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Chemodynamic behavior of complex mixtures

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Title:
Chemodynamic behavior of complex mixtures liquid-liquid partitioning and sorption of organic contaminants from mixed solvents
Creator:
Lee, L.S ( Linda Shahrabani ), 1959-
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Language:
English
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xiv, 183 leaves : ill. ; 29 cm.

Subjects

Subjects / Keywords:
Carboxylic acids ( jstor )
Chemical mixtures ( jstor )
Chemicals ( jstor )
Coal tar ( jstor )
pH ( jstor )
Soils ( jstor )
Solubility ( jstor )
Solutes ( jstor )
Solvents ( jstor )
Sorption ( jstor )
Dissertations, Academic -- Soil and Water Science -- UF
Soil and Water Science thesis Ph. D
City of Eustis ( local )
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bibliography ( marcgt )
non-fiction ( marcgt )

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Thesis:
Thesis (Ph. D.)--University of Florida, 1993.
Bibliography:
Includes bibliographical references (leaves 164-182).
General Note:
Typescript.
General Note:
Vita.
Statement of Responsibility:
by Linda S. Lee.

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University of Florida
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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.
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CHEMODYNAMIC BEHAVIOR OF COMPLEX MIXTURES:
LIQUID-LIQUID PARTITIONING AND SORPTION OF
ORGANIC CONTAMINANTS FROM MIXED SOLVENTS









by

LINDA S. LEE


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


1993





























Copyright 1993

by

Linda S. Lee














ACKNOWLEDGEMENTS


I want to thank my committee members Professor Suresh Rao, Dean Rhue,

Joe Delfino, Kirk Hatfield and John Zachara for support and helpful guidance

leading to the successful completion of this project. I especially want to thank Dr.

Rao for his continual contribution to both my personal and professional growth. The

exceptional role Dr. Rao has played as my chairman can be best summarized by his

most recently awarded title of Graduate Research Professor.

I thank my colleagues Dr. Arthur Hornsby, Ron Jessup, Lynn Wood, Dr. Mark

Brusseau, Dr. Ken Van Reese, Dr. Sam Traina, Cheryl Bellin, Denie Augustijn, Dong

Ping Dai, Itaru Okuda, and Dr. Peter Nkedi-Kizza for their assistance, support, and

friendship. Special thanks go to Cheryl Bellin for her assistance in the acid/base

titrations, Itaru Okuda for the UNIFAC simulations, Dr. Mary Collins and Dr. Ron

Kuehl for providing numerous subsamples of Webster soil from Iowa, Vicki Neary

for her technical assistance in the completion of the laboratory experiments, and

Candace Biggerstaff for her help in the preparation and submission of my final

draft.

It has been a pleasure to be affiliated with the Soil and Water Science

Department at the University of Florida through both employment and education,








and I would like to acknowledge both staff and faculty for their continual support

throughout the past fourteen years. I also thank my family, as well as two dear

friends, Donna English and Dagne Hartman, whose long-suffering and support have

not gone unnoticed, and God for His unfailing grace, love, and guidance. I would

also like to acknowledge the unique inspiration I've received from Dr. Jim Davidson

and Dr. George Bailey.

The financial support I received from Dr. Rao as my major professor and

supervisor, as well as the Subsurface Science Program, United States Department of

Energy through a contract (DE-AC06-76RLO) to Battelle PNL; United States

Environmental Protection Agency through a cooperative agreement (CR-814512);

and the Electric Power Research Institute (contract #RP-2879-7) is gratefully

acknowledged.















TABLE OF CONTENTS


ACKNOWLEDGEMENTS .......................

LIST OF TABLES ..............................


. iii

. ix


LIST OF FIGURES ............................................. x


ABSTRACT ..................................

CHAPTERS
1 INTRODUCTION .........................


xiii


................ 1


Partitioning from Multi-phasic Liquids .............
Sorption from Aqueous Solutions .................
Hydrophobic Organic Compounds (HOCs) ......
Hydrophobic ionogenic organic compounds (HIOCs)
Cosolvency ..................................
Solubility in Mixed Solvents ..................
Equilibrium Sorption from Mixed Solvents ......
Hydrophobic Organic Chemicals (HOCs) ....
Hydrophobic Ionizable Organic Chemicals
(HIOCs) .........................


. . . .. 16
. . . .. 16

........ 17


2 EQUILIBRIUM PARTITIONING OF POLYAROMATIC
HYDROCARBONS FROM ORGANIC IMMISCIBLE LIQUIDS INTO
W ATER ............................................... 20


Introduction ..........................
Theory ..........................
Application of Raoult's Law for Gasoline,
Motor Oil, and Diesel Fuel .......
Materials and Methods ..................
Chemicals ........................
Batch Equilibration Technique ........
Chromatographic Analysis ............










CHAPTER
2


Results and Discussion .........................
Coal Tar Composition ......................
Tar-Water Partitioning ...............
Analysis of Laboratory Data ..............
Analysis of Literature Data ..............
Predicting Aqueous-Phase PAH Concentrations ...
Coal Tars ...........................
Diesel Fuels .........................
Assessment of Deviations from Ideal Behavior for
for Equilibrium Conditions ...............
Sum mary ...................................


........ 32
........ 32
........ 35
........ 35
........ 41
........ 43
........ 43
........ 47

........ 49
........ 56


3 COSOLVENT EFFECTS ON SORPTION OF ORGANIC ACIDS BY SOILS


FROM METHANOL/WATER SOLUTIONS .....

Introduction ...........................
Theory ...............................
Materials and methods ...................
Sorbents ..........................
Chemicals .........................
Determination of Ionization Constants ....
pH of Soil Suspensions in Mixed Solvents .
Solubility Experiments ................
Miscible Displacement Experiments ......
Equilibrium Sorption Isotherms .........
Results ...............................
pK,' Measurements ..................
Solubility .........................
Miscible Displacement Studies .........
Batch Equilibration Studies ............
Effect of Solvent Addition .............
Discussion ...........................
Solute-solvent Interactions .............
Desorption Characterisics .............
Estimation of pH by pHx"P ............
Summary .............................


.............. 58










4 IMPACT OF pH ON SORPTION OF BENZOIC ACID FROM
METHANOL/WATER SOLUTIONS ......................... 95


Introduction ...................................
Materials and Methods ...........................
Sorbents ..................................
Chemicals .................................
Equilibrium Sorption Isotherms .................
Results and Discussion ...........................
Effects of pH on Benzoic Acid Sorption at f,<0.5 ...
Effects of pH'ap on Benzoic Acid Sorption at f,>0.75 .
Effects of pH"PP on PCP Sorption at fc>0.75 .......
Sorption of Neutral Benzoic Acid Relative to Benzoate
Soil-Solution pH'PP ..........................
Effect of pH Treatments ......................
Sorption Domains ...........................
Sum mary .....................................


. 95
. 98
. 98
. 99
101
103
106
107
108
110
113
113
114
119


5 IMPACT OF SOLUTE STRUCTURE AND ORGANIC COSOLVENT ON
THE SORPTION OF CARBOXYLIC ACIDS BY SOILS FROM MIXED
SOLVENTS .......................................... 122


Introduction ........
Materials and Methods
Sorbents .......


................................ 122
................................ 123
................................ 123


Chemicals .................................
Equilibrium Sorption Isotherms .................
Determination of Octanol-Water Partition Coefficients
Results and Discussion ...........................
Sorption of Benzoic Acid in Several Solvent-
W ater Solutions .........................
Sorption of Several Substituted Carboxylic Acids
in Methanol/Water Solutions ..............
Sum mary .....................................


..... 123
. . 125
.... 126
..... 127

..... 133

..... 143
..... 147


6 SUMMARY AND CONCLUSIONS
Complex Mixtures ..........
Liquid -Liquid Partitioning ....
Sorption of Organic Acids .....
Conclusions ...............


149
149
150
151
155


i:-








APPENDICES

A SUPERCOOLED LIQUID SOLUBILITIES ................ 156

B SAMPLE pKa DETERMINATION ...................... 159

REFERENCES ............................................ 164

BIOGRAPHICAL SKETCH .................................. 183








































viii













LIST OF TABLES


2-1. Selected physico-chemical properties for the PAHs investigated ...... 28

2-2. Range of properties observed for eight coal tars (EPRI, 1993) .. .... 33

2-3. Maximum Cw values for several PAHs based on the data compiled for eight
coal tars .............................................. 45

3-1. Selected Solute Properties .................................. 73

3-2. Retardation factors for several organic acids in aqueous and methanol
solutions from Eustis Soil ................................... 84

4-1. Cation exchange capacity (CEC) in cmol(+)/kg and elemental analysis in
mg/kg of pH treated Webster soils .......................... 100

4-2. Chemical characteristics of benzoic acid and
pentachlorophenol (PCP) .................................. 101

4-3. Parameters for linear and Freundlich fits to the isotherm data for
benzoic acid sorption as a function of pH and f. ................ 103

5-1. List of various chemical and physical solvent properties ........... 124

5-2. List of various chemical and physical solute properties ............ 125

5-3. Parameters for linear and Freundlich fits to the isotherm data for
benzoic acid in several solvent/water solutions ................ 128

5-4. Parameters for linear and Freundlich fits to the isotherm data for
substituted benzoic acids in methanol/water solutions ............. 129

5-5. The logarithms of the octanol/water partition coefficients
(log Kow) for both the neutral subscriptt n) and ionized
subscriptt i) species of several substituted carboxylic acids ......... 145













LIST OF FIGURES


1-1. Comparison of measured and calculated (Raoult's law) aqueous solubilities
in binary mixtures of benzene-toluene (A) and benzene-octanol (B). Data
from: Sanemesa et al. (1987) ................................. 6

1-2. Measured and predicted sorption of flumetsulam by several soils normalized
to organic carbon content plotted as a function of pH. (Data form Fontaine
et al., 1991) ............................................. 11

1-3. Normalized sorption coefficients for several organic acids plotted as a function
of pH-pKa. [Data from Kukowski (1989) and Jafvert (1990)] ........ 13


2-1. log Kdw values plotted versus log S, for eight PAHs along with the ideal line
(solid line) calculated form Eq. (2-6) for each diesel fuel ........... 29

2-2. Comparison of measured tar-water partition coefficients (Kt) and predictions
based on Raoult's law for ID# 1(A) and ID# 2 (B) coal tars ........ 37

2-3. Comparison of measured tar-water partition coefficients (K.) and predictions
based on Raoult's law, for ID# 3(A) and ID# 4(B) coal tars ......... 38

2-4. Comparison of measured tar-water partition coefficients (K,) and predictions
based on Raoult's law, for ID# 5(A) and ID# 7(B) coal tars ........ 39

2-5 Comparison of measured tar-water partition coefficients (K,) and predictions
based on Raoult's law, for ID# 7N(A) and ID# 9(B) coal tars collected by
EPRI ......................................... ............ 40

2-6. Comparison of measured tar-water partition coefficients (K) reported in the
literature and predictions based on Raoult's law. Literature source as
indicated ............................................... 42

2-7. Comparison of laboratory-measured aqueous-phase concentrations (C,) with
those predicted on the basis of Raoult's law for eight coal tars ........ 44

2-8. Comparison of laboratory-measured aqueous-phase concentrations (C., jg/L)
with those predicted on the basis of Raoult's law for four diesel fuel. .. 48








2-9. Schematic representation of the ideal behavior (Raoult's law) and nonideality
in liquid-liquid partitioning. ................................. 51

2-10. log K, values for several aromatic hydrocarbons resulting from UNIFAC
model calculations and the average log, values experimentally determined by
Cline et al. (1991) plotted against log S, values along with the ideal line based
on Raoult's law .......................................... 52

2-11. log Kdw values for several aromatic hydrocarbons resulting from UNIFAC
model calculations plotted against log S, values along with the ideal line based
on Raoult's law ........ ........... ........................ 54

2-12. Comparison of measured and predicted tar-water partition coefficients for
several PAHs: Raoult's law (solid line) and UNIFAC model (solid
triangle). .............................................. 55

3-1. Schematic representation of cosolvency plots for solutes with a range of log
Kow values ............................ ................... 60

3-2. Example cosolvency curves that may be predicted by the use of various
parameters in Eq. (3-6). ...................................... 68

3-3. Effect of methanol content on the pK,' of benzoic acid and
pentachlorophenol. ....................................... 82

3-4. Solubility (Sb) of benzoic acid in methanol/water solutions ......... .82

3-5. Representative sorption isotherms for (A) pentachlorophenol, (B) benzoic
acid, and (C) dicamba, on Webster soil in various methanol/water
solutions. .............................................. 87

3-6. Measured and predicted sorption by Webster soil of (A) pentachlorophenol,
and (B) benzoic acid as a function of volume fraction methanol (f). . 88

4-1. Retention data for benzoic acid as a function of pHaPP at different methanol
fraction (v/v) by RPLC. .................................... 96

4-2. Representative isotherms for benzoic acid in (A) aqueous solutions; (B)
f,=0.1;and (C) f,=0.9buffered at several pH values .............. 105

4-3. Sorption of benzoic acid by Webster soil buffered at different pH values in
methanol/water solutions of fc<0.5 .................... ..... .107








4-4. Sorption of benzoic acid by Webster soil buffered at different pH values in
methanol/water solutions of f,=0.75,0.8, and 0.9. ............... 108

4-5. Sorption of PCP by Webster soil buffered at different pH values in
methanol/water solutions of fo =0.75 and 1.0 ................... 109

4-6. Sorption data obtained as a function of pH and methanol content, for neutral
benzoic acid and benzoate. ................................ 112

4-7. Isotherm data for benzoic acid on (A) A1203, AI(OH)3, and SAz-1 (pH=8);
and (B) Pahokee muck (pH=7) along with linear and Freundlich fits 117

5-1. Representative isotherms for benzoic acid in (A) acetone/water;
(B) acetonitrile/water; (C) DMSO/water; and (D) 1,4-dioxane/water
solutions. .............................................. 131

5-2. Representative isotherms for (A) anthroic acid; (B) 2-chlorobenzoic acid (C)
2,4-dichlorobenzoic acid; and (D) 2,4,6-trichlorobenzoic acid in various
methanol/water solutions. ................................. 132

5-3. (A) Benzoic acid solubility data where Sb and S, are solubilities in the binary
solution and water, respectively; and (B) benzoic sorption data with Webster
soil in binary mixtures of water and several organic cosolvents as a function
of volume fraction cosolvent (f)). ............................ 134

5-4. Trends in pH'PP of soil-suspensions in binary mixtures of water and several
organic cosolvents. ....................................... 135

5-5. Measured and predicted (Eq. 3-6) sorption of benzoic acid by Webster soil
from (A) acetone/water; (B) acetonitrile/water; (C) DMSO/water; and (D)
1,4-dioxane/water solutions as a function of volume fraction cosolvent (f338

5-6. Normalized sorption coefficients, log (Kb/K,), for the sorption of selected
substituted carboxylic acids by Webster soil as a function of volume fraction
methanol (f,). ....................................... 145

5-7. Correlation between benzoic acid sorption in neat methanol (log KMoH) and
the log Kow values for both the ionized (i) and neutral (n) forms of the
substituted carboxylic acids. ................................ 146

A-1. Schematic representation of the steps involved in the thermodynamic cycle for
producing a hypothetical supercooled liquid from a crystal solute. .... 157














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


CHEMODYNAMIC BEHAVIOR OF COMPLEX MIXTURES:
LIQUID-LIQUID PARTITIONING AND SORPTION OF
ORGANIC CONTAMINANTS FROM MIXED SOLVENTS

By

Linda S. Lee

August 1993


Chairman: Dr. P.S.C.Rao
Major Department: Soil and Water Science

Contamination of soils and water at waste disposal sites commonly involves

various combinations of nonpolar or hydrophobic organic chemicals (HOCs) and

hydrophobic ionogenic organic chemicals (HIOCs), as well as mixtures of water and

one or more organic cosolvents (either completely or partially miscible in water).

Emphasis of this work was on understanding the chemodynamics of such complex

mixtures, specifically solubility and sorption. Experimental and theoretical analysis

presented has focused on: (1) liquid-liquid partitioning behavior of aromatic

hydrocarbons between environmentally relevant organic immiscible liquids (OILs)

and water; and (2) the solubility and sorption of HIOCs by soils from completely

miscible organic solvent/water mixtures.








Partition coefficients for several HOCs were either measured or compiled from

the literature for a wide range of OILs (e.g.,gasoline, diesel fuel, motor oil, and coal

tar). The use of the UNIFAC (UNIQUAC Functional Group Activity Coefficient)

model to estimate the likely nonidealities resulting from interactions between

components in these complex OILs is also presented. Both the UNIFAC simulations

and the observed OIL-water partition coefficients suggest that nonideality is

sufficiently small. Thus, the use of Raoult's law convention for activity coefficients

in conjunction with super-cooled liquid solubilities was considered adequate in

assessing the partitioning of HOCs between several OILs and water.

The role of solute hydrophobicity and acidity, solvent type, and pH on the

sorption of organic acids by a surface soil from mixed solvents was investigated.

Predictions of a model that incorporated effects of cosolvent-enhanced solubility and

cosolvent-suppressed speciation were compared to measured data. Sorption of

neutral benzoic acid was observed to decrease with increasing methanol content,

while benzoate sorption increased. Effects of specific solvent and solute properties

were investigated by measuring (1) benzoic acid sorption from additional binary

mixtures of water and cosolvents with a wide range in solvent properties and (2)

sorption of several substituted carboxylic acids from methanol/water solutions. Of the

different solute-solvent combinations investigated, enhanced sorption by soils was only

observed with carboxylic acids in the presence of methanol or dimethylsulfoxide

(DMSO). It was postulated that enhanced sorption resulted from hydrogen-bonding

interactions combined with the formation of heterogeneous solvation shells about the

solute and the sorbent.













CHAPTER 1
INTRODUCTION


Environmental contamination problems at most industrial waste disposal sites

or spill sites commonly involve wastes consisting of complex mixtures of organic and

inorganic chemicals. Complex mixtures are defined here as those systems comprising

multiple organic solutes and multiple solvents. The solute mixtures of interest might

consist of various combinations of nonpolar or hydrophobic organic chemicals

(HOCs) and hydrophobic ionogenic organic chemicals (HIOCs). The solvent may

be a mixture of water and one or more organic cosolvents (either completely or

partially miscible in water). Solvent mixtures of interest may consist of water and

cosolvents in a single, homogeneous liquid phase, or multi-phases that form at least

two distinct liquid phases. The behavior of such mixtures is not well understood

because the primary chemodynamic properties have usually been characterized in

aqueous solutions which are simple in composition relative to many waste mixtures

found at or near disposal/spill sites. Several researchers have made considerable

efforts during the past decade to investigate the primary processes (e.g., solubility,

sorption, transport) governing the environmental dynamics of organic chemicals in

complex mixtures.

The release and migration of organic constituents from a waste disposal/spill

source will produce a contaminant plume, either in the vadose zone or in the

saturated zone or both. The contaminant plume composition will vary with time and








2
distance as the plume size increases. For discussing solubility and sorption processes

within the plume, three separate regions may be considered: a near-field region, a

transition zone, and a far-field region. The basis for such a distinction is not the

distance from the contaminant source. Rather, the criterion employed to designate

these regions is the chemistry of the contaminant mixture within the plume as

contrasted to the waste.

In the near-field region, corresponding to the source itself and its immediate

vicinity, the composition and concentrations of most waste constituents are similar

to that in the waste. There are usually two, possibly three, liquid phases in this

region. This would be the case, for example in the vadose zone, at waste disposal

sites where we may find both "dense" and "light" organic immiscible liquids (OILs)

and an aqueous phase as well as a vapor phase. In the transition zone, if it occurs

in the saturated zone, the solution phase is likely to be predominantly a single-phase,

homogeneous liquid made up of water and varying amounts of cosolvents (if they

were present in the near-field region). The concentration of one or more waste

constituents may be so high that approximations based on expected behavior in dilute

aqueous solutions are often found to be inadequate. Finally, the far-field region

corresponds to that region of the plume in which the waste constituents are present

in an aqueous solution. Most of these chemicals will be at concentrations well below

their aqueous solubility limits. During migration of the contaminant plume through

the vadose zone and the saturated zone, chromatographic separation of the waste

constituents occurs due to their different mobilities. Furthermore, dilution resulting

from hydrodynamic dispersion and attenuation resulting from abiotic/biotic








3
transformations could decrease contaminant concentrations. Thus, high

concentrations of multiple contaminants are less likely to be found as the distance

from the source increases. Nevertheless, it is possible that these contaminant

concentrations may be higher than the standards set by regulatory agencies.



Partitioning from Multi-phasic Liquids

An understanding of solubility (or partitioning) of HOCs from complex OILs

is essential for predicting organic contaminant release from mixtures such as fuels

(e.g., gasoline, diesel, kerosene) and industrial wastes (coal tar, creosote). The

properties of an organic mixture complex only in composition are determined by the

properties of its pure components and their concentrations in the mixture. This

implies that the chemicals of interest behave ideally in the matrix containing them.

Under these conditions, the concentration in the aqueous phase of a chemical is

proportional to the mole fraction of the chemical in the organic phase corresponding

to Raoult's law. With the stated assumptions, the concentrations of a chemical in the

aqueous phase in contact with a complex mixture can be predicted using the

following simplified expression based on Raoult's law:


C, x S (1-1)



where CW is the chemical's concentration (moles/L) in the aqueous phase in

equilibrium with the organic phase, S, is the aqueous solubility (moles/L) of the pure

liquid chemical, and xo is the mole fraction of the chemical in the organic phase. The

derivation of Eq. (1-1) was based on the pure liquid chemical as the standard state.








4

Many components of interest are solid in their pure form at standard state; however,

Eq. (1-1) can be extended to solid solutes by employing hypothetical super-cooled

liquid solubilities (S, ).

Raoult's law is applicable to a vast number of mixtures of organic chemicals

and its use in predicting aqueous phase concentrations in contact with a complex

organic mixture is invaluable. These mixtures may be considered complex based on

the number of chemicals that constitute the mixture. On the other hand, complexity

of a mixture can be defined by considering how the properties of the mixture deviate

from some "ideal" behavior, regardless of the number of components. The former

view corresponds to a mixture being complex in composition, whereas the latter

implies complexity in behavior. The important point is that a mixture can be complex

in composition without being complex in behavior and vice versa.

In general terms, structurally similar chemicals are likely to form "ideal"

mixtures, and solubility of such mixtures can then be estimated using Raoult's law.

A simple example of the application of Raoult's law is shown in Figure 1-1A for a

mixture of two structurally similar compounds, benzene and toluene. The pure

aqueous compound solubilities of benzene and toluene are 23.1 and 5.60 mmol/L,

respectively. Note that the pure compound solubilities are observed only in the

absence of the second component (i.e., only when xo= 0 or 1). The concentration

of either compound in the mixture is attenuated by the presence of the other. The

excellent agreement between the measured results and those predicted from Raoult's

law (lines) clearly exemplifies the role of mole-fraction on solubility.








5
In contrast, a mixture of benzene and n-octanol illustrates a system simple in

composition, yet nonideal in behavior. Deviations from Raoult's law assuming ideal

behavior are evident in Figure 1-1B. Such deviations, however, are not surprising

when we consider the dissimilarity in the chemical nature of these two components.

Benzene is a hydrophobic aromatic compound while octanol is an alkane with a polar

functional group (-OH). The two illustrations given in Figure 1-1 were for

compositionally simple mixtures. However, in most environmental scenarios,

mixtures with a much larger number of constituents are of interest.

Deviations from ideal behavior can arise if the activity coefficient of the solute

in the organic phase is not unity and/or if the solute activity in the aqueous phase

is significantly impacted by the presence of other components. A number of

computational schemes are available to estimate various activity coefficients such that

liquid-liquid partitioning for nonideal mixtures can be evaluated. One of the most

frequently used models for this purpose is the UNIFAC (UNIQUAC Functional-

Group Activity Coefficient) model proposed by Prausnitz et al. 1980). This model

is based on the UNIQUAC model (Abrams and Prausnitz, 1975) and the solution-of-

group concept (Wilson and Deal, 1962). In this model, a mixture of different

chemicals is treated as a mixture of functional groups constituting the components

in the mixture. The interactions between functional groups in the mixture and the

likely nonidealities, resulting from such interactions, are calculated in order to

estimate the activity coefficient of a chemical for a specified phase. Calculations

based on the UNIFAC model require the values for group interaction parameters as

well as the mole fraction of each component in the mixture. The interaction











parameters required in the UNIFAC model have been continuously reviewed and

updated since the model was first introduced (Skjold-Jorgensen et al., 1979;

Magnussen et al., 1981; Gmehling et al., 1982; Alameida-Macedo et al., 1983; Hansen

et al., 1991).



25
A Raoult's Law Prediction

S 20- (Ideal Behavior)
I' *

015
E-
0
c 10 Benzene
.3 A Toluene
m CO 5 -





0
0 0.2 0.4 0.6 0.8 1

25 ,5



E -

15 -a 3


10- -2-
a *3
N A (D
5 1
CJr,


0.2 0.4 0.6 0.8
Benzene Mole Fraction in the Organic Phase


Figure 1-1.


Comparison of measured and calculated (Raoult's law) aqueous
solubilities in binary mixtures of benzene-toluene (A) and benzene-
octanol (B). Data from Sanemesa et al. (1987).










Sorption from Aqueous Solutions

Most of the available data and theories for predicting sorption and transport

of organic chemicals may be successfully applied to predict contaminant behavior in

the far-field region (i.e., dilute aqueous solutions). The following section will

highlight the information available on equilibrium sorption of organic chemicals

relevant to this dissertation work.

Sorption is one of the dominant processes affecting the mobility of organic

contaminants in soils and groundwater. This process can be conceptualized either

as binding at a two-dimensional interface of the sorbent or as a partitioning into the

three-dimensional bulk of the sorbent. Several methods for estimating the magnitude

of sorption for organic contaminants have been developed based on the chemical and

physical properties of the sorbate, the sorbent, and the solvent.

Hydrophobic Organic Compounds (HOCs)

Equilibrium sorption of hydrophobic organic compounds (HOCs) by soils and

sediments has been successfully predicted in many cases by the "solvophobic theory"

and the use of linear free energy relationships (LFER). Excellent log-log, linear

relationships have been reported between K,, the sorption coefficient normalized to

the fraction of organic carbon (OC) of the sorbent, and Kow, the octanol-water

partition coefficient for several HOCs (c.f.,Dzombak and Luthy, 1984; Karickhoff,

1981; 1984; Kenega and Goring, 1980). Linear relationships have also been found

between log Ko and solute hydrophobic surface area (HSA) (Dzombak and Luthy,

1984; Rao et al., 1985) and solute molecular connectivity (Sabljic, 1984; 1987). The








8
different slopes and intercepts found in these regression equations are predominantly

determined by the characteristics of a group of compounds (i.e., class, degree of

hydrophobicity, and structure), while the sorbent properties other than OC appear

to have only minor impact in most cases (Karickhoff, 1981, 1984; Schwarzenbach and

Westall, 1985). The equations derived from LFER and experimental data obtained

for only a few sorbents provide reasonable predictions of HOC distribution in diverse

soil-water and sediment-water systems. However, the limitations of the K, concept

have been pointed out by a number of authors (e.g.,Mingelgrin and Gerstl, 1983;

Green and Karickhoff, 1991; Gerstl, 1990). The two main concerns involve the

contribution of adsorption on mineral constituents and the possibility of site-specific

interactions between functional moieties of the solute and the sorbent.

Hydrophobic ionogenic organic compounds (HIOCs)

For hydrophobic, ionogenic organic compounds (HIOCs), several factors (e.g.,

speciation, soil-solution pH, sorbent-surface pH, charge, ionic strength, ionic

composition, multiple solutes) make predicting sorption from a single parameter

difficult due to additional mechanisms that must be considered. Several mechanisms

proposed in the literature for sorption of organic solutes from aqueous solutions

include: hydrophobic interactions; London-van der Waals or dispersion forces;

hydrogen bonding; cation and water bridging; cation and anion exchange; ligand

exchange; protonation; covalent bonding or chemisorption; and interlayer adsorption

(Koskinen and Harper, 1990). Hydrophobic interactions are driven by weak solute-

solvent interactions and the preference of an organic molecule to be near an organic








9
surface; thus, strong inverse correlations are observed between K, and solubility of

HOCs. London-van der Waals forces result from correlations in the electron

movement between molecules that produce a small net electrostatic attraction.

Although small in magnitude (2-4 kJ/mol), these interactions are additive and have

been found to be significant for the sorption of large neutral polymeric solutes.

Hydrogen bonding interactions involve the electrostatic interaction between

protons and electronegative atoms, and can be stronger than dispersion forces (2-60

kJ/mol) (Kohl and Taylor, 1961; Stumm et al., 1980). Hydrogen-bonding interactions

may occur with both inorganic and organic surfaces, but for soils interactions with

organic matter are more important due to the abundance ofcarbonyl-type functional

groups (Sposito, 1984).

Cation bridging results if a polar organic functional group displaces a water

molecule from the primary hydration shell of an exchangeable cation (i.e.,formation

of an inner-sphere complex), whereas water bridging results when interaction occurs

without displacement of the hydrating water molecules (i.e., outer-sphere

complexation) (Farmer and Russell, 1967). The occurrence of cation bridging versus

water bridging will be a function of the heat of cation hydration, which varies with

cation size and charge (i.e., charge density). For example, water bridging would be

preferred in a Ca+2-saturated sorbent due to its large negative heat of hydration

(AH=-377 kcal/mol) compared to a saturation with K' (AH=-75 kcal/mol) (Bailey

et al., 1968).

Ion exchange involves the exchange of a cation or an anion for another ion

of similar charge at specific binding sites. Cation exchange is of much greater








10
importance for most soils due to the predominance of negatively charged surfaces.

Similar to cation bridging, but a much stronger interaction, is ligand exchange which

involves the formation of an inner-sphere complex with a structural cation of a soil

mineral (i.e., displacement of either water or hydroxyl molecules from iron or

aluminum oxides)(Stumm et al., 1980; Kummert and Stumm, 1980). Ligand exchange

is commonly believed to be the mechanism responsible for the adsorption of

oxyanions. Likewise, protonation involves the formation of charge-transfer complexes

with protons on mineral surfaces and organic functional groups such as amino and

carbonyl groups. Interlayer adsorption involves the sorption and entrapment of

solute molecules within clay interlayers. From infrared spectroscopic data, Farmer

and Russell (1967) infer that benzoic acid enters the interlayer space as an unionized

monomer, and then the oxygens from both the hydroxyl and carbonyl groups become

coordinated to the interlayer cation.

