ ‘f LQ )LJXUH ,Q FRQWUDVW WKH PHDVXUHG DQG FDOFXODWHG IUDFWLRQV RI ZDWHU DGVRUEHG RQ /LNDROLQ ZHUH DOPRVW LGHQWLFDO 7KHVH GDWD VXJJHVW WKDW WKH SUHIHUHQWLDO DGVRUSWLRQ RI ZDWHU UHODWLYH WR S[\OHQH DW ORZ ZDWHU IUDFWLRQV EHORZ f ZDV GXH WR 1D K\GUDWLRQ 2QH SRVVLEOH H[SODQDWLRQ IRU WKH GLIIHUHQFH EHWZHHQ WKH PHDVXUHG DQG FDOFXODWHG IUDFWLRQ RI ZDWHU DGVRUEHG RQ 1DNDROLQ ZDV WKH VLPLODULW\ LQ WKH YDOXHV RI & HVWLPDWHG IURP ZDWHU DQG S[\OHQH VLQJOHVRUEDWH LVRWKHUPV 6LQFH WKH YDOXHV RI & ZHUH HVVHQWLDOO\ WKH VDPH WKH WZRFRPSRQHQW %(7 HTXDWLRQ RI 5KXH HW DO f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

PAGE 92

6 PJJf 6 PJJf )LJXUH 9DSRUSKDVH DGVRUSWLRQ RI Df ZDWHU DQG Ef S[\OHQH RQ &D 1D DQG /LVDWXUDWHG )LVKHU NDROLQ DW r&

PAGE 93

RI ZDWHU RQ &D 1D DQG /LNDROLQ GHULYHG IURP WKH VLQJOHVUEDWH DGVRUSWLRQ GDWD ZHUH DQG PJJ UHVSHFWLYHO\ 7DEOH f 7KHVH GDWD LQGLFDWH WKDW FDWLRQ VDWXUDWLRQ KDG D FRQVLGHUDEOH HIIHFW RQ ZDWHU DGVRUSWLRQ DQG ZHUH VLPLODU WR YDOXHV RI 6P REWDLQHG IRU 1D DQG /LNDROLQ LQ WKH SUHOLPLQDU\ VWXG\ 7KH YDOXH RI & IRU ZDWHU DGVRUSWLRQ RQ /LNDROLQ f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f +RZHYHU S[\OHQH DGVRUSWLRQ RQ 1DNDROLQ ZDV VOLJKWO\ JUHDWHU WKDQ WKDW RQ &DNDROLQ DW UHODWLYH YDSRUV SUHVVXUHV EHORZ DQG DERYH 7KH S[\OHQH PRQROD\HU DGVRUSWLRQ FDSDFLWLHV RI &D 1D DQG /L NDROLQ ZHUH DQG PJJ UHVSHFWLYHO\ 7DEOH f 7KHVH GDWD LQGLFDWH WKDW FDWLRQ VDWXUDWLRQ LQIOXHQFHG WKH DGVRUSWLRQ RI S[\OHQH YDSRUV EXW WKH VLPLODULW\ EHWZHHQ WKH YDOXHV RI 6P LQGLFDWHV WKDW WKH HIIHFW RI FDWLRQ VDWXUDWLRQ ZDV PLQLPDO ,Q RUGHU WR FRPSDUH WKH PRQROD\HU DGVRUSWLRQ FDSDFLWLHV IRU ZDWHU DQG S[\OHQH WKH YDOXH RI 6P ZDV H[SUHVVHG DV WKH DPRXQW RI VXUIDFH RFFXSLHG E\ VUEDWH PROHFXOHV SHU JUDP RI NDROLQ PJf DV GHVFULEHG LQ &KDSWHU 7DEOH

PAGE 94

7DEOH %(7 SDUDPHWHUV IRU &D 1D DQG /LNDROLQ FDOFXODWHG IURP VLQJOH VUEDWH LVRWKHUP GDWD 33 6RUEHQW 6UEDWH VP & U 6P$ 5DQJH 8VHG PJJ PJ &DNDROLQ S[\OHQH ZDWHU 1DNDROLQ S[\OHQH ZDWHU /LNDROLQ S[\OHQH ZDWHU

PAGE 95

f 7KH %(7 VXUIDFH DUHDV GHWHUPLQHG LQ WKLV PDQQHU LQGLFDWH WKDW ZKHQ WKH PROHFXODU ZHLJKW DQG VXUIDFH SDFNLQJ DUH WDNHQ LQWR FRQVLGHUDWLRQ WKH S[\OHQH PRQROD\HU DGVRUSWLRQ FDSDFLWLHV ZHUH OHVV WKDQ WKRVH PHDVXUHG IRU ZDWHU ,Q DGGLWLRQ WKH HIIHFW RI WKH VDWXUDWLQJ FDWLRQ DQG &(& WKH %(7 VXUIDFH DUHDV ZHUH DOVR VPDOOHU WKDQ WKDW REVHUYHG IRU ZDWHU ,Q RUGHU WR XWLOL]H WKH PHWKRG RI .HHQDQ HW DO f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f DQG 0DUWLQ f 7KHUHIRUH WKH XVH RI /LNDROLQ DV D UHIHUHQFH PLQHUDO VXUIDFH PD\ QRW EH YDOLG DQG FRXOG UHVXOW LQ LQFRUUHFW HVWLPDWHV RI WKH DPRXQW RI ZDWHU DVVRFLDWHG ZLWK HDFK H[FKDQJHDEOH FDWLRQ &RPSHWLWLYH $GVRUSWLRQ RI S;\OHQH DQG :DWHU RQ &D 1D DQG /LNDROLQ 'DWD IRU WKH DGVRUSWLRQ RI S[\OHQH YDSRUV RQ &D 1D DQG /LNDROLQ DW DQG b 5+ DUH SUHVHQWHG LQ )LJXUH $Q LQFUHDVH LQ 5+ IURP b WR DQG b KDG D UHODWLYHO\ PLQRU HIIHFW RQ S[\OHQH DGVRUSWLRQ UHJDUGOHVV RI WKH

PAGE 96

6 PJJf 6 PJJf 6 PJJf )LJXUH 9DSRUSKDVH DGVRUSWLRQ RI S[\OHQH RQ Df &D Ef 1D DQG Ff /L VDWXUDWHG )LVKHU NDROLQ DW DQG b 5+

PAGE 97

FDWLRQ VDWXUDWLRQ 5KXH HW DO f UHSRUWHG WKDW VL]DEOH UHGXFWLRQV LQ S[\OHQH DGVRUSWLRQ ZHUH QRW REVHUYHG XQWLO WKH 5+ ZDV JUHDWHU WKDQ WKDW UHTXLUHG WR DWWDLQ PRQROD\HU ZDWHU FRYHUDJH DV HVWLPDWHG IURP WKH VLQJOHVUEDWH %(7 HTXDWLRQ 7KH 5+V FRUUHVSRQGLQJ WR PRQROD\HU FRYHUDJH RI ZDWHU RQ &D 1D DQG /LNDROLQ ZHUH DQG b 7KXV WKH VOLJKWO\ JUHDWHU GLVSODFHPHQW RI S[\OHQH IURP &DNDROLQ ZDV FRQVLVWHQW ZLWK WKH IDFW WKDW D ORZHU 5+ ZDV UHTXLUHG WR DFKLHYH PRQROD\HU FRYHUDJH RQ &DNDROLQ WKDQ RQ 1D DQG /LNDROLQ 7KH PHDVXUHG IUDFWLRQ RI ZDWHU DGVRUEHG RQ &D 1D DQG /LNDROLQ YHUVXV WKH IUDFWLRQ FDOFXODWHG IURP WKH WZRFRPSRQHQW %(7 HTXDWLRQ RI 5KXH HW DO f LV SUHVHQWHG LQ )LJXUH D %HORZ HQKDQFHG ZDWHU DGVRUSWLRQ ZDV H[KLELWHG E\ DOO H[FKDQJHDEOH FDWLRQV VWXGLHG EXW ZDV OHVV IRU /LNDROLQ WKDQ &D DQG 1DNDROLQ 7KH GHJUHH RI SUHIHUHQWLDO ZDWHU DGVRUSWLRQ ZDV FRQVLVWHQW ZLWK WKH &(& YDOXHV SUHYLRXVO\ UHSRUWHG IRU RYHQGULHG &D 1D DQG /LNDROLQ 7KHVH GDWD IXUWKHU VXSSRUW WKH FRQWHQWLRQ WKDW /LNDROLQ UHSUHVHQWV D VXUIDFH RI UHGXFHG FKDUJH 7KH IUDFWLRQ RI ZDWHU DGVRUEHG RQ NDROLQ ZDV DOVR SUHGLFWHG XVLQJ WKH WZR FRPSRQHQW %(7 HTXDWLRQ SURSRVHG E\ +LOO D Ef ,I WKH VUEDWH LV DVVXPHG WR DGVRUE RQO\ RQWR WKH PLQHUDO VXUIDFH RU VRUEHG OD\HUV RI LWVHOI +LOOfV HTXDWLRQ FDQ EH VLPSOLILHG WR 6D ;D>&D;Ef ;E&6DP ;D;Ef> ;D&Df ;E&Ef@ f ZKHUH 6D LV WKH DPRXQW RI VUEDWH D DGVRUEHG PJJf 6DP LV WKH PRQROD\HU

PAGE 98

&DOFXODWHG )UDFWLRQ &DOFXODWHG )UDFWLRQ Df \ \ \ ? [ \ \ \n r \nb Vn r b V Br ‘ &DNDROLQ r 1DNDROLQ f /LNDROLQ )LJXUH 0HDVXUHG IUDFWLRQ RI ZDWHU DGVRUEHG RQ &D 1D DQG /L VDWXUDWHG )LVKHU NDROLQ YHUVXV WKH IUDFWLRQ FDOFXODWHG XVLQJ WKH WZRFRPSRQHQW %(7 HTXDWLRQ RI Df 5KXH HW DO f DQG Ef +LOO D Ef

PAGE 99

DGVRUSWLRQ FDSDFLW\ RI VUEDWH D PJJf ;D DQG ;E DUH WKH UHODWLYH YDSRU SUHVVXUHV RI VUEDWH D DQG E UHVSHFWLYHO\ DQG &D DQG &E DUH WKH %(7 SDUDPHWHUV UHODWHG WR WKH KHDW RI DGVRUSWLRQ RI VUEDWH D DQG Ef UHVSHFWLYHO\ 7KH SUHGLFWHG DGVRUSWLRQ RI ZDWHU DQG S[\OHQH RQ &D 1D DQG /LNDROLQ LV SUHVHQWHG LQ 7DEOH 7KH DGVRUSWLRQ RI ZDWHU DQG S[\OHQH RQ NDROLQ ZDV ZHOO SUHGLFWHG UHJDUGOHVV RI WKH FDWLRQ VDWXUDWLRQ +RZHYHU WKH SUHGLFWHG YDOXHV IRU /LNDROLQ ZHUH PRUH DFFXUDWH WKDQ WKRVH HVWLPDWHG IRU &D DQG 1DNDROLQ 7KH PHDVXUHG IUDFWLRQ RI ZDWHU DGVRUEHG RQ &D 1D DQG /LNDROLQ YHUVXV WKH IUDFWLRQ SUHGLFWHG XVLQJ WKH WZRFRPSRQHQW %(7 HTXDWLRQ RI +LOO D Ef DUH SUHVHQWHG LQ )LJXUH E 7KH PHDVXUHG DQG FDOFXODWHG IUDFWLRQV RI ZDWHU DGVRUEHG RQ /LNDROLQ ZHUH VLPLODU IRU DOO PL[HGYDSRU V\VWHPV VWXGLHG $W IUDFWLRQ OHVV WKDQ &D DQG 1DNDROLQ H[KLELWHG HQKDQFHG ZDWHU DGVRUSWLRQ +RZHYHU WKH PDJQLWXGH RI WKH SUHIHUHQWLDO ZDWHU DGVRUSWLRQ REVHUYHG KHUH ZDV IDU OHVV WKDQ WKDW REWDLQHG XVLQJ WKH WZRFRPSRQHQW %(7 HTXDWLRQ RI 5KXH HW DO f 7KLV ZDV SULPDULO\ GXH WR WKH IDFW WKDW +LOOfV WZRFRPSRQHQW %(7 HTXDWLRQ LQFRUSRUDWHV WKH YDOXH RI 6P GHWHUPLQHG IURP VLQJOHVUEDWH DGVRUSWLRQ LVRWKHUPV 7KXV WKH DGVRUSWLRQ RI ZDWHU DQG S[\OHQH SUHGLFWHG E\ +LOOfV HTXDWLRQ LV EDVHG LQ SDUW RQ WKH PRQROD\HU DGVRUSWLRQ FDSDFLW\ RI HDFK VRUEHQW ,Q FRQWUDVW WKH HTXDWLRQ RI 5KXH HW DO f GRHV QRW LQFOXGH D PRQROD\HU DGVRUSWLRQ FDSDFLW\ WHUP 7KHUHIRUH WKH YDOXH RI & PXVW EH UHODWHG WR WKH FDWLRQ K\GUDWLRQ HQHUJ\ LQ RUGHU IRU WKH IUDFWLRQ RI ZDWHU FDOFXODWHG XVLQJ WKH WZRFRPSRQHQW %(7 HTXDWLRQ WR UHIOHFW GLIIHUHQFHV LQ WKH PRQROD\HU DGVRUSWLRQ FDSDFLW\ GXH WR FDWLRQ VDWXUDWLRQ