In many cases, it is difficult to definitively conclude what particular mechanism

is responsible for the observed sorption; however, frequently we can predict the

magnitude of sorption by incorporation a few parameters. For example, on the basis

of an analysis of a large data set for pentachlorophenol (PCP) sorption from aqueous

solutions by several sorbents over a broad pH range, Lee et al. (1990) showed that

equilibrium sorption could be predicted with a knowledge of pH, organic carbon

(OC) content of the soil, and the acid dissociation constant (pK.) for PCP. Their

model for predicting sorption coefficient is:


Koc Koc,An + Koc,i (1 4>)


(1-2)











where


(1-3)


n (1 + 10PH-PKa)-1


and K is the measured distribution ratio for the sorbed- and solution-phase

concentrations; Ko =(K/OC); OC is the soil organic carbon content (mass fraction);

0, is the fraction of the neutral HIOC; and the subscripts n and i refer to neutral and

ionized species, respectively.

Sorption data compiled from the literature for several other organic acids

could be, in most cases, adequately described by Eq. (1-2). Shown in Figure 1-2 for

example, is reasonable predictions by Eq. (1-2) of OC normalized sorption of the

herbicide flumetsulam compiled from Fontaine et al. (1991) for several soils.


Figure 1-2.


0 1 2 3 4 5 6 7 8 9 10 11 12
pH
Measured and predicted sorption of flumetsulam by several soils
normalized to organic carbon content plotted as a function of pH.
(Data form Fontaine et al., 1991)


Flumetsulam Sorption by Soils








7F4P46


S Measured
Predicted


91


N-SO/ N CH,
F H
(Data from Fontaine et al.; 1991)
I i i ; i


'"'''








12

Data compiled from Kukowski (1989) and Jafvert (1990) for sorption of a variety

of organic acids by soils from aqueous solutions are shown in Figure 1-3. To

facilitate viewing of sorption data from different solute-sorbent combinations

simultaneously, the pH scale is referenced to the solute's pK, (i.e., pH-pK,) and

sorption is scaled to the solute's Kn and Ki values as follows: (Kobs Ki)/(Kn Ki).

Values for K, and Ki were estimated in the sorption experiments where pH-pK, was

less than or greater than one (i.e., acid was predominately neutral or ionic,

respectively). Agreement of Eq. (1-2) with the measured data suggests that the

measured bulk soil-solution pH is representative of the pH seen by the solute, and

that K. and K, are additive. Note that this does not infer a particular sorption

mechanism or that the mechanisms for the neutral and ionized species are the same.

For organic bases, sorption is affected by similar factors as for organic acids.

However, ion-exchange has been shown to be the controlling sorption mechanism for

organic bases even at pH values as much as two units greater than the solute pK.

(Zachara et al., 1987, 1990; Ainsworth et al., 1987; Bellin, 1993). Competitive

sorption between compounds has also been observed for organic cations (Zachara

et al., 1987; Felice et al., 1985) In contrast, for HOCs and neutral HIOCs

competition is minimal (Zachara et al., 1987; Karickhoff et al., 1979; Schwarzenbach

and Westall, 1981; Chiou et al., 1983; Maclntyre and deFur, 1985; Rao et al., 1986).

The predominance of ion-exchange in the sorption of organic bases suggests the use

of a sorption coefficient normalized to the cation exchange capacity of the sorbent

as a first approximation, analogous to the use of Ko for describing sorption of HOCs.






































-4 -3 -2 -1 0
pH pKa


0.8


0.2

ft


1 2 3 4 5 -


-4 -3 -2 -1 0
pH pKa


1 2 3


Figure 1-3.


Normalized sorption coefficients for several organic acids plotted as a function of pH-pK,. [Data from
Kukowski (1989) and Jafvert (1990)]


e 0.8
C
S0.6


. 0.4
0

0.2


0
-5
5


A Muck Soil
__O O 2-4-D
A O 2,4,6-trichlorophenol
A 4-nltrophenol
S0 Predicted




0
00


(Data from Kukowski, 1989) C3
_ I 1


Sediment
o pentachlorophenol
0 dinitro-o-cresol
Sdichlorobutyric acid
SIIvex
Predicted




0

0
(Data from Jafvert, 1990) oo
I_ I I 1 1 0 0%0o o '


4 5


i


i










Cosolvency

The effects on solubility and sorption (hence, on transport) of organic

chemicals upon addition of one or more organic cosolvents to an aqueous solution

are defined here as cosolvency. This section will focus on the most significant

interactions affecting solubility and sorption of both HOCs and HIOCS. Such

interactions include solute-cosolvent, cosolvent-cosolvent, and cosolvent-water

interactions for solubility; for sorption, solvent-sorbent interactions must also be

considered.

Solubility in Mixed Solvents

The log-linear cosolvency model and the UNIFAC model are among the

theoretical approaches that have been used to examine cosolvent effects on solubility

(Fu and Luthy, 1986a; Pinal et al., 1990). The log-linear cosolvency model

(Yalkowsky and Roseman, 1981) is based on the central assumption that the

logarithm of the solute solubility in a mixed solvent is given by the weighted-average

of the logarithms of solubilities in the component solvents in the mixture; the

weighting coefficient is taken to be the volume fraction of each solvent component.

Thus,

log Sm- fi log S (1-4)

where S is solubility (mg/L), f is volume fraction of the solvent, and the subscript m

denotes mixed solvent and i the i-th cosolvent. Note that averaging the logarithms

of solubilities is equivalent to averaging the free energies of solution in different

solvents in the mixture.








15
In many cases the UNIFAC model may be preferred over the log-linear model

because (i) it has a more sound theoretical basis, (ii) activity coefficients in mixtures

can be calculated given only pure component data, and (iii) all possible interactions

among the components in the mixture are explicitly considered. A limitation of the

UNIFAC model, however, is that although the group interaction parameters required

to estimate the solute activity coefficients are continuously reviewed and updated,

their values are not available for a number of systems of interest here. Also, there

are both experimentally-based (Banerjee, 1985; Arbuckle, 1986) and theoretically

based (Pinal, 1988) reasons that limit the applicability of UNIFAC to aqueous

systems.

A convenient measure of the impact of a cosolvent on the solubility of an

organic chemical is the cosolvency power (a), which is defined as


a log (1-5)




where the subscripts c and w refer to neat cosolvent and pure water, respectively.

HOC solubility in organic solvents is larger than that in water, thus a > 0. Larger

values of a indicate a greater solubilizing power of the solvent for a specific solute.

Rubino and Yalkowsky (1987a) and Pinal et al. (1990) have shown that a

values can be viewed as being equivalent to hypothetical partition coefficients for the

HOC between a cosolvent and water. Morris et al. (1988) have shown that a values

can be correlated to HOC octanol-water partition coefficient (K,) as follows:










o a log Ko + b (1-6)



where a and b are empirical constants unique for a given cosolvent. Other cosolvent

and solute properties may also be used to estimate a values (Rubino and Yalkowsky,

1987a,b; Morris et al., 1988).

Although both Eq. (1-5) and (1-6) provide useful first-order approximations

of the cosolvency power of a solvent for a solute, measured HOC solubility profiles

in solvent mixtures often exhibit deviations from the expected log-linear behavior

primarily due to solvent-cosolvent interactions. The observed cosolvency in a binary

mixed solvent can be more generally defined as,


log Sb log S, + ac fc (1-7)

where Sb is the solubility in the binary mixture.



Equilibrium Sorption from Mixed Solvents

Hydrophobic Organic Chemicals (HOCs)

A log-linear cosolvency model describing the decrease in sorption of HOCs

with increasing f, in a binary solvent is given by (Rao et al., 1985; Fu and Luthy,

1986b):


log Kb log K, -a oc f,


(1-8)








17
where K is the equilibrium sorption coefficient (mL/g), a is an empirical constant

for describing solvent-sorbent interactions, and the subscript b stands for binary

mixed solvent.

An extensive amount of data has shown that in binary mixed solvents, HOC

solubility increases and sorption decreases in a log-linear manner as the volume

fraction of the organic cosolvent increases (Rao et al., 1985, 1986, 1989, 1990; Nkedi-

Kizza et al., 1985, 1987, 1989; Woodburn et al., 1986; Fu and Luthy, 1986a,b;

Yalkowsky 1985, 1987; Rubino and Yalkowsky, 1985, 1987a,b,c; Walters and

Guiseppi-Ellie, 1988). These experimental findings are consistent with the predictions

of both the UNIFAC model and the log-linear cosolvency model. Also, for the

sorption of HOCs, solvent-solute interactions as described by solubility are found to

predominate such that the impact of solvent-sorbent interactions has been considered

minor. However, for solutes containing specific functional groups, the impact of the

cosolvent on the sorbent may have considerable impact.

Hydrophobic Ionizable Organic Chemicals (HIOCs)

For hydrophobic ionogenic compounds (HIOCs) of environmental interest,

data on solubility, sorption, and transport in mixed solvents are limited. However,

pharmaceutical literature contains solubility data for several drugs spanning a wide

polarity range. Yalkowsky and Roseman (1981) observed that as solute polarity

increases relative to the solvent, the solubilization curves become increasingly more

parabolic in shape until an inverse relationship occurs (i.e.,decreased solubility with

cosolvent additions). Such behavior is explained on the basis of the solute-solute and

solute-cosolvent interactions.

The sorption of HIOCs from mixed solvents has received little research

attention to date. For several HIOCs of environmental relevance (log Ko > 1.0),








18
solubility does increase with increasing f,; thus, a decrease in sorption is expected.

Fu and Luthy (1986b) observed an inverse log-linear behavior in the sorption by

three different soils of naphthol, quinoline, and dichloroaniline in methanol/water

and acetone/water solutions up to 50% by volume. Similar behavior was observed

by Zachara et al. (1986) for quinoline sorption by a natural clay isolate and

montmorillonite in the same binary mixtures. However, for the sorption of an

ionizable fluorescent dye (Rhodamine WT) from binary mixtures of methanol/water

and acetone/water, Soerens and Sabatini (1992) observed adherence to the log-linear

model only for cosolvent fractions less than 30%, while at higher fractions sorption

increased.

For hydrophobic, ionogenic organic compounds (HIOCs), several factors (e.g.,

speciation, soil-solution pH, sorbent-surface pH, charge, ionic strength, ionic

composition, multiple solutes) make predicting sorption from a single parameter

difficult due to additional mechanisms that must be considered. As discussed

previously, prediction of HIOC sorption by soils from aqueous solutions is already

complicated due to the potential for a variety of different sorption mechanisms.

Prediction of HIOC sorption from mixed solvents is further confounded by a number

of indirect effects resulting from cosolvent-induced phenomena occurring either in

the solution phase or on the sorbent. For example, for an organic acid in solvents

of low dielectric constants (e.g.,methanol, acetone, dimethylsulfoxide) an alkaline

shift in the solute pKa results in an increase in the fraction of neutral species.

Similar impacts on the ionization of sorbent functional groups and subsequent solute-

sorbent interactions must also be considered. Also, the impact of cosolvent-water

interactions that have been considered negligible in predicting the chemodynamic

behavior of HOCs may become important when assessing the behavior of HIOCs.








19
In addition, the different propensities of the cosolvent and water to solvate both the

solute and the sorbent will be important in understanding the sorption of HIOCs.

The existence of codisposal sites, implementation of cosolvents in remediation

schemes, and the development of alcohol-based fuels further warrants a better

understanding of the behavior of HIOCs in complex solvent mixtures.

Emphasis of this work was on understanding the solubility and sorption of

HOCs in multi-phasic mixtures, and of HIOCs in complex miscible-solvent/water

mixtures. The liquid-liquid partitioning behavior of aromatic hydrocarbons between

environmentally relevant organic immiscible liquids (OILs) and water was

investigated. The applicability of Raoult's law was assessed by measuring and

compiling partitioning data from several multi-component OILs, and the UNIFAC

model was utilized to estimate the likely nonidealities resulting from interactions

between components in these complex OILs. These results are discussed in Chapter

2. For the partitioning of HIOCs from binary miscible-cosolvent/water mixtures, the

role of solute hydrophobicity and acidity, solvent type, and pH on the sorption of

organic acids by a surface soil from mixed solvents was investigated. These studies

included (1) sorption of several organic acids from methanol/water solutions

(Chapter 3), (2) sorption of benzoic acid and PCP as a function of pH at several

fixed methanol/water compositions (Chapter 4), and (3) benzoic acid sorption from

additional binary mixtures of water and cosolvents with a wide range in solvent

properties, as well as, sorption of several substituted carboxylic acids from

methanol/water solutions (Chapter 5). The observed sorption of these HIOCs was

assessed in terms of cosolvent-enhanced solubility, cosolvent-induced speciation, as

well as specific and nonspecific solvent association mechanisms.













CHAPTER 2
EQUILIBRIUM PARTITIONING OF POLYAROMATIC HYDROCARBONS
FROM ORGANIC IMMISCIBLE LIQUIDS INTO WATER


Introduction

Background

Environmental contamination problems at most industrial waste disposal sites

or spill sites commonly involve the presence of an immiscible organic phase

constituting a multi-phasic waste with multiple components. Of great concern is the

transport of organic constituents from these wastes resulting in contamination of soil

and water. Near the source of contamination where a separate organic phase is

present, solubility is the primary process controlling the release of organic chemicals

to the aqueous phase. Therefore, an understanding of the solubility (or partitioning)

of polyaromatic hydrocarbons (PAHs) from a complex liquid such as those suggested

is essential in predicting contaminant release.

Over the last few years efforts have been made to measure the partitioning

of PAHs from environmentally relevant organic liquid wastes such as gasoline, motor

oil, diesel fuel, and coal tar. Coal tars are among the most complex organic liquid

wastes and comprise a large number of hydrocarbons spanning a broad spectrum of

molecular weights. The concentrations of individual constituents in coal tars vary

significantly from one manufacturing gas plant (MGP) site to another. The








21

manufacturing of gas from coal and oil for residential, commercial, and industrial use

in the late 1800s and early 1900s resulted in the production of large amounts of coal

tar wastes. Eng and Menzies (1985) reported that more than 11 billion gallons of

coal tar were generated in the U.S. during the period 1816-1947, but the disposition

of several billion gallons is unknown and remains unaccounted. In many cases, the

wastes were left on-site in pits or containers, placed in near by ponds or lagoons, or

taken to off-site areas for land disposal. Such practices resulted in contamination of

soils and groundwater at most former MGP sites. Hydrophobic organic chemicals

(HOCs) have been detected at former MGP sites, and are of particular concern due

to their potential carcinogenic nature (Guerin, 1978). Several of these compounds

have already been included on the U.S. EPA list of priority pollutants.

In the past, it has often been assumed that concentrations of organic

contaminant in the aqueous phase leaving a coal tar source would be equal to their

corresponding pure-compound aqueous solubilities. This may be a reasonable

estimate if the source of interest was composed of a single contaminant (e.g.,

trichloroethylene, tetrachloroethylene). However, most complex wastes (e.g.,coal tar,

diesel, gasoline) consist of mixtures of contaminants. These mixtures may be

considered complex based on the number of chemicals that constitute the mixture.

On the other hand, complexity of a mixture can be defined by considering how the

properties of the mixture deviate from some "ideal" behavior, regardless of the

number of components. The former view corresponds to a mixture being complex

in composition, whereas the latter implies complexity in behavior. The important








22
point is that a mixture can be complex in composition without being complex in

behavior and vice versa.

To assess the extent of groundwater contamination and the long-term

environmental impacts from land disposal or spill sites containing multi-phasic

wastes, it is necessary to characterize the total amounts released and the release rates

of HOCs from the waste matrix. The properties of an organic mixture complex only

in composition are determined by the properties of its pure components and their

concentrations in the mixture. This implies that the chemicals of interest behave

ideally in the matrix containing them. Under these conditions Raoult's law would

suggest that the concentration in the aqueous phase of a chemical is proportional to

the mole fraction of the chemical in the organic phase.

This chapter will focus on the use of equilibrium theory to characterize the

total amounts of PAHs released from organic liquid wastes. Coal-tar/water partition

coefficients for several PAHs were measured from several coal tars spanning a wide

range in physical and chemical properties. To estimate aqueous-phase concentrations

of PAHs in equilibrium with coal tar, the utility of applying Raoult's law convention

for activity coefficients in conjunction with supercooled liquid solubilities for PAHs

that are crystalline in their pure form will be assessed. Although the majority of this

chapter is on coal tar wastes, a reassessment of diesel fuel/water and gasoline/water

partitioning data will also be presented including the use of the UNIFAC

(UNIQUAC functional group activity coefficient) model to estimate the likely

nonidealities resulting from interactions between components in these complex

organic liquids.










Theory

The release of a chemical from an organic liquid phase can be estimated from

a liquid-liquid partition coefficient (Kd) which is defined as


Kd o (2-1)
C,

where Co and C, are the molar concentrations (mol/L) of the chemical of interest

in the organic and aqueous phases at equilibrium, respectively. The partition

coefficients (K) for coal tar, diesel fuel, and gasoline will be designated using

subscripts tw, dw, and gw, respectively.

For liquid-liquid partitioning, thermodynamic equilibrium is defined by the

equality of the chemical potentials in the aqueous and organic phases. This equality,

in conjunction with the choice of pure (liquid) solute as the standard state and the

Raoult's law convention for activity coefficients, results in the following expression

at equilibrium

(2-2)
SYo Xw Y (2-2)

where subscripts o and w denote organic and aqueous phases, respectively; xo and

x, are the respective mole fractions of the chemical in the organic and aqueous

phase; Yo* is the activity coefficient of the chemical in the organic phase in

equilibrium with the aqueous phase; and y, is the activity coefficient of the chemical

in the aqueous phase in equilibrium with the organic phase.

From Eq. (2-2), molar concentration of a solute in the aqueous phase (Cw) can

be approximated with the following assumptions: (1) the presence of other








24
components in the aqueous phase is ignored, i.e., y,' is set equal to the aqueous

phase activity coefficient of the solute in equilibrium with the pure solute (y,); (2)

the solute behaves ideally in the organic phase, i.e.,Yo* is unity; (3) the aqueous mole

fraction solubility (Sx,) of the pure liquid solute is equal to 1/ y; and (4) the

solution is sufficiently dilute (i.e., moles of the solute are small relative to the total

moles of solvent; C = x V and S/ V, = S,w where S, is the aqueous solubility of the

pure liquid solute in moles/L) and V, is the molar volume of water. Application of

these four assumptions yields


Cw xo St (2-3)

Therefore, the partition coefficient (Eq. 2-1) for a solute can be approximated

as follows,


C
Kd (2-3)
xo S1
For mixtures comprising a large number of constituents, each contributing a

small fraction to the total, xo/Co can be replaced by the molar volume (Vo, L/mole)

of the organic phase. The molar volume can then be approximated by the ratio of

the average molecular weight (MW,, g/mole) and density (po, g/L). The resulting

expression for Kd is:


1 (P. / MW.)
Kd (2-5)
VSt St








25
Taking logarithms of both sides of Eq. (2-5), it is evident that the inverse relationship

between log Kd and log St results in a unit negative slope and an intercept that is

dependent upon the molar volume of the organic phase (i.e.,MW,/ p):


log Kd -log S log M(2-6)

Derivation of Eq. (2-6) was based on a choice of the pure liquid solute as the

standard state. Most of the PAHs investigated in this study are solids in their pure

form; therefore, the hypothetical supercooled liquid solubilities of the solid solutes

must be employed. The supercooled liquid solubility (S) of a solute at a given

temperature can be calculated directly from the solute's measured heat of fusion

(AHf) and melting point (T) (Yalkowsky, 1980), or alternately can be estimated by

assuming a constant entropy of fusion (ASf=AH/T.) for the PAHs of interest

(Yalkowsky, 1979; Martin et al., 1979) (see Appendix A).

Application of Raoult's Law for Gasoline. Motor Oil, and Diesel Fuel

The utility of the relationship defined by Eq. (2-6) was successfully

demonstrated for several gasolines by Cline et al. (Cline et al., 1991) for several

monocyclic aromatic hydrocarbons (MAHs). Gasoline is composed of several

branched-chain paraffins, cycloparaffins, alkanes, aromatic compounds, and small

amounts of various additives. Results presented by Cline et al. (1991) revealed that

although gasoline is complex in composition, MAH partitioning into water behavior

was essentially ideal. None of these MAHs exhibit crystalline structure in their pure

form which is common to most PAHs. Chen (1993) investigated the applicability of








26
Raoult's law for the partitioning of MAHs as well as some PAHs from new and used

motor oil. Given the absence of experimental artifacts, nonideality was noted for the

partitioning of MAHs from the new motor oils, whereas, the one PAH investigated

(phenanthrene) partitioning was successfully predicted using Raoult's law and

supercooled liquid solubilities. However, Raoult's law appeared applicable within

a factor-of-four for the partitioning of both MAHs and several PAHs from used

motor oil.

Hagwall (1992) measured the partitioning of several PAHs from diesel fuel

into water and concluded that the use of supercooled liquid solubilities (S.) in

applying Raoult's law was not successful. However, Hagwall (1992) used an

inaccurate estimation of S., resulting in a wrong conclusion regarding the

applicability of Raoult's law. Using the crystal solubilities (Sw) given in Table 2-1

and assuming a constant ASf of 13.5 eu, a much better relationship was observed

between log Kd, and log S,. In Figure 2-1, the measured log Kdw values are plotted

against their log S, for the eight PAHs investigated along with the ideal line (solid

line) calculated from Eq. (2-6) for each diesel fuel using the MW, and p, given by

Hagwall (1992). For most PAHs in all four diesel fuels, the log Kdw values lie near

the ideal line suggesting that the assumption of ideal behavior may be adequate for

describing the partitioning of PAHs from diesel fuels to water. The confidence

intervals (bars) shown in Figure 2-1 were estimated using an error propagation

method (Shoemaker et al., 1980) which incorporates the errors incurred in the

analysis of both the neat fuel and aqueous phase concentrations. Arrowheads reflect








27
the few cases where the propagated error was larger than the average KdW value as

was the case for anthracene and fluoranthene. Note that both compounds were

present in small quantities in the neat fuel and or analytical problems were

encountered in detecting small aqueous phase concentrations. Several factors other

than nonideal behavior could result in apparent deviations such as analytical

uncertainty in Kw, as well as, errors incurred in the estimations of S, (i.e., reported

S, values and the use of a constant ASf value).

The success in applying Raoult's law for gasolines, diesel fuels, and motor oils

leads to the question of whether ideal behavior can also be assumed for coal tars.

Compared to gasolines, diesel fuels, and motor oils coal tars are even more complex

in composition, especially because over 60% of their constituents are not known.

Gasolines, diesel fuels, and coal tars collected from different sites vary greatly in

their composition, but only a small variance exists in their molecular weights (Cline

et al., 1991; Hagwall, 1992). In contrast, different coal tars exhibit a wide range in

composition, MWo and po (EPRI, 1993). The applicability of Raoult's law to

tar/water partitioning will be assessed as well as the potential for nonideal behavior.










Table 2-1. Selected physico-chemical properties for the PAHs investigated.


Melting' Molecular
Point Weight" S,b
Compound (Co) (g/mole) (mg/L) log SId


Naphthalene 80.2 128.2 32 -3.05

1-methylnaphthalene -22 142.2 27" -3.72e

2-methylnaphthalene 34 142.2 26' -3.62

Acenaphthylene 82 152.2 3.93 -4.02

Acenaphthene 93 154.2 3.42 -3.98

Fluorene 116.5 166.2 1.9 -4.03

Phenanthrene 100 178.2 1.0 -4.5

Anthracene 216.3 178.2 0.07 -4.49

Fluoranthene 107 202 0.27 -5.19

Pyrene 150 202 0.16 -4.85

Chrysene 254 228.2 0.006 -5.29

Benzo(a)anthracene 156 228.2 0.0057 -6.29

Benzo(a)pyrene 179 252 0.0038 -6.28



"Verschuren (1983); b Crystal solubility at 250C (Little, 1981) unless stated otherwise;
' Miller et al. (1985); d Supercooled liquid solubility (moles/L) calculated assuming
a constant ASf for PAHs; e liquid solute at standard state.










5.5 h


4.5 F


3.5 F


- 3 3L
-3 -6


-3.5 -3 -6 -5.5
log [Sscl, moles/L]


Figure 2-1.


log Kdw values plotted versus log S, for eight PAHs along with the ideal line (solid line)
Eq. 2-6 for each diesel fuel.


calculated from


DF #2
6



80 7-
84 2
3


0


-5.5 -5 -4.5 -4 -3.5


-5.5 -5 -4.5 -4 -3.5 -3










Materials and Methods

Chemicals

For all the PAHs investigated (see Table 2-1) standards were purchased from

Aldrich Chemical Co. at > 98% purity except for acenaphthene, which was available

only at 85% purity. Methylene chloride, the solvent used for the aqueous phase

extractions, was purchased from Fisher Scientific at Fisher grade Optima.

Batch Equilibration Technique

Approximately 0.3-0.5 g of coal tar were added to a glass centrifuge tube

(nominal volume 40 mL); enough electrolyte solution (0.01 N CaC2) was added such

that no headspace remained; and tubes were closed with phenolic caps fitted with

Teflon-lined septa. Prior to sampling the coal tar for equilibration with an aqueous

phase, coal tars were rotated end-over-end at room temperature (23 + 2"C) for 12-18

hours. The coal tar/water (0.01 N CaCl) mixtures were then equilibrated for 3-7

days in the dark. Preliminary studies where samples were equilibrated for 1, 3, 5,

and 7 days showed no measurable differences in PAH concentrations after 3 days.

Following centrifugation (300 RCF for 30 minutes) of the equilibrated coal tar/water

mixtures, a portion of the aqueous phase (z25 mL) was quantitatively removed for

extraction with methylene chloride and subsequent concentration prior to analysis.

Due to the large masses of the compounds of interest present in the coal tar phase,

experimental artifacts from PAH sorption to the equilibration vessels were

considered negligible. To avoid volatilization losses and contamination of the

aqueous phase aliquot with the coal tar phase, the aqueous aliquot was removed

through the septa using a 50-mL Teflon-backed gas/liquid syringe equipped with a








31
3-inch needle. The equilibration vessel was vented during sampling by piercing the

septa with a second needle.

Following aqueous phase transfers, as much residual water as possible was

removed from the equilibration vessel without loss of the coal tar. The coal tar in

the equilibration vessel and the cap were rinsed with methylene chloride into a 100-

mL volumetric flask and brought to volume. Dissolved coal tar samples were filtered

(0.45 pm) prior to analysis. For the coal tar samples from which it was difficult to

remove residual water without loss (i.e., thin liquid coal tars), an aliquot of the neat

coal tar was sampled for analysis as well.

Chromatographic Analysis

PAH concentrations in the coal tar and aqueous phases were determined using

a gas chromatograph (GC) equipped with an ion trap detector (ITD). The GC/ITD

method included an HP Ultra 2 column (95% methyl, 5% phenyl polysiloxane, 0.5

micron thickness; 30 cm x 0.32 mm ID); helium as a carrier gas at a flow rate of

approximately 1.0 Ml/min; temperature gradient program, and an ion trap detector.

The temperature gradient program consisted of a 1 minute hold at 50"C; a ramp to

1300C at 30*C/min followed by a 3 minute hold; a ramp to 1800C at 12*C/min

followed by a 1 minute hold; a ramp to 240 C at 7C/min; and a ramp to 300 C at

12 C/min followed by a 15 minute hold. The ITD was set at an electron energy of

70 eV and scanned from 45 to 450 amu at 2 scans/sec. The electron multiplier

voltage was 1650 volts and the transfer temperature from the GC was 2800C. Prior

to GC analysis, samples were usually spiked with an internal standard consisting of

naphthalene-d8 and anthracene-dg.










Results and Discussion

Coal Tar Composition

The coal tars used in this study were received from META Environmental, Inc.

Various physical and chemical properties of these coal tars had been characterized

(EPRI, 1993), including density, viscosity, water and ash content, average molecular

weight, elemental and organic analysis. The ranges observed for these properties in

terms of percentages or concentrations are summarized in Table 2-2.

The viscosity of the coal tars ranged from approximately 34 cps to 6600 cps

(40C), with the coal tar consistency varying from thin liquids (ID# 1,4, and 5) to

thick liquids (ID# 7) and from soft (ID# 3 and 9) to sticky (ID# 2) "taffy-like"

materials. Coal tar viscosity will generally increase with aging and decrease with

temperature. Some coal tars had high ash contents, suggesting the presence of other

solids. For example, coal tar ID# 7N had a high content (37%) of what appeared

to be sand and silt. The PAH concentrations for this coal tar were corrected to

represent the mass of PAH present per actual mass of coal tar. For the remaining

coal tars an occasional rock or pellet was found, which was easily removed prior to

experimentation.

Water content of the thin liquid coal tars was small (<1% mass basis). For

the more viscous coal tars, reported water contents were as high as 30% (mass basis);

however, high molecular weights and densities for these coal tars strongly suggests

that these high water contents were in actuality a sampling artifact. It appears that

water may have been trapped as a separate liquid phase within the taffy-like matrix

of the coal tar.












Table 2-2. Range of properties observed for eight coal tars (EPRI, 1993).


Physical Properties:
Ash
Water Content
TOC "
Viscosityb
Density
MW d




Organic Compounds
monocyclics
polycyclic:
2 & 3 rings
> 3 rings
NPAHsf
SPAHsg
Pitch


Range
0-50%
0-30%
40-90%
34-6,600 cps (400C)
1.06-1.43 g/mL (24C)
230-780e g/mole




Range (mg/kg)
13-25,300


6,800-218,000
12,000-110,000
70-1,000
0-4,000


Elemental Analysis:
Carbon
Hydrogen
Nitrogen
Oxygen
Sulfur
Cyanide




Metals Analysis
Arsenic
Beryllium
Cadmium
Lead
Nickel
Selenium
Vanadium
Chromium


Range(%)
43-90
2-7
<0.5-1
1-33%
0.4-4%
< 1-580 mg/kgh
< 1-150 mg/kg'


Range (mg/kg)
3-23
<1
<1-4
1-930
2-74
< 1-5
6-230
< 1-230


" Total Organic Carbon; b Test Methods ASTM D445 and D88; c Test Methods
ASTM D70, D369, or D1429; d Average molecular weight determined using vapor
pressure osmometry; e Exception: asphaltene-like tar 1600 g/mole; f Nitrogen
polyaromatic hydrocarbons; g Sulfur polyaromatic hydrocarbons; h Determined using
EPA Method 4500;' Determined using EPA Method 9010.








34

Similar compounds were found in all of the tars, but individual hydrocarbon

concentrations varied significantly from one MGP site to another. PAH

concentrations ranged from 7,000mg/kg to 220,000mg/kg, with various naphthalenes

as the dominant components. Several monocyclic aromatic hydrocarbons (e.g.,

benzene, toluene, ethylbenzene, and xylenes (BTEX), and styrene) were also present

in concentrations ranging from 13 to 25,300 mg/kg. Much smaller amounts of

nitrogen- and sulfur-containing aromatic hydrocarbons (e.g., carbazole and

dibenzothiophene) were also found.