PAGE 100

7DEOH &RPSDULVRQ RI PHDVXUHG S[\OHQH DQG ZDWHU DGVRUSWLRQ RQ &D 1D DQG /LNDROLQ IURP PL[HGYDSRU V\VWHPV ZLWK YDOXHV SUHGLFWHG XVLQJ WKH PXOWLVRUEDWH %(7 HTXDWLRQ RI +LOO D Ef 33R 0HDVXUHG 3UHGLFWHG 6RUEHQW :DWHU 3; :DWHU 3; :DWHU 3; PJJ &DNDROLQ 1DNDROLQ /LNDROLQ

PAGE 101

+RZHYHU .HHQDQ HW DO f QRWHG WKDW WKH YDOXH RI & HVWLPDWHG IURP ZDWHU DGVRUSWLRQ RQ D VHULHV RI DONDOLVDWXUDWHG NDROLQ VDPSOHV UDQJHG IURP WR DQG VKRZHG QR FRUUHODWLRQ ZLWK WKH SURSHUWLHV RI WKH H[FKDQJH FDWLRQ 7KH XWLOLW\ RI WKH WZRFRPSRQHQW %(7 HTXDWLRQ RI 5KXH HW DO f ZDV DOVR OLPLWHG E\ XQFHUWDLQW\ LQ WKH YDOXH RI & $V QRWHG SUHYLRXVO\ WKH & SDUDPHWHU REWDLQHG IRU /LNDROLQ YDULHG FRQVLGHUDEO\ HYHQ WKRXJK WKH YDOXH RI 6P DSSHDUHG WR EH UHDVRQDEOH 7KLV W\SH RI EHKDYLRU ZDV DOVR REVHUYHG IRU 1DNDROLQ 7KH FDOFXODWHG IUDFWLRQ RI ZDWHU DGVRUEHG RQ 1DNDROLQ XVLQJ WKH WZRFRPSRQHQW %(7 HTXDWLRQ RI 5KXH HW DO f DW GLIIHUHQW YDOXHV RI & IRU ZDWHU &LV SUHVHQWHG LQ )LJXUH )RU D S[\OHQH & YDOXH &S[f RI WKH FDOFXODWHG IUDFWLRQ RI ZDWHU EHFRPH ODUJHU DV WKH YDOXH RI &Z ZDV LQFUHDVHG 7KH YDOXH RI &Z f GHWHUPLQHG IURP WKH VLQJOHVRUEDWH LVRWKHUP ZDV FRQVLVWHQW ZLWK WKH YDOXH UHTXLUHG IRU WKH FDOFXODWHG DQG PHDVXUHG IUDFWLRQV RI ZDWHU WR DJUHH IRU IUDFWLRQV JUHDWHU WKDQ :KHQ WKH YDOXH RI &S[ ZDV GHFUHDVHG WKH FDOFXODWHG IUDFWLRQ RI ZDWHU VKLIWHG WR ODUJHU YDOXHV DQG VHSDUDWLRQ EHWZHHQ WKH FXUYHV LQFUHDVHG )LJXUH Ef 7KHVH GDWD LQGLFDWH WKDW WKH FDOFXODWHG IUDFWLRQ RI DGVRUEHG ZDWHU SUHGLFWHG E\ WKH WZR FRPSRQHQW %(7 HTXDWLRQ RI 5KXH HW DO f ZDV H[WUHPHO\ VHQVLWLYH WR FKDQJHV LQ WKH YDOXH RI & IRU ERWK ZDWHU DQG S[\OHQH 6XPPDU\ 7KH GDWD SUHVHQWHG KHUH LQGLFDWH WKDW YDSRUSKDVH DGVRUSWLRQ RI ZDWHU RQ NDROLQ ZDV D IXQFWLRQ RI ERWK WKH VDWXUDWLQJ FDWLRQ DQG &(& RI WKH NDROLQ 7KH

PAGE 102

&DOFXODWHG )UDFWLRQ &DOFXODWHG )UDFWLRQ )LJXUH 7KH HIIHFW RI GLIIHUHQW YDOXHV RI & IRU ZDWHU &RQ WKH IUDFWLRQ RI ZDWHU DGVRUEHG RQ 1DNDROLQ XVLQJ WKH WZRFRPSRQHQW %(7 HTXDWLRQ RI 5KXH HW DO f DW YDOXHV RI & IRU S[\OHQH RI Df DQG Ef

PAGE 103

DPRXQW RI ZDWHU DGVRUEHG RQ &D DQG 1DNDROLQ ZDV GLUHFWO\ UHODWHG WR WKH K\GUDWLRQ HQHUJ\ RI WKH H[FKDQJHDEOH FDWLRQ ,Q FRQWUDVW /LNDROLQ DGVRUEHG FRQVLGHUDEO\ OHVV ZDWHU WKDQ 1DNDROLQ HYHQ WKRXJK WKH K\GUDWLRQ HQHUJ\ RI /L LV VOLJKWO\ JUHDWHU WKDQ WKDW RI 1D 7KLV SKHQRPHQRQ KDV EHHQ UHSRUWHG SUHYLRXVO\ DQG ZDV DWWULEXWHG WR WKH DEVHQFH RI /L K\GUDWLRQ .HHQDQ HW DO 0DUWLQ f +RZHYHU /LNDROLQ H[KLELWHG D b UHGXFWLRQ LQ &(& DIWHU GU\LQJ DW r& VXJJHVWLQJ WKDW WKH UHGXFHG ZDWHU DGVRUSWLRQ REVHUYHG IRU /LNDROLQ ZDV GXH WR D GHFUHDVH LQ &(& 7KXV /LNDROLQ PD\ UHSUHVHQW D VXUIDFH RI UHGXFHG FKDUJH UDWKHU WKDQ D UHIHUHQFH VXUIDFH IUHH RI FDWLRQ K\GUDWLRQ HIIHFWV 7KH VSHFLILF PHFKDQLVPV UHVSRQVLEOH IRU FKDUJH UHGXFWLRQ DQG LWV HIIHFW RQ WKH K\GUDWLRQ SURSHUWLHV RI /LNDROLQ ZLOO EH DGGUHVVHG LQ &KDSWHU 7KH HIIHFW RI WKH VDWXUDWLQJ FDWLRQ DQG &(& RI NDROLQ RQ S[\OHQH DGVRUSWLRQ ZHUH VLPLODU EXW WR D OHVVHU H[WHQW WKDQ WKDW REVHUYHG IRU ZDWHU 7KHVH GDWD VXJJHVW WKDW VSHFLILF LQWHUDFWLRQV RFFXUUHG EHWZHHQ S[\OHQH PROHFXOHV DQG H[FKDQJHDEOH FDWLRQV ZKLFK KDV QRW EHHQ UHSRUWHG SUHYLRXVO\ ,W ZDV K\SRWKHVL]HG WKDW YDSRUSKDVH DGVRUSWLRQ RI S[\OHQH RQ NDROLQ FDQ EH FKDUDFWHUL]HG E\ ZHDN LQWHUDFWLRQV DW FDWLRQ H[FKDQJH VLWHV DQG SK\VLFDO DGVRUSWLRQ HJ GLSROHGLSROH LQWHUDFWLRQVf RQ WKH UHPDLQLQJ PLQHUDO VXUIDFH 6LQFH WKH HQHUJ\ RI DGVRUSWLRQ ZRXOG EH VLPLODU DW WKHVH ORFDWLRQV S[\OHQH DGVRUSWLRQ PD\ DSSURDFK WKHRUHWLFDO PRQROD\HU FRYHUDJH SULRU WR WKH RQVHW RI PXOWLOD\HU IRUPDWLRQ ,Q FRQWUDVW ZDWHU DGVRUSWLRQ DW ORZ 5+V LV OLNHO\ WR EH FRQFHQWUDWHG DW FDWLRQ H[FKDQJH VLWHV UHVXOWLQJ LQ WKH IRUPDWLRQ RI GLVFUHWH

PAGE 104

SDWFKHV RI ZDWHU $V WKH 5+ LQFUHDVHV PXOWLOD\HU IRUPDWLRQ ZRXOG RFFXU RQ K\GUDWHG FDWLRQV DORQJ ZLWK DGVRUSWLRQ RQ WKH UHPDLQLQJ H[SRVHG PLQHUDO VXUIDFH ,QFUHDVLQJ WKH 5+ IURP b WR DQG b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f DW IUDFWLRQV OHVV WKDQ 7KH REVHUYHG GLIIHUHQFH FRXOG EH DWWULEXWHG LQ SDUW WR WKH VLPLODULW\ LQ WKH YDOXHV RI & GHWHUPLQHG IURP S[\OHQH DQG ZDWHU DGVRUSWLRQ LVRWKHUPV ,Q DGGLWLRQ XQFHUWDLQW\ LQ WKH YDOXH RI & OLPLWHG WKH XWLOLW\ RI WKH WZRFRPSRQHQW %(7 HTXDWLRQ RI 5KXH HW DO f ,Q FRQWUDVW WKH WZRFRPSRQHQW %(7 HTXDWLRQ RI +LOO D Ef LQFRUSRUDWHV ERWK WKH 6P DQG & SDUDPHWHUV GHWHUPLQHG IURP VLQJOHVRUEDWH DGVRUSWLRQ LVRWKHUPV XVLQJ WKH %(7 HTXDWLRQ 1HYHUWKHOHVV D VPDOO GHJUHH RI SUHIHUHQWLDO ZDWHU DGVRUSWLRQ ZDV REVHUYHG RQ &D DQG 1DNDROLQ DW ZDWHU IUDFWLRQV OHVV WKDQ LQGLFDWLQJ WKDW DW ORZ 5+ DQG UHODWLYHO\ KLJK S[\OHQH YDSRU SUHVVXUH WKH DGVRUSWLRQ RI ZDWHU ZDV JUHDWHU WKDQ FRXOG EH DFFRXQWHG IRU EDVHG RQ VLQJOH VRUEDWH DGVRUSWLRQ LVRWKHUPV :DWHU DQG S[\OHQH DGVRUSWLRQ RQ &D 1D DQG /L

PAGE 105

NDROLQ SUHGLFWHG IURP +LOOfV PXOWLVRUEDWH %(7 HTXDWLRQ GHYLDWHG RQ WKH DYHUDJH E\ D IDFWRU RI IURP WKH PHDVXUHG DGVRUSWLRQ 7KHVH GDWD VXJJHVW WKDW WKH WZRFRPSRQHQW HTXDWLRQ RI +LOO D Ef ZDUUDQWV IXUWKHU LQYHVWLJDWLRQ DV D WRRO WR SUHGLFW WKH FRPSHWLWLYH DGVRUSWLRQ RI ZDWHU DQG RUJDQLF YDSRUV DW ORZ VXUIDFH FRYHUDJHV

PAGE 106

&+$37(5 7+( ())(&7 2) +($7 75($70(176 21 7+( 727$/ &+$5*( $1' (;&+$1*($%/( &$7,216 2) &$ 1$ $1' /,6$785$7(' .$2/,1 ,QWURGXFWLRQ 7KH HIIHFW RI H[FKDQJHDEOH ,RQV RQ WKH DGVRUSWLRQ DQG GHVRUSWLRQ RI ZDWHU YDSRU E\ NDROLQ KDV EHHQ VWXGLHG LQ JUHDW GHWDLO -XULQDN -XULQDN DQG 9ROPDQ D E .HHQDQ HW DO 0DUWLQ f 2I SDUWLFXODU LQWHUHVW LV WKH /L LRQ ZKLFK KDV EHHQ VKRZQ WR KDYH QR DSSDUHQW HIIHFW RQ ZDWHU DGVRUSWLRQ 0DUWLQ f UHSRUWHG WKDW /LVDWXUDWHG NDROLQ GLG QRW H[KLELW K\VWHUHVLV GXH WR FDWLRQ K\GUDWLRQ HIIHFWV DW UHODWLYH KXPLGLWLHV EHORZ b ZKHUHDV &D 0J DQG 1DVDWXUDWHG NDROLQ \LHOGHG K\VWHUHWLF DGVRUSWLRQ GHVRUSWLRQ LVRWKHUPV ,Q DGGLWLRQ NDROLQ VDWXUDWHG ZLWK /L KDV EHHQ IRXQG WR DGVRUE OHVV ZDWHU WKDQ NDROLQ VDWXUDWHG ZLWK 1D GHVSLWH WKH IDFW WKDW /L KDV D VOLJKWO\ JUHDWHU K\GUDWLRQ HQHUJ\ WKDQ 1D .HHQDQ HW DO f %DVHG RQ WKHVH GDWD /LVDWXUDWHG NDROLQ LV JHQHUDOO\ FRQVLGHUHG WR UHSUHVHQW D PLQHUDO VXUIDFH LQGHSHQGHQW RI FDWLRQ K\GUDWLRQ HIIHFWV DQG KDV IUHTXHQWO\ EHHQ XWLOL]HG DV D UHIHUHQFH VXUIDFH LQ WKH VWXG\ RI ZDWHU DQG RUJDQLF YDSRU VRUSWLRQ RQ NDROLQ -XULQDN -XULQDN DQG 9ROPDQ D 5KXH HW DO f $OWKRXJK SXEOLVKHG GDWD SUHVHQW VWURQJ HYLGHQFH IRU WKH DEVHQFH RI /L K\GUDWLRQ WKH PHFKDQLVPV UHVSRQVLEOH IRU VXFK EHKDYLRU KDYH QRW EHHQ FOHDUO\

PAGE 107

LGHQWLILHG .HHQDQ HW DO f K\SRWKHVL]HG WKDW /L LRQV ILW LQWR WKH WHWUDKHGUDO OD\HU RI NDROLQ VXFK WKDW K\GUDWLRQ LV VWHULFDOO\ KLQGHUHG E\ WKH RXWHU R[\JHQ DWRPV ,Q FRQWUDVW 0DUWLQ f SRVWXODWHG WKDW WKH K\GUDWLRQ HQHUJ\ RI /L ZDV QRW VXIILFLHQW WR RYHUFRPH WKH VSHFLILF DGVRUSWLRQ HQHUJ\ RI WKH LRQ IRU WKH FOD\ VXUIDFH DQG WKXV WUXH LRQLF K\GUDWLRQ GLG QRW RFFXU ,Q ERWK RI WKHVH VWXGLHV WKH NDROLQ ZDV GULHG DW r& LQ D YDFXXP ZKLFK KDV EHHQ VKRZQ WR EH HTXLYDOHQW WR DLUGU\LQJ DW r& .HHQDQ HW DO f SULRU WR WKH DGVRUSWLRQ H[SHULPHQWV 7KH HIIHFW RI KHDWLQJ RQ WKH FDWLRQ H[FKDQJH FDSDFLW\ &(&f RI NDROLQ VDWXUDWHG ZLWK &D 0J 1D DQG /L ZDV VWXGLHG E\ *UHHQH.HOO\ f ,QWHUHVWLQJO\ WKH &(& RI /LNDROLQ DV GHWHUPLQHG IURP 1+ H[FKDQJH ZDV b RI WKH RULJLQDO OHYHO DIWHU KHDWLQJ WR r& 7KH KHDW WUHDWPHQW KDG QR DSSDUHQW HIIHFW RQ WKH &(& RI &D 0J DQG 1DNDROLQ $ UHGXFWLRQ LQ 1+ H[FKDQJH E\ /LNDROLQ DIWHU KHDWLQJ WR r& ZDV DOVR UHSRUWHG E\ &DVKHQ f 7KHVH GDWD VXJJHVW WKDW WKH UHDVRQ ZDWHU DGVRUSWLRQ RQ /LVDWXUDWHG NDROLQ ZDV OHVV WKDQ WKDW RI 1DVDWXUDWHG NDROLQ ZDV DFWXDOO\ GXH WR D UHGXFWLRQ LQ &(& -XULQDN f .HHQDQ HW DO f DQG 0DUWLQ f IDLOHG WR UHSRUW WKH &(& RI NDROLQ IROORZLQJ FDWLRQ VDWXUDWLRQ DQG KHDW WUHDWPHQWV DQG ZHUH DSSDUHQWO\ XQDZDUH RI SRVVLEOH FKDUJH UHGXFWLRQV XSRQ KHDWLQJ *UHHQH.HOO\ f DOVR UHSRUWHG WKDW KHDWLQJ VXEVWDQWLDOO\ GHFUHDVHG WKH WKH DPRXQW RI /L WKDW FRXOG EH H[WUDFWHG IURP /LNDROLQ XVLQJ 1 1+$2F 7KHVH GDWD VXJJHVW WKDW D SRUWLRQ RI WKH /L LRQV ZHUH IL[HG ZLWKLQ WKH NDROLQLWH VWUXFWXUH $ VLPLODU SKHQRPHQRQ WKH PLJUDWLRQ RI /L LRQV LQWR WKH FOD\ ODWWLFH KDV

PAGE 108

EHHQ REVHUYHG IRU PRQWPRULOORQLWH DQG LV FRPPRQO\ UHIHUUHG WR DV WKH +RIPDQQ .OHPHQ HIIHFW %ULQGOH\ DQG (UWHP &DOYHW DQG 3URVW *ODVHU DQG 0HULQJ *UHHQH.HOO\ +RIPDQQ DQG .OHPHQ -D\QHV DQG %LJKDP /LP DQG -DFNVRQ /XFD DQG &DUGLOH /XFD HW DO 6SRVLWR HW DO f 7ZR SRVLWLRQV KDYH EHHQ SURSRVHG IRU WKH ORFDWLRQ RI QRQH[FKDQJHDEOH /L LRQV LQ PRQWPRULOORQLWH f WKH ERWWRP RI WKH SVHXGRKH[DJRQDO FDYLWLHV RI WKH EDVDO VXUIDFH DQG f YDFDQW RFWDKHGUDO VLWHV &DOYHW DQG 3URVW f XVLQJ LQIUDUHG ,5f VSHFWURVFRS\ IRXQG WKDW RQO\ D IUDFWLRQ RI WKH QRQH[FKDQJHDEOH /L UHVLGHV ZLWKLQ WKH RFWDKHGUDO OD\HU WKH UHPDLQGHU EHLQJ ORFDWHG LQ WKH KH[DJRQDO FDYLWLHV 7KHVH GDWD ZHUH VXSSRUWHG E\ /XFD DQG &DUGLOH f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f ,QIUDUHG VSHFWURVFRS\ ZDV XWLOL]HG WR LQIHU WKH ORFDWLRQ RI /L LRQV LQ KHDWWUHDWHG NDROLQ 7KH HIIHFW RI KHDW DQG YDFXXP WUHDWPHQWV RQ WKH DGVRUSWLRQ DQG GHVRUSWLRQ RI ZDWHU YDSRU E\ NDROLQ ZDV DOVR VWXGLHG

PAGE 109

0DWHULDOV DQG 0HWKRGV .DROLQLWH 6DPSOHV 7KH NDROLQLWH VDPSOHV VWXGLHG ZHUH FROORLGDO NDROLQ /RW f REWDLQHG IURP )LVKHU 6FLHQWLILF 3URGXFWV DQG .*D NDROLQLWH IURP :DVKLQJWRQ &RXQW\ *HRUJLD REWDLQHG IURP WKH 6RXUFH &OD\V 5HSRVLWRU\ RI 7KH &OD\ 0LQHUDOV 6RFLHW\ 7KH UHSRUWHG &(& YDOXHV IRU .*D NDROLQLWH UDQJH IURP WR FPROANJ YDQ 2OSKHQ DQG )ULSLDW f 7KH .*D NDROLQLWH ZDV FRQVLGHUHG WR EH ZHOOFU\VWDOOL]HG ZLWK D 1 VXUIDFH DUHD RI s PJ 7KH )LVKHU NDROLQ KDG D VOLJKWO\ ODUJHU &(& FPROANJ DW S+ f DQG ZDV SUHGRPLQDQWO\ 1D VDWXUDWHG ZLWK WUDFH DPRXQWV RI H[FKDQJHDEOH &D 0J DQG 5KXH DQG 5HYH f $GGLWLRQDO SK\VLFDO DQG FKHPLFDO FKDUDFWHULVWLFV RI )LVKHU NDROLQ DUH JLYHQ LQ &KDSWHU ;5D\ 'LIIUDFWLRQ 6WXGLHV 'XH WR WKH ODFN RI PLQHUDORJLFDO GDWD IRU )LVKHU NDROLQ [UD\ GLIIUDFWLRQ ;5'f VWXGLHV ZHUH XQGHUWDNHQ WR SURYLGH D SUHOLPLQDU\ PLQHUDORJLFDO FKDUDFWHUL]DWLRQ DQG WR GHWHUPLQH WKH UHODWLYH GHJUHH RI RUGHU LQ WKH PLQHUDO VWUXFWXUH 2ULHQWHG PRXQWV RI )LVKHU NDROLQ ZHUH SUHSDUHG IRU ;5' DQDO\VLV E\ GHSRVLWLQJ DSSUR[LPDWHO\ PJ RI NDROLQ IURP VXVSHQVLRQ RQWR D FHUDPLF WLOH XQGHU VXFWLRQ 7KH NDROLQ PRXQWV ZHUH WUHDWHG ZLWK 0 0J&O] DQG .&, DQG ZDVKHG IUHH RI VDOWV ZLWK GHLRQL]HG ZDWHU $ b JO\FHURO VROXWLRQ ZDV DSSOLHG WR WKH 0JVDWXUDWHG VDPSOHV $OO PRXQWV ZHUH VFDQQHG ZLWK D FRPSXWHUFRQWUROOHG ;5' V\VWHP RSHUDWHG DW r SHU PLQXWH XVLQJ &X.D UDGLDWLRQ 7KH ;5'

PAGE 110

DQDO\VHV ZHUH SHUIRUPHG DW URRP WHPSHUDWXUH r&f DQG DIWHU RYHUQLJKW KHDWLQJ DW DQG r& &DWLRQ ([FKDQJH &DSDFLW\ ([SHULPHQWV 3ULRU WR FDWLRQ VDWXUDWLRQ )LVKHU NDROLQ ZDV WUHDWHG ZLWK 0 1D$2F EXIIHUHG WR S+ ZLWK DFHWLF DFLG WR UHPRYH FDUERQDWHV +RPRLRQLF VDPSOHV RI &D 1D DQG /LVDWXUDWHG )LVKHU NDROLQ ZHUH SUHSDUHG IROORZLQJ WKH SURFHGXUH GHVFULEHG LQ &KDSWHU :LWK WKH H[FHSWLRQ RI WKH 1D$2F WUHDWPHQW WKH VDPH SURFHGXUH ZDV IROORZHG WR VDWXUDWH WKH .*D NDROLQ ZLWK &D 1D DQG /L $ SUHOLPLQDU\ H[SHULPHQW ZDV FRQGXFWHG WR GHWHUPLQH WKH HIIHFW RI KHDWLQJ r&f RQ WKH &(& RI )LVKHU NDROLQ VDWXUDWHG ZLWK &D 1D DQG /L 7KH DPRXQW RI VDWXUDWLQJ FDWLRQ ZKLFK UHPDLQHG H[FKDQJHDEOH DIWHU DQG GD\V RI H[SRVXUH WR KHDW ZDV PHDVXUHG XVLQJ D 0J1f H[WUDFWLRQ SURFHGXUH $SSUR[LPDWHO\ J RI NDROLQ ZDV SODFHG LQ D P/ SRO\HWK\OHQH FHQWULIXJH WXEH 7R HDFK WXEH P/ RI 0 0J1f ZDV DGGHG ZKLFK ZDV PL[HG XQWLO WKH NDROLQ ZDV FRPSOHWHO\ GLVSHUVHG DQG VHSDUDWHG E\ FHQWULIXJDWLRQ DW USP IRU PLQXWHV 7KH VXSHUQDWDQW IURP ILYH 0J1f ZDVKHV ZDV FROOHFWHG LQ D P/ YROXPHWULF IODVN ZKLFK ZDV EURXJKW WR YROXPH ZLWK GHLRQL]HG ZDWHU 7KH FRQFHQWUDWLRQ RI WKH DSSURSULDWH FDWLRQ LH &D 1D /Lf LQ WKH 0J1f H[WUDFW ZDV PHDVXUHG E\ DWRPLF DEVRUSWLRQ VSHFWURVFRS\ DQG H[SUHVVHG DV FPROFNJ $OXPLQXP ZDV DOVR PHDVXUHG LQ WKH 0J1f H[WUDFWV RI 1D DQG /LVDWXUDWHG NDROLQ RQ GD\