It is important to recognize that less than 40% (on a mass basis) of the coal

tar constituents can be quantified (see Table 2-2) using common extraction and

chromatographic techniques. The unidentified tar fraction is often referred to as the

"pitch" for operational purposes. Current sophisticated analytical techniques still lack

the capability needed to identify most of the pitch constituents; however, their

general nature may be surmised based on coal composition (e.g.,Whitehurst et al.,

1980) or oil composition. A majority of the pitch constituents are aromatic

compounds with high molecular weights and low aqueous solubilities; thus, they may

not be of direct concern in terms of groundwater contamination. However, the

physical and chemical characteristics of the pitch may exert a strong influence on the

rates of release and the equilibrium partitioning of the more-soluble tar constituents

(e.g., BTEX, naphthalenes) that are of greater environmental concern. Also,

nitrogen- and sulfur-containing aromatic hydrocarbons present in coal tars may

impart nonideal behavior.










Tar-Water Partitioning

The relative success in applying a model based on Raoult's law convention for

gasolines (Cline et al., 1991), diesel fuels, and motor oil prompted the investigation

of whether ideal behavior could also be assumed for coal tars. Compared to

gasolines and diesel fuels, coal tars are compositionally more complex; thus, greater

deviations from ideal behavior might be expected. The assumption of ideal behavior

for coal tar is postulated here for practical expediency, since it reduces the number

of parameters needed to estimate PAH concentrations in groundwater. Ideal

behavior is not necessarily expected for such materials, but it is hoped that the

assumption will be adequate within a specified acceptance factor; a factor-of-two has

been chosen here to be adequate for field-scale applications. Experimental

measurements of tar-water partition coefficients are difficult, and are subject to

significant errors. Thus, experimental artifacts as a possible cause must be

eliminated before attributing nonideal behavior to a given coal tar or even to one or

more constituents within a coal tar. It is with this pragmatic perspective that we will

interpret tar-water partitioning data. The investigations of tar-water partitioning

involved analysis of data collected in this study for eight tars, analysis of published

data, and theoretical analysis of solute-solute interactions that might lead to nonideal

behavior.

Analysis of Laboratory Data

The tar-water partitioning data for the eight tars examined in this study are

presented in Figures 2-2 through 2-5. The logarithm of the average K, value and

the calculated standard deviations are shown along with the prediction based on Eq.








36
(2-6) (solid line) and the factor-of-two tolerance intervals. For most coal tars, the

data points are scattered about the ideal line within the factor-of-two bounds

suggesting that the assumption of ideal behavior suffices (again, within a factor-of-two

error) in predicting KI for the PAHs. For the one exception (ID# 1), measured

data points lie consistently above the ideal line (Figure 2-2A) indicative of an error

in the estimate of the molar volume. Specific causes for the systematic deviation

observed with coal tar ID# 1 need to be further explored.

Benzo(a)anthracene is the only PAH that consistently lies substantially below

the ideal line for most of the coal tars. Uncertainties arising from both analysis and

parameter estimation may have resulted in the observed negative deviations.

Analysis of benzo(a)anthracene in the aqueous phase approached detection limits,

thus contributing to uncertainties. A greater source of error was probably incurred

in the estimation of the supercooled liquid solubility for benzo(a)anthracene. The

S, values (given in Table 2-1) used in plotting log K, values in Figures 2-2 through

2-5 were estimated assuming a constant entropy of fusion (ASE)(Yalkowsky, 1979).

For most compounds, this method may be preferred over attempts to find reliable

measured AHf values needed for a direct calculation. However, in the case of

benzo(a)anthracene the S, values estimated using the average ASf value was about

one order of magnitude higher than that calculated using the AHf value reported by

Chio et al. (1985). Thus, the reasons for the observed deviation of

benzo(a)anthracene data points from the ideal line are indeterminate.





























-5.5 -5 -4.5


-3.5


-5.5 -5 -4.5 -4 -3.5 -3
log [S, moles/L]


Figure 2-2.


Comparison of measured tar-water partition coefficients
predictions based on Raoult's law for ID# 1(A) and ID#
tars.


5
'3=
o

2=n
o


36
-6


(K.) and
2(B) coal














6-


5.5


.5-


4.5


4


3.5


i35
7
0)
0 1

6-



5



4


3L
-6


Figure 2-3.


-4.5


-3.5


-5.5 -5 -4.5 -4 -3.5
log [S, ,moles/L]

Comparison of measured tar-water partition coefficients
predictions based on Raoult's law, for ID# 3(A) and ID#
tars.


-3



(IK) and
4(B) coal



























5
~
o

ai,
o


3-
-6


Figure 2-4.


-5.5


-4.5


-3.5


-5.5 -5 -4.5 -4 -3.5 -3
log [S, moles/L]


Comparison of measured tar-water partition coefficients (K,) and
predictions based on Raoult's law, for ID# 5(A) and ID# 7(B) coal
tars.










7



6



5



4


SA
S-6
6

5.5
be
5

4.5

4

3.5

B
-6



Figure 2-5.


-5.5 -5


-4.5 -4 -3.5


-5.5 -5 -4.5 -4 -3.5 -3
log [S, moles/L]


Comparison of measured tar-water partition coefficients
predictions based on Raoult's law, for ID# 7N(A) and ID#
tars collected by EPRI.


O(K) and
9(B) coal









Analysis of Literature Data

The tar-water partition coefficients (K,) for several PAHs compiled from the

literature (Rostad, 1985; Groher, 1990; Picel, 1988) for three different coal tars, are

plotted in Figure 2-6 in a manner similar to Figures 2-2 through 2-5. For each coal

tar, the ideal line (solid line) shown was calculated from Eq. (2-6) using the best

estimates available for MW, and p,,. For the coal tar investigated by Rostad et al.

(1985) (Figure 2-6A), the ideal line was calculated using the Pet reported and a MWVt

value estimated from a weighted average of the mole fraction and molecular weight

of each known component. For the unknown fraction, an average molecular weight

of 300 g/mole was assumed. Picel et al. (1988) reported values for both pt and

MW,. Groher (1990) did not report values fore MW, and pc; therefore, data for a

coal tar, similar in composition, obtained from the same site a few years later was

used to estimate the ideal line (Figure 2-6B).

For most of the PAHs, the measured KI values are within a factor-of-two

from the ideal line, with the best agreement observed for the Picel et al. (1988) data

(Figure 2-6C). Observed deviations from the ideal line could be the result of

considerable nonideality in the tar-water system or a consequence of various

experimental artifacts including inadequate time for equilibration and poor recovery

of the PAH from the aqueous phase. The probability of such experimental artifacts

increases for the larger PAHs where a greater difficulty is often encountered in

accurately measuring the solubility of rather insoluble compounds.








42


6.5
Rostad et al., 198
S- dibenz(a,h)anthr cRostad et al., 1985
5.5 benzo(a)anthracene '-..
5 -... ".--.-methylnaphthalen
Ideal Line anthracen~e
4.5 -
MWt = 265 g/mole fluorene-..hthalen
4 p = 1.03 g/mL --
A p acenaphthene
3.5
-6.5 -6 -5.5 -5 -4.5 -4 -3.5 -3
7 -... chrysene Groher, 1990
6.5 --- fluoranthene
Sp-yrene
60 --. anthracene
5.5 .phenanthrene
0) 5~ i 'e U--. -fluorene
O 5 Ideal Line ----.....
4.5 MWct = 230 g/mole acenaphthelne--.
4 P ct = 1.064 g/mL 2-methylnaphtihaen.
B naphthatene
-6 -5.5 -5 -4.5 -4 -3.5 -3

6.5 -.. pyrene Picel et al., 1988
..fluor.nthene
6 --- -
s. phenanthrene biphenyl
I -l --... fluorene
5 Ideal Line 1.... __ ... .-- -methylnaphthalene
MWct = 150 g/mole acenaPt e h phtha
4.5 -.. aphthalene
p C = 0.99 g/mL ---.-
4 naP. ne'
3 .5 -3

log [S, moles/L]

Figure 2-6. Comparison of measured tar-water partition coefficients (K,) reported
in the literature and predictions based on Raoult's law. Literature
source as indicated.








43
A decrease in the measured K, values would be anticipated for deviations

resulting from sufficient nonideality as observed in Figure 2-6A for the Rostad et al.

(1985) data. The expectation of the presence of nonideality resulting in negative

deviations for PAHs is based on work by Chiou and Schmedding (1982) and Chio et

al. (1985) where the activity coefficients of several PAHs were measured in water-

saturated octanol and mixtures of benzene and cyclohexane. In both cases, the

activity coefficient of a given PAH in the organic phase (Yo') were found to be

greater than unity. Values of y., greater than unity will result in log K, values

smaller than those estimated assuming ideal behavior.

Predicting Aqueous-Phase PAH Concentrations

Coal Tars

The log Kt, versus log S, relationship observed for several coal tars (Figures

2-2 through 2-5) suggests that the application of Raoult's law and the assumption of

ideal behavior may be adequate to predict the concentration of PAHs in groundwater

(C,) in contact with a coal-tar source. Equation (2-3) was used to estimate the

concentrations of several PAHs expected to be present in a groundwater in

equilibrium with a coal tar were estimated using Eq. (2-3) for the coal tars

investigated. The mole fraction of the PAH in the organic phase (xo) needed in Eq.

(2-3) was approximated by the product of the mass fraction (mg/g) in the coal tar

and MWt, (i.e., C, = Mi MW, St). A log-log plot comparing predicted aqueous

concentrations (converted to commonly reported units of mg/L) and those measured

during the laboratory partitioning studies is shown in Figure 2-7. The error bars









44

shown in Figure 2-7 for the laboratory-measured concentrations represent the

standard errors calculated from replicate averages. An arrowhead on an error bar

indicates that the lower bound approached the limit of detection. For the predicted

concentrations, the error bars shown in Figure 2-7 were estimated from the standard

errors calculated from the replicate average of Mi. Also given in Figure 2-7 is the

ideal line (i.e., 1:1 correlation) with the corresponding factor-of-two tolerance

intervals.


a 0

E

?-1
0)
o
-0 -2

a,
a. -3


-3 -2 -1 0 1 2
Measured [log (C, mg/L)]


Figure 2-7. Comparison of laboratory-measured aqueous-phase concentrations
(C,) with those predicted on the basis of Raoult's law for eight coal
tars.








45

Confidence in the C, values predicted using Eq. (2-3) is dependent on several

factors other than the premise of ideal behavior, including uncertainty about the

input parameters (e.g., Mi, 1MWt, and S). Both Mi and MW, can be determined

experimentally; therefore, errors associated with these parameters can be obtained

from replicate analysis information. Sampling and chromatographic analysis of this

heterogeneous liquid waste is prone to considerable errors; therefore, the deviation

associated with Mi is probably the greatest source of error in estimating C, values.

A majority of the data presented in Figure 2-7 lie within the factor-of-two

intervals given about the 1:1 correlation. The data that lie outside the factor-of-two

intervals result in predicted concentrations greater than those measured, with the

exception of the data points below the 1:1 correlation which correspond to

benzo(a)anthracene. Benzo(a)anthracene is present in small amounts in coal tar, thus

often approaching the limits of analytical detection. In addition, aqueous solubility

measurements for compounds with small values (i.e., <10-2 mg/L) become

increasingly less reliable. Good agreement for a majority of PAHs within a factor-of-

two suggests that the use of Eq. (2-3), based on Raoult's law, may be adequate for

estimating PAH concentrations. At the very least, aqueous concentrations estimated

using this approach should be considered more appropriate and definitive than

merely assuming crystal solubilities for aqueous-phase concentrations.

Given the variations that may exist in (1) the different coal tar deposits at a

given site, and (2) the extent of weathering at that site, it would be advantageous to

estimate maximum PAH concentrations that might be found at any site. In order to








46

estimate maximum CW values, the eight coal tars investigated were assumed to be

representative of coal tars that might be found at any site in the United States. The

maximum concentrations of the PAHs investigated based on the data compiled for

the eight coal tars, are given in Table 2-3 along with the ratios of C, to S,. Note

that the maximum Cw expected is the crystal aqueous solubility for anthracene,

chrysene, and benzo(a)anthracene.



Table 2-3. Maximum CW values for several PAHs based on the data compiled for
eight coal tars.



Compound SW Maximum
(mg/L) CWa CJ/S

Naphthalene 32 14b 0.44
1-methylnaphthalene 27 2 0.05
2-methylnaphthalene 26 1.4 0.05
Acenapthylene 3.93 0.5 0.13
Acenapthene 3.42 0.3 0.1
Fluorene 1.9 0.3 0.16
Phenanthrene 1.0 0.4 0.3
Anthracene 0.07 SW 1.0
Fluoranthene 0.27 0.01 0.4
Pyrene 0.16 0.1 0.5
Benzo(a)anthracene 0.0057 SW 1.0
Chrysene 0.006 SW 1.0
Benzo(a)pyrene 0.0038 0.001 0.3


T=25oC
Result from data compiled for seven
resulted in a prediction of 26 mg/L.


of the eight coal tars; data for one tar








47
In the absence of cosolvents and other solubility-enhancing adjuvants (e.g.,

dissolved organic carbon, surfactants, etc.), the maximum aqueous-phase

concentration (C,) is limited by the crystal solubility (Sw). Although the hypothetical

supercooled liquid solubility is used to obtain best estimates for C,, mixing of the

chemical with the aqueous phase is ultimately governed by interactions with the

solvent. These are expressed through the crystal solubility (S,) (Pinal, 1988). For

a PAH that has a low aqueous solubility, high melting point, and is present in high

concentration in the coal tar, the concentration predicted in the aqueous phase

assuming ideal behavior would be the crystal aqueous solubility (S,).

Diesel Fuels

Reasonable agreement shown previously in the predicted and measured log

Kdw versus log S, relationships for most PAHs (Figure 2-1) also supports the use of

Raoult's law in predicting maximum PAH concentrations that may be present in the

aqueous leachate leaving a diesel-fuel contaminated area. Using Raoult's law and

assuming ideal behavior, the concentration of a constituent in the aqueous phase in

equilibrium with the organic phase is proportional to the mole fraction of that

constituent in the organic phase (see Eq. 2-3). Substituting Eq. (2-5) into Eq. (2-1)

gives the following equation for the equilibrium aqueous-phase concentrations:


C C, MW, St (2-7)
P f








48

where the subscripts df and w refer to diesel fuel and water, respectively. In Figure

2-8, PAH concentrations predicted using eq 2-7 were converted to commonly

reported units (ig/L) and plotted against concentrations measured in the laboratory

partitioning studies with the four diesel fuels.








3
ID*
i 1:1
'i2- A 2 A
03
0 4 naphthalene
1 1-methylnaphthalene
S2-methylnaphthalene




C acenaphthene fluorene
)- 1 a- phenanthrene
anthracene
fluoranthene
-2


-3 I
-1 0 1 2 3
log [Measured C, ug/L]


Figure 2-8.


Comparison of laboratory-measured aqueous-phase
concentrations (C,, /g/L) with those predicted on the basis of
Raoult's law for four diesel fuels.








49
Also included in Figure 2-8 are the confidence intervals for both the measured and

predicted concentrations. Measured concentration errors were estimated from the

standard deviations observed in triplicate analyses of the aqueous phase; confidence

intervals with arrows reflect limits of detection. Similarly, the errors associated with

the predicted values were estimated from the standard deviations obtained from

triplicate analyses of the neat diesel fuel, i.e., the determination of Cdf. The

confidence intervals given for the predicted C, in Figure 2-8 did not include errors

incurred in estimating MWdf or pdf. Overall, the correspondence between measured

and predicted equilibrium aqueous phase concentrations shown in Figure 2-8 is to

be very good.

Assessment of Deviations from Ideal Behavior for Equilibrium Conditions

The relationship between Kd and S, assumed previously (el 2-6) was based on

the simplifying assumption of ideal behavior (i.e., yo = 1 and yw = yw). Several

factors may cause deviations from the assumed ideal behavior for diesel-water

partitioning of PAHs. For example, negative deviations from the ideal line could

result from the presence of surfactants or emulsions or sufficient nonideality, while

positive deviations can be expected if equilibrium has not been reached, and

apparent deviations (positive or negative) can result from uncertainty in parameter

estimation.

For a mixture which is complex in composition and behaves in a "nonideal"

fashion, the partition coefficient (Kd) between an organic liquid and an aqueous

phase can be related to the aqueous solubility of the pure liquid (S) in the following









manner (Chiou and Schmedding, 1982):


log Kd -log S, logf MW
SP" ) (2-8)

log Yo + log



Comparison of Eqs. (2-6) and (2-8) suggests that any deviations due to nonideal

behavior will arise from the last two terms on the right hand side of Eq. (2-8).

Banerjee (1984) observed that the presence of other components in the aqueous

phase had a minimal effect on solute activity; therefore, it was assumed that y,'*/y,

= 1, thus requiring only estimates of Yo'. The UNIFAC model UNIFAC

(UNIQUAC Functional-Group Activity Coefficient) model proposed by Prausnitz et

al. (1980) for estimating activity coefficients in liquid-liquid equilibria was employed

to estimate yo values needed in Eq. (2-8). In this model, a mixture of different

chemicals is treated as a mixture of functional groups constituting the components

of the mixture. Interactions between functional groups in the mixture, and the likely

nonidealities resulting from such interactions, are calculated in order to estimate the

activity coefficient of a chemical for a specified phase. Interaction parameters

required in the UNIFAC model were obtained from the most current update

(Hansen et al., 1991).

A schematic representation of Eqs. (2-6) and (2-8) is shown in Figure 2-9 as

a plot of log KD versus log S1. Note that the expected relationship for an ideal

mixture is depicted by the solid line, with a unit slope and the intercept given as the








51
log Vo (see Eq. 2-8). The single data point represents a possible value for a solute

partitioning between a hypothetical nonideal mixture and water. Note that the

magnitude of deviation from the ideal line is given by the last two terms on the right

hand side of Eq. (2-8) plus an error term, E, representing experimental uncertainty.


Log SI (moles/I) 0

Pure lquid aqueous solubility


Figure 2-9. Schematic representation of the ideal behavior (Raoult's law) and
nonideality in liquid-liquid partitioning.

Application of the UNIFAC model for assessing the potential for nonideality

is presented for a gasoline, diesel fuel, and coal tar. Using the UNIFAC model,

activity coefficients (Yo') of several aromatic compounds were estimated for an

unleaded gasoline simulated to represent the relative compositions (see inset in

Figure 2-10) reported in Cline et al. (1991).


















7
6-
A

0 A
.-J 5 10

Gasoline composition
Alkanes mole fraction
pentane 0.20
octane 0.20
decane 0.15
dodecane 0.15
Aromatic Hydrocarbons
1 MTBE -
2 benzene 0.07
3 toluene 0.07
4 xylene 0.07
5 ethylbenzene 0.07
6 1,2,3-trimethylbenzene -
7 n-propylbenzene -
8 3,4-ethyltoluene -
9 naphthalene 0.014
10 anthracene 5E-3
11 pyrene 1E-6
3,4-benzopyrene 1 E-7
Others
H20 1E-4


A UNIFAC
0 Cline et al. (6)







3 2
2


-3 -2
Log S (moles/L)


Figure 2-10. log K, values for several aromatic hydrocarbons resulting from
UNIFAC model calculations and the average log, values
experimentally determined by Cline et al. (1991) plotted against log S,
values along with the ideal line based on Raoult's law.




The estimated y* values were then used to predict log K, values (shown as solid

triangles in Figure 2-10) according to Eq. (2-8). UNIFAC model calculations for the

monocyclic aromatic compounds represented in Figure 2-10 (compounds 2-5) confirm

the experimental observations of Cline et al. (1991) that gasoline-water partition

coefficients of several liquid hydrocarbons can be approximated by assuming ideal


t f


--








53

behavior. However, for compounds with increasingly more aromaticity and are solids

in their standard state (PAH compounds 9-11 in Figure 2-10), the UNIFAC model

predicted some negative deviation from ideal behavior. Partition coefficients for

these compounds were not measured by Cline et al. (1991) as they are present only

in small quantities in gasoline. Compared to gasolines, diesel fuels contain a larger

fraction of low-solubility PAHs. Therefore, it was of interest to see if the UNIFAC

model estimations of Yo* for these PAHs resulted in deviations from ideality.

The composition of the diesel fuel assumed in the UNIFAC model

calculations is shown in Figure 2-11. The concentrations of the eight PAHs chosen

were comparable to those found in the diesel fuels used in this investigation; the

concentrations of monocyclic aromatic hydrocarbons used were based on analyses

reported by Thomas and Delfino (1991); and the mole fraction of water was selected

based on the maximum ASTM limiting requirement for diesel fuel (Kirk-Othmer,

1980). To simulate the alkane fraction of the diesel fuel, a representative compound

for each alkane (n-, iso-, and cyclo-alkane) was selected (see Figure 2-11) in

proportion to those reported by Mackay et al. (1985). The UNIFAC model

calculations for the yo* values of the PAHs ranged between 0.99 for toluene to 1.16

for fluoranthene. The close proximity of the calculated log Kdw values (solid triangles

in Figure 2-6) to the ideal line based on Raoult's law for the simulated diesel fuel

suggest that deviations from ideal behavior for PAHs smaller than fluoranthene may

be negligible. These calculations suggest that deviations from the ideal line for the

larger PAHs noted in Figure 2-1 cannot be attributed to solute-solute interactions,








54
lending support to analytical sources of error for the observed deviations.

Independently assessing the potential for nonideal behavior emphasizes the need to

account for experimental and analytical sources of errors when judging whether the

deviation noted from the ideal line is indeed the result of nonideal behavior.


Figure 2-11. log Kd, values for several aromatic hydrocarbons resulting from
UNIFAC model calculations plotted against log S, values along with
the ideal line based on Raoult's law.



Based on the success for gasoline and diesel fuel, an attempt was made to use

the UNIFAC model to assess the likelihood of nonideality for coal tar ID#4. Since

less than 40% of the composition of this coal tar was unknown (as usually is the

case), it was represented by a single compound indicated in Figure 2-12. The

UNIFAC model simulations suggested that nonidealities are indeed small, and that








55
Raoult's law approximation was justified (Figure 2-3). A note of caution is in order,

however, the UNIFAC model results depend heavily on the presumed composition

of the pitch (62% mole fraction in our example with coal tar ID#4), and on the

presence of polar constituents in coal tar (none were present in significant

quantities in this example).


-5 -4.5 -4
log [S, moles/L]


Figure 2-12. Comparison of measured and predicted tar-water partition coefficients
for several PAHs: Raoult's law (solid line) and UNIFAC model (solid
triangle).










Summary



Release of aromatic hydrocarbons from an immiscible organic liquid waste is

governed primarily by solubility phenomena. In assessing the likelihood of soil and

water contamination from complex organic wastes (e.g.,gasoline, diesel fuel, and coal

tar), it is incorrect to assume that PAH concentrations in groundwater would be

equal to the corresponding aqueous solubilities of the pure compounds. Such an

assumption usually leads to considerable over-predictions of the PAH concentrations

likely to be found in groundwater.

According to the model based on Raoult's law, the concentration of an

organic constituent in the aqueous phase in equilibrium with an "ideal" organic

mixture is proportional to the mole fraction of that constituent in the organic phase.

An experimental evaluation of a model based on ideal behavior was presented for

the partitioning of aromatic hydrocarbons from diesel fuel and coal tar into water,

and the results compared to data reported earlier for gasoline/water and motor

oil/water partitioning. The diesel fuel/water and tar/water partitioning of several

PAHs, all solids in their standard state, was well described within a factor of four for

diesel fuels, and within a factor of two for coal tars by employing supercooled liquid

solubilities and assuming ideal behavior. Good agreement between the observed

partitioning of several PAHs and UNIFAC model calculations for a simulated

gasoline, diesel fuel, and coal tar further suggests that the extent of deviations from

ideal behavior may be relatively small.

Agreement between the model predictions based on Raoult's law and
measured liquid-liquid partitioning data for several aromatic hydrocarbons is not to

be taken as evidence that such compositionally-complex organic liquid wastes are








57
indeed ideal mixtures. Rather, the assumption of ideal behavior might suffice for

practical considerations in providing first-order estimates for maximum PAH

concentrations likely to be found in groundwater leaving an area contaminated with

residual OILs. Several site-specific hydrogeologic factors might lead to significant

mass transfer constraints for solute partitioning. Such factors include: random

spatial variability in aquifer hydraulic properties, the patterns of residual fuel

entrapment, and the source of fuel contamination (e.g.,surface spill versus subsurface

leaks). Under nonequilibrium mass transfer conditions, the concentrations of organic

constituents detected in groundwater are likely to be smaller than those estimated

using the equilibrium approach presented here. In contrast, larger concentrations

might be observed in the presence of surfactants, emulsifiers, or cosolvents.














CHAPTER 3
COSOLVENT EFFECTS ON SORPTION OF ORGANIC ACIDS
BY SOILS FROM METHANOL/WATER SOLUTIONS


Introduction

The codisposal of contaminants, as well as the potential use of alternative

fuels and mixing of contaminant plumes from different sources, will result in

environmental contamination problems consisting of a complex mixture of chemicals

including both polar and nonpolar organic in miscible and immiscible solvent

mixtures. Solubility, sorption, and transport of hydrophobic organic compounds

(HOCs) are well characterized in aqueous solutions and various complex mixtures.

Solubility of HOCs increases with increasing volume fraction cosolvent of an organic

cosolvent (Yalkowsky and Roseman, 1981; Yalkowsky, 1985; 1987; Rubino and

Yalkowsky, 1987a; 1987b; Fu and Luthy, 1986; Pinal et al., 1990; 1991). Sorption of

HOCs is inversely related to solubility and as a result, an increase in solubility from

the addition of a cosolvent leads to a proportional decrease in sorption (Rao et al.,

1985; 1990; Nkedi-Kizza et al., 1985; 1987; Rao and Lee, 1988; Woodburn et al.,

1986; Fu and Luthy, 1986).

For hydrophobic ionizable compounds (HIOCs) of environmental interest,

data on solubility, sorption, and transport in mixed solvents are limited. Some

research investigating the impact of multiple solutes on HIOC sorption (i.e.,








59
competitive sorption) by soils from aqueous solutions has been documented (Felice

et al., 1985; Zachara et al., 1987; Rao and Lee, 1987); however, little attention has

been given to the behavior of HIOCs in solvent mixtures.

Pharmaceutical literature contains solubility data for several drugs spanning

a wide polarity range. As shown in Figure 3-1, Yalkowsky and Roseman (1981)

observed that as solute polarity increases relative to the solvent, cosolvency curves

become increasingly more parabolic in shape until an inverse relationship occurs (i.e.,

decreased solubility with cosolvent additions). Such behavior is explained on the

basis of the solute-solute and solute-cosolvent interactions. Therefore, for

compounds that exhibit a decrease in solubility with addition of a cosolvent (log Ko,

< 1), sorption may increase with increasing cosolvent composition.

For the sorption of naphthol, quinoline, and dichloroaniline by three different

soils from methanol/water and acetone/water solutions up to 50% by volume, Fu

and Luthy (1986b) observed log-linear behavior inversely proportional to

corresponding solubility data (Fu and Luthy, 1986a) as observed with HOCs. Similar

behavior was observed by Zachara et al. (1986) for quinoline sorption by a natural

clay isolate and montmorillonite in binary mixtures of methanol or acetone and water

regardless if the protonated or neutral species predominated in solution. For these

HIOCs it appears that the cosolvent effect on sorption is dominated by solvation

forces (i.e., solubility) similar to that observed with HOCs even though sorption

mechanisms for HIOCs and HOCs are different (electrostatic and ion exchange

versus hydrophobic partitioning).


1








60

log KOW


5.0 2.0 1.5 0.0 -1.0



_o




Volume Fraction Cosolvent, f





Figure 3-1. Schematic representation of cosolvency plots for solutes with a range
of log Kow values.



For an acidic fluorescent dye (Rhodamine WT) in binary mixtures of

methanol/water and acetone/water at cosolvent fractions above 30%, sorption was

observed to increase even though at lower cosolvent fractions (< 30%) sorption

appeared to follow an inverse log-linear relationship (Soerens and Sabatini, 1992).

Previous use of Rhodamine WT as a surface and groundwater tracer prompted an

investigation on the potential use of this dye as a tracer in alternative fuel research

(i.e.,alcohol-based fuels). In soil thin-layer chromatography (TLC) studies (Hassett

et al., 1981), the herbicide dicamba (3,6-dichloro-2-methoxybenzoic acid) moved with

the solvent front in both aqueous and 50/50 (v/v) ethanol/water solutions, but was

strongly retained by soil with neat ethanol as the mobile phase.








61
For analysis of various carboxylic acids and substituted phenols by reversed-

phase chromatography using an acidified mobile phase (i.e., when neutral species

dominate), retention is inversely proportional to cosolvent content as observed for

HOCs. Lewis and Wilson (1984) observed similar behavior for several carboxylic

acids in non-acidified methanol/water solutions (0 to 80%) using reversed-phase TLC

plates impregnated with an ion-pairing agent tetra-n-butylammonium bromide (TBA).

However, in the absence of an acidified mobile phase or an ion-pairing reagent,

cosolvent effects were minor. These data suggest that the retention behavior of

organic acids by a hydrophobic surface is similar to HOCs only when the charge is

compensated (e.g., neutral by protonation or paired with a counterion).

In considering the impact of cosolvents on sorption, the following interactions

must be considered: solute-solute; solvent-solvent; solvent-solute, solvent-sorbent,

and solute-solvent-sorbent interactions. The first three pairs of interactions can be

assessed from solubility studies. For HOCs, solute-solute interactions are ignored

due to the absence of both specific functional groups and high solute concentrations.

For most miscible solvents (e.g., alcohols), irregular behavior due to specific

complexation of solvent and water molecules doesn't appear to be of concern. For

sorption of HOCs, solvent-solute interactions, as described by solubility, are found

to predominate such that the impact of solvent-sorbent interactions have been

considered minor. However, for solutes containing specific functional groups, the

impact of the cosolvent on the sorbent may have considerable impact.








62
For HIOCs, the impact of adding a cosolvent to aqueous solutions on the

conditional ionization constant of a HIOC must be considered. Likewise, similar

impacts on the ionization of sorbent functional groups and subsequent solute-sorbent

interactions must also be considered. Also, the impact of solvent-water interactions

that were considered negligible in predicting HOC behavior may be of importance

in understanding the chemodynamic behavior of HIOCs, as well as the different

propensities of the cosolvent and water to hydrate both the solute and the sorbent.

Cosolvent-induced interactions involving the sorbent surface include:

speciation of organic matter functional groups, clay surface acidity, and ion-

association with the surface. Both acidic and basic groups tend to become neutral

with increasing cosolvent content as a result of shifts in the pKa' (Perrin et al., 1981),

leading to a net increase in hydrophobicity of soil organic matter. This phenomenon

may explain why decreases in HOC sorption with increasing f, are smaller in

magnitude than would be predicted from solubility profiles in mixed solvents (Rao

et al., 1990; Nkedi-Kizza et al., 1985; 1987; Rao and Lee, 1988). Parallel to changes

in pK,', Kan and Tomson (1990) observed a decrease in naphthalene sorption by

Lincoln fine sand from aqueous solutions by increasing pH (pK, fixed, but pH

varied). However, the increase in sorption resulting from such changes on surface

hydrophobicity are likely to be more than compensated by cosolvency effects.