PAGE 111

$IWHU VHYHQ GD\V RI KHDWLQJ WKH WRWDO FKDUJH RI WKH &D 1D DQG /L VDWXUDWHG )LVKHU NDROLQ ZDV GHWHUPLQHG E\ &DH[FKDQJH $Q DGGLWLRQDO J VDPSOH RI NDROLQ ZDV SODFHG LQ D P/ SRO\HWK\OHQH FHQWULIXJH WXEH 7KH NDROLQ ZDV ZDVKHG ILYH WLPHV ZLWK P/ RI 0 &D&, DQG H[FHVV VDOW ZDV UHPRYHG E\ UHSHDWHGO\ ZDVKLQJ WKH NDROLQ ZLWK b HWKDQRO XQWLO D QHJDWLYH FKORULGH WHVW ZDV DFKLHYHG XVLQJ $J1 &DOFLXP ZDV H[WUDFWHG ZLWK 0 0J1f IROORZLQJ WKH VDPH SURFHGXUH DV GHVFULEHG SUHYLRXVO\ $ VHFRQG PRUH H[WHQVLYH VWXG\ ZDV LQLWLDWHG WR GHWHUPLQH WKH HIIHFW RI KHDWLQJ DW r& RQ WKH WRWDO FKDUJH DQG H[FKDQJHDEOH FDWLRQV RI &D 1D DQG /LVDWXUDWHG )LVKHU DQG .*D NDROLQ $SSUR[LPDWHO\ J RI NDROLQ ZDV SODFHG LQ LQGLYLGXDO P/ SRO\HWK\OHQH FHQWULIXJH WXEHV 7KH VDPSOHV ZHUH ZDVKHG ZLWK P/ RI 0 1+&, WR H[WUDFW H[FKDQJHDEOH &D 1D /L 0J DQG $O 7KH WRWDO FKDUJH RI WKH NDROLQ ZDV WKHQ GHWHUPLQHG E\ &DH[FKDQJH DV GHVFULEHG SUHYLRXVO\ 7KH 1D DQG /LVDWXUDWHG NDROLQ VDPSOHV ZHUH DOVR WUHDWHG ZLWK 0 +&, IRU PLQXWHV WR H[WUDFW DGGLWLRQDO 1D /L DQG $O $OO H[WUDFWLRQV GHVFULEHG KHUH ZHUH UHSOLFDWHG IRXU WLPHV +\VWHUHVLV ([SHULPHQWV 7KHUPDOJUDYLPHWULF DQDO\VLV 7*$f RI &D DQG /LVDWXUDWHG )LVKHU DQG .*D NDROLQ ZDV FRQGXFWHG WR GHWHUPLQH WKH HIIHFW RI KHDWLQJ RQ ZDWHU YDSRU DGVRUSWLRQ DQG GHVRUSWLRQ $SSUR[LPDWHO\ PJ RI NDROLQ ZDV SODFHG LQ WKH VDPSOH SDQ RI D FRPSXWHUFRQWUROOHG WKHUPDOJUDYLPHWULF DQDO\]HU 7KH VDPSOHV ZHUH HTXLOLEUDWHG ZLWK D KLJK 5+ bf DLU IORZ VWUHDP IRU KRXUV DW r&

PAGE 112

KHDWHG WR r& DW D UDWH RI r& SHU PLQXWHf IRU KRXUV DQG DOORZHG WR UHHTXLOLEUDWH ZLWK WKH KLJK 5+ IORZ VWUHDP DW r& IRU DSSUR[LPDWHO\ KRXUV $ VHFRQG WUHDWPHQW VHTXHQFH FRQVLVWHG RI H[SRVXUH WR WKH KLJK 5+ IORZ VWUHDP ZLWK WKH WHPSHUDWXUH DOWHUQDWLQJ EHWZHHQ r& DQG r& HYHU\ KRXUV $ &DKQp HOHFWUREDODQFH ZDV XVHG WR VWXG\ WKH HIIHFW RI H[SRVXUH WR D YDFXXP RQ WKH DGVRUSWLRQ DQG GHVRUSWLRQ RI ZDWHU YDSRU E\ &D DQG /LVDWXUDWHG )LVKHU NDROLQ $SSUR[LPDWHO\ PJ RI NDROLQ ZDV SODFHG RQ D KDQJLQJ VDPSOH SDQ ORRS $f ZKLFK ZDV FRXQWHUEDODQFHG E\ DQ HPSW\ KDQJLQJ SDQ ORRS &f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p PLFURSURFHVVRU YLD D 56 FDEOH ,QIUDUHG 6SHFWURVFRS\ ([SHULPHQWV 6XVSHQVLRQV RI )LVKHU NDROLQ ZHUH PDGH E\ SODFLQJ DSSUR[LPDWHO\ J RI NDROLQ LQ P/ RI GHLRQL]HG ZDWHU $ VDPSOH IURP WKH VXVSHQVLRQ ZDV DLUGULHG RQWR D VPDOO SLHFH RI D PP ; PP =Q6H GLVN 7KH =Q6H ZDV SRVLWLRQHG RQ D VWDQGDUG .%U PRXQW LQ D VDPSOH FRPSDUWPHQW HYDFXDWHG WR WRUU LQ RUGHU WR

PAGE 113

HOLPLQDWH LQWHUIHUHQFHV IURP DWPRVSKHULF & DQG ZDWHU YDSRUV ,QIUDUHG VSHFWUD ZHUH FROOHFWHG XVLQJ D %RPHP '$ )RXULHUWUDQVIRUP ,5 VSHFWURPHWHU 7KH '$ VSHFWURPHWHU ZDV HTXLSSHG ZLWK D 0LFKHOVRQ LQWHUIHURPHWHU FRQWDLQLQJ D .%U EHDPVSOLWWHU SRVLWLRQHG DW D r DQJOH WR WKH RSWLFDO D[LV $ PHUFXU\ FDGPLXPWHOOXULGH 0&7f GHWHFWRU ZLWK D 'r YDOXH RI ; FP+] DQG D ORZ IUHTXHQF\ FXWRII RI FPn Pf ZDV XVHG LQ WKLV VWXG\ 7KH %RPHP '$ VSHFWURPHWHU ZDV FRQWUROOHG E\ D '(& 9D[VWDWLRQOO FRPSXWHU YLD DQ ,((( LQWHUIDFH $Q RSWLFDO UHVROXWLRQ RI ZDYHQXPEHUV ZDV XVHG IRU WKH FROOHFWLRQ RI WKH UHSRUWHG ,5 VSHFWUD 5HVXOWV DQG 'LVFXVVLRQ ;5D\ 'LIIUDFWLRQ 6WXGLHV 7KH .VDWXUDWHG VDPSOH H[KLELWHG VWURQJ SHDNV DW DQG QP ZKLFK DUH FKDUDFWHULVWLF RI DQG SHDNV IRU NDROLQLWH )LJXUH f $ YHU\ VPDOO SHDN ORFDWHG DW QP ZDV LQYHVWLJDWHG LQ PRUH GHWDLO WR GHWHUPLQH LI WKH NDROLQ ZDV FRQWDPLQDWHG ZLWK VPHFWLWH +HDWLQJ WKH VDPSOH WR DQG r& KDG QR GLVFHUQDEOH HIIHFW RQ WKH QP SHDN KRZHYHU DOO SHDNV ZHUH HOLPLQDWHG DW r& )LJXUH f 7KH 0JVDWXUDWLRQ DQG JO\FHURO WUHDWPHQW GLG QRW UHVXOW LQ D VKLIW RI WKH QP SHDN )LJXUH Ef 7KHVH GDWD LQGLFDWH WKDW WKH QP SHDN ZDV QRW GXH WR VPHFWLWH FRQWDPLQDWLRQ EXW ZDV SUREDEO\ DWWULEXWDEOH WR D FKORULWH RI ORZ WKHUPDO VWDELOLW\

PAGE 114

QP )LJXUH ;5' SDWWHUQV RI .VDWXUDWHG )LVKHU .DROLQ DIWHU RYHUQLJKW H[SRVXUH WR WKH VSHFLILHG WHPSHUDWXUHV

PAGE 115

)LJXUH (IIHFW RI RYHUQLJKW H[SRVXUH WR WKH VSHFLILHG WHPSHUDWXUHV RQ WKH QP SHDN RI .VDWXUDWHG )LVKHU NDROLQ

PAGE 116

QP )LJXUH ;5' SDWWHUQ RI 0JVDWXUDWHG DQG JO\FHURO WUHDWHG Df FOD\ IUDFWLRQ DQG Ef XQIUDFWLRQDWHG )LVKHU NDROLQ

PAGE 117

7KH NDROLQ VDPSOH ZDV VHSDUDWHG LQWR VLOW SPf DQG FOD\ SPf IUDFWLRQV WR GHWHUPLQH LI WKH FRQWDPLQDQW FRXOG EH LVRODWHG 6HSDUDWLRQ RI WKH NDROLQ ZDV DFKLHYHG E\ UHSHDWHG GLVSHUVLRQ FHQWULIXJDWLRQ DQG FROOHFWLRQ RI WKH VXSHUQDWDQW 3ULRU WR HDFK FHQWULIXJDWLRQ S+ ZDWHU ZDV DGGHG WR WKH NDROLQ VDPSOH &HQWULIXJDWLRQ SURFHHGHG DV IROORZV f USP IRU PLQXWHV f USP IRU PLQXWHV DQG f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f 7KH .VDWXUDWHG VLOW IUDFWLRQ ZDV LGHQWLFDO WR WKDW RI WKH ZKROH FOD\ LQGLFDWLQJ WKDW WKH QP SHDN H[LVWV LQ ERWK IUDFWLRQV +RZHYHU WKH VPDOO SHDN DW QP ZDV DWWULEXWHG WR PLFD )LJXUH f $ IDLQW SHDN ZDV DOVR REVHUYHG LQ WKH ZKROH FOD\ VDPSOH DW DSSUR[LPDWHO\ QP 7KH FRQWDPLQDWLRQ QRWHG KHUH ZDV OLNHO\ WR KDYH OLWWOH HIIHFW RQ WKH &(& DQG VXUIDFH DUHD RI WKH NDROLQ EHFDXVH LW DSSHDUHG WR EH DWWULEXWDEOH WR QRQH[SDQGDEOH SK\OORVLOLFDWH PLQHUDOV RI ORZ VXUIDFH FKDUJH 6HPLUDQGRP SRZGHU PRXQWV RI WKH )LVKHU NDROLQ ZHUH SUHSDUHG E\ JHQWO\ SDFNLQJ DLUGU\ NDROLQ LQWR WKH VDPSOH UHVHUYRLU RI D SODVWLF PRXQW $ SRZGHU PRXQW DOORZV DOO FU\VWDO SODQHV KNOf WR EH GHWHFWHG E\ ;5' DQDO\VLV $V WKH

PAGE 118

QP )LJXUH ;5' SDWWHUQ RI .VDWXUDWHG VLOW IUDFWLRQ RI )LVKHU NDROLQ

PAGE 119

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r& WKH DPRXQW RI &D H[WUDFWHG IURP &D VDWXUDWHG )LVKHU NDROLQ KDG QRW FKDQJHG ZKHUHDV H[WUDFWDEOH 1D DQG /L ZDV DQG b UHVSHFWLYHO\ RI WKH RULJLQDO OHYHO 7KH WRWDO FKDUJH RI &D DQG 1DNDROLQ DV GHWHUPLQHG E\ &D H[FKDQJH ZDV QRW DIIHFWHG E\ WKH KHDW WUHDWPHQW EXW GHFUHDVHG E\ DSSUR[LPDWHO\ b IRU /LNDROLQ 7KH GLVSDULW\ EHWZHHQ WKH FKDUJH DWWULEXWDEOH WR WKH VDWXUDWLQJ FDWLRQ DQG WKDW GHWHUPLQHG E\ &D H[FKDQJH IRU 1D DQG /LNDROLQ VXJJHVWV WKDW RWKHU LRQV ZHUH LQYROYHG LQ WKH H[FKDQJH SURFHVV 7R WHVW WKLV K\SRWKHVLV WKH 0J1f H[WUDFWV RI 1D DQG /LNDROLQ ZHUH DQDO\]HG IRU $O RQ GD\ $OXPLQXP ZDV QRW GHWHFWHG LQ WKH 1DNDROLQ H[WUDFW EXW ZDV SUHVHQW LQ WKH /LNDROLQ H[WUDFW VXJJHVWLQJ WKDW /L GLVSODFHG $O IURP WKH NDROLQ ODWWLFH ,W VKRXOG DOVR EH QRWHG WKDW WKH FRORU RI WKH /LNDROLQ FKDQJHG IURP QHDUO\ ZKLWH WR JUD\ XSRQ KHDWLQJ 7KH FRORU RI &DNDROLQ ZDV QRW DIIHFWHG WKH KHDW

PAGE 120

)LJXUH ;5' SDWWHUQV IURP SRZGHU PRXQWV RI Df ZHOOFU\VWDOOL]HG *D NDROLQ Ef )LVKHU NDROLQ DQG Ff SRRUO\FU\VWDOOL]HG *D NDROLQ

PAGE 121

7DEOH 5HVXOWV RI SUHOLPLQDU\ H[SHULPHQW WR GHWHUPLQH WKH HIIHFW RI KHDWLQJ DW r& RQ WKH &(& RI &D 1D DQG /LVDWXUDWHG )LVKHU NDROLQ (ODSVHG ([WUDFWLRQ &DNDROLQ 1DNDROLQ /LNDROLQ 'D\V 0HWKRG FPROMNJ 0J1fD s s s 0J1f s s s 0J1f s s s &D&,E s s s 0J1f s s 0J1f$OF s s D 0J1f H[WUDFWLRQ RI VDWXUDWLQJ FDWLRQ E &D&, ZDVK b HWKDQRO ULQVH DQG 0J1f H[WUDFWLRQ RI &D F 0J1f H[WUDFWLRQ RI $O

PAGE 122

WUHDWPHQW ZKLOH WKDW RI 1DNDROLQ EHFDPH VOLJKWO\ GDUNHU $ VLPLODU FRORU FKDQJH KDV EHHQ UHSRUWHG IRU /LVDWXUDWHG PRQWPRULOORQLWH VXEMHFW WR KHDW WUHDWPHQWV -D\QHV DQG %LJKDP f 7R VXEVWDQWLDWH WKH ILQGLQJV RI WKH SUHOLPLQDU\ H[SHULPHQW D VHFRQG VWXG\ ZDV FRQGXFWHG WR GHWHUPLQH WKH HIIHFW RI KHDWLQJ RQ WKH &(& DQG H[WUDFWDEOH FDWLRQV RI NDROLQ 7KH WRWDO FKDUJH DV GHWHUPLQHG E\ &D H[FKDQJH RI )LVKHU DQG .*D NDROLQ DLUGULHG DW r& LV SUHVHQWHG LQ 7DEOHV DQG UHVSHFWLYHO\ $IWHU VHYHQ GD\V RI KHDWLQJ WKH WRWDO FKDUJH RI &D 1D DQG /LVDWXUDWHG )LVKHU NDROLQ ZDV DQG b UHVSHFWLYHO\ RI WKH FKDUJH SULRU WR KHDWLQJ 7KH .*D NDROLQV H[KLELWHG D VLPLODU WUHQG DIWHU GD\V RI KHDWLQJ DOWKRXJK WKH GHFUHDVH LQ FKDUJH RI &D DQG /LNDROLQ ZDV OHVV WKDQ WKDW RI WKH FRUUHVSRQGLQJ )LVKHU NDROLQ 7KH UHGXFWLRQ LQ WRWDO FKDUJH RU &(& RI /LNDROLQ ZDV FRQVLVWHQW ZLWK WKH ILQGLQJV RI *UHHQH.HOO\ f DQG &DVKHQ f ,Q DGGLWLRQ QR FKORULGH ZDV GHWHFWHG LQ WKH 0J1f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f

PAGE 123

7DEOH 7RWDO FKDUJH RI &D 1D DQG /LVDWXUDWHG )LVKHU NDROLQ DV GHWHUPLQHG E\ &D H[FKDQJH DLUGULHG DW r& (ODSVHG 'D\V &DNDROLQ 1DNDROLQ /LNDROLQ &DWLRQ ([FKDQJH &DSDFLW\ FPROFNJ s s s s s s s s s

PAGE 124

7DEOH 7RWDO FKDUJH RI &D 1D DQG /LVDWXUDWHG .*D NDROLQ DV GHWHUPLQHG E\ &D H[FKDQJH DLUGULHG DW r& (ODSVHG 'D\V &DNDROLQ 1DNDROLQ &DWLRQ ([FKDQJH &DSDFLW\ /LNDROLQ L QMLM9UY\ s s s s s s s s s s s s

PAGE 125

7DEOH &KDUJH DWWULEXWDEOH WR &D 1D /L 0J DQG $O H[WUDFWHG IURP &D 1D DQG /LVDWXUDWHG )LVKHU NDROLQ DLUGULHG DW r& (ODSVHG 'D\V &DWLRQ &DNDROLQ 1DNDROLQ /LNDROLQ L OXLAUY\ &D s s s 1D s s s /L s $O s s s 0J s s s &D s s s 1D s s s /L s $O s s s 0J s s s &D s s s 1D s s s /L s $O s s s 0J s s s &D s s s 1D s s s /L s $O s s s 0J s s s &D s s s 1D s s s /L s $O s s s 0J s s s

PAGE 126

7DEOH &KDUJH DWWULEXWDEOH WR &D 1D /L 0J DQG $O H[WUDFWHG IURP &D 1D DQG /LVDWXUDWHG .*D NDROLQ DLUGULHG DW r& (ODSVHG 1+&, &DNDROLQ 1DNDROLQ /LNDROLQ 'D\V ([WUDFW FPROMNJ &D s s 1D s s s /L s $O s s s 0J s s s &D s s s 1D s s s /L s $O s s s 0J s s s &D s s s 1D s s s /L s $O s s s 0J s s s &D s s s 1D s s s /L s $O s s s 0J s s s

PAGE 127

$ VLPLODU WUHQG ZDV REVHUYHG IRU 1DNDROLQ EXW WR D PXFK OHVVHU GHJUHH WKDQ WKDW RI /LNDROLQ ,W VKRXOG EH QRWHG WKDW WKH )LVKHU DQG .*D NDROLQ H[KLELWHG DQ DOPRVW LGHQWLFDO GHFUHDVH LQ WKH SHUFHQWDJH RI /L LRQV H[WUDFWHG ZLWK 0 1+&, +RZHYHU WKH LQLWLDO UHGXFWLRQ GD\ f LQ H[WUDFWDEOH /L ZDV OHVV WKDQ WKDW PHDVXUHG DW r& ZKLFK VXJJHVWV WKDW WHPSHUDWXUH LQIOXHQFHG WKH UDWH RI /L UHWHQWLRQ 7KH GDWD SUHVHQWHG KHUH FOHDUO\ GHPRQVWUDWH WKDW KHDWLQJ /LVDWXUDWHG NDROLQ UHVXOWV LQ /L UHWHQWLRQ DQG D GHFUHDVH LQ WRWDO FKDUJH RU &(& 7KH VXP RI FKDUJH DWWULEXWDEOH WR &D 1D 0J DQG $O H[WUDFWHG IURP &D VDWXUDWHG )LVKHU DQG .*D NDROLQ UHPDLQHG HVVHQWLDOO\ FRQVWDQW RYHU WKH WUHDWPHQW SHULRGV )LJXUHV D DQG Df 7KHVH GDWD ZHUH LQ DJUHHPHQW ZLWK WKH WRWDO FKDUJH PHDVXUHG E\ &DH[FKDQJH ,Q FRQWUDVW WKH VXP RI FDWLRQ FKDUJHV IRU 1DNDROLQ GHFUHDVHG VOLJKWO\ ZKLOH WKDW RI /LNDROLQ GHFUHDVHG VXEVWDQWLDOO\ DV D UHVXOW RI KHDWLQJ )LJXUHV F DQG F FOHDUO\ LQGLFDWH WKDW H[FKDQJHDEOH $O FRQWULEXWHG VLJQLILFDQWO\ WR WKH FKDUJH RI /LNDROLQ DIWHU KHDWLQJ DQG VXJJHVW WKDW D SRUWLRQ RI WKH /L UHWDLQHG E\ WKH NDROLQ GLVSODFHG $O IURP WKH FOD\ ODWWLFH 7KHVH GDWD DUH FRQWUDU\ WR WKRVH UHSRUWHG E\ *UHHQH.HOO\ f ZKR H[WUDFWHG RQO\ WUDFH DPRXQWV RI $O IURP /LNDROLQ EHIRUH DQG DIWHU KHDWLQJ XVLQJ D 0 +&, DQG 0 1+&, H[WUDFWLRQ SURFHGXUH +RZHYHU *UHHQH.HOO\ f DSSDUHQWO\ ZDVKHG WKH NDROLQ ZLWK 0 1+$2F S+ f SULRU WR H[WUDFWLQJ /L LRQV 7KLV WUHDWPHQW PD\ KDYH SUHFLSLWDWHG H[FKDQJHDEOH $O ZKLFK ZDV WKHQ QRW H[WUDFWDEOH ZLWK WKH ZHDN DFLG DQG 1+&,

PAGE 128

2 2 2 Df (ODSVHG 'D\V UKH VXP RI &D 1D /L 0J DQG $O H[WUDFWHG IURP Df &D Ef 1D LQG Ff /LVDWXUDWHG )LVKHU NDROLQ

PAGE 129

2 2 2 2 (ODSVHG 'D\V RI &D 1D VDWXUDWHG /L 0J DQG $O H[WUDFWHG IURP Df &D Ef 1D DQG D NDROLQ

PAGE 130

(YHQ WKRXJK $O FRQWULEXWHG WR WKH FKDUJH RI 1D DQG /L NDROLQ D FRQVLGHUDEOH GLIIHUHQFH UHPDLQHG EHWZHHQ WKH WRWDO FKDUJH GHWHUPLQHG E\ &D H[FKDQJH DQG WKDW GHWHUPLQHG IURP WKH VXP RI H[WUDFWDEOH &D 1D /L 0J DQG $O 7KLV GLVFUHSDQF\ VXJJHVWV WKDW RWKHU FDWLRQV FRQWULEXWHG WR WKH WRWDO FKDUJH RI WKH NDROLQ ,QWHUHVWLQJO\ &DVKHQ f UHSRUWHG WKDW KHDWHG VDPSOHV RI 1D DQG /L VDWXUDWHG 3HHUOHVV 1R NDROLQ ZHUH IDU PRUH DFLG WKDQ XQWUHDWHG VDPSOHV 7KXV WKH KHDWLQJ RI /LNDROLQ DQG VXEVHTXHQW UHWHQWLRQ RI /L LRQV PD\ DOVR KDYH FDXVHG WKH GLVSODFHPHQW RI + LRQV IURP WKH FOD\ ODWWLFH 7KLV K\SRWKHVLV LV VXSSRUWHG E\ )DUPHU DQG 5XVVHOO f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f $ WRWDO HOHPHQWDO DQDO\VLV RI WKH KHDWWUHDWHG NDROLQ ZRXOG EH OLNHO\ WR UHFRYHU DOO WKH UHWDLQHG /L KRZHYHU WKH H[DFW TXDQWLW\ RI /L LQYROYHG LQ FKDUJH UHGXFWLRQ ZRXOG VWLOO EH GLIILFXOW WR DVFHUWDLQ $IWHU WKH RULJLQDO KHDW WUHDWPHQW *UHHQH.HOO\ f UHSRUWHG WKDW 3HHUOHVV NDROLQ ZDV FDSDEOH RI IL[LQJ DQ DGGLWLRQDO FPROANJ RI /L DIWHU QLQH /L&, ZDVKHV DQG KHDW WUHDWPHQWV ZLWK