The presence of cosolvents may also alter the surface acidity of the clay

fraction. Loeppert et al. (1977, 1979) found that the amount of base required to

titrate the pH-dependent sites of kaolinite varied in the following manner: methanol








63
< water < DMSO < acetonitrile. The fact that larger titers in DMSO and

acetonitrile were required was attributed to (1) pH-dependent sites for which a

quantitative endpoint was not obtained in aqueous media due to the acidic properties

of water, and (2) increased surface acidity in organic solvents. Loeppert et al. (1986)

also observed an increase acidity of montmorillonite in acetonitrile and

dimethylformamide. No apparent changes were observed in surface acidity with neat

methanol (Loeppert et al., 1979). Similar conclusions were made by Hesleitner et

al. (1991), who noted that addition of methanol (f <5 0.5) caused no apparent change

in the surface charge density of a hematite surface (iron oxide) or in the point of

zero charge which coincided with the isoelectric point.

Cosolvent-enhanced formation of ion-pairs with positive charges on the

sorbent surface may cause an increase in sorption of organic acids with addition of

an organic cosolvent even if solubility increases. As previously mentioned, Hesleitner

et al. (1991) observed no changes in the total surface charge of hematite in the f,

range investigated (f, < 0.5), but noted a pronounced decrease in electrokinetic

potentials with increasing methanol fractions (i.e., effective surface charge was

lowered). They attributed the decrease in electrokinetic permittivity to an

enhancement of counterion association with the surface charged groups. This

counterion association could include both the formation of outer-sphere complexes

by bridging of the carbonyl to the solvent (water and/or cosolvent) coordinated on

the exchange cation (Farmer and Russell, 1967) and inner-sphere complexation by

hydrogen bonding of the carbonyl group with protonated hydroxyls on the surface








64
(Kohl and Taylor, 1961; Stumm et al., 1980). These mechanisms have been included

among those proposed in the literature for sorption of organic acids in aqueous

solutions (Farmer and Russell, 1967; Kohl and Taylor, 1961; Stumm et al., 1980;

Davis, 1982; Kummert and Stumm, 1980); however, the impact of cosolvents on such

interactions has yet to be investigated.

In this chapter, the overall impact of methanol additions on (1) the

enhancement of solute-solvent interactions as described by solubility; and (2)

speciation changes due to cosolvent induced changes in the solute's pK,' will be

assessed for the sorption of several organic acids by soils. Subsequent chapters will

assess (1) speciation changes due to changing pH at several fixed methanol/water

compositions for benzoic acid and PCP sorption; (2) the overall impact of several

solvents with a wide range in solvent properties on the sorption of benzoic acid; and

(3) the relationship between solute properties, such as acidity and hydrophobicity, on

the shapes of the sorption curves observed in methanol/water solutions.



Theory

The following log-linear model successfully describes (Yalkowsky and

Roseman, 1981; Fu and Luthy,1986; Pinal et al., 1990; Rao et al., 1985; Nkedi-Kizza

et al., 1985, 1987; Rao and Lee, 1988; Woodburn et al., 1986) solubility and sorption

of HOCs in miscible solvent-water systems,


log Sb log S, + of, (3-1)








65

log(S,/Sw ) a (3-2)


log Kb log K, aof, (3-3)



where S is solubility (mg/L), K is sorption coefficient (mL/g) with subscripts b, c,

and w referring to binary mixtures, pure cosolvent, and water, respectively; f is

volume fraction cosolvent; a describes the cosolvency power of a solvent for a solute;

and a accounts for solvent-sorbent interactions.

Sorption of HIOCs is dependent on the formation of neutral and ionized

species, as determined by pH and the solute acid dissociation constant (pK,). For

many organic acids, the neutral species is sorbed more than its dissociated (anionic)

species, and the differences in the sorption coefficient values can be rather large.

Thus, the measured sorption coefficient for HIOCs is a strong function of pH and

conditional dissociation constants (pKa') of the solute in the solvent system of

interest. Lee et al. (1990) showed that the pH-dependence of pentachlorophenol

(PCP) sorption from aqueous solutions can be described by,


K Kw,nF + Kwi(1-#) (3-4)

where


c" (1 + 1O3-P')-1


(3-5)








66
and subscripts n and i refer to neutral and ionized species, respectively. Similar

findings for the sorption of several other organic acids by various sorbents have been

reported in the literature (Jafvert, 1990; Kukowski, 1989; Fontaine et al., 1991).

If solubility of a solute increases with addition of a cosolvent to an aqueous

solution (see Figure 3-1), a decrease in sorption is expected. Also, the addition of

a solvent with a low dielectric constant will result in an alkaline shift in the pK,' of

an organic acid (Perrin et al., 1981), leading to an increase in the fraction of neutral

species. In the absence of specific adsorption reactions, the neutral species will be

sorbed to a greater extent. Therefore, the addition of a cosolvent brings about two

opposing effects. To incorporate both speciation and cosolvent effects, Eq. (3-1) and

Eqs. (3-3, 3-4, and 3-5) were combined,


Kb KwA, n n + K,,(1-n) (3-6)

where


3, 10-l-"'" ; Pi 10-a,'a (3-7)

The cosolvency power for the neutral species (as) will increase relative to

hydrophobicity. The cosolvency power for the ionized species (ai) will be a function

of the relative hydrophobicity of the anion and the potential for ion-pairing. For

example, Lee et al. (1990) observed a log-linear decrease in sorption of PCP by

Webster soil in methanol/water (0.01 N CaC12) solutions (f,= 0 to 40%) for both the

neutral species (pH < 3) and ionized species (pH < 9) with resulting values for aiai and

ana, were 2.56 and 3.88, respectively. The decrease in sorption observed with








67

increasing f, for pentachlorophenolate was attributed to the relatively large

hydrophobicity of the anion and the formation of neutral ion-pairs.

Figure 3-2 illustrates the types of cosolvency curves for the sorption of organic

acids that might be predicted using Eq. (3-6). Using parameter set #3 results in the

presence of primarily the neutral species of the HIOC (pH-pK,' <-1) thus yielding

cosolvency curves similar to that observed for HOCs (Eq. 3-3). In the absence of

specific interactions, a reduction in solubility with increasing cosolvent content might

be expected for a solute existing as an anion in solution, thus potentially increasing

sorption (parameter set #6). Similar results are predicted using Eq. (3-6) for a

solute with relatively small hydrophobicity (a=l ) and assuming no impact of

cosolvency on the anionic species (ai=0) (parameter set #2 and #5). Note how the

magnitude of the increased sorption predicted by Eq. (3-6) is a function of the inter-

relationship between initial soil-solution pH (i.e.,pH-pK,,) and the a values. The

a values used in sets #1 and #3 are larger than those used for sets #2 and #5

changing the impact of pH variations. For sets #1 and #3, enhanced linearity and

an upward shift is observed with decreasing pH; whereas, for sets #2 and #5, the

shape of the sorption curve changes from a convex to a concave shape as pH

decreased. Therefore, the overall magnitude and direction of the sorption observed

will vary as a function of cosolvency power (a), soil-solution pH, and cosolvent

induced shifts in the observed pK,'.









-0.6-
K, = 0.1
a=a=1

-0.8 .--



-1 -1

0
-1.2



-1.4 --- 1
2

--- 34
7-77- 4
-1.6 .................. 5
-------- 6


0



Figure 3-2. Example


0.2 0.4 0.6 0.8 1

Volume Fraction Methanol

cosolvency curves that may be predicted by the use of various parameters in Eq. (3-6).








69
The success of Eq. (3-6) in describing sorption of organic acids is predicated

on the ability to measure (or define) the ionization constant (pK,') and pH in the

solutions of interest. Defining pK,' and pH is fairly straightforward for aqueous

systems; however, various complications must be considered for mixed solvent

systems. The pH of an aqueous solution is thermodynamically defined as the

negative logarithm of the hydrogen ion activity (aH+)


pH -log aR. -log H[H'] (3-8)


where YH+ and [H+] are the hydrogen activity coefficient and concentration,

respectively. Experimentally, an electrometric method is usually employed (e.g.,pH

meter) where the determination of pH is based on the measurement of the

electromotive forces (e.m.f.)of standard aqueous buffer solutions. Therefore, the pH

of an unknown solution (pHx) can be determined by


E-E
pH, pH, + x E (3-9)
(RT In 10/F)

or at T=298,


pH H pH, + E- E (3-10)
0.06

where Ex and E, are the e.m.f. values of the solutions, R and F are the gas and

Faraday's constants, respectively, and T is absolute temperature. Not shown in Eq.

(3-9) are the potentials that arise from the liquid junction and the standard potential

of the glass electrode. The difference in these potentials between the standard and








70
unknown solutions are assumed to be the same when the solution matrix is similar,

thus cancelling out in the (E,-E) term.

Likewise, in mixed solvents (denoted by *), pH is thermodynamically defined

as


pH* -log y.t[H] (3-11)



If standard mixed solvent buffers are employed, pH can be operationally defined as

follows:



pH* pH + E -E (3-12)
0.06


It is usually expedient to employ readily available standard aqueous buffers in which

case Eq. (3-12) must be modified to estimate the pH of a solution in mixed solvents,



pH pH Es (3-13)
0.06


where pHaPP is the measured pH of a mixed solvent solution relative to a standard

aqueous buffer solution. The differences in the liquid junction potential and the

standard potential of the glass electrode between mixed solvents and aqueous

solutions cannot be assumed to be the same and must be considered. However,

Gelsema et al. (1967) have shown that differences in the standard potentials of the

glass electrodes between mixed solvents and aqueous solutions are negligible. The








71
operational definition of pH for a mixed solvent solution (pHx*) referenced to an

aqueous standard can then be written as


pH E, E, E-E (3-14)
pH. pH, + -1
0.06 0.06


Therefore, differences in the apparent pH and the actual pH arise from the

difference in the liquid junction potentials:


8 pHxa pH* jE'- (3-15)
0.06


Van Uitert and Haas (1953) achieved a practical standardization of pH

measurements in dioxane-water solutions by measuring the pH of a series of HCI

solutions of known concentration in the mixed solvents. The difference between the

measured pH and the known hydrogen concentration was assumed to be a

reasonable estimate for 6. This approach yields estimates for 6 that encompass all

differences (i.e.,liquid junction potential, standard potential, activity, solvent medium

effects) observed between a measurement in aqueous versus solvent/water solutions

irrespective of the source. The magnitude of 6 increases with increasing amounts of

an organic solvent. For methanol/water solutions at fc<0.8, 6 values are relatively

small, but 6 values may become greater than 2 as the neat organic solvent is

approached (Van Uitert and Haas, 1953; De Ligny and Rehbach, 1960). Although

there are obvious shortcomings to this simplified approach, it appears adequate in

many cases for estimating pH in several mixed solvent solutions.












Materials and Methods

Sorbents

The primary sorbents used in this study were Eustis fine sand (Psammentic

Paleudult) from Florida containing 96.4%, 1.8%, 1.8%,and 0.39% sand, silt, clay, and

organic carbon (OC), respectively; and Webster silty clay loam (Typic Haplaquoll)

from Iowa (5 miles north and 3 miles east of Ames) containing 30.7%,42.8%, 27%,

3.0% sand, silt, clay (predominately montmorillonite), and OC, respectively. Specific

surface measurements by N2-BET of approximately 4 m2/g was obtained for a similar

Webster soil subsample used in previous studies (Rao et al., 1988). Both the Eustis

and Webster soils were collected from the surface horizon (0-30 cm). The soil OC

contents were determined using the Walkley-Black method (Nelson and Sommers,

1982). The soil-solution pH in 0.01 N CaC12 was 5.0 and 6.9 for Eustis and Webster

soils, respectively. Soils were air-dried and passed through a 2 mm sieve prior to use.

Chemicals

The organic acids used in this study are listed in Table 3-1 along with selected

physical and chemical properties. All crystalline compounds had a chemical purity

of >98%. All solvents were purchased from J.T. Baker (high purity, HPLC grade)

and used without further preparation. For sorption experiments with

pentachlorophenol (PCP), 14C uniformly ring-labeled compound was purchased from

Sigma Chemical Co. with a specific activity of 12 mCi/mmol and a reported

radiochemical purity of >98%.







Table 3-1. Selected Solute Properties


Aqueous
Melting Molecular pK, Solubility' Log
Solute Point' (oC) Weight' Aqueous Methanol2 (mg/L) Kow

Pentachlorophenol 190 266.3 4.744 8.6 14 5.01
2,4-Dichlorophenol 42 163.0 7.854 11.9 4,500 3.23
Picric Acid (2,4,6-trinitrophenol) 121 229.1 0.419' 4.1 14,000 2.03
Gentisic Acid 205 154.1 2.97' 7.6 21,5002 NA9
(2,5-dihydroxybenzoic acid)
2,4,5-trichlorophenoxy acetic acid 156 255.5 2.85 7.4 278 NA
2,4-dichlorophenoxy acetic acid 138 221.0 2.64' 7.6 890 NA
Benzoic Acid 122 122.1 4.201 9.0 2,900 1.87
Pentafluorobenzoic acid 101 212.1 1.496 5.8 NA NA
Dicamba (3,6-dichloro-o-anisic acid) 115 221.9 1.947 6.9 7,900 2.468


'From Dean (1985); 2 This study; 3 From Verschueren (1983); 4 From Callahan et al.(1979); S Koskinen and O'Connor
(1979); 6 From Walters (1982); From Kearney and Kaufman (1976); a EPA Environmental Fate One-Line Data Base,
Version 3.04; 9 Not available.










Determination of Ionization Constants

The conditional ionization constants (pKa') for benzoic acid, gentisic acid, 2,4-

dichlorophenoxyacetic acid, PCP, 2,4-dichlorophenol, and dicamba were determined

in methanol/water solutions by measuring pH as a function of NaOH additions

(Albert and Sergeant, 1984). Solvent mixtures were prepared with 0 to 100%

methanol and degassed prior to use. For all solutes except for PCP and dicamba,

0.01 M solutions were titrated with 0.1 M NaOH. For PCP and dicamba, 0.001 M

solutions were titrated with 0.01 M NaOH. A Metrohm 686 Titroprocessor,

employing a combined pH glass electrode (6.0202.100)and a resistance thermometer

(6.1103.000), continuously measured pH and temperature, respectively. The pH

meter was calibrated using aqueous buffers. The temperature of the solutions was

24 0.5 C. Titrations were performed in duplicate in 50 mL beakers placed on a

stirring plate to mix the solutions. The ionization constants determined in this study

are mixed ionization constants (Albert and Sergeant, 1987) rather than true

thermodynamic ionization constants. A brief discussion on the difference between

the various ionization constants are given in Appendix B along with sample sets of

titration data from this study and corresponding calculations.

In calculating pK.' values, adjustments for the impact of methanol on pH

measurements were made using a method similar to that employed by Van Uitert

and Haas (1953) as described above for the measurement of pH in mixed solvents.

This method consisted of measuring the pH of 0.001 M hydrochloric acid in the

mixed solvent. The difference (6) between the pH measured in water and in the








75
mixed solvent was added to the pKa estimated from the titration curve (i.e.,

pK,'=pK. + 6). From 0 to 70% methanol, 6 values were negligible. At higher

methanol fractions, 6 values were approximately 0.1,0.4, and 2.3 for f,values of 0.8,

0.9 and 1.0, respectively. Similar results were obtained by De Ligny and Rehbach

(1960) for methanol/water solutions by comparing pH measured in aqueous standard

buffers (KC1 saturated solutions) and standard buffers prepared in the appropriate

mixed solvent using the method proposed by the National Bureau of Standards

(Bates et al., 1963). Therefore, the corrections needed to adjust the pK, determined

in mixed solvents relative to the use of aqueous standard buffers are only significant

at f,>0.9.

pH of Soil Suspensions in Mixed Solvents

When considering the measurement of pH in mixed solvent soil-suspensions,

problems in addition to those previously discussed for pH measurements in mixed

solvents arise. It has long been recognized that the ambiguity of measuring the pH

in aqueous soil solutions, and even more so in soil suspensions, is due to the inability

to accurately determine liquid junction potential differences between standard buffer

solutions (Ej,) and soil-solutions (Ej,x). Even with this ambiguity, the error in the

measured pH resulting from differences in the liquid junction potentials (EFj, E,,

is usually assumed to be within 0.2 pH units for an aqueous soil-solution or dilute

soil-suspension given a background electrolyte concentration of approximately 0.01

N (Sposito, 1989).

In these studies, pH of the supernatant and/or the resuspended soil sample








76
were measured using a Coming Model 130 pH meter and a Fisher Scientific or

Orion combination micro-electrode (AgCl saturated 3 M KC1 filling solution)

following equilibration and analysis of the sample. For suspensions of Webster silty

clay loam in methanol/water solutions with a background electrolyte of 0.01N CaCl2,

changes in the measured pH (pH"xPP) of less than 0.5 pH units were observed going

from aqueous to methanol solutions. Recall that a change (6) of over 2 pH units

were previously noted for solutions going from aqueous to methanol solutions. This

prompts questions regarding (1) the interactions between the liquid junction

potentials arising from the solvent and soil medium; and (2) the effect of methanol

on the activity of hydronium ions on the soil surface. Given the difficulty of

answering such questions at this time, pH/,"P will be used in combination with pK,'

to estimate solute speciation.

Solubility Experiments

Experimental techniques described by Pinal et al. (1990) were employed to

measure benzoic acid solubility in methanol/water solutions that were either acidified

with 0.01 M HC1 or made basic with 0.3 N NaOH. These data were compared to

solubilities obtained by Yalkowsky (1985) without additions of an acid or a base.

Solute concentrations were analyzed using reversed-phase liquid chromatography

(RPLC) techniques. The RPLC system consisted of a ternary solvent pump (LDC

Milton Roy Model CM4000, Eldex Model 9600, or Gilson Model 302), a Waters

Radial Compression Column with a C-18 cartridge, a UV detector (Gilson Model

115 or Waters Model 490), and a Waters Intelligent Sample Processor (Model 710B

or 715). The composition of the mobile phase (acetonitrile/methanol/water; pH2








77
w/HCl) and the UV wavelength were optimized for analysis of each solute. When

necessary, samples were diluted to within an optimal concentration range of the

specific analytical method.

Miscible Displacement Experiments

Miscible displacement techniques described by Brusseau et al. (1990) and Lee

et al. (1991), were used to estimate retardation factors with water and neat methanol

as the eluent for the solutes listed in Table 3-1. The column was packed with air-

dried Eustis soil and 0.01 N CaCl2 solution was pumped through the column until

steady-state, water-saturated conditions were established. All solutions were filtered

(0.45 pm) and degassed with helium before use. The physical properties of the

Eustis soil column were as follows: 5 cm length, 0.4 mL/cm3 volumetric water

content (0), 1.69g/cm3 bulk density (p), and a column pore volume of 9.64 mL. A

pore-water velocity (v) of about 90 cm/hr was used for all experiments.

Solute concentrations in the influent solutions were approximately 100 pg/mL,

except for PCP which was 3 4g/mL. Solute concentrations in the column effluent

were monitored continuously as described by Brusseau et al. (1990) using a flow-

through, variable-wavelength UV detector (Gilson Holochrome, Waters 450 or LDC

UV) connected to a linear chart recorder (Fisher Recordall 5000). Retardation

factors (R) were obtained by calculating the area above the measured breakthrough

curves (Nkedi-Kizza et al., 1987). Periodic measurements were made of the column

effluent pH with a combination glass electrode using a Coming 130 pH meter or a

Brinkman 686 unit.










Equilibrium Sorption Isotherms

Equilibrium sorption isotherms were measured using the batch-equilibration

method (Rao et al., 1990). The vials used for this study were 5 mL (1 dram) screw

cap borosilicate glass autosampler vials with teflon-lined septa inserts. Amber vials

were employed to minimize photolysis. Soil mass to solution volume ratios ranged

from 1:2 to 2:3 to achieve sorption of 50% ( 20%) of the chemical added. All

solutions used had a 0.01 N CaC1, matrix unless noted otherwise. Initial solution

concentrations added to the soils ranged from 5 to 45 jig/mL for all solutes with the

exception of PCP. A concentration range of 0.25 to 3 gg/mL was used in the PCP

equilibration studies. All sorption isotherms were measured at room temperature

(T=22-25" C). Following equilibration, the solution and solid phases were separated

by centrifuging the soil samples at approximately 300 RCF (relative centrifugal force)

using a Sorvall RT6000 centrifuge.

Each isotherm consisted of sorption measured in duplicate at four or more

concentrations and at least 30% of the isotherms were replicated. Also for each

isotherm, blanks containing the solvent with and without soil were run to check for

coelution of any peaks from the soil. Samples were usually equilibrated by rotating

for 16-24 hours. For f. <0.2,degradation was noted after 4 hours in control studies

where the soil-solution matrix was removed from the soil and spiked with the

appropriate solute concentrations. Therefore, equilibration of samples in solutions

of f,<0.2was reduced to a maximum of 2 hours with no differences observed in

sorption coefficients measured after 1 and 2 hours.








79

Nonradiolabeled samples were analyzed by RPLC techniques as described

previously for the solubility studies. The use of autosampler vials in conjunction with

the Waters Intelligent Sample Processor (WISP 715) enabled direct analysis of the

samples by RPLC techniques without further sample transfer. The WISP 715 has the

capability of varying sampling depths within a vial allowing sampling of the

supernatant without removal of the soil. The higher mass to volume ratios (2:3),

however, necessitated transfer of the supernatant to a new vial. For 4C-labeled

solutes, 0.5 mL aliquots of the supernatant were taken from each sample and mixed

with 20 mL of Scinti-Verse II for analysis. Solute concentrations were then assayed

using liquid scintillation counting (LSC) methods employing a Searle Delta 300 liquid

scintillation counter.

Sorption coefficients, K (mL/g), were estimated by fitting the sorption data

to a linear isotherm: S. = K Ce, where Se and C. are sorbed (mg/g) and solution

(Ag/mL) concentrations, respectively, at equilibrium. The solution concentrations

were directly determined, whereas S. values were determined by difference: S. =

(Ci C)(V/M), where Ci is the initial solution concentration (Ajg/mL) of the solute;

V is the solution volume (mL); and M is the soil mass (g).


Results
pK Measurements

The pK,' values measured as a function of volume fraction (fQ) methanol

increased linearly up to approximately f,=0.6,and then increased markedly at higher

cosolvent contents. Representative data for benzoic acid and pentachlorophenol








80
(PCP) are presented in Figure 3-3. Similar results were observed for the other

compounds. For organic bases, a decrease in pK,' (an acid shift) occurs upon

addition of a cosolvent (shift towards neutral species); however, the overall shift from

aqueous to neat solvents is usually much less than a single pH unit. Also shown in

Figure 3-3 are pK,' values for benzoic acid determined conductometrically by Pal et

al. (1983) up to 80% methanol, and the pK,' value reported by Bacarella et al. (1955)

in neat methanol using a different type of potentiometric method with an electrode

system void of a liquid junction. Good agreement between our data and the

published data suggests that the procedure used in this study was adequate. The

lower pKa' value obtained in this study for benzoic acid in neat methanol is most

likely due to the use of hydrated methanol (0.05%); residual water was removed from

the methanol used in the cited studies. Also the constants determined in this study

are mixed ionization constants, whereas thermodynamic ionization constants were

reported by Bacarella et al. (1955).

Solubility

Solubility data reported by Yalkowsky (1985) for benzoic acid in

methanol/water solutions are shown in Figure 3-4. Solubility increased with

increasing volume fraction methanol. For the solubility of an organic acid in an

unbuffered solution, the pH at saturation will be less than the solute pKa. For

example, the pH of an aqueous solution saturated with benzoic acid is approximately

2.8 (Bates, 1973). Thus, the neutral species dominates over the solubility profile,

with over 90% existing in the neutral form at f_>0.3. Also shown in Figure 3-4 are








81
the solubilities of benzoic acid in acidified methanol/water solutions (0.01 M HC1)

measured in this study. At saturation, the acidified samples remained near a pH of

2. Minimal differences were observed between the solubility of benzoic acid in

acidified and nonacidified methanol/water solutions. Solubility curves were not

measured for other solutes in this study, but benzoic acid is believed to be

representative of the general behavior of carboxylic acids in methanol/water

solutions. For example, the solubility reported for dicamba in ethanol is over a 100

times greater than its aqueous solubility (Humberg et al., 1989). The observed

solubility of benzoic acid in methanol/water solutions is similar to the curve shown

in Figure 3-1 for a log Ko of 2.

To further investigate the effect of speciation on solubility, benzoic acid

solubility in solutions containing approximately 0.3 M NaOH was measured for 0 to

40% volume fraction methanol. In the presence of a base, the solubility of benzoic

acid was greater than that observed in the unbuffered or acidified solutions. At the

solubility limits, the saturated solution pH was 5.0. Given the pK,' and measured pH

(pH"P), speciation of benzoic acid in saturated solutions was estimated to range from

approximately 90% to 60% ionized going from aqueous solutions to f,=0.4. The

increase observed in solubility with increasing f, parallels the increase in the neutral

species suggesting that cosolvent effects on benzoate solubility are negligible in the

range investigated (i.e., aari = 0).


1









---e--* Benzoic Acid (This study)
Benzoic Acid (Pal et al., 1983)
A Benzoic Acid (Bacarella et al., 1955)
...... Pentachlorophenol




........... .......'

.......................-- -'
.----


) 0.2 0.4 0.6 0.8
Volume Fraction Methanol, fo
a


Figure 3-3.






6-


Effect of methanol
pentachlorophenol.


content on the pKa' of benzoic acid and


5.5 k


3.5#


0.2
Volume


Benzoic Acid (0.01 M HCI)
A Benzoic Acid (Yalkowsky, 1985)
O Benzoic Acid (0.3 M NaOH)

0.4 0.6 0.8
Fraction Cosolvent, fo
C


Solubility (Sb) of benzoic acid in methanol/water solutions.


-2
CL


Figure 3-4.










Miscible Displacement Studies

The retardation factors (R) estimated from the miscible displacement studies

with Eustis soil column are shown in Table 3-2. The column effluent pH ranged

between approximately 4 and 4.8 for the different solute/solvent combinations.

Comparisons of influent pulse sizes with zero-th moments showed greater than 97%

mass recovery for all solute pulses. Loss of soil organic matter from the soil column

during elution with methanol was considered negligible as shown previously by Lee

et al. (1991). For the substituted phenols, R values determined in methanol were

smaller than those water (f,=0). For both chlorophenols in neat methanol,

retardation factors decreased to one corresponding to no sorption (R= 1). A decrease

in R with increasing f is expected from the log-linear cosolvency model in the

absence of any specific interactions. The opposite trend, however, was observed for

all of the substituted benzoic acids. Benzoic acid and dicamba were chosen for

further investigation in several methanol/water solutions using batch techniques with

PCP included as a control. For the batch studies, Webster soil with a higher organic

carbon content was used to better differentiate sorption in the various

methanol/water solutions. Although the greatest increase in retardation was

observed with gentisic acid, preliminary batch isotherm data exhibited extreme

nonlinearity (data not shown). Since problems associated with isotherm nonlinearity

may confound assessment of the proposed model, further investigation of gentisic

acid was not pursued.











Table 3-2. Retardation factors for several organic acids in aqueous and methanol
solutions from Eustis Soil.


Retardation Factors

Solute Aqueous Methanol


Substituted Phenols

Pentachlorophenol 4.7 1.0

2,4-Dichlorophenol 3.6 1.0

Picric Acid 1.9 1.4
(2,4,6-trinitrophenol)




Substituted Benzoic Acids


Gentisic Acid 1.9 3.1
(2,5-dihydroxy acetic acid)

2,4,5 Trichlorophenoxy Acetic Acid 1.7 2.1

2,4-Dichlorophenoxy Acetic Acid 1.4 2.7

Benzoic Acid 1.2 2.2

Pentafluorobenzoic Acid 1.0 1.6

Dicamba 1.0 2.0










Batch Equilibration Studies

Sorption of benzoic acid, dicamba, and PCP by Webster soil was measured

from several methanol/water solutions. Representative isotherms are shown in

Figure 3-5. Sorption isotherms were linear for PCP and dicamba in both aqueous

and mixed-solvent systems over the concentration range investigated. Sorption

isotherms for benzoic acid were slightly nonlinear, but a linear approximation of the

sorption coefficients (K) adequately described the data. The correlation coefficients

(r2) ranged between 0.95 and 1.0.

Effect of Solvent Addition

As noted previously, addition of an organic cosolvent to an aqueous solution

results in an increase in the pKa' for organic acids. Changes in speciation become

significant at fe >0.5 as marked changes occur in the pK,' values. In neat methanol,

the measured soil-solution pH for Webster soil ranged between 6.2 and 6.5;

therefore, essentially all the benzoic acid and PCP existed in the neutral form, while

20% to 30% of dicamba remained ionized.

The sorption coefficients estimated from batch equilibration studies of PCP

and benzoic acid are plotted in Figure 3-6 as a function of volume fraction methanol

(fo). Sorption of PCP in methanol/water systems was well described by the log-linear

model with speciation given by Eq. (3-6) (Figure 3-6A) except in neat methanol. Of

the required model parameters, bulk pH and pK, 'were measured; pn was estimated

using Eq. (3-5); and K,,K,, ,,a,, and a.on were taken from Lee et al. (1990) where

sorption of PCP was measured as a function of f, while pH was maintained such that








86
PCP was either completely ionized or completely neutral. The values for KE,i and

Kw,n were adjusted for differences in the OC content of the Webster soil used in the

two studies (i.e., K=Ko OC).

Benzoic acid sorption decreased with the addition of methanol up to fc0.2,

but then increased with f, thereafter (Figure 3-6B). Eq. (3-6) was applied to the

benzoic acid data using four reasonable parameter sets to investigate if this behavior

was mostly due to changes in speciation with methanol additions. For all cases, the

sorption coefficient for benzoate (K,,i) was measured at pH = 6.9; K,, was

estimated by measuring the K, at pH = 3.0 and applying Eq. (3-4); and ao was

estimated by regressing benzoic acid solubility data in methanol/water solutions (data

in f,=0 to 0.8; Yalkowsky, 1985). Two values for ai were used. In one case, ai was

set equal to zero as suggested by the solubility data (Figure 3-4), and in the second

case, ai was set equal to 0.65 as estimated from the initial portion of the log K.

versus f, curve (i.e., fe 0.2) where benzoic acid remained 2 99% ionized. For two

parameter sets, solvent-sorbent interactions were ignored (a,=ai=l) while in the

remaining two parameter sets an average a value of 0.5 observed by Fu and Luthy

(1986b) for several solute, soil, and solvent combinations was used as an initial

estimate of solvent-sorbent interactions. In all cases, Eq. (3-6) failed to adequately

predict the magnitude of sorption observed for benzoic acid at higher methanol

contents (Figure 3-6B). Similar sorption data were observed for dicamba (data not

shown). Model parameters were estimated for the dicamba sorption data in a

manner analogous to the calculations for benzoic acid with similar results.




Full Text
116
Freundlich fits. The results from this wide range of sorbents are similar to that
observed for both Webster and Eustis soils; the addition of methanol enhanced
sorption. The greater sorption by the muck suggests that sorption in the organic
matter domain still might be of greatest importance, eventhough hydrophobic
interactions alone were not sufficient to describe the sorption of benzoic acid by
Webster soil.
Organic matter, especially the muck soil, also has a considerable amount of
CEC sites. Given that these studies were conducted in 0.01 N CaCl2, most of the
exchange sites were occupied by Ca+2. From the previous experiment, the Ca+2-
saturated system resulted in enhanced sorption of benzoic acid upon methanol
addition, whereas the K+-saturated system did not. If we assume that methanol
enhanced sorption in the presence of CaCl2 is due to the solution-phase formation
and exchange of positively charged ion-pairs, then sorption by SAz-1 would have
been expected to be much greater than that observed (i.e.,muck and SAz-1 have
similar CEC). This apparent contradiction is similar to that implied in Chapter 3
when comparing the inferences from the results of increasing CaCl2 concentrations
versus the differences observed between Ca+2- and K+-saturated Webster soil.
Likewise, these data further suggests the presence of another mechanism that is
impacted by cation-type, but not necessarily the formation and exchange of positively-
charged ion-pairs.


ug/g
CD
Figure 5-2.
Ce> ug/mL
Representative isotherms for (A) anthroic acid; (B) 2-chlorobenzoic acid; (C) 2,4-dichlorobenzoic acid;
and (D) 2,4,6-trichlorobenzoic acid in various methanol/water solutions.
u>
IsJ


24
components in the aqueous phase is ignored, i.e.,yw* is set equal to the aqueous
phase activity coefficient of the solute in equilibrium with the pure solute (yw); (2)
the solute behaves ideally in the organic phase, i.e.,y0* is unity; (3) the aqueous mole
fraction solubility (SX J of the pure liquid solute is equal to 1/yw; and (4) the
solution is sufficiently dilute (i.e., moles of the solute are small relative to the total
moles of solvent; C = xl V and S/ Vw = Sx w where S¡ is the aqueous solubility of the
pure liquid solute in moles/L) and Vw is the molar volume of water. Application of
these four assumptions yields
Cw S, (2-3)
Therefore, the partition coefficient (Eq. 2-1) for a solute can be approximated
as follows,
K -% (2-3)
For mixtures comprising a large number of constituents, each contributing a
small fraction to the total, xjCG can be replaced by the molar volume (V0, L/mole)
of the organic phase. The molar volume can then be approximated by the ratio of
the average molecular weight (MW0, g/mole) and density (pD, g/L). The resulting
expression for Kd is:
r 1 (P JMW)
r.*, s>
(2-5)


log K
Figure 3-2. Example cosolvency curves that may be predicted by the use of various parameters in Eq. (3-6).
ON
oo


93
distribution of cations on the soil surface and in the diffuse double layer gives rise
to the potential of an effective pH (e.g.,pH at the soil surface) much lower than that
measured in the bulk solution. In measuring the distribution of various dyes between
an immiscible organic liquid and an aqueous solution (liquid-liquid equilibria), a
similar decrease in pH at the liquid-liquid interface was noted for amine-type dyes
(Peters, 1931). However, dyes containing long chain carboxylic acid groups resulted
in a pH at the liquid-liquid interface much greater than the pH measured in the
aqueous solution (~2 pH units) (Peters, 1931). An alkaline shift in the sorption
versus pH curve observed for the sorption of 2,4-dichlorophenoxy acetic acid by soils
(Nicholls and Evans, 1991) also implies an effective pH at the surface less than that
measured in the bulk. Lee et al. (1990) found that the sorption of PCP from
aqueous solutions by soils could be adequately described by using the measured soil-
solution pH and the solute pKa to estimate solute speciation. Similar success was
shown in Chapter 1 for the sorption of several organic acids by soil (Figure 1-2 and
1-3). The apparent contradiction between measured pH and effective pH for the
different solutes suggests that either a misinterpretation of the macroscopic response
observed or that the probing solute locally alters the surface pH upon interaction.
Summary
Sorption of substituted chlorophenols and carboxylic acids by soils was
measured from methanol-water solutions. Decreased sorption in methanol compared
to that measured in aqueous solutions was observed for the substituted phenols
investigated; this trend is similar to that observed for nonpolar organic solutes.


78
Equilibrium Sorption Isotherms
Equilibrium sorption isotherms were measured using the batch-equilibration
method (Rao et al., 1990). The vials used for this study were 5 mL (1 dram) screw
cap borosilicate glass autosampler vials with teflon-lined septa inserts. Amber vials
were employed to minimize photolysis. Soil mass to solution volume ratios ranged
from 1:2 to 2:3 to achieve sorption of 50% ( 20%) of the chemical added. All
solutions used had a 0.01 N CaCl2 matrix unless noted otherwise. Initial solution
concentrations added to the soils ranged from 5 to 45 qg/mL for all solutes with the
exception of PCP. A concentration range of 0.25 to 3 Mg/mL was used in the PCP
equilibration studies. All sorption isotherms were measured at room temperature
(T=22-25C). Following equilibration, the solution and solid phases were separated
by centrifuging the soil samples at approximately 300 RCF (relative centrifugal force)
using a Sorvall RT6000 centrifuge.
Each isotherm consisted of sorption measured in duplicate at four or more
concentrations and at least 30% of the isotherms were replicated. Also for each
isotherm, blanks containing the solvent with and without soil were run to check for
coelution of any peaks from the soil. Samples were usually equilibrated by rotating
for 16-24 hours. For fc <0.2,degradation was noted after 4 hours in control studies
where the soil-solution matrix was removed from the soil and spiked with the
appropriate solute concentrations. Therefore, equilibration of samples in solutions
of fc<0.2was reduced to a maximum of 2 hours with no differences observed in
sorption coefficients measured after 1 and 2 hours.


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.
Graduate Research Professor of
Soil and Water 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.
iP. Qm* i wL.
R. Dean Rhue
Associate Professor of Soil and
Water 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.
Associate Professor of Civil Engineering
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.
Joseph J. Delfino
Professor of Environmental
Engineering Sciences


180
van Uitert, LeGrand G. and Charles G. Haas. 1953. Studies on Coordination
compounds. I. A method for determining thermodynamic equilibrium
constants in mixed solvents. J. of Am. Chem. Soc., 75:451-455.
Verschueren,K. 1983. Handbook of Environmental Data of Organic Chemicals,
2nd ed. Van Nostrand Reinhold Company, New York, NY.
Walters, G. 1982. Theoretical and experimental determination of matrix diffusion
and related transport properties of fractured tuffs from the Nevada Test
Site, LA-9471-MS. Los Alamos National Laboratory.
Walters, R. and A. Guissepi-Ellie. 1988. Sorption of 2,3,7,8-tetrachlorodibenzo-p-
dioxin to soils from water/methanol mixtures. Envir. Sci. Tech., 22:819-
825.
Westall, J.C. 1984. Properties of organic compounds in relation to chemical
binding. IN: Proceedings of a Symposium held in Stockholm, Nov. 17-19,
1983, pp. 65-90.
Westall, J.C.,C. Leuenberger, and R.P. Scwarzenbach. 1985. Influence of pH and
ionic strength on aqeous-nonaqueous distribution of chlorinated phenols.
Environ. Sci. Tech., 19:193-198.
Whitehurst, D.,T.O. Mitchell, and Farcasiu. 1980. Coal liquefaction: The
Chemistry and Technology of Thermal Processes., Academic Press, New
York, NY.
Wilson, G.M. and C.H. Deal. 1962. Activity coefficients and molecular structure.
Industrial Engineering and Chemistry Fundamentals, 1:20-23.
Wood, A.L.,D.C. Bouchard, M.L. Brusseau, and P.S.C.Rao. 1990. Cosolvent
effects on sorption and mobility of organic contaminants in soils.
Chemosphere, 21: 575-587.
Wood, A.L.,D.C. Bouchard, and P.S.C.Rao. 1987. Sorption and transport of
hydrophobic organic solutes in miscible solvent systems. Presented at the
Annual Amer. Soc. Agron. Conf., Atlanta, GA, Nov. 20-Dec. 3. Agron.
Abstr., Amer. Soc. Agron., Madison, WI, p. 36.
Woodbum, K.B., L.S. Lee, P.S.C.Rao, and J.J. Delfino. 1989. Comparison of
sorption energetics for hydrophobic organic chemicals by synthetic and
natural sorbents from methanol/water solvent mixtures. Environ. Sci.
Tech., 23:407-412.


23
Theory
The release of a chemical from an organic liquid phase can be estimated from
a liquid-liquid partition coefficient (Kd) which is defined as
*/-
(2-1)
where CQ and Cw are the molar concentrations (mol/L) of the chemical of interest
in the organic and aqueous phases at equilibrium, respectively. The partition
coefficients (K) for coal tar, diesel fuel, and gasoline will be designated using
subscripts tw, dw, and gw, respectively.
For liquid-liquid partitioning, thermodynamic equilibrium is defined by the
equality of the chemical potentials in the aqueous and organic phases. This equality,
in conjunction with the choice of pure (liquid) solute as the standard state and the
Raoults law convention for activity coefficients, results in the following expression
at equilibrium
X V* X Y* (2'2)
xo O W I W
where subscripts o and w denote organic and aqueous phases, respectively; xQ and
*w are the respective mole fractions of the chemical in the organic and aqueous
phase; y0* is the activity coefficient of the chemical in the organic phase in
equilibrium with the aqueous phase; and yw* is the activity coefficient of the chemical
in the aqueous phase in equilibrium with the organic phase.
From Eq. (2-2), molar concentration of a solute in the aqueous phase (Cw) can
be approximated with the following assumptions: (1) the presence of other


25
20
15
10
5
0
87
A />
Pentachlorophenol
fc
t>
0
o
0.5

0.75
P

B
Benzoic Acid
fc
0
0.2
o
0.9

1.0
Ce,(ug/mL)
preservative sorption isotherms for (A) pentachlorophenol, (B)
izoic acid, and (C) dicamba, on Webster soil in various
thanol/water solutions.


125
Table 5-2. List of various chemical and physical properties of solutes.
Compound
PKa,w
Aqueous
Solubility
(mg/L)
benzoic acid
4.2a
3,000
2-naphthoic acid
4.6a
58
9-anthroic acid
3.65a
63b
o-chlorobenzoic acid
2.94a
2,100
m-chlorobenzoic acid
3.84a
400
p-chlorobenzoic acid
4.a
77
2,4-dichlorobenzoic acid
2.85b, 2.68f,2.75f
NAe
2,5-dichlorobenzoic acid
2.6 lb, 2.47f
NA
2,6-dichlorobenzoic acid
1.49b; 1.59f
NA
2,4,6-trichlorobenzoic acid
1.24b,c
NA
* Perrin, (1972); b Measured; c Values uncertain; d Levitan and Barker (1972); e not
available; f Seijeant and Boyd (1979); g Stephen (1963).
Equilibrium Sorption Isotherms
Equilibrium sorption isotherms were measured using the same
batch-equilibration method as described in Chapters 3 and 4. A soil mass to solution
volume ratio of either 1:1 or 1:2 was used in all studies. All solutions used had a
0.01 N CaCl2 matrix. Initial solution concentrations added to the soils ranged from


41
Analysis of Literature Data
The tar-water partition coefficients (K^) for several PAHs compiled from the
literature (Rostad, 1985; Groher, 1990; Picel, 1988) for three different coal tars, are
plotted in Figure 2-6 in a manner similar to Figures 2-2 through 2-5. For each coal
tar, the ideal line (solid line) shown was calculated from Eq. (2-6) using the best
estimates available for AiWct and pct. For the coal tar investigated by Rostad et al.
(1985) (Figure 2-6A), the ideal line was calculated using the pct reported and a MWcl
value estimated from a weighted average of the mole fraction and molecular weight
of each known component. For the unknown fraction, an average molecular weight
of 300 g/mole was assumed. Picel et al. (1988) reported values for both pct and
MWcr Groher (1990) did not report values fore AfW;t and pct; therefore, data for a
coal tar, similar in composition, obtained from the same site a few years later was
used to estimate the ideal line (Figure 2-6B).
For most of the PAHs, the measured values are within a factor-of-two
from the ideal line, with the best agreement observed for the Picel et al. (1988) data
(Figure 2-6C). Observed deviations from the ideal line could be the result of
considerable nonideality in the tar-water system or a consequence of various
experimental artifacts including inadequate time for equilibration and poor recovery
of the PAH from the aqueous phase. The probability of such experimental artifacts
increases for the larger PAHs where a greater difficulty is often encountered in
accurately measuring the solubility of rather insoluble compounds.


130
(Table 5-4 continued)
Solvent
fc
Kd(mL/g)
Kf(mLN/xg1-Ng1)
NSEa
2,4,6-trichlorobenzoic acid
0
0.11
0.10
1.020.09
0.2
0.07
0.05
1.120.13
0.4
0.07
0.18
0.65+0.32
0.6
0.11
0.24
0.730.10
0.8
0.15
0.20
0.900.05
1
0.99
0.88
1.040.05
2,4-dichlorobenzoic acid
0
0.25
0.40
0.830.04
0.2
0.19
0.50
0.640.08
0.4
0.17
0.28
0.820.02
0.6
0.22
0.15
1.160.04
0.8
0.43
0.42
1.010.04
1
2.75
2.94
0.960.03
2,5-dichlorobenzoic acid
0
0.19
0.45
0.640.09
0.2
0.11
0.20
0.780.07
0.4
0.11
0.12
1.000.07
0.6
0.15
0.02
1.820.15
0.8
0.34
0.28
1.080.08
1
2.22
2.53
0.920.06
2,6-dichlorobenzoic acid
0.4
0.04
0.04
1.000.18
0.6
0.09
0.13
0.860.12
0.8
0.23
0.44
0.750.06
1
1.29
1.10
1.080.05
Standard Error
This Webster sample was obtained from the Webster site at a different time.


181
Woodbum, K.B.,P.S.C.Rao, M. Fukui, and P. Nkedi-Kizza. 1986. Solvophobic
approach for predicting sorption of hydrophobic organic chemicals on
synthetic sorbents and soils. Journal of Contaminant Hydrology, 1:227-241.
Yalkowsky, S.H. 1979. Estimation of entropies of fusion of organic compounds.
I&EC Fundam., 18:108-111.
Yalkowsky, S.H. 1985. Solubility of organic solutes in mixed aqueous solvents.
Project Completion Report, CR# 811852-01. U.S. Environmental
Protection Agency, Ada, OK.
Yalkowsky, S.H. 1987. Solubility of organic solutes in mixed aqueous solvents.
Project Completion Report, CR# 812581-01. U.S. Environmental
Protection Agency, Ada, OK.
Yalkowsky, S.H.,R.J. Orr, and S.C. Valvani. 1979. Solubility and partitioning. 3.
The solubility of halobenzenes in water. Ind. Chem. Eng. Fundam., 18:351.
Yalkowsky, S.H. and T. Roseman. 1981. Solubilization of drugs by cosolvents.
IN: Techniques of Solubilization of Drugs, S.H. Yalkowsky (Ed.). Marcel
Dekker, Inc., New York, NY, pp. 91-134,
Yalkowsky, S.H.and J.T. Rubino. 1984. Solubilization by cosolvents I: Organic
solutes in propylene glycol-water mixtures. Journal of Pharmaceutical
Sciences, 74:416-421.
Yalkowsky, S.H. and S.C. Valvani. 1979. Solubilities and partitioning: 2.
Relationships between aqueous solubilities, partition coefficients, and
molecular surface areas of rigid aromatic hydrocarbons. J. Chem. Eng.
Data, 24:127-129.
Yalkowsky, S.H. and S.C. Valvani. 1980. Solubility and partitioning I: solubility of
nonelectrolytes in water. J. Pharm. Sci.,69:912-922.
Zachara, J.M.,C.C. Ainsworth, C.E. Cowan, B.L. Thomas. 1987. Sorption of
binary mixtures of aromatic nitrogen heterocyclic compounds on subsurface
materials. Environmental Science and Technology, 21:397-402.
Zachara, J.M., C.C. Ainsworth, L.J. Felice, and C.T. Resch. 1986. Quinoline
sorption to subsurface material: Role of pH and retention of the organic
cation. Env. Sci. Tech., 20:620-627.


CHEMODYNAMIC BEHAVIOR OF COMPLEX MIXTURES:
LIQUID-LIQUID PARTITIONING AND SORPTION OF
ORGANIC CONTAMINANTS FROM MIXED SOLVENTS
by
LINDA S. LEE
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
1993


BIOGRAPHICAL SKETCH
Linda Shahrabani Lee was bom in Dover, Delaware, in 1959. She
graduated from Piper High School in Ft. Lauderdale, Florida, in 1977. Linda
received a B.S. in chemistry from the University of Florida (Gainesville, Florida)
in 1983 and her ACS certification in 1984.
During her undergraduate college career she worked as a technician in the
Forest Soils laboratory in the Soil Science Department at UF. She also taught
junior and senior high students for two years at the Westwood Hills Christian
Academy. Linda was married in August of 1979 to Russell E. Lee. She has two
sons, James Russell and Joshua Russell Lee, bom in 1980 and 1989, respectively.
After receiving her B.S. degree, Linda worked as a chemist and lab
manager in the Soil Physics laboratory in the Soil Science Department at UF
where she received most of her laboratory training. She conducted studies in the
fate and transport of toxic organic chemicals in aqueous and mixed solvent
systems. Linda quickly became interested in the processes that affect chemical
disposition in the environment which prompted her to pursue graduate study in
both the environmental sciences and in soil science. Therefore, she pursued and
completed a masters degree in environmental engineering sciences (May 1989)
and during the following year initiated a Ph.D. program in the Soil & Water
Science Department. Upon completion of her Ph.D. she will join the faculty at
Purdue University in the Department of Agronomy with a 80/20
research/teaching appointment.
183


log [Kb, mL7g]
108
groups on the sorbent become increasingly more negative. Soil surfaces, unlike
RPLC supports, are predominately negatively charged over a large pH range.
Exclusion of inorganic anions by soils with high clay contents has been observed in
aqueous systems; however, a similar phenomenon was not observed for benzoic acid
in aqueous and low fc solutions.
0.4
0.2
0
-0.2
-0.4
-0.6
-0.8
-4-3-2-10123
phw- Pka
Benzoic Acid-Webster Soil
Methanol/Water Solutions
fc
(0
*
Q.
0.9
6.95
0.8
6.26
A 0.75
6.03
[]





* A
^ A A
Figure 4-4. Sorption of benzoic acid by Webster soil buffered at different pH
values in methanol/water solutions of fc=0.75,0.8,and 0.9.
Effects of pHapp on PCP Sorption at f>0.75
To investigate whether this phenomenon with benzoic acid was an anomaly,
PCP sorption by Webster soil was also measured as a function of pH in fc = 0.75 and
in neat methanol. At fc=0.75,PCP sorption decreased with increasing pH, similar


71
operational definition of pH for a mixed solvent solution (pHx*) referenced to an
aqueous standard can then be written as
PK PB, +
K Es
0.06
~ Ei,
0.06
(3-14)
Therefore, differences in the apparent pH and the actual pH arise from the
difference in the liquid junction potentials:
5 pH?p PH'X -
El E.
j
0.06
(3-15)
Van Uitert and Haas (1953) achieved a practical standardization of pH
measurements in dioxane-water solutions by measuring the pH of a series of HC1
solutions of known concentration in the mixed solvents. The difference between the
measured pH and the known hydrogen concentration was assumed to be a
reasonable estimate for S. This approach yields estimates for S that encompass all
differences (i.e.,liquid junction potential, standard potential, activity, solvent medium
effects) observed between a measurement in aqueous versus solvent/water solutions
irrespective of the source. The magnitude of 6 increases with increasing amounts of
an organic solvent. For methanol/water solutions at fc<0.8, S values are relatively
small, but 6 values may become greater than 2 as the neat organic solvent is
approached (Van Uitert and Haas, 1953; De Ligny and Rehbach, 1960). Although
there are obvious shortcomings to this simplified approach, it appears adequate in
many cases for estimating pH in several mixed solvent solutions.


177
Rostad, C.E.,W.E. Pereira, and M.F. Hult. 1985. Partitioning studies of coal-tar
constituents in a two phase contaminated ground-water system.
Chemosphere, 14:1023-1036.
Rubino, J. 1988. Electrostatic and non-electrostatic free energy contributions to
acid dissociation constants in cosolvent-water mixtures. International J.
Pharmaceutics, 42:181-191.
Rubino, J. T. and J.T. Berryhill. 1986. Effects of solvent polarity on the acid
dissociation constants of benzoic acids. J. Pharm. Sci., 75:182-186.
Rubino, J.T.,J. Blanchard, and S.H. Yalkowsky. 1984. Solubilization by
cosolvents II: Phenytoin in binary and ternary solvents. J. Parenteral Sci.
fe Tech., 38:215-221.
Rubino, J.T. and S.H. Yalkowsky. 1985. Solubilization by cosolvents III:
Diazepam and benzocaine in binary solvents. J. Parenteral Sci. <& Tech.,
39:106-111.
Rubino, J.T. and S.H. Yalkowsky. 1987a. Cosolvency and cosolvent polarity.
Pharm. Res., 4:220-230.
Rubino, J.T. and S.H. Yalkowsky, 1987b. Cosolvency and deviations from log-
linear behavior. Pharm. Res., 4:231-236.
Rubino, J.T. and S.H. Yalkowsky. 1987c. Solubilization by cosolvents IV:
Benzocaine, diazepam and phenytoin in aprotic solvent-water mixtures. J.
Parenteral Sci. fe Tech., 41:172-176.
Sabljic, A. 1984. Predictions of the nature and strength of soil sorption of organic
pollutants by molecular topology. J. Agrie. Food Chem., 32:243-246.
Sabljic, A. 1987. On the prediction of soil sorption coefficients of organic
pollutants from molecular structure: Applications of a molecular topology
model. Envir. Sci. Tech., 21:358-366.
Sanemasa, I., Y. Miyazaki, S. Arakawa, M. Kumamaru, and T. Deguchi. 1987.
The solubility of benzene-hydrocarbon binary-mixtures in water. Bull.
Chem. Soc. Jpn., 60(2):517-523.
Sangster, J. 1989. Octanol-water partition coefficients of simple organic
compounds. Phys. and Chem. Ref. Data., 18:1111.


UNIVERSITY OF FLORIDA
3 1262 08554 8468


141
forming DMSO(H20)2 (Kelm et al., 1975); thus acquiring hydrogen-donating
characteristics (Kelm et al., 1975; Bertoluzza et al., 1979; 1981). The opposing trends
observed for the sorption of benzoic acid by Ca+2- and K+-saturated Webster soil is
also consistent with a hydrogen bonding mechanism as previously discussed. Thus,
hydrogen-bonding interactions as a potential explanation for the enhancement of
benzoic acid sorption by soils is plausible, especially given the hydrogen-bonding
nature of carboxylate groups (this includes solute and sorbent functional groups) and
of methanol and DMSO (H2)2. The relevant question at this point is how could the
addition of methanol or DMSO strengthen hydrogen-bonding interactions of the
solute with the sorbent.
For sorption of HOCs from aqueous and mixed solvents, the bulk solution
properties are considered to be the driving force (i.e.,solute-solvent interactions) in
the sorption process with stabilization occurring at the local scale (preferential
interaction with organic matter regions). In the chromatographic literature regarding
the retention of HOCs by RPLC supports, references are commonly made to the
preferential solvation of the reversed-phase support with cosolvent molecules, but its
significance is usually dismissed due to the predominance of bulk-scale solute-solvent
interactions. Similar assumptions appear to also be adequate for retention of organic
acids by the same RPLC supports. However, it is apparent from the sorption studies
presented here that preferential or selective solvation may be of extreme importance
for sorption of organic acids.


15
In many cases the UNIFAC model may be preferred over the log-linear model
because (i) it has a more sound theoretical basis, (ii) activity coefficients in mixtures
can be calculated given only pure component data, and (iii) all possible interactions
among the components in the mixture are explicitly considered. A limitation of the
UNIFAC model, however, is that although the group interaction parameters required
to estimate the solute activity coefficients are continuously reviewed and updated,
their values are not available for a number of systems of interest here. Also, there
are both experimentally-based (Baneijee, 1985; Arbuckle, 1986) and theoretically
based (Pinal, 1988) reasons that limit the applicability of UNIFAC to aqueous
systems.
A convenient measure of the impact of a cosolvent on the solubility of an
organic chemical is the cosolvency power (o), which is defined as
a log (1-5)
w
where the subscripts c and w refer to neat cosolvent and pure water, respectively.
HOC solubility in organic solvents is larger than that in water, thus a > 0. Larger
values of a indicate a greater solubilizing power of the solvent for a specific solute.
Rubino and Yalkowsky (1987a) and Pinal et al. (1990) have shown that a
values can be viewed as being equivalent to hypothetical partition coefficients for the
HOC between a cosolvent and water. Morris et al. (1988) have shown that o values
can be correlated to HOC octanol-water partition coefficient (Kow) as follows:


TABLE OF CONTENTS
ACKNOWLEDGEMENTS iii
LIST OF TABLES ix
LIST OF FIGURES x
ABSTRACT xiii
CHAPTERS
1 INTRODUCTION 1
Partitioning from Multi-phasic Liquids 3
Sorption from Aqueous Solutions 7
Hydrophobic Organic Compounds (HOCs) 7
Hydrophobic ionogenic organic compounds (HIOCs) 8
Cosolvency 13
Solubility in Mixed Solvents 14
Equilibrium Sorption from Mixed Solvents 16
Hydrophobic Organic Chemicals (HOCs) 16
Hydrophobic Ionizable Organic Chemicals
(HIOCs) 17
2 EQUILIBRIUM PARTITIONING OF POLYAROMATIC
HYDROCARBONS FROM ORGANIC IMMISCIBLE LIQUIDS INTO
WATER 20
Introduction 20
Theory 23
Application of Raoults Law for Gasoline,
Motor Oil, and Diesel Fuel 25
Materials and Methods 30
Chemicals 30
Batch Equilibration Technique 30
Chromatographic Analysis 31
v


126
10 to 40 /Lig/mL for all solutes. All sorption isotherms were measured at room
temperature (T=20-24C). Following equilibration, the solution and solid phases
were separated by centrifuging the soil samples at approximately 300 RCF (relative
centrifugal force) using a Sorvall RT6000 centrifuge.
Each isotherm consisted of sorption measured in duplicate at four
concentrations. Also for each isotherm, blanks containing the solvent with and
without soil were run to check for coelution of chromatographic peaks resulting from
dissolved soil components or to obtain an appropriate background count in the LSC
analysis. Samples were equilibrated by rotating for 16-24 hours. Nonradiolabelled
samples were analyzed by RPLC techniques as described previously in Chapter 3,
and radiolabeled samples were analyzed by liquid scintillation counting (LSC)
techniques as previously described in Chapter 4. For the RPLC analysis of each of
the substituted carboxylic acids, the mobile phase composition was varied to
maximize separation and minimize elution time. Sorption coefficients, K (mL/g),
were estimated by difference from initial and equilibrium solute concentration data
as previously described in Chapter 3.
Determination of Octanol-Water Partition Coefficients
Octanol-water partition coefficients were individually determined for the
neutral and ionized species for each of the substituted carboxylic acids listed in Table
5-2. Approximately 1 mL of double-distilled octanol containing 200 to 500 mg/L of
a single solute was added to 25 mL of pH-adj usted aqueous solution in 35 mL
borosilicate Kimax centrifuge tubes. Samples were equilibrated overnight on a
rotator, followed by centrifugation at 300 RCF for 25 minutes. Aliquots of the


168
Gelsemsa, WJ..C.L. De Ligny, A.G. Remijnse and Miss H.A. Blijleven. 1967.
pH-measurements in alcohol-water mixtures, using aqueous standard buffer
solutions for calibration. Recueil, pp. 647-660.
Gerstl, Z. 1990. Estimation of organic chemical sorption by soils. J. Contam.
Hydrol., 6:357-375.
Gmehling, J., P.A. Rasmussen, and A. Fredenslund. 1982. Vapor-liquid equilibria
by UNIFAC group contribution. Revision and extension. 2, Ind. Eng.
Chem. Process Des. Dev., 21:118- 127.
Goldwasser, J.M., A. Rudin, and W.L. Eldson. 1982. Characterization of
copolymers and polymer mixtures by gel permeation chromatography. J.
Liq. Chromat., 5:2253-2257.
Green, R.E. and S.W. Karickhoff. 1990. Sorption estimates for modeling. IN:
Pesticides in the soil environment. H.H. Cheng (Ed.). Soil Sci. Soc.
Amer., Inc., Madison, WI. pp. 70-102.
Groher, D.M. 1990. An Investigation of factors affecting the concentrations of
polyaromatic hydrocarbons in groundwater at coal tar waste sites. Masters
Thesis, Massachusetts Institute of Technology, Boston, MA.
Grover, R. and Smith, A. E. 1974. Adsorption studies with acid and
dimethylamine forms of 2,4-D and dicamba. Can. J. Soil 54:179-186.
Guerin, M.R. 1978. Energy sources of polycyclic aromatic hydrocarbons. IN:
Polycyclic Hydrocarbons and Cancer. H.V. Gelboin and P.O.P.Tso (Eds.).
Academic Press, New York, Vol I.,pp 3-42.
Hagwall, M. 1992. Partitioning of aromatic constituents into water from diesel
fuel. Masters Thesis, The Royal Institute of Technology, Stockholm,
Sweden.
Hansen, H.K., P. Rasmussen, and A. Fredenslund. 1991. Decomposition of
dichlorodifluoromethane on BP04. Ind. Eng. Chem. Res., 30:2355.
Hamed, H.S. and B.B. Owen. 1958. The Physical Chemistry of Electrolyte
Solutions. Amer. Chem. Soc.,Washington DC.
Hassett, J.J., W.L. Banwart, S.G. Wood, and J.C. Means. 1981. Sorption of <*-
naphthol: Implications concerning the limits of hydrophobic sorption. Soil
Sci. Soc. Amer. J., 45:38-42.