PAGE 131

7DEOH $PRXQW RI /L 1D DQG $O H[WUDFWHG IURP 1D DQG /LVDWXUDWHG )LVKHU NDROLQ DLUGULHG DW r& XVLQJ 0 +&, (ODSVHG +&, 1D .DROLQ /L .DROLQ 'D\V 7UW 1D $O /L $O PLQ FPROFNJ s s s s s s s s s s s s s s s s s s s s s s s s s s s s s s s s s s s s

PAGE 132

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mb 5+ VXEMHFW WR WKH IROORZLQJ VHTXHQFH RI KHDW WUHDWPHQWV f URRP WHPSHUDWXUH IRU WZR KRXUV f r& IRU KRXUV DQG f URRP WHPSHUDWXUH IRU DSSUR[LPDWHO\ KRXUV 7KH &D DQG /LNDROLQ UHJDLQHG DQ DYHUDJH RI s b DQG s b UHVSHFWLYHO\ RI WKHLU RULJLQDO ZHLJKW ORVW GXH WR WKH r& KHDW WUHDWPHQW 7KH GHJUHH RI K\VWHUHVLV H[KLELWHG E\ /LNDROLQ ZDV FRQVLVWHQW ZLWK WKH b UHGXFWLRQ LQ WKH WRWDO FKDUJH PHDVXUHG IRU /LNDROLQ DIWHU VHYHQ GD\V DW DQG r& DQG DIWHU ORQJWHUP H[SRVXUH WR KHDW DV UHSRUWHG LQ &KDSWHU 7KH DEVHQFH RI K\VWHUHVLV REVHUYHG IRU &DNDROLQ ZDV LQ DJUHHPHQW ZLWK WKH VWDELOLW\ RI WKH WRWDO FKDUJH RI &DNDROLQ XSRQ KHDWLQJ 7KH .*D NDROLQ DOVR H[KLELWHG K\VWHUHVLV &D DQG /LVDWXUDWHG .*D NDROLQ UHJDLQHG s b DQG s b UHVSHFWLYHO\ RI WKH RULJLQDO ZHLJKW ORVW DIWHU KHDWLQJ 7KH WRWDO FKDUJH UHGXFWLRQ RI &D DQG /LNDROLQ ZDV DQG b UHVSHFWLYHO\ RI WKH OHYHO SULRU WR KHDWLQJ 7KLV GLVFUHSDQF\ PD\ KDYH EHHQ GXH WR SDUWLFOH FRDOHVFHQFH RI WKH ZHOO FU\VWDOOL]HG .*D NDROLQ GXULQJ KHDW WUHDWPHQWV +RZHYHU WKH RYHUDOO VLPLODULW\

PAGE 133

)LJXUH $GVRUSWLRQ DQG GHVRUSWLRQ RI ZDWHU E\ Df &DVDWXUDWHG DQG Ef /LVDWXUDWHG )LVKHU NDROLQ PHDVXUHG E\ 7*$

PAGE 134

)LJXUH $GVRUSWLRQ DQG GHVRUSWLRQ RI ZDWHU E\ Df &DVDWXUDWHG DQG Ef /LVDWXUDWHG .*D NDROLQ PHDVXUHG E\ 7*$

PAGE 135

7LPD 0LQf )LJXUH $GVRUSWLRQ DQG GHVRUSWLRQ RI ZDWHU E\ Df &DVDWXUDWHG DQG Ef /LVDWXUDWHG )LVKHU NDROLQ H[SRVHG WR UHSHDWHG r& WUHDWPHQWV

PAGE 136

EHWZHHQ WKH PDJQLWXGH RI K\VWHUHVLV DQG UHGXFWLRQ LQ WRWDO FKDUJH RI NDROLQ XSRQ KHDWLQJ VXJJHVWV WKDW UHGXFWHG ZDWHU DGVRUSWLRQ REVHUYHG IRU /LNDROLQ ZDV VLPSO\ GXH WR WKH UHGXFWLRQ LQ WKH WRWDO FKDUJH RU &(& RI WKH /LNDROLQ 7KH SHUFHQWDJH RI ZHLJKW UHJDLQHG E\ /L s bf DQG &DVDWXUDWHG s bf )LVKHU NDROLQ VXEMHFW WR WHPSHUDWXUHV RI DQG r& IRU DOWHUQDWLQJ WZR KRXU LQWHUYDOV ZDV HVVHQWLDOO\ WKH VDPH DV WKDW PHDVXUHG DIWHU KRXUV DW r& )LJXUH f 7KHVH GDWD LQGLFDWH WKDW WKH KRXU WUHDWPHQW DW r& ZDV VXIILFLHQW WR UHGXFH ZDWHU DGVRUSWLRQ WR WKH H[WHQW RI FKDUJH UHGXFWLRQ REVHUYHG DIWHU GD\V DW DQG r& 7KLV ILQGLQJ ZDV FRQVLVWHQW ZLWK WKH LQFUHDVHG UDWH RI /L UHWHQWLRQ REVHUYHG DW r& YHUVXV r& DQG LQGLFDWHV WKDW WHPSHUDWXUH LQIOXHQFHG WKH UDWH RI /L UHWHQWLRQ DQG &(& UHGXFWLRQ 6LPLODU H[SHULPHQWV ZHUH FRQGXFWHG WR GHWHUPLQH LI H[SRVXUH WR D YDFXXP ZRXOG LQGXFH K\VWHUHVLV E\ /LVDWXUDWHG )LVKHU NDROLQ $IWHU HTXLOLEUDWLRQ LQ D KLJK 5+ DWPRVSKHUH &D DQG /LNDROLQ UHJDLQHG s b DQG s b RI WKH ZHLJKW ORVW IROORZLQJ H[SRVXUH WR WKH YDFXXP )LJXUH f 7KH FRQVLGHUDEOH K\VWHUHVLV REVHUYHG IRU &DNDROLQ VXJJHVWV WKDW WKH DFWXDO HIIHFW RI WKH YDFXXP RQ ZDWHU DGVRUSWLRQ E\ /LNDROLQ ZDV PLQLPDO ,W LV TXLWH SODXVLEOH WKDW WKH YDFXXP UHVXOWHG LQ FRQVLGHUDEOH SDUWLFOH FRDOHVFHQFH 7KXV HYHQ WKRXJK WKH UHVXOWV RI WKHVH H[SHULPHQWV VXJJHVW WKH YDFXXP WUHDWPHQW LQGXFHG D VOLJKW UHGXFWLRQ LQ WKH ZDWHU DGVRUSWLRQ FDSDFLW\ RI /LNDROLQ WKH XWLOLW\ RI VXFK D WHFKQLTXH LV OLPLWHG E\ FRLQFLGHQWDO K\VWHUHVLV HIIHFWV

PAGE 137

:(,*+7 PJf :(,*+7 PJf 7,0( KUVf )LJXUH $GVRUSWLRQ DQG GHVRUSWLRQ RI ZDWHU E\ Df &DVDWXUDWHG DQG Ef /LVDWXUDWHG )LVKHU NDROLQ H[SRVHG WR D YDFXXP

PAGE 138

/RFDWLRQ RI 1RQH[FKDQJDEOH /L 7KH ORFDWLRQ RI H[FKDQJHDEOH FDWLRQV RQ NDROLQ LV FRQVLGHUHG WR EH OLPLWHG WR WKH EDVDO SODQH RI WKH WHWUDKHGUDO OD\HU LQ UHVSRQVH WR SHUPDQHQW FKDUJH DULVLQJ IURP WKH VXEVWLWXWLRQ RI $O IRU 6L LQ WKH RXWHU WHWUDKHGUDO VKHHW %ROODQG HW DO )ROOHW :HLVV DQG 5XVVRZ f )LJXUH f +RZHYHU D SRUWLRQ RI WKH QHJDWLYH FKDUJH PD\ VWLOO EH WKH UHVXOW RI S+ GHSHQGHQW FKDUJHV 5HGXFHG ZDWHU DGVRUSWLRQ RQ /LNDROLQ OHG .HHQDQ HW DO f WR SURSRVH WKDW /L RFFXSLHG D SRVLWLRQ LQ WKH WHWUDKHGUDO OD\HU IURP ZKLFK K\GUDWLRQ ZDV VWHULFDOO\ KLQGHUHG E\ RXWHU R[\JHQ DWRPV +RZHYHU RWKHU FDWLRQV DOWKRXJK VPDOO HQRXJK WR ILW EHWZHHQ R[\JHQ DWRPV RI WKH WHWUDKHGUDO OD\HU ZHUH UHDGLO\ K\GUDWHG *UHHQH.HOO\ f DZDUH RI WKH IDFW WKDW /L UHWHQWLRQ DQG &(& UHGXFWLRQV RFFXUUHG DIWHU KHDWLQJ /L NDROLQ SURSRVHG WKDW /L LRQV PLJUDWH LQWR YDFDQW RFWDKHGUDO FRRUGLQDWLRQ VLWHV DV KDV EHHQ VXJJHVWHG WR H[SODLQ D VLPLODU SKHQRPHQRQ LQ PRQWPRULOORQLWH 7KLV K\SRWKHVLV ZRXOG PRUH UHDGLO\ H[SODLQ WKH GLVSODFHPHQW RI $O DQG + IURP WKH RFWDKHGUDO OD\HU 7KH LQQHU K\GUR[\OV RI NDROLQ ZKLFK DUH RULHQWHG WRZDUG WKH RFWDKHGUDO FDYLW\ \LHOG DQ ,5 VSHFWUD EDQG DW FPn ,W ZDV K\SRWKHVL]HG WKDW WKH PLJUDWLRQ RI /L LQWR WKH YDFDQW RFWDKHGUDO VLWH ZRXOG DOWHU WKH RULHQWDWLRQ RI LQQHU K\GUR[\OV UHVXOWLQJ LQ D VKLIW LQ WKH FPn EDQG RU WKH FUHDWLRQ RI VHYHUDO XQUHVROYHG EDQGV 7KH ,5 VSHFWUD REWDLQHG IURP DLUGU\ 1D DQG /LNDROLQ DQG KHDWHGWUHDWHG /LNDROLQ DUH VKRZQ LQ )LJXUH $ VXEWUDFWLRQ SURFHGXUH LQGLFDWHG WKDW WKH LQQHU K\GUR[\O VWUHWFKLQJ EDQG RI 1DNDROLQ DQG KHDWWUHDWHG /LNDROLQ ZHUH QRW WKH

PAGE 139

)LJXUH 3URMHFWLRQ RI NDROLQLWH VWUXFWXUH RQWR WKH SODQH

PAGE 140

)LJXUH ,5 VSHFWUD RI Df KHDWHG 1DVDWXUDWHG Ef KHDWHG /LVDWXUDWHG DQG Ff DLUGULHG /LVDWXUDWHG )LVKHU NDROLQ LQ WKH LQQHU K\GUR[\O VWUHWFKLQJ UHJLRQ

PAGE 141

VDPH 7R VXEVWDQWLDWH WKLV ILQGLQJ D GHFRQYROXWLRQ SURJUDP ZDV XVHG WR TXDQWLWDWLYHO\ GHWHUPLQH WKH SRVLWLRQ ZLGWK DQG LQWHQVLW\ RI HDFK EDQG -RKQVWRQ HW DO f $LUGU\ 1DNDROLQ \LHOGHG D VLQJOH SHDN DW FPn ZKHUHDV KHDW WUHDWHG /LNDROLQ H[KLELWHG SHDNV DW DQG FPn 7KH H[LVWDQFH RI D VHFRQG SHDN DW D ORZHU ZDYH QXPEHU VXJJHVWV WKDW /L GLVSODFHG D SRUWLRQ RI WKH $O IURP WKH NDROLQ VWUXFWXUH XSRQ KHDWLQJ & 7 -RKQVWRQ SHUVRQDO FRPPXQLFDWLRQf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

PAGE 142

([WUDFWLRQ RI /LNDROLQ ZLWK 1+&, UHYHDOHG WKDW RQO\ b RI WKH /L LRQV UHPDLQHG H[FKDQJHDEOH DIWHU KHDW WUHDWPHQW $ FRQVLGHUDEOH DPRXQW RI $O ZDV H[WUDFWHG IURP WKH /LNDROLQ DQG \HW WKH VXP RI $O /L 0J 1D DQG &D DFFRXQWHG IRU RQO\ b RI WKH UHGXFHG &(& %DVHG RQ SUHYLRXV UHSRUWV RI LQFUHDVHG DFLGLW\ IROORZLQJ KHDWLQJ LW DSSHDUV OLNHO\ WKDW + FRQWULEXWHG WR WKH UHVLGXDO FKDUJH 7KXV WKH UHPDLQLQJ H[FKDQJH FDSDFLW\ RI WKH KHDWHG /LNDROLQ ZDV VDWLVILHG E\ /L $O DQG SRVVLEO\ + 7KH /L LRQV UHQGHUHG QRQH[FKDQJHDEOH E\ KHDWLQJ DSSDUHQWO\ DFWHG WR f WR UHGXFH WKH WRWDO FKDUJH DQG f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f