159
APPENDIX B
SAMPLE pKa DETERMINATION
True thermodynamic ionization constants should be independent of solute
concentration. However, the two types of ionization constants typically determined
experimentally are concentration ionization constants, better known as "the classical
constant" (Albert and Sergeant, 1987), or mixed ionization constants as determined
in this study. The true thermodynamic constant (KaT) must be expressed in terms of
activities (a) as follows
(B-l)
where H+, A", and HA refer to the hydrogen ion, ionized acid, and neutral acid,
respectively. The "classical constant" is written in terms of concentrations as follows
[HI [A ]
[HA]
(B-2)
where the brackets ([]) refer to concentrations. The differences between activity- and
concentration-based ionization constants principally arise from electrostatic
interactions of the ions produced such that some of the ions are not free and active
in solution. This results in molar concentrations that are different than the species
activities. These differences become increasingly more significant with increasing


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
CHEMODYNAMIC BEHAVIOR OF COMPLEX MIXTURES:
LIQUID-LIQUID PARTITIONING AND SORPTION OF
ORGANIC CONTAMINANTS FROM MIXED SOLVENTS
By
Linda S. Lee
August 1993
Chairman: Dr. P.S.C.Rao
Major Department: Soil and Water Science
Contamination of soils and water at waste disposal sites commonly involves
various combinations of nonpolar or hydrophobic organic chemicals (HOCs) and
hydrophobic ionogenic organic chemicals (HIOCs), as well as mixtures of water and
one or more organic cosolvents (either completely or partially miscible in water).
Emphasis of this work was on understanding the chemodynamics of such complex
mixtures, specifically solubility and sorption. Experimental and theoretical analysis
presented has focused on: (1) liquid-liquid partitioning behavior of aromatic
hydrocarbons between environmentally relevant organic immiscible liquids (OILs)
and water; and (2) the solubility and sorption of HIOCs by soils from completely
miscible organic solvent/water mixtures.
xiii


61
For analysis of various carboxylic acids and substituted phenols by reversed-
phase chromatography using an acidified mobile phase (i.e.,when neutral species
dominate), retention is inversely proportional to cosolvent content as observed for
HOCs. Lewis and Wilson (1984) observed similar behavior for several carboxylic
acids in non-acidified methanol/water solutions (0 to 80%) using reversed-phase TLC
plates impregnated with an ion-pairing agent tetra-n-butylammonium bromide (TBA).
However, in the absence of an acidified mobile phase or an ion-pairing reagent,
cosolvent effects were minor. These data suggest that the retention behavior of
organic acids by a hydrophobic surface is similar to HOCs only when the charge is
compensated (e.g.,neutral by protonation or paired with a counterion).
In considering the impact of cosolvents on sorption, the following interactions
must be considered: solute-solute; solvent-solvent; solvent-solute, solvent-sorbent,
and solute-solvent-sorbent interactions. The first three pairs of interactions can be
assessed from solubility studies. For HOCs, solute-solute interactions are ignored
due to the absence of both specific functional groups and high solute concentrations.
For most miscible solvents (e.g., alcohols), irregular behavior due to specific
complexation of solvent and water molecules doesnt appear to be of concern. For
sorption of HOCs, solvent-solute interactions, as described by solubility, are found
to predominate such that the impact of solvent-sorbent interactions have been
considered minor. However, for solutes containing specific functional groups, the
impact of the cosolvent on the sorbent may have considerable impact.


127
octanol phase (0.5 mL) were then taken and added to 0.5 mL aliquots of methanol
for RPLC analysis. After removal of the remaining octanol from the aqueous phase,
1 mL aliquots of the aqueous phase were added to 0.5 mL methanol aliquots for
RPLC analysis. Following aliquots for analysis, pH measurements of the remaining
aqueous phase were made using a Fisher Accumet Model 925 pH meter and an
Ingold micro-electrode (AgCl saturated 3 M KC1 filling solution).
Results and Discussion
Sorption of benzoic acid by Webster soil was measured in different
solvent/water solutions to investigate the impact of solvent type. In addition,
sorption of several substituted benzoic acids by Webster soil was measured in
methanol/water solutions to investigate the role of solute acidity and hydrophobicity.
Linear approximations of the sorption coefficients (Kb) were considered adequate for
this preliminary assessment of the effect of solvent and solute structure on carboxylic
acid sorption; however, nonlinearity was noted in some of the solute/sol vent/water
combinations. Although linear estimates of Kb given in Tables 5-3 and 5-4 will be
used in comparing the impact of the different solvents and solutes, respectively, the
Freundlich fit to the isotherm data is also given. Nkedi-Kizza et al. (1985) had noted
increased isotherm linearity with increasing fc; however, no consistent trend is
apparent for the isotherm data given in Tables 5-3 and 5-4. Representative
isotherms along with linear fits for sorption of benzoic acid in several solvent/water
mixtures and for sorption of substituted carboxylic acids in methanol/water solutions
are shown in Figures 5-1 and 5-2, respectively.


147
Summary
Sorption profiles observed for the sorption of benzoic acid by soils from
methanol/water solutions (Chapter 3) could not be predicted by incorporating
cosolvent enhanced solubility and cosolvent-induced speciation (Eq. 3-6) prompting
an investigation of benzoic acid sorption in binary mixtures of water and several
other organic solvents. The sorption of benzoic acid from DMSO/water solutions
was found similar to that observed for methanol/water solutions; however, Eq. (3-6)
was successfully applied to benzoic acid sorption in acetone/water, acetonitrile/water,
and 1,4-dioxane/water solutions. No single parameter for describing bulk solvent
properties could be used to explain the similarities and dissimilarities observed in
benzoic acid sorption from different solvent/water systems. However, DMSO appears
to acquire hydrogen donating characteristics similar to methanol by forming
DMS0(H202) complexes.
The importance of solute structure was also investigated by measuring the
sorption of several substituted carboxylic acids by Webster soil from methanol/water
solutions. Correlations of log KMe0H, log and pKa>w with log Kow values for both
the ionized and neutral species consistently showed substantially better correlations
with KOW(i values. This further supports the conclusion made in Chapter 4 that the
carboxylate is the predominate species responsible for the enhanced carboxylic acid
sorption by soils from methanol/water solutions. Similar observations were not
observed for substituted phenols in methanol/water solutions (Chapter 3). Enhanced
sorption of carboxylic acids appeared to be a function solute, solvent, and electrolyte


2
distance as the plume size increases. For discussing solubility and sorption processes
within the plume, three separate regions may be considered: a near-field, region, a
transition zone, and a far-field region. The basis for such a distinction is not the
distance from the contaminant source. Rather, the criterion employed to designate
these regions is the chemistry of the contaminant mixture within the plume as
contrasted to the waste.
In the near-field region, corresponding to the source itself and its immediate
vicinity, the composition and concentrations of most waste constituents are similar
to that in the waste. There are usually two, possibly three, liquid phases in this
region. This would be the case, for example in the vadose zone, at waste disposal
sites where we may find both "dense" and "light" organic immiscible liquids (OILs)
and an aqueous phase as well as a vapor phase. In the transition zone, if it occurs
in the saturated zone, the solution phase is likely to be predominantly a single-phase,
homogeneous liquid made up of water and varying amounts of cosolvents (if they
were present in the near-field region). The concentration of one or more waste
constituents may be so high that approximations based on expected behavior in dilute
aqueous solutions are often found to be inadequate. Finally, the far-field region
corresponds to that region of the plume in which the waste constituents are present
in an aqueous solution. Most of these chemicals will be at concentrations well below
their aqueous solubility limits. During migration of the contaminant plume through
the vadose zone and the saturated zone, chromatographic separation of the waste
constituents occurs due to their different mobilities. Furthermore, dilution resulting
from hydrodynamic dispersion and attenuation resulting from abiotic/biotic


91
significant changes were observed in the sorption of benzoic acid with increasing
CaCl2 concentrations (0.002 to 0.05 N) from either a 25% methanol solution or neat
methanol. This apparent contradiction indicates the presence of a different sorption
mechanism that is similarly impacted by cation-type. For example, an increase in
valence state of a cation, i.e.,K+ versus Ca+ + enhances polarization of the molecules
in the solvation sphere of the cation and results in stronger hydrogen bonding
characteristics (Bailey etal.,1968). This mechanism may be of particular importance
for methanol considering the pronounced hydrogen-bonding characteristics of
alcohols. Also, cation-type affects the probability of cation- versus water-bridging
(i.e.,inner-versus outer-sphere complexation) as previously discussed in Chapter 1.
To further elucidate the processes of importance, a preliminary assessment of the
sorption of benzoic acid on other sorbents from aqueous and methanol solutions will
be made in the Chapter 4.
Desorption Characteristics
A preliminary desorption experiment was performed to assess the reversibility
of the sorption mechanism and the potential for chemisorption. An adsorption
isotherm was measured in triplicate for a single concentration of benzoic acid (40
/ig/mL) at a mass to volume ratio of 2 using a subsample of Webster soil and 0.01
N CaCl2 methanol. (Note this Webster subsample was taken from the Webster site
in Iowa a year after the batch that was used in the previous experiments.) After
equilibration, centrifugation, and sampling for analysis, the remaining methanol was
decanted and replaced with an aqueous 0.01 N CaCl2 solution (resulting fe was


16
o a log Kow + b (1-6)
where a and b are empirical constants unique for a given cosolvent. Other cosolvent
and solute properties may also be used to estimate o values (Rubino and Yalkowsky,
1987a,b; Morris et al., 1988).
Although both Eq. (1-5) and (1-6) provide useful first-order approximations
of the cosolvency power of a solvent for a solute, measured HOC solubility profiles
in solvent mixtures often exhibit deviations from the expected log-linear behavior
primarily due to solvent-cosolvent interactions. The observed cosolvency in a binary
mixed solvent can be more generally defined as,
log Sb = log Sw + oc fc (1-7)
where Sb is the solubility in the binary mixture.
Equilibrium Sorption from Mixed Solvents
Hydrophobic Organic Chemicals (HOCs)
A log-linear cosolvency model describing the decrease in sorption of HOCs
with increasing fc in a binary solvent is given by (Rao et al., 1985; Fu and Luthy,
1986b):
log Kb log Kw -cl o c fc
(1-8)


83
Miscible Displacement Studies
The retardation factors (R) estimated from the miscible displacement studies
with Eustis soil column are shown in Table 3-2. The column effluent pH ranged
between approximately 4 and 4.8 for the different solute/solvent combinations.
Comparisons of influent pulse sizes with zero-th moments showed greater than 97%
mass recovery for all solute pulses. Loss of soil organic matter from the soil column
during elution with methanol was considered negligible as shown previously by Lee
et al. (1991). For the substituted phenols, R values determined in methanol were
smaller than those water (fc=0). For both chlorophenols in neat methanol,
retardation factors decreased to one corresponding to no sorption (R=l). A decrease
in R with increasing fc is expected from the log-linear cosolvency model in the
absence of any specific interactions. The opposite trend, however, was observed for
all of the substituted benzoic acids. Benzoic acid and dicamba were chosen for
further investigation in several methanol/water solutions using batch techniques with
PCP included as a control. For the batch studies, Webster soil with a higher organic
carbon content was used to better differentiate sorption in the various
methanol/water solutions. Although the greatest increase in retardation was
observed with gentisic acid, preliminary batch isotherm data exhibited extreme
nonlinearity (data not shown). Since problems associated with isotherm nonlinearity
may confound assessment of the proposed model, further investigation of gentisic
acid was not pursued.


148
composition; therefore, it was deduced that hydrogen-bonding interactions coupled
with preferential or selective solvation are the likely mechanisms of importance in
this study.


99
Analysis of OC content, cation exchange capacity (CEC), and total elemental
analysis were performed on the treated soils to assess the effect of the pH
treatments. No change was observed in the OC content of the soil before and after
pH treatment, as determined using the Walkley-Black method (Nelson and Sommers,
1988). The cation exchange capacity (CEC) was measured on the pH-treated soils
using a procedure denoted as "method II" by Rhue and Reve (1990). The pH of the
solutions during extraction for determining CEC was similar to the pH of the treated
soils. Elemental analysis was performed by a laboratory in the Soil and
Environmental Department at UC-Riverside using a technique by Bakhtar et al.
(1989). This method involved digesting 0.5 g soil samples with a peroxide/acid
solutions followed by elemental analysis by inductively coupled optical emission and
absorption spectrometry. Solutions from sample digests were diluted 500 fold for all
elemental analysis with the exception of Si which required a 50,000 fold dilution.
Results from the elemental analysis and CEC are given in Table 4-1.
Chemicals
Pentachlorophenol (PCP) and benzoic acid were used in this study (Chemical
characteristics are given in Table 4-2). The crystalline compounds were all of >98%
purity. Of the solvents employed, methanol (high purity, HPLC grade) was
purchased from J.T. Baker and used without further preparation, and the water was
deionized. Uniformly ring-labeled [14C] pentachlorophenol (PCP) and benzoic acid
(specific activity, 12 mCi/mmol and 13.3 mCi/mmol, respectively) was purchased
from Pathfinders Laboratories with a radiopurity of 99.6%,and a chemical purity of
>98%.


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179
Sposito, G. 1984. The Surface Chemistry of Soils. Oxford University Press, New
York, pp. 78-88.
Sposito, G. 1989. The Chemistry of Soils. Oxford University Press, New York.
Stauffer, T.B. 1988. Sorption of nonpolar organics on minerals and aquifer
materials. Ph.D. Dissertation., School of Marine Sciences, The College of
William and Mary, VA.
Stephen, H.,and T. Stephen. 1963. Solubilities of Inorganic and Organic
Compounds. Vol. 1, Binary Systems, Part 1. Pergamon Press, Macmillan
Co., New York.
Strehlow, H. and H.M. Koepp. 1958. Uber auswahlende solvatation von ionen in
losungsmttelgemischen. Z. Elektrock, 62(3):373-378.
Stumm, W.,R. Kummert, and L. Sigg. 1980. A ligand exchange model for the
adsorption of inorganic and organic ligands at hydrous oxide interfaces.
Crotica Chemica Acta, 53: 291-312.
Swarc, M. 1974. Ions and Ion Pairs in Organic Reactions. Volume 2; John Wiley
and Sons; New York.
Thomas, D.H. and J.J. Delfino. 1991. A gas chromatographic/chemical indicator
approach to assessing ground water contamination by petroleum products.
Ground Water Monitoring Rev., 11:90-100.
Tomlinson, E. 1983. Enthalpy-entropy compensation analysis of pharmaceutical,
biochemical, and biological systems. Intern. J. of Pharmaceutics,
13:115-144.
U.S. EPA. 1990. Solvent extraction treatment. EPA/540/2-90/013, Engineering
Bulletin, Office of Emergency and Remedial Response, U.S. EPA,
Washington, DC.
U.S. EPA. 1991. In situ soil flushing. EPA/540/2-91/021, Engineering Bulletin,
Office of Emergency and Remedial. EPA, Washington, DC.
Van de Venne, J.L.M. and J.L.H.M. Hendrikx. 1978. Retention behaviour of
carboxylic acids in reversed-phase column liquid chromatography. J.
Chromat., 167:1-16.


77
w/HCl) and the UV wavelength were optimized for analysis of each solute. When
necessary, samples were diluted to within an optimal concentration range of the
specific analytical method.
Miscible Displacement Experiments
Miscible displacement techniques described byBrusseau et al. (1990) and Lee
et al. (1991), were used to estimate retardation factors with water and neat methanol
as the eluent for the solutes listed in Table 3-1. The column was packed with air-
dried Eustis soil and 0.01 N CaCl2 solution was pumped through the column until
steady-state, water-saturated conditions were established. All solutions were filtered
(0.45 nm) and degassed with helium before use. The physical properties of the
Eustis soil column were as follows: 5 cm length, 0.4 mL/cm3 volumetric water
content (0), 1.69 g/cm3 bulk density (p), and a column pore volume of 9.64 mL. A
pore-water velocity (v) of about 90 cm/hr was used for all experiments.
Solute concentrations in the influent solutions were approximately 100 /xg/mL,
except for PCP which was 3 jug/mL. Solute concentrations in the column effluent
were monitored continuously as described by Brusseau et al. (1990) using a flow
through, variable-wavelength UV detector (Gilson Holochrome, Waters 450 or LDC
UV) connected to a linear chart recorder (Fisher Recordall 5000). Retardation
factors (R) were obtained by calculating the area above the measured breakthrough
curves (Nkedi-Kizza et al., 1987). Periodic measurements were made of the column
effluent pH with a combination glass electrode using a Coming 130 pH meter or a
Brinkman 686 unit.


92
approximately 0.22) and reequilibrated for 16 hours. The single point sorption
coefficients for the adsorption from neat methanol and the desorption from fc~0.22
was 12 mL/g and 0.4 mL/g, respectively. These data suggest that the sorption
process is reversible and hysteresis minimal.
Estimation of pH by pHapp
A brief discussion on the impact of assuming that pHapp was a reasonable
estimate of the soil-solution pH relative to assessing observed deviations from Eq.
(3-6) is now warranted. If the true pH of the soil-solution was higher than pHapp as
was observed in the absence of soil, predictions from Eq. (3-6) would be similar to
that observed for parameter set #2 in Figure 3-2. This prediction would still under
estimate the overall sorption observed. Alternately, if surface acidity increased with
increasing cosolvent addition (i.e.,pH at the surface decreases with fc,thus pH-pKa w
becomes increasingly more negative), increased sorption may occur. However, as
previously discussed, Loeppert et al. (1979) observed no apparent change in surface
acidity of montmorillonite (the dominate clay in Webster soil) in neat methanol.
Also, similar suppositions did not need to be invoked to describe the data for
chlorophenols. Problems associated with using inaccurate pH estimates in Eq. (3-6),
however, cannot be completely ruled out especially given the difficulty in assessing
the differences between the true soil-solution pH and pHapp in mixed solvents.
An added level of complexity arises when an attempt is made to define what
the pH is that is directly influencing solute speciation at the soil surface (e.g.,effective
pH), thus sorption. For the case of soil and inorganics, it has been proposed that the


log K
37
log [S, moles/L]
Figure 2-2. Comparison of measured tar-water partition coefficients (K^) and
predictions based on Raoults law for ID# 1(A) and ID# 2(B) coal
tars.


45
Confidence in the Cw values predicted using Eq. (2-3) is dependent on several
factors other than the premise of ideal behavior, including uncertainty about the
input parameters (e.g.,M¡, AfWct, and S). Both M¡ and MWcl can be determined
experimentally; therefore, errors associated with these parameters can be obtained
from replicate analysis information. Sampling and chromatographic analysis of this
heterogeneous liquid waste is prone to considerable errors; therefore, the deviation
associated with is probably the greatest source of error in estimating Cw values.
A majority of the data presented in Figure 2-7 lie within the factor-of-two
intervals given about the 1:1 correlation. The data that lie outside the factor-of-two
intervals result in predicted concentrations greater than those measured, with the
exception of the data points below the 1:1 correlation which correspond to
benzo(a)anthracene. Benzo(a)anthracene is present in small amounts in coal tar, thus
often approaching the limits of analytical detection. In addition, aqueous solubility
measurements for compounds with small values (i.e., < 10'2 mg/L) become
increasingly less reliable. Good agreement for a majority of PAHs within a factor-of-
two suggests that the use of Eq. (2-3), based on Raoults law, may be adequate for
estimating PAH concentrations. At the very least, aqueous concentrations estimated
using this approach should be considered more appropriate and definitive than
merely assuming crystal solubilities for aqueous-phase concentrations.
Given the variations that may exist in (1) the different coal tar deposits at a
given site, and (2) the extent of weathering at that site, it would be advantageous to
estimate maximum PAH concentrations that might be found at any site. In order to


31
3-inch needle. The equilibration vessel was vented during sampling by piercing the
septa with a second needle.
Following aqueous phase transfers, as much residual water as possible was
removed from the equilibration vessel without loss of the coal tar. The coal tar in
the equilibration vessel and the cap were rinsed with methylene chloride into a 100-
mL volumetric flask and brought to volume. Dissolved coal tar samples were filtered
(0.45 /m) prior to analysis. For the coal tar samples from which it was difficult to
remove residual water without loss (i.e.,thin liquid coal tars), an aliquot of the neat
coal tar was sampled for analysis as well.
Chromatographic Analysis
PAH concentrations in the coal tar and aqueous phases were determined using
a gas chromatograph (GC) equipped with an ion trap detector (ITD). The GC/ITD
method included an HP Ultra 2 column (95% methyl, 5% phenyl polysiloxane, 0.5
micron thickness; 30 cm x 0.32 mm ID); helium as a carrier gas at a flow rate of
approximately l.OMl/min; temperature gradient program, and an ion trap detector.
The temperature gradient program consisted of a 1 minute hold at 50 C; a ramp to
130C at 30C/min followed by a 3 minute hold; a ramp to 180C at 12C/min
followed by a 1 minute hold; a ramp to 240C at 7C/min; and a ramp to 300C at
12C/min followed by a 15 minute hold. The ITD was set at an electron energy of
70 eV and scanned from 45 to 450 amu at 2 scans/sec. The electron multiplier
voltage was 1650 volts and the transfer temperature from the GC was 280C. Prior
to GC analysis, samples were usually spiked with an internal standard consisting of
naphthalene-dg and anthracene-dg.


167
Eng, R. and M. Menzies. 1985. Survey of town gas and by-product production
and location in the United States (1880-1950), PB-8 J 1738B. National
Technical Information Service, Washington, DC.
EPRI. 1989. MYGRT code version 2.0: An IBM code for simulating migration
of organic and inorganic chemicals in Groundwater. Report EN-6531.
EPRI, Washington, DC.
EPRI. 1993. Chemical and physical characteristics of coal tar from selected
manufactured gas plant (MGP) sites. EPRI-RP2879-01,12 EPRI,
Washington, DC (In press).
Farmer, V.C. and J.D. Russell. 1967. IN: Fifteenth Conference of Clays and Clay
Minerals, pp. 121-142.
Felice, L.J.,J.M. Zachara, R.L. Schmidt, and R.T. Resch. 1985. Quinoline
partitioning in subsurface materials: Adsorption, desorption and solute
competition. IN: Proc. 2nd Inteml. Conf. on Groundwater Quality
Research. N.N. Durham and A.E. Redelfs (Eds.) Tulsa, OK. pp. 39-41.
Fontaine, D.D.,R.G. Lehmann, and J.R. Miller. 1991. Soil adsorption of neutral
and anionic forms of a sulfonamide herbicide, flumetsulam. J. Envir.
Qual., 20(4):759-762.
Franks, F. and D.G. Ives. 1966. The structural properties of alcohol-water
mixtures. Quarterly Reviews, 20:1-45.
Fredenslund, A., R. Jones, and J.M. Prausnitz. 1975. Group-contribution
estimation of activity coefficients in nonideal liquid mixtures. Amer. Inst.
Chem. Eng. J., 21:1086-1099.
Freeman, D.H. and L.W. Cheung. 1981. A gel-partition model for organic
desorption from a pond sediment. Sci.,214:790.
Fu, J.K. and R.G. Luthy. 1986a. Aromatic compound solubility in solvent/water
mixtures. J. Envir. Eng., 112:328-345.
Fu, J.K. and R.G. Luthy. 1986b. Effect of organic solvent on sorption of aromatic
solutes onto soils. J. Envir. Eng., 112:346-366.
Gehron, M.J. 1988. Advanced Mass Spectrometric Methods of Jet Fuel Analysis,
Ph.D. Dissertation. University of Florida, Gainesville, FL.


log K
42
dibenz(a,h)anthrac£
6.5
6
5.5 f- benzo(a)anthracene
5
4.5
4
3.5
Rostad et al., 1985
Ideal Line
MWrt = 265 g/mole
Pet = 1-03 g/mL
''--..^\v^''---2-metlylnaphthalene
anthracene./^^'''''-..
fluorene#--0^nWhalene
acenaphthene
-6.5
-6
-5.5
-5
-4.5
-4
-3.5
-3
<| chrysene
f fluoranthene
'"--t. pyrene
Groher, 1990
Ideal Line
MWct = 230 g/mole
pct = 1.064 g/mL
I $ anthracene
^Jjhenanthrene
fluorene
acenaphthene*
2-methylnaphthleF
naphthalene1
-5.5
-5
-4.5
-3.5
-3
... pyrene
fluoranthene
Picel et al., 1988
Ideal Line
MWe, = 150 g/mole
P ct = 0.99 g/mL
jDhenanthrene ^biphenyl
^fluorene
aoenapthene<^',:i'-|,hylnaphthalene
Ina'phthalene
-5.5
-5
-4.5
-4
-3.5
-3
log [S/ moles/L]
Figure 2-6. Comparison of measured tar-water partition coefficients (K,w) reported
in the literature and predictions based on Raoults law. Literature
source as indicated.


10
8
6
4
2
0
i
25
20
15
10
5
1.
C0, ug/mL
Representative isotherms for benzoic acid in (A) acetone/water; (B) acetonitrile/water; (C) DMSO/water;
and (D) 1,4-dioxane/water solutions.


74
Determination of Ionization Constants
The conditional ionization constants (pKa) for benzoic acid, gentisic acid, 2,4-
dichlorophenoxyacetic acid, PCP, 2,4-dichlorophenol, and dicamba were determined
in methanol/water solutions by measuring pH as a function of NaOH additions
(Albert and Sergeant, 1984). Solvent mixtures were prepared with 0 to 100%
methanol and degassed prior to use. For all solutes except for PCP and dicamba,
0.01 M solutions were titrated with 0.1 M NaOH. For PCP and dicamba, 0.001 M
solutions were titrated with 0.01 M NaOH. A Metrohm 686 Titroprocessor,
employing a combined pH glass electrode (6.0202.100)and a resistance thermometer
(6.1103.000), continuously measured pH and temperature, respectively. The pH
meter was calibrated using aqueous buffers. The temperature of the solutions was
24 0.5 C. Titrations were performed in duplicate in 50 mL beakers placed on a
stirring plate to mix the solutions. The ionization constants determined in this study
are mixed ionization constants (Albert and Sergeant, 1987) rather than true
thermodynamic ionization constants. A brief discussion on the difference between
the various ionization constants are given in Appendix B along with sample sets of
titration data from this study and corresponding calculations.
In calculating pKa values, adjustments for the impact of methanol on pH
measurements were made using a method similar to that employed by Van Uitert
and Haas (1953) as described above for the measurement of pH in mixed solvents.
This method consisted of measuring the pH of 0.001 M hydrochloric acid in the
mixed solvent. The difference (6) between the pH measured in water and in the


6
parameters required in the UNIFAC model have been continuously reviewed and
updated since the model was first introduced (Skjold-Jorgensen et al., 1979;
Magnussen et al., 1981; Gmehling et al., 1982; Alameida-Macedo et al., 1983;Hansen
et al., 1991).
Benzene Mole Fraction in the Organic Phase
Figure 1-1. Comparison of measured and calculated (Raoults law) aqueous
solubilities in binary mixtures of benzene-toluene (A) and benzene-
octanol (B). Data from Sanemesa et al. (1987).


165
Ball, W.P. and P.V. Roberts. 1991a. Long-term sorption of halogenated organic
chemicals by aquifer material. 1. Equilibrium. Environ. Sci. Tech., 25:1223-
1237.
Ball, W.P. and P.V. Roberts. 1991b. Long-term sorption of halogenated organic
chemicals by aquifer material. 2. Intraparticle diffusion. Environ. Sci.
Tech. 25:1237-1249.
Baneijee, S. 1984. Solubilities of organic mixtures in water. Environ. Sci. Tech.,
18:587-591.
Bates, R.G. 1973. pKa values for carboxylic acids and anilinium ions.
Determination of pH, Theory and Practice, 2nd ed.; Wiley, New York, p
452.
Bates, R.G., 1963. Interpretation of pH measurements in alcohol-water solvents.
J. Phys. Chem., 67:1833.
Beilin, C. A. 1993. Ph.D. Dissertation. Coupled-Processes: Interactions of
Contamiants, Bacteria, and Surfaces. University of Florida, Gainesville, FL.
Bourguignon, B., F. Marcenac, H.R. Keller, P.F. de Qguiar, and D.L. Massart.
1993. Simultaneous optimization of pH and organic modifier content of
the mobile phase for the separation of chlorophenols using a Doehlert
design. J. Chromatog., 628:171-189.
Brenner,H. 1962. The diffusion model of longitudinal mixing in beds of finite
length. Numerical Values. Chem. Eng. Sci., 17:229.
Briggs, G.G. 1981. Theoretical and experimental relationships between soil
adsorption, octanol/water partition coefficients, water solubilities,
bioconcentration factors, and the parachor. J. Agrie. Food Chem., 29:1050.
Brown, D.S. and G. Combs. 1985. A modified Langmuir equation for predicting
sorption of methylacridinium in soils and sediments. J. Environ. Qual.,
14:195-199.
Brusseau, M.L.,R.E. Jessup, and P.S.C.Rao. 1990. Sorption kinetics of organic
chemicals: Evaluation of gas-purge and miscible-displacement techniques.
Environ. Sci. Tech., 24:727-735.


CHAPTER 5
IMPACT OF SOLUTE STRUCTURE AND ORGANIC COSOLVENTS ON THE
SORPTION OF CARBOXYLIC ACIDS BY SOILS FROM MIXED SOLVENTS
Introduction
Investigations of the pH and cosolvent dependence of benzoic acid sorption
by soils (Chapter 4) suggested that the enhanced sorption observed in
methanol/water (0.01 N CaClj) solutions may be due to either (1) methanol-
enhanced electrostatic interactions of benzoate with soil organic matter, or (2) the
formation and exchange of positively-charged ion-pairs. To better distinguish
between specific and nonspecific solvent interactions, sorption of benzoic acid by
Webster soil was measured from binary mixtures of water and several organic
cosolvents. Cosolvents were chosen that were miscible with water and spanned a
range of bulk solvent properties.
In conjunction with an investigation on the role of the cosolvent on benzoic
acid sorption, a similar investigation seemed warranted on the role of solute acidity
on sorption, especially given that methanol additions did not appear to enhance
sorption of substituted phenols (Chapter 3). Carboxylic acids are more acidic than
phenols and have a greater propensity for hydrogen bonding. Therefore, sorption by
Webster soil of several substituted benzoic acids varying in acidity (pKJ and
hydrophobicity (log Kow) was measured from methanol/water solutions. For both the
122


155
Conclusions
Sorption of organic acids by soils from mixed solvents was solute and solvent
dependent.
Enhanced sorption could not be attributed to a single bulk solvent property.
Acidity and Kow>i correlated well with KMe0H suggesting the predominant role
of benzoate.
Organic matter is the soil domain of greatest importance.
Electrolyte composition significantly impacts sorption of carboxylic acids in
mixed solvents (i.e.,valence).
Sorption reversible and hysteresis minimal.
Hydrogen bonding proposed to be a significant mechanism in the
enhancement of carboxylic acid sorption in methanol/water and DMSO/water
solutions.
Solute and sorbent heterogeneity (hydrophobic and polar regions), selective
solvation, and preferential orientation of solvent molecules were also
concluded to be of importance in the sorption of organic acids.