PAGE 143

&+$37(5 6800$5< $1' &21&/86,216 $QWHFHGHQW PRLVWXUH FRQWHQW RU UHODWLYH KXPLGLW\ 5+f LV DUJXDEO\ WKH PRVW LPSRUWDQW IDFWRU LQIOXHQFLQJ YDSRUSKDVH VRUSWLRQ LQ WKH XQVDWXUDWHG ]RQH ,Q &KDSWHU WKH HIIHFW RI 5+ RQ WKH VRUSWLRQ RI S[\OHQH YDSRUV LQ WKH XQVDWXUDWHG ]RQH ZDV LQYHVWLJDWHG DW D PHFKDQLVWLF OHYHO 6RLOV DQG FOD\ PLQHUDOV H[KLELWHG D VL]DEOH FDSDFLW\ WR DGVRUE RUJDQLF YDSRUV DW ORZ 5+ ZKLFK ZDV FKDUDFWHUL]HG E\ 7\SHOO DGVRUSWLRQ LVRWKHUPV :KHQ WKH 5+ ZDV LQFUHDVHG WR DQG b S [\OHQH VRUSWLRQ GHFUHDVHG GUDPDWLFDOO\ DQG LVRWKHUPV VKLIWHG IURP 7\SHOO WR 7\SH UHJDUGOHVV RI WKH RUJDQLF FDUERQ 2&f FRQWHQW ,QFUHDVHG VRUSWLRQ DW UHODWLYH YDSRU SUHVVXUHV DERYH KDV QRW EHHQ UHSRUWHG SUHYLRXVO\ DQG LQGLFDWHV WKDW K\GUDWHG VRLOV PD\ DGVRUE VLJQLILFDQW TXDQWLWLHV RI RUJDQLF YDSRUV QHDU WKH FRQWDPLQDQW VRXUFH 7KH DGVRUSWLRQ RI S[\OHQH YDSRUV RQ DQK\GURXV VRUEHQWV ZDV VWURQJO\ FRUUHODWHG WR PLQHUDO VXUIDFH DUHD GHWHUPLQHG IURP 1 DGVRUSWLRQ LVRWKHUPV ,Q FRQWUDVW JUHDWHU VRUSWLRQ ZDV REVHUYHG IRU XQWUHDWHG WKDQ K\GURJHQ SHUR[LGH WUHDWHG :HEVWHU VRLO DW b 5+ 7KHVH GDWD VXJJHVW WKDW VRLO RUJDQLF PDWWHU IXQFWLRQV DV D SDUWLWLRQLQJ PHGLXP IRU RUJDQLF YDSRUV IROORZLQJ K\GUDWLRQ ,Q DGGLWLRQ WKH XVH RI YDOXHV WR SUHGLFW YDSRUSKDVH VRUSWLRQ DW KLJK 5+ ZDV RQO\ DSSOLFDEOH WR VRUEHQWV RI KLJK 2& FRQWHQW DW S[\OHQH UHODWLYH YDSRUV OHVV WKDQ

PAGE 144

3UHGLFWLRQV RI WKH VXUIDFH H[FHVV EDVHG RQ WKH *LEEV DGVRUSWLRQ HTXDWLRQ VXJJHVW WKDW DGVRUSWLRQ DW WKH JDVOLTXLG LQWHUIDFH ZDV WKH GRPLQDQW PHFKDQLVP UHVSRQVLEOH IRU S[\OHQH VRUSWLRQ RQ NDROLQ DQG VLOLFD JHO 9DSRUSKDVH VRUSWLRQ ZDV DOVR VWXGLHG E\ JDV FKURPDWRJUDSK\ ZKLFK RIIHUV DQ HIILFLHQW DQG YHUVDWLOH DOWHUQDWLYH WR FRQYHQWLRQDO EDWFK WHFKQLTXHV &KDSWHU f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f ZLOO EH VLJQLILFDQWO\ UHGXFHG LQ VDOWDIIHFWHG VRLOV ,Q &KDSWHU WKH DGVRUSWLRQ RI ZDWHU DQG S[\OHQH YDSRUV RQ &D 1D DQG Â’VDWXUDWHG NDROLQ ZDV LQYHVWLJDWHG IRU VLQJOH DQG PL[HGYDSRU V\VWHPV 7KH DPRXQW RI ZDWHU DGVRUEHG RQ &D DQG 1DNDROLQ ZDV GLUHFWO\ UHODWHG WR WKH K\GUDWLRQ HQHUJ\ RI WKH FDWLRQ ,Q FRQWUDVW /LNDROLQ H[KLELWHG OHVV DGVRUSWLRQ WKDQ 1DNDROLQ HYHQ WKRXJK WKH K\GUDWLRQ HQHUJ\ RI /L LV VOLJKWO\ JUHDWHU WKDQ WKDW RI 1D $ VLPLODU HIIHFW ZDV REVHUYHG IRU S[\OHQH YDSRUV ZKLFK VXJJHVWV WKDW ZHDN LQWHUDFWLRQV RFFXUUHG EHWZHHQ H[FKDQJHDEOH FDWLRQV DQG S[\OHQH PROHFXOHV

PAGE 145

:KHQ WKH 5+ ZDV LQFUHDVHG WR DQG b S[\OHQH DGVRUSWLRQ GHFUHDVHG VXFFHVVLYHO\ (QKDQFHG ZDWHU DGVRUSWLRQ H[KLELWHG DW KLJK S[\OHQH UHODWLYH YDSRU SUHVVXUHV ZDV DWWULEXWHG WR FDWLRQ K\GUDWLRQ HIIHFWV ,Q DGGLWLRQ WKH FRPSHWLWLYH DGVRUSWLRQ RI ZDWHU DQG S[\OHQH ZDV ZHOO SUHGLFWHG E\ WKH WZRFRPSRQHQW PRGHO RI +LOO D Ef 5HGXFHG ZDWHU DGVRUSWLRQ RQ /LNDROLQ KDV EHHQ DWWULEXWHG WR WKH ODFN RI /L K\GUDWLRQ GXH WR VWHULF KLQGUDQFH HIIHFWV .HHQDQ HW DO f +RZHYHU PHDVXUHPHQWV RI FDWLRQ H[FKDQJH FDSDFLW\ &(&f LQGLFDWHG WKDW WKH WRWDO FKDUJH RI /LNDROLQ ZDV UHGXFHG E\ b DIWHU KHDWLQJ WR r& 7KH UHGXFWLRQ LQ &(& DQG ZDWHU DGVRUSWLRQ IRU /LNDROLQ ZDV FRQILUPHG E\ H[WUDFWLRQ WHFKQLTXHV DQG JUDYLPHWULF DQDO\VLV LQ &KDSWHU ([WUDFWLRQV ZLWK 1+&, UHYHDOHG WKDW RQO\ b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

PAGE 146

7KH HIIHFW RI 5+ RQ YDSRUSKDVH VRUSWLRQ RI 92&V E\ VRLO PDWHULDOV LV VXPPDUL]HG LQ )LJXUH ,Q RUGHU WR DFFRXQW IRU WKH GUDPDWLF FKDQJH LQ VRUSWLYH FDSDFLW\ DV D IXQFWLRQ RI 5+ LW LV UHFRPPHQGHG WKDW YDSRUSKDVH VRUSWLRQ EH GHVFULEHG E\ D PXOWLPHFKDQLVWLF DSSURDFK ZKLFK LQFOXGHV f DGVRUSWLRQ RQ H[SRVHG PLQHUDO VXUIDFHV f SDUWLWLRQLQJ LQWR RUJDQLF FDUERQ f GLVVROXWLRQ LQWR DGVRUEHG ZDWHU ILOPV DQG f DGVRUSWLRQ DW WKH JDVOLTXLG LQWHUIDFH 7KH RULJLQDO %(7 HTXDWLRQ DQG WZRFRPSRQHQW %(7 HTXDWLRQ RI +LOO D Ef SURYLGHG DFFXUDWH SUHGLFWLRQV RI S[\OHQH DGVRUSWLRQ XQGHU DQK\GURXV DQG ORZ 5+ FRQGLWLRQV UHVSHFWLYHO\ $W 5+V DERYH ZKLFK WKH VUEDWH VXUIDFH LV FRYHUHG E\ DW OHDVW D PRQRPROHFXODU OD\HU RI ZDWHU VRUSWLRQ PD\ UHVXOW IURP GLVVROXWLRQ LQWR DGVRUEHG ZDWHU ILOPV SDUWLWLRQLQJ LQWR 2& DQG DGVRUSWLRQ DW WKH JDVOLTXLG LQWHUIDFH 7KH LPSRUWDQFH RI HDFK PHFKDQLVP ZLOO EH JRYHUQHG E\ VUEDWH SURSHUWLHV VXFK DV VROXELOLW\ DQG K\GURSKRELFLW\ DQG VRUEHQW SURSHUWLHV VXFK DV 2& FRQWHQW

PAGE 147

7 !r J ( M mM f r ( 76 ( r MJ p R ; f& F ,f§ mFR 6RU3WLRQ

PAGE 148

$33(1',; $ :$7(5 $1' 3;
PAGE 149

7DEOH $ 6RUSWLRQ RI ZDWHU DQG S[\OHQH YDSRUV RQ :HEVWHU VRLO IURP VLQJOH DQG PL[HGYDSRU V\VWHPV 33R 6RUEHG 6\VWHP S[\OHQH ZDWHU S[\OHQH ZDWHU S[\OHQH sf PJJ sf sf sf sf sf &D&, sf sf S[\OHQH sf f§ r1f sf sf DQG sf f§ f§f sf sf ZDWHU sf f§ f sf sf sf f§ sf sf sf f§ f sf sf sf f§ sf sf sf f§ fff sf sf sf f§ sf sf sf f§ sf sf &D&, sf f§ sf sf

PAGE 150

7DEOH $ 6RUSWLRQ RI ZDWHU DQG S[\OHQH YDSRUV RQ :HEVWHU +3 IURP VLQJOH DQG PL[HGYDSRU V\VWHPV 6\VWHP 33R 6RUEHG S[\OHQH ZDWHU S[\OHQH ZDWHU PJJ S[\OHQH sf sf sf sf sf sf 2D&, sf sf S[\OHQH sf f§ f sf sf DQG sf f§ r1f sf sf ZDWHU sf f§ sf sf sf sf sf sf f§ sf sf sf f§ sf sf &D&, sf f§ sf sf sf f§ r1f sf sf

PAGE 151

7DEOH $ 6RUSWLRQ RI ZDWHU DQG S[\OHQH YDSRUV RQ )LVKHU NDROLQ IURP VLQJOH DQG PL[HGYDSRU V\VWHPV 33R 6RUEHG 6\VWHP S[\OHQH ZDWHU S[\OHQH ZDWHU PJJ S[\OHQH sf sf sf sf sf sf sf sf ZDWHU sf sf sf sf sf sf sf sf S[\OHQH sf sf sf sf DQG sf sf sf sf ZDWHU sf sf sf sf sf sf sf sf sf sf sf sf

PAGE 152

7DEOH $ 3UHOLPLQDU\ GDWD IRU WKH VRUSWLRQ RI ZDWHU DQG S[\OHQH YDSRUV RQ /L VDWXUDWHG )LVKHU NDROLQ IURP VLQJOH DQG PL[HGYDSRU V\VWHPV 33R 6RUEHG 6\VWHP S[\OHQH ZDWHU S[\OHQH ZDWHU S[\OHQH sf PJJ sf sf sf sf sf sf sf ZDWHU sf sf sf sf sf sf sf sf S[\OHQH sf DQG sf sf sf ZDWHU

PAGE 153

7DEOH $ 6RUSWLRQ RI ZDWHU DQG S[\OHQH YDSRUV RQ VLOLFD JHO IURP PL[HGYDSRU V\VWHPV 33R 6\VWHP S[\OHQH ZDWHU 6RUEHG S[\OHQH ZDWHU PJJ S[\OHQH sf DQG sf ZDWHU s sf sf sf sf sf sf sf sf sf