36
(2-6) (solid line) and the factor-of-two tolerance intervals. For most coal tars, the
data points are scattered about the ideal line within the factor-of-two bounds
suggesting that the assumption of ideal behavior suffices (again, within a factor-of-two
error) in predicting for the PAHs. For the one exception (ID# 1), measured
data points lie consistently above the ideal line (Figure 2-2A) indicative of an error
in the estimate of the molar volume. Specific causes for the systematic deviation
observed with coal tar ID# 1 need to be further explored.
Benzo(a)anthracene is the only PAH that consistently lies substantially below
the ideal line for most of the coal tars. Uncertainties arising from both analysis and
parameter estimation may have resulted in the observed negative deviations.
Analysis of benzo(a)anthracene in the aqueous phase approached detection limits,
thus contributing to uncertainties. A greater source of error was probably incurred
in the estimation of the supercooled liquid solubility for benzo(a)anthracene. The
S¡ values (given in Table 2-1) used in plotting log K,w values in Figures 2-2 through
2-5 were estimated assuming a constant entropy of fusion (ASf)(Yalkowsky, 1979).
For most compounds, this method may be preferred over attempts to find reliable
measured AHf values needed for a direct calculation. However, in the case of
benzo(a)anthracene the S; values estimated using the average ASf value was about
one order of magnitude higher than that calculated using the AHf value reported by
Chio et al. (1985). Thus, the reasons for the observed deviation of
benzo(a)anthracene data points from the ideal line are indeterminate.


27
the few cases where the propagated error was larger than the average Kdw value as
was the case for anthracene and fluoranthene. Note that both compounds were
present in small quantities in the neat fuel and or analytical problems were
encountered in detecting small aqueous phase concentrations. Several factors other
than nonideal behavior could result in apparent deviations such as analytical
uncertainty in Kdw, as well as, errors incurred in the estimations of Sz (i.e.,reported
Sw values and the use of a constant aSz value).
The success in applying Raoults law for gasolines, diesel fuels, and motor oils
leads to the question of whether ideal behavior can also be assumed for coal tars.
Compared to gasolines, diesel fuels, and motor oils coal tars are even more complex
in composition, especially because over 60% of their constituents are not known.
Gasolines, diesel fuels, and coal tars collected from different sites vary greatly in
their composition, but only a small variance exists in their molecular weights (Cline
et al., 1991; Hagwall, 1992). In contrast, different coal tars exhibit a wide range in
composition, MW0 and p0 (EPRI, 1993). The applicability of Raoults law to
tar/water partitioning will be assessed as well as the potential for nonideal behavior.


72
Materials and Methods
Sorbents
The primary sorbents used in this study were Eustis fine sand (Psammentic
Paleudult) from Florida containing 96.4%, 1.8%, 1.8%,and 0.39% sand, silt,clay,and
organic carbon (OC), respectively; and Webster silty clay loam (Typic Haplaquoll)
from Iowa (5 miles north and 3 miles east of Ames) containing 30.7%, 42.8%, 27%,
3.0% sand, silt, clay (predominately montmorillonite), and OC, respectively. Specific
surface measurements by N2-BET of approximately 4 m2/g was obtained for a similar
Webster soil subsample used in previous studies (Rao et al., 1988). Both the Eustis
and Webster soils were collected from the surface horizon (0-30 cm). The soil OC
contents were determined using the Walkley-Black method (Nelson and Sommers,
1982). The soil-solution pH in 0.01 N CaCl2 was 5.0and 6.9 for Eustis and Webster
soils, respectively. Soils were air-dried and passed through a 2 mm sieve prior to use.
Chemicals
The organic acids used in this study are listed in Table 3-1 along with selected
physical and chemical properties. All crystalline compounds had a chemical purity
of >98%. All solvents were purchased from J.T. Baker (high purity, HPLC grade)
and used without further preparation. For sorption experiments with
pentachlorophenol (PCP), I4C uniformly ring-labeled compound was purchased from
Sigma Chemical Co. with a specific activity of 12 mCi/mmol and a reported
radiochemical purity of >98%.


172
Little, Arthur D. 1981. Reference constants for priority pollutants and selected
chemicals. Reference #84204. Report to Wald, Harkrader, and Ross.
Washington, DC.
Loeppert Jr., R.H., L.W. Zelany, and B.G. Volk. 1977. Acidic properties of
kaolinite in water and acetonitrile. Soil Sci. Soc. Am. J., 41:1101-1106.
Loeppert Jr., R.H., L.W. Zelany, and B.G. Volk. 1979. Titration of pH-dependent
sites of kaolinite in water and selected nonaqueous solvents. Clays and
Clay Minerals, 27: 57-62.
Loeppert Jr., R.H., L.W. Zelany, and B.G. Volk. 1986. Acid properties of
montmorillonite in selected solvents. Clays and Clay Minerals, 34:87-92.
Ludwig, M., V. Baron, K. Kalfus, O. Pytela, and M. Vecera. 1986. Dissociation
constants of substituted benzoic acids in water and in organic solvents.
Collection Czechoslovak Chem. Commun., 51:2135-2142.
Luthy, R.G., D.A. Dzombak, C.A. Peters, M.A. Ali, and S.B. Roy. 1993. In situ
solvent extraction for remediation of coal tar sites. Technical Report,
Carnegie Mellon University, Pittsburgh, PA (in press).
MacIntyre, W.G. and P.O. deFur. 1985. The effect of hydrocarbon mixtures on
adsorption of substituted naphthalenes by clay and sediment from water.
Chemosphere, 14(1): 103-111.
MacKay, D.,W.Y. Shui, A. Chau, J. Southwood, and C.I. Johnson. 1985.
Environmental fate of diesel fuel spills on land. Report for Assoc, of
Amer. Railroads, Dept. Chem. Eng. and Applied Chem., University of
Toronto.
Mangnussen, T., P. Rasmussen, and A. Fredenslund. 1981. UNIFAC parameter
table for prediction of liquid-liquid equilibria. Ind. Eng. Cem. Process Des.
Dev., 20:331-334.
Marcus, Y. 1984. The effectivity of solvents as electron pair donors. J. Solution
Chem., 13:599-624.
Marques, R.M.L. and P.J. Schoenmakers. 1992. Modeling retention in reversed-
phase liquid-chromatography as a function of pH and solvent composition.
J. Chromat., 592(1-2): 157-182.
Martin, E.,S.H. Yalkowsky, and J.E. Wells. 1979. Fusion of disubstituted
benzenes. J. Pharm. Sci.,68:565-568.


64
(Kohl and Taylor, 1961; Stumm et al.,1980). These mechanisms have been included
among those proposed in the literature for sorption of organic acids in aqueous
solutions (Farmer and Russell, 1967; Kohl and Taylor, 1961; Stumm et al., 1980;
Davis, 1982;Kummert and Stumm, 1980); however, the impact of cosolvents on such
interactions has yet to be investigated.
In this chapter, the overall impact of methanol additions on (1) the
enhancement of solute-solvent interactions as described by solubility; and (2)
speciation changes due to cosolvent induced changes in the solutes pKa will be
assessed for the sorption of several organic acids by soils. Subsequent chapters will
assess (1) speciation changes due to changing pH at several fixed methanol/water
compositions for benzoic acid and PCP sorption; (2) the overall impact of several
solvents with a wide range in solvent properties on the sorption of benzoic acid; and
(3) the relationship between solute properties, such as acidity and hydrophobicity, on
the shapes of the sorption curves observed in methanol/water solutions.
Theory
The following log-linear model successfully describes (Yalkowsky and
Roseman, 1981; Fu and Luthy,1986; Pinal et al., 1990; Rao et al., 1985; Nkedi-Kizza
et al., 1985,1987; Rao and Lee, 1988; Woodbum et al., 1986) solubility and sorption
of HOCs in miscible solvent-water systems,
log Sb log Sw + ofc
(3-1)


54
lending support to analytical sources of error for the observed deviations.
Independently assessing the potential for nonideal behavior emphasizes the need to
account for experimental and analytical sources of errors when judging whether the
deviation noted from the ideal line is indeed the result of nonideal behavior.
5 3
x>
CO
o
1 2
11*
Diesel Fuel Composition
Monocyclic aromatics
benzene
4.42E-3
1 toluene
4.22E-2
2 ethylbenzene
5.24E-2
3 m,p,o-xylene
7.95E-2
4 trimethylbenzene 1.64E-1
Polycyclic aromatics
5 naphthalene
7.36E-2
6 methylnaphthalenes 4.88E-1
7 acenaphthene
2.34E-2
8 fluorene
3.58E-2
9 phenanthrene
5.18E-3
10 anthracene
1.06E-2
11 fluoranthene
3.41 E-3
Alkanes
n-alkane
7.36E-3
cyclohexane
3.03E-3
isoalkane
2.72E-3
aniline
7.6E-4
H20
3.83E-3
-4 -3
Log S, (moles/L)
Figure 2-11. log Kdw values for several aromatic hydrocarbons resulting from
UNIFAC model calculations plotted against log S, values along with
the ideal line based on Raoults law.
Based on the success for gasoline and diesel fuel, an attempt was made to use
the UNIFAC model to assess the likelihood of nonideality for coal tar ID#4. Since
less than 40% of the composition of this coal tar was unknown (as usually is the
case), it was represented by a single compound indicated in Figure 2-12. The
UNIFAC model simulations suggested that nonidealities are indeed small, and that


67
increasing fc for pentachlorophenolate was attributed to the relatively large
hydrophobicity of the anion and the formation of neutral ion-pairs.
Figure 3-2 illustrates the types of cosolvency curves for the sorption of organic
acids that might be predicted using Eq. (3-6). Using parameter set #3 results in the
presence of primarily the neutral species of the HIOC (pH-pKa<-l) thus yielding
cosolvency curves similar to that observed for HOCs (Eq. 3-3). In the absence of
specific interactions, a reduction in solubility with increasing cosolvent content might
be expected for a solute existing as an anion in solution, thus potentially increasing
sorption (parameter set #6). Similar results are predicted using Eq. (3-6) for a
solute with relatively small hydrophobicity (crn= 1) and assuming no impact of
cosolvency on the anionic species (a¡=0) (parameter set #2 and #5). Note how the
magnitude of the increased sorption predicted by Eq. (3-6) is a function of the inter
relationship between initial soil-solution pH (i.e.,pH-pKa w) and the o values. The
a values used in sets t 1 and ft3 are larger than those used for sets #2 and #5
changing the impact of pH variations. For sets ffl and #3, enhanced linearity and
an upward shift is observed with decreasing pH; whereas, for sets #2 and #5, the
shape of the sorption curve changes from a convex to a concave shape as pH
decreased. Therefore, the overall magnitude and direction of the sorption observed
will vary as a function of cosolvency power (a), soil-solution pH, and cosolvent
induced shifts in the observed pKa.


151
OILs can be provided with the knowledge of approximate PAH concentrations in the
organic phase and the molar volume of the organic phase.
Sorption of Organic Acids
The behavior of organic acids in solvent/water solutions was exceedingly
complex. Sorption of organic acids by soils was measured from cosolvent/water
solutions as a function of pH and cosolvent fraction (fc). In methanol/water solutions
(0.01 N CaCy, decreased sorption compared to that measured in aqueous solutions
was observed for the substituted phenols investigated; this finding was similar to that
observed for nonpolar organic solutes. Sorption of PCP was adequately characterized
by combining the log-linear cosolvency model for predicting cosolvency effects with
a model for describing solute speciation effects. For carboxylic acids, the magnitude
of sorption observed in methanol/water solutions could not be predicted. Inclusion
of cosolvent-induced changes in the solute dissociation constant (pK,) and the
uncertainty of the formation and exchange of charged ion-pairs suggest that
deviations from Eq. (3-6) predictions was due to other types of solvent-driven
complexation reactions.
To better understand the influence of ionic equilibria on the sorption of
organic acids from methanol/water solutions, sorption of benzoic acid by Webster
soil was investigated as a function of pH at fixed methanol fractions. Sorption of
neutral benzoic acid was observed to decrease with increasing fc, while benzoate
sorption increased. Thus, benzoate is responsible for the enhanced sorption of
benzoic acid by soils from methanol/water solutions. Similar trends were not


103
Results and Discussion
Sorption of benzoic acid and PCP by Webster soil adjusted to different pH
values was measured from several methanol/water solutions. In the concentration
range investigated, PCP sorption isotherms were linear in both aqueous and mixed-
solvent systems. For benzoic acid, sorption isotherms were slightly nonlinear;
however, a linear approximation of the sorption coefficients (K) was still considered
adequate. Representative isotherms for sorption of benzoic acid are shown in Figure
2. Correlation coefficients (r2) were greater than 0.92 for most data sets with smaller
r2 values usually resulting from a scatter in the data rather than from nonlinear
behavior. For completeness, the coefficients from a Freundlich fit to the benzoic
acid isotherm data are shown in Table 4-3 along with a linear approximation of the
sorption coefficients.
Table 4-3. Parameters for linear and Freundlich fits to the isotherm data for
benzoic acid as a function of pH and fc.
fc
pH
Kd(mL/g)
K^mL^g-V)
NSE
0
3.63
4.84
7.69
0.750.02
3.68
4.32
7.80
0.720.04
4.9
1.15
2.28
0.750.02
4.81
1.0
2.45
0.700.04
6.9
0.12
0.07
1.100.06
8.2
0.06
0.07
0.920.10
0.10
3.59
3.38
5.17
0.780.02
3.75
2.26
3.78
0.780.01
4.85
0.80
1.57
0.770.04
5.3
0.54
0.96
0.810.03


obs
-2
1 0 1
pH pKa
0.8
0.6
0.4
0.2
Sediment
pentachlorophenol
O dlnltro-o-cresol
A dlchlorobutyrlc acid
* Sllvex
Predicted
-5 -4 -3
(Data from Jafvert, 1990) D
-2 -1 O
pH pKa
Figure 1-3. Normalized sorption coefficients for several organic acids plotted as a function of pH-pKa. [Data from
Kukowski (1989) and Jafvert (1990)]


Se Ovg/g)
117
O 2 4 6 8 10 12
Ce (A/g/mL)
Figure 4-7. Isotherm data for benzoic acid on (A) A1203, Al(OH)3, and SAz-1
(pH~8); and (B) Pahokee muck (pH~7) along with linear and
Freundlich fits.


CHAPTER 3
COSOLVENT EFFECTS ON SORPTION OF ORGANIC ACIDS
BY SOILS FROM METHANOL/WATER SOLUTIONS
Introduction
The codisposal of contaminants, as well as the potential use of alternative
fuels and mixing of contaminant plumes from different sources, will result in
environmental contamination problems consisting of a complex mixture of chemicals
including both polar and nonpolar organics in miscible and immiscible solvent
mixtures. Solubility, sorption, and transport of hydrophobic organic compounds
(HOCs) are well characterized in aqueous solutions and various complex mixtures.
Solubility of HOCs increases with increasing volume fraction cosolvent of an organic
cosolvent (Yalkowsky and Roseman, 1981; Yalkowsky, 1985; 1987; Rubino and
Yalkowsky, 1987a; 1987b; Fu and Luthy, 1986; Pinal et al., 1990; 1991). Sorption of
HOCs is inversely related to solubility and as a result, an increase in solubility from
the addition of a cosolvent leads to a proportional decrease in sorption (Rao et al.,
1985; 1990; Nkedi-Kizza et al., 1985; 1987; Rao and Lee, 1988; Woodbum et al.,
1986; Fu and Luthy, 1986).
For hydrophobic ionizable compounds (HIOCs) of environmental interest,
data on solubility, sorption, and transport in mixed solvents are limited. Some
research investigating the impact of multiple solutes on HIOC sorption (i.e.,
58


80
(PCP) are presented in Figure 3-3. Similar results were observed for the other
compounds. For organic bases, a decrease in pKa (an acid shift) occurs upon
addition of a cosolvent (shift towards neutral species); however, the overall shift from
aqueous to neat solvents is usually much less than a single pH unit. Also shown in
Figure 3-3 are pKa values for benzoic acid determined conductometrically by Pal et
al. (1983) up to 80% methanol, and the pKa value reported byBacarella et al. (1955)
in neat methanol using a different type of potentiometric method with an electrode
system void of a liquid junction. Good agreement between our data and the
published data suggests that the procedure used in this study was adequate. The
lower pKa value obtained in this study for benzoic acid in neat methanol is most
likely due to the use of hydrated methanol (0.05%); residual water was removed from
the methanol used in the cited studies. Also the constants determined in this study
are mixed ionization constants, whereas thermodynamic ionization constants were
reported by Bacarella et al. (1955).
Solubility
Solubility data reported by Yalkowsky (1985) for benzoic acid in
methanol/water solutions are shown in Figure 3-4. Solubility increased with
increasing volume fraction methanol. For the solubility of an organic acid in an
unbuffered solution, the pH at saturation will be less than the solute pKa. For
example, the pH of an aqueous solution saturated with benzoic acid is approximately
2.8 (Bates, 1973). Thus, the neutral species dominates over the solubility profile,
with over 90% existing in the neutral form at fc>0.3. Also shown in Figure 3-4 are


55
Raoults law approximation was justified (Figure 2-3). A note of caution is in order,
however, the UNIFAC model results depend heavily on the presumed composition
of the pitch (62% mole fraction in our example with coal tar ID#4), and on the
presence of polar constitutents in coal tar (none were preesent in significant
quantities in this example).
Figure 2-12. Comparison of measured and predicted tar-water partition coefficients
for several PAHs: Raoults law (solid line) and UNIFAC model (solid
triangle).


96
from methanol/water solutions (fc<0.5) (Marques and Schoenmakers, 1992;
Schoenmakers et al., 1991; Van De Venne et al., 1978), and for chlorophenols from
acetonitrile/water solutions (fc<0.6) within the same pH range (Bourguignon et al.,
1993). Models similar to that presented in Chapter 3 (Eq. 3-6) for sorption of organic
acids by soils in mixed solvents have been employed to successfully describe retention
of organic acids in RPLC. Shown in Figure 4-1 are RPLC retention data and model
predictions (Schoenmakers et al., 1991) for benzoic acid as a function of pH and
methanol composition using mobile phases buffered with 1:2 stoichiometric mixtures
of citrate and phosphate with sodium as the counter ion. Model predictions by
Schoenmakers et al. (1991) were derived in a manner analogous to that given in
Chapter 3 (Eq. 3-6). The chromatographic retention model presented by
Schoenmakers et al. (1991) is defined in terms of chromatographic capacity factors,
whereas, the sorption model presented in Chapter 3 uses sorption coefficients.
Figure 4-1. Retention data for benzoic acid as a function of pHapp at different
methanol fraction (v/v) by RPLC.


163
Table B-2. Parameters and equations for calculating results in Table B-l.
U+ b)
(B-3)
'o,T
= C;
V. + V,
'HA,T
- C. (VT CT)
CA ~,T
c, -
'HA,T
(B-4)
(B-5)
(B-6)
pK [A1 a(B-7)
where
C¡ = Initial benzoic acid concentration (0.01 M)
Cr = Titer concentration (0.01 M NaOH)
V; = Initial Volume (25 mL)
VT = volume of titer added (mL 0.01 M NaOH)
pH meter coefficients used to calculate pH from e.m.f:
m = slope = -1
b = intercept = 6.86E-06
subscripts:
T refers to at a given point (VT,pH) on the titration curve
HA refers to neutral species of the organic acid
A' refers to ionized species of the organic acid


106
Effects of pH on Benzoic Acid Sorption at fe<0.5
Sorption coefficients estimated from batch equilibration studies of benzoic
acid in methanol/water solutions (fc<0.5) are plotted as a function of pHapp in Figure
4-3. Also included in Figure 4-3 are predictions based on an equation analogous to
Eq. (3-4):
+ *(! V <4->
where Kb n and Kbji are the sorption coefficients in the binary solvent solution of
interest of the neutral and ionized species, respectively. Recall that the conditional
dissociation constant (pKa) increases with increasing methanol content; therefore, the
fraction of the species that is neutral ($b n) is based on the pKa determined in the
solvent mixture. Values for Kb n and Kb ¡ were estimated from the measured sorption
data at the lowest and the highest pHapp, respectively. The patterns of decreased
sorption observed with increasing pHapp, and the decrease in Kb n values with
increasing fc resemble the curves shown in Figure 4-1 for retention of benzoic acid
in RPLC. However, at the higher pH values where benzoate dominates, sorption by
soils increased while retention by RPLC supports continued to decrease. Note,
however, that for the RPLC data exemplified in Figure 4-1 mobile phases were
buffered with 1:1 stoichiometric mixtures of citrate and phosphate with sodium as the
counter ion. Recall from Chapter 3 that the use K+-saturated Webster soil resulted
in the opposite sorption trends with fc compared to the Ca+2-saturated Webster soil.
Therefore, the differences observed between the soil and RPLC data could very well
be due to the different electrolyte composition.


84
Table 3-2. Retardation factors for several organic acids in aqueous and methanol
solutions from Eustis Soil.
Solute
Retardation
Aqueous
Factors
Methanol
Substituted Phenols
Pentachlorophenol
4.7
1.0
2,4-Dichlorophenol
3.6
1.0
Picric Acid
(2,4,6-trinitrophenol)
1.9
1.4
Substituted Benzoic Acids
Gentisic Acid
1.9
3.1
(2,5-dihydroxy acetic acid)
2,4,5Trichlorophenoxy Acetic Acid
1.7
2.1
2,4-Dichlorophenoxy Acetic Acid
1.4
2.7
Benzoic Acid
1.2
2.2
Pentafluorobenzoic Acid
1.0
1.6
Dicamba
1.0
2.0


140
sorption of benzoic acid, sorption is driven by two completely different mechanisms;
(2) in the presence of water, one of the two solvents acquires a property common to
the other solvent; and (3) preferential or selective solvation interactions.
For sorption of organic solutes from aqueous solutions, several mechanisms
have been proposed in the literature, including hydrophobic interactions, London-van
der Waals or dispersion forces, hydrogen bonding, cation and water bridging, cation
and anion exchange, ligand exchange, protonation, covalent bonding or
chemisorption, and interlayer adsorption. These mechanisms have not been assessed
for mixed solvent systems; however, through a deductive process, inferences can be
made from the data presented in this work regarding the relative importance of these
mechanisms for sorption of organic acids by soils. Results presented here suggested
the predominance of soil organic matter interactions, the significance of cation-type
in the sorption process, the unlikelihood of formation and exchange of positively
charged ion-pairs, and absence of chemisorption. Also, van der Waals forces can be
assumed to be negligible considering the relatively small molecular size of the
organic acids investigated, and the incorporation of hydrophobic interactions were
found to be inadequate for describing the observed sorption. Therefore, only
hydrogen bonding, and cation- or water-bridging interactions warrant further
discussion.
As previously noted from bulk solvent properties, it appears that only
methanol is capable of donating hydrogen bonds; however, there is spectroscopic
evidence (Raman and infrared spectroscopy) that DMSO complexes with water


79
Nonradiolabeled samples were analyzed by RPLC techniques as described
previously for the solubility studies. The use of autosampler vials in conjunction with
the Waters Intelligent Sample Processor (WISP 715) enabled direct analysis of the
samples by RPLC techniques without further sample transfer. The WISP 715 has the
capability of varying sampling depths within a vial allowing sampling of the
supernatant without removal of the soil. The higher mass to volume ratios (2:3),
however, necessitated transfer of the supernatant to a new vial. For 14C-labeled
solutes, 0.5 mL aliquots of the supernatant were taken from each sample and mixed
with 20 mL of Scinti-Verse II for analysis. Solute concentrations were then assayed
using liquid scintillation counting (LSC) methods employing a Searle Delta 300 liquid
scintillation counter.
Sorption coefficients, K (mL/g), were estimated by fitting the sorption data
to a linear isotherm: Se = K Ce, where Se and Ce are sorbed (jug/g) and solution
(jug/mL) concentrations, respectively, at equilibrium. The solution concentrations
were directly determined, whereas Se values were determined by difference: Se =
(C¡ Ce)(V/M), where C; is the initial solution concentration (jug/mL) of the solute;
V is the solution volume (mL); and M is the soil mass (g).
Results
pKa Measurements
The pKa values measured as a function of volume fraction (fc) methanol
increased linearly up to approximately fc=0.6,and then increased markedly at higher
cosolvent contents. Representative data for benzoic acid and pentachlorophenol


152
observed for retention of benzoic acid by RPLC supports in methanol/water
solutions buffered with 1:2 stoichiometric mixtures of citrate and phosphate withNa+
as the counterion. In the latter case, retention of both neutral and ionized benzoic
acid, although different in magnitude, decreased with increasing fc as observed for
HOCs.
A preliminary assessment of the data for benzoic acid sorption by several
sorbents suggested that the predominant sorbent fraction of interest is still organic
matter, as is generally conceptualized to be the case for the sorption of HOCs.
Numerous positive correlations have been observed between retention of HOCs by
soils and RPLC supports. The lack of such strong correlations between retention by
soils and RPLC supports for organic acids reflects the increasing importance of soil
functional groups as determinants of HIOC sorption. To explain the enhanced
sorption of benzoate by soils, other sorption mechanisms considered were: specific
solvent-sorbent and solute-sorbent interactions.
To investigate solvent-sorbent interactions, sorption of benzoic acid in binary
mixtures of water and several solvents varying in a wide range of bulk properties was
measured. The model based on cosolvent-enhanced solubility and cosolvent-
suppressed speciation effects was successful in describing benzoic acid sorption from
acetone/water, acetonitrile/water, and 1,4-dioxane/water solutions. Enhanced
sorption of benzoic acid from dimethylsulfoxide (DMSO)/water mixtures was similar
to that observed from methanol/water solutions; however, the similarities and
dissimilarities observed for the different solvent/water systems could not be


81
the solubilities of benzoic acid in acidified methanol/water solutions (0.01 M HC1)
measured in this study. At saturation, the acidified samples remained near a pH of
2. Minimal differences were observed between the solubility of benzoic acid in
acidified and nonacidified methanol/water solutions. Solubility curves were not
measured for other solutes in this study, but benzoic acid is believed to be
representative of the general behavior of carboxylic acids in methanol/water
solutions. For example, the solubility reported for dicamba in ethanol is over a 100
times greater than its aqueous solubility (Humberg et al., 1989). The observed
solubility of benzoic acid in methanol/water solutions is similar to the curve shown
in Figure 3-1 for a log Kow of 2.
To further investigate the effect of speciation on solubility, benzoic acid
solubility in solutions containing approximately 0.3MNaOH was measured for 0 to
40% volume fraction methanol. In the presence of a base, the solubility of benzoic
acid was greater than that observed in the unbuffered or acidified solutions. At the
solubility limits, the saturated solution pH was 5.0. Given the pKa and measured pH
(pHapp), speciation of benzoic acid in saturated solutions was estimated to range from
approximately 90% to 60% ionized going from aqueous solutions to fc=0.4. The
increase observed in solubility with increasing fe, parallels the increase in the neutral
species suggesting that cosolvent effects on benzoate solubility are negligible in the
range investigated (i.e.,a¡a¡ = 0).


53
behavior. However, for compounds with increasingly more aromaticity and are solids
in their standard state (PAH compounds 9-11 in Figure 2-10), the UNIFAC model
predicted some negative deviation from ideal behavior. Partition coefficients for
these compounds were not measured by Cline et al. (1991) as they are present only
in small quantities in gasoline. Compared to gasolines, diesel fuels contain a larger
fraction of low-solubility PAHs. Therefore, it was of interest to see if the UNIFAC
model estimations of y0* for these PAHs resulted in deviations from ideality.
The composition of the diesel fuel assumed in the UNIFAC model
calculations is shown in Figure 2-11. The concentrations of the eight PAHs chosen
were comparable to those found in the diesel fuels used in this investigation; the
concentrations of monocyclic aromatic hydrocarbons used were based on analyses
reported by Thomas and Delfino (1991); and the mole fraction of water was selected
based on the maximum ASTM limiting requirement for diesel fuel (Kirk-Othmer,
1980). To simulate the alkane fraction of the diesel fuel, a representative compound
for each alkane (n-, iso-, and cyclo-alkane) was selected (see Figure 2-11) in
proportion to those reported by Mackay et al. (1985). The UNIFAC model
calculations for the y0* values of the PAHs ranged between 0.99 for toluene to 1.16
for fluoranthene. The close proximity of the calculated log Kdw values (solid triangles
in Figure 2-6) to the ideal line based on Raoults law for the simulated diesel fuel
suggest that deviations from ideal behavior for PAHs smaller than fluoranthene may
be negligible. These calculations suggest that deviations from the ideal line for the
larger PAHs noted in Figure 2-1 cannot be attributed to solute-solute interactions,


107
Figure 4-3. Sorption of benzoic acid by Webster soil buffered at different pHapp
values in methanol/water solutions of fc<0.5.
Effects of pHapp on Benzoic Acid Sorption at fc>0.75
To further investigate the effect of pH and solvent composition, sorption of
benzoic acid was measured at higher methanol volume fractions (fc>0.75). The log
Kb values estimated from these studies are plotted as a function of pH-pKa in Figure
4-4. At higher methanol fractions, the curves are the inverse of those observed at
fc<0.05 (Figure 4-3); the magnitude of sorption and log(Kb n/Kb i) now increases with
pH and fc, respectively. Also note that sorption appears to be at a maximum where
pH=pKa. Anion exclusion at relatively high pH values has been noted for RPLC
supports (Schoemakers et al., 1991) where the solute and the unreacted silanol


62
For HIOCs, the impact of adding a cosolvent to aqueous solutions on the
conditional ionization constant of a HIOC must be considered. Likewise, similar
impacts on the ionization of sorbent functional groups and subsequent solute-sorbent
interactions must also be considered. Also, the impact of solvent-water interactions
that were considered negligible in predicting HOC behavior may be of importance
in understanding the chemodynamic behavior of HIOCs, as well as the different
propensities of the cosolvent and water to hydrate both the solute and the sorbent.
Cosolvent-induced interactions involving the sorbent surface include:
speciation of organic matter functional groups, clay surface acidity, and ion-
association with the surface. Both acidic and basic groups tend to become neutral
with increasing cosolvent content as a result of shifts in the pKa (Perrin et al., 1981),
leading to a net increase in hydrophobicity of soil organic matter. This phenomenon
may explain why decreases in HOC sorption with increasing fc are smaller in
magnitude than would be predicted from solubility profiles in mixed solvents (Rao
et al., 1990; Nkedi-Kizza et al., 1985; 1987; Rao and Lee, 1988). Parallel to changes
in pKa, Kan and Tomson (1990) observed a decrease in naphthalene sorption by
Lincoln fine sand from aqueous solutions by increasing pH (pKa fixed, but pH
varied). However, the increase in sorption resulting from such changes on surface
hydrophobicity are likely to be more than compensated by cosolvency effects.
The presence of cosolvents may also alter the surface acidity of the clay
fraction. Loeppert et al. (1977, 1979) found that the amount of base required to
titrate the pH-dependent sites of kaolinite varied in the following manner: methanol


137
fc was estimated assuming a linear combination of the weighted fractions [e.g.,
fce,+(l-fc)ew] (Franks and Ives, 1966). The effect of solvent composition on an acids
pKa can be expressed in terms of electrostatic and nonelectrostatic medium effects
(Popovych and Tomkins, 1981). The electrostatic contribution to the medium effect
(e.g.,ability of a solvent to separate charged species in solution) can be represented
by the Bom equation. The nonelectrostatic portion of the medium effect represents
the difference between cohesive and adhesive forces between the solute and solvent
species, assuming all solute species are uncharged. Rubino and Berryhill (1986)
suggested taking the difference between measured pKa values and those calculated
using the Bom equation in order to estimate the contribution of the nonelectrostatic
medium effects (A). Therefore, to better estimate pKa values in the various binary
mixtures, nonelectrostatic medium effects (A) were estimated by using A values
estimated from methanol/water solutions in the manner suggested by Rubino and
Berryhill (1986).
Equation (3-6) predictions for sorption of benzoic acid in the different binary
mixtures using the parameters as just described are shown in Figure 5-5 along with
the measured data. In acetone/water, acetonitrile/water solutions and dioxane/water
solutions, Eq. (3-6) does a reasonable job in estimating the observed benzoic acid
sorption. These data suggests that for some solvent/water systems, Eq. (3-6) may be
adequate to predict sorption of organic acids. However, a very poor prediction
resulted from application of Eq. (3-6) to the sorption of benzoic acid in
DMSO/water solutions similar to that observed in methanol/water solutions.