PAGE 154

7DEOH $ 6RUSWLRQ RI ZDWHU DQG S[\OHQH YDSRUV RQ /LVDWXUDWHG )LVKHU NDROLQ IURP VLQJOH DQG PL[HGYDSRU V\VWHPV 6\VWHP 33R 6RUEHG S[\OHQH ZDWHU S[\OHQH ZDWHU PJJ S[\OHQH sf sf sf sf sf sf sf sf sf sf ZDWHU sf sf sf sf§f§f sf sf sf f sf sf S[\OHQH sf sf sf sf DQG sf sf sf sf ZDWHU sf sf sf sf sf sf sf sf sf sf sf sf sf sf sf sf

PAGE 155

7DEOH $ 6RUSWLRQ RI ZDWHU DQG S[\OHQH YDSRUV RQ 1DVDWXUDWHG )LVKHU NDROLQ IURP VLQJOH DQG PL[HGYDSRU V\VWHPV 6\VWHP 33R 6RUEHG S[\OHQH ZDWHU S[\OHQH ZDWHU PJJ S[\OHQH sf sf sf sf sf sf sf sf sf sf sf sf sf sf ZDWHU sf sf sf sf sf sf S[\OHQH sf sf sf sf DQG sf sf sf sf ZDWHU sf sf sf sf sf sf sf sf sf sf sf sf sf sf sf sf

PAGE 156

7DEOH $ 6RUSWLRQ RI ZDWHU DQG S[\OHQH YDSRUV RQ &DVDWXUDWHG )LVKHU NDROLQ IURP VLQJOH DQG PL[HGYDSRU V\VWHPV 6\VWHP 33R ZDWHU $GVRUEHG S[\OHQH S[\OHQH ZDWHU PJJ S[\OHQH sf sf sf sf sf sf sf sf sf sf ZDWHU sf sf sf sf sf sf S[\OHQH sf sf sf sf DQG sf sf sf sf ZDWHU sf sf sf sf sf sf sf sf sf sf sf sf sf sf sf sf

PAGE 157

$33(1',; % 685)$&( 7(16,21 '$7$

PAGE 158

7DEOH % 6XUIDFH WHQVLRQ RI GHLRQL]HG ZDWHU H[SRVHG RW S[\OHQH 3;f YDSRUV 3UHVVXUH PP +Jf 6XUIDFH 7HQVLRQ 3;:DWHU JVf 'O :DWHU JVf sf sf sf sf sf sf sf sf sf sf sf sf sf sf sf sf sf sf sf sf sf sf sf sf sf sf sf

PAGE 159

7DEOH % 6XUIDFH WHQVLRQ RI 0 &D&, H[SRVHG WR S[\OHQH 3;f YDSRUV 3UHVVXUH PP +Jf 6XUIDFH 7HQVLRQ 3; 0 &D&, JVf 0 &D&, JVf sf sf f sf sf sf sf sf f sf sf sf sf sf sf sf sf sf sf sf sf

PAGE 160

5()(5(1&(6 $GDPVRQ $: 3K\VLFDO FKHPLVWU\ RI VXUIDFHV QG HG -RKQ :LOH\ t 6RQV 1HZ
PAGE 161

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f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f &5 $FDG 6FL 6HULH

PAGE 162

*ORWIHOW\ '( DQG &6FKRPEXUJ 9RODWLOL]DWLRQ RI SHVWLFLGHV IURP VRLO SS ,Q %/ 6DZKQH\ DQG %URZQ HGf 5HDFWLRQV DQG PRYHPHQW RI RUJDQLF FKHPLFDOV LQ VRLOV $6$ 6SHF 3XEO $6$ &66$ DQG 666$ 0DGLVRQ :O *UHHQH.HOO\ 5 ,UUHYHUVLEOH GHK\GUDWLRQ LQ PRQWPRULOORQLWH 3DUW ,, &OD\ 0LQHUDOV %XOO *UHHQH.HOO\ 5 /LWKLXP DEVRUSWLRQ E\ NDROLQ PLQHUDOV 3K\V &KHP *ULP 5( &OD\ PLQHUDORJ\ 0F*UDZ+LOO 1HZ
PAGE 163

-RKQVWRQ &7 6SRVLWR DQG 55 %LUJH 5DPDQ VSHFWURVFRSLF VWXG\ RI NDROLQLWH LQ DTXHRXV VXVSHQVLRQ &OD\V DQG &OD\ 0LQHUDOV -XULQDN -7KH HIIHFW RI FOD\ PLQHUDOV DQG H[FKDQJHDEOH FDWLRQV RQ WKH DGVRUSWLRQ RI HWK\OHQH GLEURPLGH 6RLO 6FL 6RF $P 3URF -XULQDN -7KH HIIHFW RI SUHWUHDWPHQW RQ WKH DGVRUSWLRQ DQG GHVRUSWLRQ RI ZDWHU YDSRU E\ OLWKLXP DQG FDOFLXP NDROLQLWH 3K\V &KHP -XULQDN -0XOWLOD\HU DGVRUSWLRQ RI ZDWHU E\ NDROLQLWH 6RLO 6FL 6RF $P 3URF -XULQDN -DQG '+ 9ROPDQ $SSOLFDWLRQ RI WKH %UXQDXHU (PPHWW DQG 7HOOHU HTXDWLRQ WR HWK\OHQH GLEURPLGH DGVRUSWLRQ E\ VRLOV 6RLO 6FL -XULQDN -DQG '+ 9ROPDQ D 7KHUPRG\QDPLFV RI ZDWHU DQG QEXWDQH DGVRUSWLRQ E\ /LNDROLQLWH DW ORZ FRYHUDJHV 3K\V &KHP -XULQDN -DQG '+ 9ROPDQ E &DWLRQ K\GUDWLRQ HIIHFWV RQ WKH WKHUPRG\QDPLFV RI ZDWHU DGVRUSWLRQ E\ NDRORQLWH 3K\V &KHP -XU\ :$ 5XVVR 6WUHLOH DQG + (O $EG (YDOXDWLRQ RI YRODWLOL]DWLRQ E\ RUJDQLF FKHPLFDOV UHVLGLQJ EHORZ WKH VRLO VXUIDFH :DWHU 5HVRXU 5HV .DUJHU %/ 5& &DVWHOOV 3$ 6HZHOO DQG $ +DUWNRSI D 6WXG\ RI WKH DGVRUSWLRQ RI LQVROXEOH DQG VSDULQJO\ VROXEOH YDSRUV DW WKH JDVOLTXLG LQWHUIDFH RI ZDWHU E\ JDV FKURPDWRJUDSK\ 3K\V &KHP .DUJHU %/ 3$ 6HZHOO 5& &DVWHOOV DQG $ +DUWNRSI E *DV FKURPDWRJUDSKLF VWXG\ RI WKH DGVRUSWLRQ RI LQVROXEOH YDSRUV RQ ZDWHU &ROORLG ,QWHUIDFH 6FL .DULFNKRII 6: 2UJDQLF SROOXWDQW VRUSWLRQ LQ DTXDWLF V\VWHPV +\GUDXOLF (QJ .DUQDXNKRY $3 ,PSURYHPHQW RI PHWKRGV IRU VXUIDFH DUHD GHWHUPLQDWLRQV &ROORLG ,QWHUIDFH 6FL .HHQDQ $* 5: 0RRQH\ DQG /$ :RRG 7KH UHODWLRQ EHWZHHQ H[FKDQJHDEOH LRQV DQG ZDWHU DGVRUSWLRQ RQ NDROLQLWH 3K\V &KHP

PAGE 164

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f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

PAGE 165

3LQGHU *) DQG /0 $EULOD 2Q WKH VLPXODWLRQ RI QRQDTXHRXV SKDVH RUJDQLF FRPSRXQGV LQ WKH VXEVXUIDFH :DWHU 5HVRXU 5HV 6 6 3LQQDYDLD 73/ +DOO 6& &DG\ DQG 00 0RUWODQG $URPDWLF UDGLFDO FDWLRQ IRUPDWLRQ RQ WKH LQWUDFU\VWDO VXUIDFHV RI WUDQVLWLRQ PHWDO OD\HU ODWWLFH VLOLFDWHV 3K\V &KHP 3LQQDYDLD 7DQG 00 0RUWODQG ,QWHUODPHOODU PHWDO FRPSOH[HV RQ OD\HU VLOLFDWHV &RSSHU OOf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f 5KXH 5' 36& 5DR DQG 5( 6PLWK 9DSRUSKDVH DGVRUSWLRQ RI DON\OEHQ]HQHV DQG ZDWHU RQ VRLOV DQG FOD\V &KHPRVSKHUH 5KXH 5' DQG :+ 5HYH (IIHFW RI FKORULWH DQG SHUFKORUDWH DQLRQV RQ &(& RI VHYHUDO VRLO DQG FOD\ PDWHULDOV 6RLO 6FL 6RF $P 5RVV 6 DQG 2OLYLHU 2Q SK\VLFDO DGVRUSWLRQ -RKQ :LOH\ t 6RQV 1HZ
PAGE 166

6OHHS %( DQG -) 6\NHV 0RGHOLQJ WKH WUDQVSRUW RI YRODWLOH RUJDQLFV LQ YDULDEO\ VDWXUDWHG PHGLD :DWHU 5HVRXU 5HV 6SHQFHU :) DQG 00 &OLDWK 'HVRUSWLRQ RI OLQGDQH IURP VRLO DV UHODWHG WR YDSRU GHQVLW\ 6RLO 6FL 6RF $PHU 3URF 6SHQFHU :) DQG 00 &OLDWK 9RODWLOLW\ RI ''7 DQG UHODWHG FRPSRXQGV $JU )RRG &KHP 6SHQFHU :) DQG 00 &OLDWK )DFWRUV DIIHFWLQJ YDSRU ORVV RI WULIOXUDOLQ IURP VRLO $JU )RRG &KHP 6SRVLWR 5 3URVW DQG -3 *DXOWLHU ,QIUDUHG VSHFWURVFRSLF VWXG\ RI DGVRUEHG ZDWHU RQ UHGXFHGFKDUJH 1D/LPRQWPRULOORQLWHV &OD\V DQG &OD\ 0LQHUDOV 9DOVDUDM .7 DQG /7KLERGHDX[ (TXLOLEULXP DGVRUSWLRQ RI FKHPLFDO YDSRUV RQ VXUIDFH VRLOV ODQGILOOV DQG ODQG IDUPV$ UHYLHZ +D]DUGRXV 0DWHU YDQ 2OSKHQ + DQG -)ULSLDW 'DWD KDQGERRN IRU FOD\ PDWHULDOV DQG RWKHU QRQPHWDOOLF PLQHUDOV 3HUJDPRQ 3UHVV 1HZ
PAGE 167

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

PAGE 168

, FHUWLI\ WKDW KDYH UHDG WKLV VWXG\ DQG WKDW LQ P\ RSLQLRQ LW FRQIRUPV WR DFFHSWDEOH VWDQGDUGV RI VFKRODUO\ SUHVHQWDWLRQ DQG LV IXOO\ DGHTXDWH LQ VFRSH DQG TXDOLW\ DV D GLVVHUWDWLRQ IRU WKH GHJUHH RI 'RFWRU RI 3KLORVRSK\ /,£,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

PAGE 169

, FHUWLI\ WKDW KDYH UHDG WKLV VWXG\ DQG WKDW LQ P\ RSLQLRQ LW FRQIRUPV WR DFFHSWDEOH VWDQGDUGV RI VFKRODUO\ SUHVHQWDWLRQ DQG LV IXOO\ DGHTXDWH LQ VFRSH DQG TXDOLW\ DV D GLVVHUWDWLRQ IRU WKH GHJUHH RI 'RFWRU RI 3KLORVRSK\ 5DPHVK 5HGG\ 3URIHVVRU RI 6RLO 6FLHQFH 7KLV GLVVHUWDWLRQ ZDV VXEPLWWHG WR WKH *UDGXDWH )DFXOW\ RI WKH &ROOHJH RI $JULFXOWXUH DQG WR WKH *UDGXDWH 6FKRRO DQG ZDV DFFHSWHG DV SDUWLDO IXOILOOPHQW RI WKH UHTXLUHPHQWV IRU WKH GHJUHH RI 'RFWRU RI 3KLORVRSK\ 'HFHPEHU n=F$A DOOHJH RI $JULRGWL 'HDQ WWXUH 'HDQ *UDGXDWH 6FKRRO W