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.
John Zachara
Battelle Pacific Northwest Laboratories
Geosciences Department
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 Philosopl
August 1993
Dean, College of Agriculture
Dean, Graduate School


log K
log [Ssc,, moles/L]
Figure 2-1. log Kdw values plotted versus log S, for eight PAHs along with the ideal line (solid line) calculated from
Eq. 2-6 for each diesel fuel.
to
VO


In the absence of cosolvents and other solubility-enhancing adjuvants (e.g.,
dissolved organic carbon, surfactants, etc.), the maximum aqueous-phase
concentration (Cw) is limited by the crystal solubility (Sw). Although the hypothetical
supercooled liquid solubility is used to obtain best estimates for Cw, mixing of the
chemical with the aqueous phase is ultimately governed by interactions with the
solvent. These are expressed through the crystal solubility (Sw) (Pinal, 1988). For
a PAH that has a low aqueous solubility, high melting point, and is present in high
concentration in the coal tar, the concentration predicted in the aqueous phase
assuming ideal behavior would be the crystal aqueous solubility (Sw).
Diesel Fuels
Reasonable agreement shown previously in the predicted and measured log
Kdw versus log S¡ relationships for most PAHs (Figure 2-1) also supports the use of
Raoults law in predicting maximum PAH concentrations that may be present in the
aqueous leachate leaving a diesel-fuel contaminated area. Using Raoults law and
assuming ideal behavior, the concentration of a constituent in the aqueous phase in
equilibrium with the organic phase is proportional to the mole fraction of that
constituent in the organic phase (see Eq. 2-3). Substituting Eq. (2-5) into Eq. (2-1)
gives the following equation for the equilibrium aqueous-phase concentrations:


158
A second estimation method simplifies Eq. (A-l) by assuming that the entropy
of fusion (AH/T^ (Yalkowsky, 1979; Martin et al., 1979) is the same for all
compounds approximately 13.5 cal/mole K yielding the following equation,
log Sxl log S ^ (A-2)
Eq. (A-2) reduces the number of parameters needed to obtain Sscl for a particular
compound. Note that when calculating SscI values for a compound at a specific
temperature, the corresponding Sw value for that compound at that same temperature
must be used. When measured crystal aqueous solubilities are not available at a
temperature of interest, various temperature-solubility correlations available in the
literature can be used (May, 1980).


LIST OF TABLES
2-1. Selected physico-chemical properties for the PAHs investigated 28
2-2. Range of properties observed for eight coal tars (EPRI, 1993) ....... 33
2-3. Maximum Cw values for several PAHs based on the data compiled for eight
coal tars 45
3-1. Selected Solute Properties 73
3-2. Retardation factors for several organic acids in aqueous and methanol
solutions from Eustis Soil 84
4-1. Cation exchange capacity (CEC) in cmol(+)/kg and elemental analysis in
mg/kg of pH treated Webster soils 100
4-2. Chemical characteristics of benzoic acid and
pentachlorophenol (PCP) 101
4-3. Parameters for linear and Freundlich fits to the isotherm data for
benzoic acid sorption as a function of pH and fc 103
5-1. List of various chemical and physical solvent properties 124
5-2. List of various chemical and physical solute properties 125
5-3. Parameters for linear and Freundlich fits to the isotherm data for
benzoic acid in several solvent/water solutions 128
5-4. Parameters for linear and Freundlich fits to the isotherm data for
substituted benzoic acids in methanol/water solutions 129
5-5. The logarithms of the octanol/water partition coefficients
(log Kow) for both the neutral (subscript n) and ionized
(subscript i) species of several substituted carboxylic acids 145
IX


90
predominant species at higher cosolvent fractions, hydrogen from the neutral acid
may be displaced by the cations in the electrolyte matrix (e.g.,0.01 N CaCl2 in the
present study). Solvent-enhanced ion-pairing could result in the formation of either
neutral or charged ion-pairs in solution. Since neutral ion-pairs have been shown to
behave in a manner similar to nonpolar organic compounds (Lee et al.,1990; Westall
et al., 1985), their sorption should only decrease with increasing cosolvent content.
However, the formation of positively charged ion-pairs followed by exchange on
negatively charged soil surfaces would result in an increase in sorption.
To assess the role of the formation of charged ion-pairs (e.g., Ca-
carboxylate+), benzoic acid sorption was measured by K+-saturated Webster soil and
compared with measurements from where Ca+2 dominated the Webster soil CEC
sites, and the effect of CaCl2 concentration on benzoic acid sorption was investigated.
Sorption of benzoic acid by a K+-saturated Webster soil did not exhibit the same
behavior as observed earlier with the Ca+2 dominated soil (Figure 3-6B) where
sorption increased upon methanol addition. Note that this experiment was done on
a more recently obtained subsample of Webster soil (see Chapter 5). The sorption
coefficients measured for benzoic acid on the K+-saturated soil were 0.4 mL/g and
0.1 mL/g for fc=0.26and 0.66, respectively, compared to 0.3 mL/g and 0.7 mL/g
obtained from the Ca+2-saturated sample. This demonstrates the significance of
electrolyte composition on the sorption of HIOCs and the possibility of cosolvent-
induced formation of positively charged ion-pairs. From this conclusion an increase
in sorption with increasing Ca++ concentrations would be expected; however, no


REFERENCES
Abrams, D.S. and J.M. Prausnitz. 1975. Statistical thermodynamics of liquid
mixtures: A new expression for the excess Gibbs energy of partly or
completely miscible systems. Am. Inst. Chem. Eng. J., 21:116-128.
Ainsworth, C.C.,J.M. Zachara, and R.L. Schmidt. 1987. Quinoline sorption on
Na-montmorillonite: Contributions of the protonated and neutral species.
Clays and Clay Minerals, 35: 121-128.
Albert, A. and E.P. Sergeant. 1984. Determination of Ionization Constants: A
Laboratory Manual, 3rd ed.; Chapman and Hall, Ltd., London.
Almeida Macedo, E.,U. Weidlich, J. Gmehling, and P.A. Rasmussen. 1983.
Vapor-liquid equilibria by UNIFAC Group Contribution. Revision and
Extension. 3, Ind. Eng. Chem. Process Des. Dev., 22:676-678.
Augustijn, D.C.M.,R.E. Jessup, P.S.C.Rao, and A.L. Wood. 1992. Remediation
of contaminated soils by solvent flushing. J. Environ. Eng. (in review).
Arbuckle, W.B. 1986. Using UNIFAC to calculate aqueous solubilities. Environ.
Sci. Technol., 20:1060-1064.
Bacarella, A.L.,E. Grunwald, H.P. Marshall, and E.L. Purlee. 1955. The
potentiometric measurement of acid dissociation constants and pH in the
system methanol/water. Potentiometric Meas., 20:747-763.
Bailey, G.W., J.L. Qhite, and T. Rothberg. 1968. Adsorption of organic herbicides
by montmorillonite: role of pH and chemical character of adsorbate. Soil
Sci. Soc. Amer. Proc., 32:222-234.
Bakhtar, D., G.R. Bradford, and L.J Lund. 1989. Dissolution of soils and
geological materials for simultaneaous elemental analysis by inductively
coupled plasma optical-emission spectrometry and atomic-adsorption
spectrometry. Analyst, 114(8):901-999.
Ball, W.P.,C.H. Buehler, T.C. Harmon, D.M. Mackay, and P.V. Roberts. 1990.
Characterization of a sandy aquifer material at the grain scale. J. Contain.
Hydrol., 5:253-295.
164


98
In this study, sorption of organic acids was measured as a function of pH at
several methanol fractions with the most attention given to data collection of benzoic
acid sorption by Webster soil. However, to further elucidate the mechanisms of
importance for benzoic acid sorption by soils and how to relate various solute and
sorbent characteristics to the sorption process, preliminary data was collected for
benzoic acid sorption by other sorbents in aqueous and neat methanol solutions as
well as for sorption of PCP by Webster soil in methanol/water solutions.
Materials and Methods
Sorbents
The sorbent used in this study was a Webster silty clay loam (Typic
Haplaquoll) from Iowa containing 30.7% sand, 42.8% silt, 27% clay, and 3.0%
organic carbon (OC). Soil samples were air-dried and passed through a 2 mm sieve
prior to use. For the equilibration studies conducted at different pHs (range 3 to 9)
subsamples of the Webster soil were further treated to be homoionic with Ca2+ using
a method similar to that employed by Rhue and Reeve (1990). Soil (25 grams) was
equilibrated in 250-mL polycarbonate centrifuge bottles with 125 mL of 1.0 N
calcium acetate adjusted to the desired pH with either hydrochloric acid (HC1) or
sodium hydroxide (NaOH), centrifuged and decanted. This procedure was repeated
twice, followed by two washes with pH adjusted 1.0 N CaCl2. Final rinsing with
ethanol was done to remove excess salts. The presence of excess salts was tested by
adding a few drops of silver nitrate to the supernatant. Ethanol rinsing continued
until no precipitate (AgCl) was detected in the supernatant. The soils were then air-
dried, gently ground, and stored for future use.


100
Table 4-1. Cation exchange capacity (CEC) in cmol(+)/kg and elementental
analysis in mg/kg of pH treated Webster soils.
Element
pH Treatment
3
4
5
9
Untreated (7)
CEC
30
42
35
42
40
Ca
7,050
9,250
10,200
10,300
9,080
Mg
3,870
4,380
4,690
4,140
4,850
Na
7,090
6,910
6,770
8,130
7,490
K
11,200
14,000
14,000
12,500
13,600
P
383
415
502
420
434
Si
288,000
292,000
279,000
283,000
267,000
B
24.3
30.5
24.5
24.1
19
Ba
434
482
541
495
420
Sr
113
116
126
131
111
Li
11.1
15
14
11.4
12
Ti
2,250
2,440
2,530
2,280
2,090
A1
47,000
49,500
52,300
47,400
45,000
Fe
22,700
24,600
26,200
21,200
21,900
Mn
322
387
503
362
376
Cu
2.14
12.1
32.2
19.1
ND
Zn
53.3
61.1
66.1
52.7
45
V
52.1
68
68.6
53.6
62.5
Ni
15.1
18.1
18.5
14.2
14
Co
3.11
5.22
4.69
3.17
6.32
Cr
33.3
41.3
45.2
31.8
37.1
Be
2.38
2.82
2.89
2.48
1.67
Ba
24.1
44.7
35.1
14.1
32.7
Y
11.5
13.6
14.1
11.5
10.5
Total
12,100
13,900
14,800
13,800
11,700


66
and subscripts n and i refer to neutral and ionized species, respectively. Similar
findings for the sorption of several other organic acids by various sorbents have been
reported in the literature (Jafvert, 1990; Kukowski, 1989; Fontaine et al., 1991).
If solubility of a solute increases with addition of a cosolvent to an aqueous
solution (see Figure 3-1), a decrease in sorption is expected. Also, the addition of
a solvent with a low dielectric constant will result in an alkaline shift in the pKa of
an organic acid (Perrin et al., 1981), leading to an increase in the fraction of neutral
species. In the absence of specific adsorption reactions, the neutral species will be
sorbed to a greater extent. Therefore, the addition of a cosolvent brings about two
opposing effects. To incorporate both speciation and cosolvent effects, Eq. (3-1) and
Eqs. (3-3, 3-4, and 3-5) were combined,
(3-6)
where
p lo'*0"4 ; p. 10'ao¡/*
(3-7)
The cosolvency power for the neutral species (aj will increase relative to
hydrophobicity. The cosolvency power for the ionized species (ct¡) will be a function
of the relative hydrophobicity of the anion and the potential for ion-pairing. For
example, Lee et al. (1990) observed a log-linear decrease in sorption of PCP by
Webster soil in methanol/water (0.01 N CaCl2) solutions (fc= 0 to 40%) for both the
neutral species (pH < 3) and ionized species (pH < 9) with resulting values for aiai and
ann were 7.56 and 3.88, respectively. The decrease in sorption observed with


157
Solid (T )
' nr
(2)
- Liquid (Tm)
(1)
Crystal-Super-cooled liquid
Solid (T)
(A)
(3)
(B)
Liquid (T) - Solution
Figure A-l. Schematic representation of the steps involved in the thermodynamic
cycle for producing a supercooled liquid from a crystal solute.
Supercooled liquid solubilities (Sscl) cannot be determined directly; however,
several estimation methods are available. Two of the most widely used methods will
be discussed briefly. First, Sscl of a compound can be calculated directly from its
measured heat of fusion (AHf) and melting point (T^:
l0g Sscl l0g SyvJ + 2.303 R T T ^Tm~ ^ ^ ^
tn
where Sw T is the crystal aqueous solubility (moles/L) at a given temperature T (K);
R is the gas constant (kJ/degree mole); AHf is the heat of fusion (Kcal/mole), and
Tm is the melting point in K. For most chemicals of interest, the parameters needed
in Eq. (A-l) are available in the literature. Little variation was noted in AHf values
for compounds found in more than one literature source; however, in some cases the
units reported were in error (e.g.,calories vs. joules).


Table 3-1. Selected Solute Properties
Solute
Melting
Point1 (C)
Molecular
Weight1
PK.
Aqueous
Methanol2
Aqueous
Solubility3
(mg/L)
Log
Kow3
Pentachlorophenol
190
266.3
4.744
8.6
14
5.01
2,4-Dichlorophenol
42
163.0
7.854
11.9
4,500
3.23
Picric Acid (2,4,6-trinitrophenol)
121
229.1
0.4191
4.1
14,000
2.03
Gen ti sic Acid
205
154.1
2.971
7.6
21,5002
NA9
(2,5-dihydroxybenzoic acid)
2,4,5-trichlorophenoxy acetic acid
156
255.5
2.85
7.4
278
NA
2,4-dichlorophenoxy acetic acid
138
221.0
2.641
7.6
890
NA
Benzoic Acid
122
122.1
4.201
9.0
2,900
1.87
Pentafluorobenzoic acid
101
212.1
1.496
5.8
NA
NA
Dicamba (3,6-dichloro-o-anisic acid)
115
221.9
1.947
6.9
7,900
2.468
1 From Dean (1985); 2 This study; 3 From Verschueren (1983); 4 From Callahan et al.(1979); 5 Koskinen and OConnor
(1979); 6 From Walters (1982); 7 From Kearney and Kaufman (1976); 8 EPA Environmental Fate One-Line Data Base,
Version 3.04;9 Not available.


48
where the subscripts df and w refer to diesel fuel and water, respectively. In Figure
2-8, PAH concentrations predicted using eq 2-7 were converted to commonly
reported units (/ig/L) and plotted against concentrations measured in the laboratory
partitioning studies with the four diesel fuels.
log [Measured C, ug/L]
Figure 2-8.
Comparison of laboratory-measured aqueous-phase
concentrations (Cw, /xg/L) with those predicted on the basis of
Raoults law for four diesel fuels.


14
Cosolvency
The effects on solubility and sorption (hence, on transport) of organic
chemicals upon addition of one or more organic cosolvents to an aqueous solution
are defined here as cosolvency. This section will focus on the most significant
interactions affecting solubility and sorption of both HOCs and HIOCS. Such
interactions include solute-cosolvent, cosolvent-cosolvent, and cosolvent-water
interactions for solubility; for sorption, solvent-sorbent interactions must also be
considered.
Solubility in Mixed Solvents
The log-linear cosolvency model and the UNIFAC model are among the
theoretical approaches that have been used to examine cosolvent effects on solubility
(Fu and Luthy, 1986a; Pinal et al., 1990). The log-linear cosolvency model
(Yalkowsky and Roseman, 1981) is based on the central assumption that the
logarithm of the solute solubility in a mixed solvent is given by the weighted-average
of the logarithms of solubilities in the component solvents in the mixture; the
weighting coefficient is taken to be the volume fraction of each solvent component.
Thus,
log sm Y,fi lo9 si (1_4)
where S is solubility (mg/L), f is volume fraction of the solvent, and the subscript m
denotes mixed solvent and i the i-th cosolvent. Note that averaging the logarithms
of solubilities is equivalent to averaging the free energies of solution in different
solvents in the mixture.


160
concentrations due to the enhancement of the electrostatic interactions. Hydrogen
ion activities were used in combination with concentration-based measurements of
the neutral and ionized species of the acid were used to estimate the ionization
constant in this study, thus refered to as a "mixed constant".
Titration data for the determination of the mixed ionization constant (KaM)
for benzoic acid in 10/90 methanol/water solutions are given in Table B-l. Also
shown in Tables B-l and B-2 for each point on the titration curve (pH as a function
of base added), are the calculation results for each subsequent steps used to
determine KaM as given by Albert and Sergeant (1987). Each step is referenced to
an equation which is define in Table B-2.


154
with selective solvation and preferential orientation of the solvent molecules in the
solvation shells about the solute and sorbent are most likely responsible for the
enhanced sorption of organic acids by soils in methanol/water and DMSO/water
solutions.
Although there remains many uncertainties concerning the specific mechanism
responsible for the enhanced sorption of carboxylic acids by soils in mixed solvents,
results of this research point to the fallacy of assuming that all organic acids undergo
enhanced transport in the presence of an organic cosolvent. This may be directly
applied to the assessment of contaminant mobility from a codisposal site, extraction
schemes for simultaneous extraction of HIOCs and HOCs, as well as to the expedient
design of tracers for alcohol-based fuels (e.g., alternate fuels). In addition, the
different sorption profiles observed with various solutes (i.e., HOCs, phenols,
carboxylic acids) from solvent/water solutions suggests the use of different solutes to
probe solvent-sorbent interactions. Likewise, solute interactions with soil surfaces
that are considered negligible in aqueous solutions may become unmasked upon
addition of a solvent.


10
importance for most soils due to the predominance of negatively charged surfaces.
Similar to cation bridging, but a much stronger interaction, is ligand exchange which
involves the formation of an inner-sphere complex with a structural cation of a soil
mineral (i.e., displacement of either water or hydroxyl molecules from iron or
aluminum oxides)(Stumm et al., 1980;Kummert and Stumm, 1980). Ligand exchange
is commonly believed to be the mechanism responsible for the adsorption of
oxyanions. Likewise, protonation involves the formation of charge-transfer complexes
with protons on mineral surfaces and organic functional groups such as amino and
carbonyl groups. Interlayer adsorption involves the sorption and entrapment of
solute molecules within clay interlayers. From infrared spectroscopic data, Farmer
and Russell (1967) infer that benzoic acid enters the interlayer space as an unionized
monomer, and then the oxygens from both the hydroxyl and carbonyl groups become
coordinated to the interlayer cation.
In many cases, it is difficult to definitively conclude what particular mechanism
is responsible for the observed sorption; however, frequently we can predict the
magnitude of sorption by incorporation a few parameters. For example, on the basis
of an analysis of a large data set for pentachlorophenol (PCP) sorption from aqueous
solutions by several sorbents over a broad pH range, Lee et al. (1990) showed that
equilibrium sorption could be predicted with a knowledge of pH, organic carbon
(OC) content of the soil, and the acid dissociation constant (pKa) for PCP. Their
model for predicting sorption coefficient is:
Koc *oc,A + Koc.i (1 4>a)
(1-2)


97
The impact of speciation changes, resulting from cosolvent-induced changes
in the solute pKa, on organic acid sorption was explored in the Chapter 3. For
carboxylic acids, the magnitude of sorption observed in methanol/water solutions
could not be predicted by combining the log-linear cosolvency model which was
successful for describing sorption of HOCs from mixed solvents, and a speciation
model successfully used to describe sorption of HIOCs from aqueous solutions (Eq.
3-6). Inclusion of cosolvent-induced changes in pKa and elimination of the charged
ion-pair formation in solution suggested that observed deviations from Eq. (3-6)
predictions were probably due to specific, surface complexation reactions.
Consideration was given to the potential errors associated with measuring soil-
solution pH in mixed solvents and how these errors might effect model predictions;
however, this issue was not definitively resolved.
An investigation of the impact of pH changes within a given solvent/water
fraction may help to better differentiate the roles of the ionized and neutral species
on the overall sorption of carboxylic acids by soils. An estimate of pH will be done
as in Chapter 3 by using the measured pH of the soil solution (pHapp) without any
corrections. Schoenmakers et al. (1991) also used pHapp as an estimate of the system
pH (Figure 4-1). Note that comparing pH effects at a given volume fraction
cosolvent (fc) is less problematic than comparing cosolvent effects at a given pH,
especially at high fc (i.e.,the trends within a given solvent/water solution will be
similar). Therefore, an investigation of pH effects at a given fc on sorption of organic
acids may also help to elucidate the effective pH of the soil-suspension in mixed
solvents.


166
Callahan, M.A.,M.W. Slimak, N.W. Gabel, I.P. May, C. Fowler, J.R. Freed, P.
Jennings, R.L. Durfee, F.C. Whitmore, B. Maestri, M.W. Mabey, B.R. Holt,
and C. Gould. 1979. Water-related environmental fate of 129 priority
pollutants. USEPA, Washington, DC. Vol. I and II, EPA-440/4-79-029a
and EPA-440/4-79-029b.
Chen, C. S-H. 1993. Partitioning of Motor Oil Components into Water. Masters
Thesis, University of Florida, Gainesville, FL.
Chiou, C.T.,L.S. Peters, and V.H. Freed. 1979. A physical concept of soil-water
equilibria for nonionic organic compounds. Sci., 206:831-832.
Chiou, C.T.,P.E. Porter, and D.W. Schmedding. 1983. Partition equilibria of
nonionic organic compounds between soil organic matter and water.
Environ. Sci. Tech., 17: 227-231.
Chiou, C.T. and D.W. Schmedding. 1982. Partitioning of organic compounds in
octanol-water systems. Environ. Sci. Tech., 16:4-10.
Choi, P.B.,C.P. Williams, K.G. Buehring, and E. McLaughlin. 1985. Solubility of
aromatic hydrocarbons in mixtures of benzene and cyclohexane. J. Chem
Eng. Data, 30:403-409.
Cline, P.V.,J.J. Delfino, and P.S.C.Rao. 1991. Partitioning of aromatic
constituents into water from gasoline and other complex solvent mixtures.
Environ. Sci. Tech., 25:914-920.
Davis, J.A. 1982. Adsorption of natural dissolved organic matter at the
oxide/water interface. Geochimica et Cosmochimica Acta, 46:2381-2393.
Dean, J.A. 1985. Langes Handbook of Chemistry, 13th ed. McGraw-Hill Inc.,
New York, NY.
De Ligny, C.L. and M. Rehbach. 1960. The liquid-junction potentials between
some buffer solutions in methanol and methanol-water mixtures and a
saturated KC1 solution in water at 25C. Recueil, pp.727-730.
Dzombak, D.A. and R.G. Luthy. 1984. Estimating sorption of polycyclic aromatic
hydrocarbons on soils. Soil Sci., 137:292-308.
Eisenberg, D. and W. Kauzmann. 1969. The Structure and Properties of Water.
Oxford University Press, New York.


and I would like to acknowledge both staff and faculty for their continual support
throughout the past fourteen years. I also thank my family, as well as two dear
friends, Donna English and Dagne Hartman, whose long-suffering and support have
not gone unnoticed, and God for His unfailing grace, love, and guidance. I would
also like to acknowledge the unique inspiration Ive received from Dr. Jim Davidson
and Dr. George Bailey.
The financial support I received from Dr. Rao as my major professor and
supervisor, as well as the Subsurface Science Program, United States Department of
Energy through a contract (DE-AC06-76RLO) to Battelle PNL; United States
Environmental Protection Agency through a cooperative agreement (CR-814512);
and the Electric Power Research Institute (contract #RP-2879-7) is gratefully
acknowledged.
IV


26
Raoults law for the partitioning of MAHs as well as some PAHs from new and used
motor oil. Given the absence of experimental artifacts, nonideality was noted for the
partitioning of MAHs from the new motor oils, whereas, the one PAH investigated
(phenanthrene) partitioning was successfully predicted using Raoults law and
supercooled liquid solubilities. However, Raoults law appeared applicable within
a factor-of-four for the partitioning of both MAHs and several PAHs from used
motor oil.
Hagwall (1992) measured the partitioning of several PAHs from diesel fuel
into water and concluded that the use of supercooled liquid solubilities (S^,) in
applying Raoults law was not successful. However, Hagwall (1992) used an
inaccurate estimation of S^, resulting in a wrong conclusion regarding the
applicability of Raoults law. Using the crystal solubilities (Sw) given in Table 2-1
and assuming a constant ASf of 13.5 eu, a much better relationship was observed
between log Kdw and log S,. In Figure 2-1, the measured log Kdw values are plotted
against their log S, for the eight PAHs investigated along with the ideal line (solid
line) calculated from Eq. (2-6) for each diesel fuel using the MWQ and p0 given by
Hagwall (1992). For most PAHs in all four diesel fuels, the log Kdw values lie near
the ideal line suggesting that the assumption of ideal behavior may be adequate for
describing the partitioning of PAHs from diesel fuels to water. The confidence
intervals (bars) shown in Figure 2-1 were estimated using an error propagation
method (Shoemaker et al., 1980) which incorporates the errors incurred in the
analysis of both the neat fuel and aqueous phase concentrations. Arrowheads reflect


log K
38
log [S, moles/L]
Figure 2-3. Comparison of measured tar-water partition coefficients (K^) and
predictions based on Raoults law, for ID# 3(A) and ID# 4(B) coal
tars.


Copyright 1993
by
Linda S. Lee


50
manner (Chiou and Schmedding, 1982):
(MW\
log Kd -log S¡ log
j
- log y* + log
/ .\
Yw
V Yw>/
(2-8)
Comparison of Eqs. (2-6) and (2-8) suggests that any deviations due to nonideal
behavior will arise from the last two terms on the right hand side of Eq. (2-8).
Baneijee (1984) observed that the presence of other components in the aqueous
phase had a minimal effect on solute activity; therefore, it was assumed that yw7yw
= 1, thus requiring only estimates of y0*. The UNIFAC model UNIFAC
(UNIQUAC Functional-Group Activity Coefficient) model proposed by Prausnitz et
al. (1980) for estimating activity coefficients in liquid-liquid equilibria was employed
to estimate y* values needed in Eq. (2-8). In this model, a mixture of different
chemicals is treated as a mixture of functional groups constituting the components
of the mixture. Interactions between functional groups in the mixture, and the likely
nonidealities resulting from such interactions, are calculated in order to estimate the
activity coefficient of a chemical for a specified phase. Interaction parameters
required in the UNIFAC model were obtained from the most current update
(Hansen et al., 1991).
A schematic representation of Eqs. (2-6) and (2-8) is shown in Figure 2-9 as
a plot of log Kd versus log S¡. Note that the expected relationship for an ideal
mixture is depicted by the solid line, with a unit slope and the intercept given as the


161
Table B-l. Determination of the ionization constant (pKaM) for benzoic acid in
10/90 methanol/water.
VT
Meas.
o
u
C-ha/t
C-a-.t
(mL)
PH
(M)
(M)
(M)
[HA]/[A-] pKa
0.00
3.15
1.00E-02
1.00E-02
0.00E+00
0.05
3.23
9.98E-03
9.80E-03
1.80E-04
54.43
4.97
0.10
3.29
9.96E-03
9.60E-03
3.60E-04
26.65
4.72
0.15
3.36
9.94E-03
9.40E-03
5.40E-04
17.40
4.60
0.20
3.43
9.92E-03
9.20E-03
7.21E-04
12.77
4.54
0.25
3.49
9.90E-03
9.00E-03
9.01E-04
9.99
4.49
0.30
3.54
9.88E-03
8.80E-03
1.08E-03
8.14
4.45
0.35
3.60
9.86E-03
8.60E-03
1.26E-03
6.81
4.43
0.40
3.65
9.84E-03
8.40E-03
1.44E-03
5.82
4.42
0.45
3.70
9.82E-03
8.20E-03
1.62E-03
5.05
4.40
0.50
3.75
9.80E-03
8.00E-03
1.80E-03
4.43
4.40
0.55
3.79
9.78E-03
7.80E-03
1.98E-03
3.93
4.38
0.60
3.84
9.77E-03
7.60E-03
2.17E-03
3.51
4.39
0.65
3.88
9.75E-03
7.40E-03
2.35E-03
3.15
4.38
0.70
3.92
9.73E-03
7.20E-03
2.53E-03
2.85
4.37
0.75
3.96
9.71E-03
7.00E-03
2.71E-03
2.58
4.37
0.80
3.99
9.69E-03
6.80E-03
2.89E-03
2.35
4.36
0.85
4.03
9.67E-03
6.60E-03
3.07E-03
2.15
4.36
0.90
4.06
9.65E-03
6.40E-03
3.25E-03
1.97
4.35
0.95
4.10
9.63E-03
6.20E-03
3.43E-03
1.81
4.36
1.00
4.13
9.62E-03
6.00E-03
3.62E-03
1.66
4.35
1.05
4.17
9.60E-03
5.80E-03
3.80E-03
1.53
4.35
1.10
4.20
9.58E-03
5.60E-03
3.98E-03
1.41
4.35
1.15
4.24
9.56E-03
5.40E-03
4.16E-03
1.30
4.35
1.20
4.27
9.54E-03
5.20E-03
4.34E-03
1.20
4.35
(Table B-l continued)


CHAPTER 6
SUMMARY AND CONCLUSIONS
Complex Mixtures
Contamination of soils and water at waste disposal sites commonly involve
various combinations of nonpolar or hydrophobic organic chemicals (HOCs) and
hydrophobic ionogenic organic chemicals (HIOCs), as well as mixtures of water and
one or more organic cosolvents (either completely or partially miscible in water).
These mixtures may be considered complex based on the number of chemicals that
constitute the mixture. On the other hand, complexity of a mixture can be defined
by considering how the properties of the mixture deviate from some "ideal" behavior,
regardless of the number of components. The former view corresponds to a mixture
being complex in composition, whereas the latter implies complexity in behavior. The
important point is that a mixture can be complex in composition without being
complex in behavior and vice versa. In general terms, structurally similar chemicals
are likely to form "ideal" mixtures. Emphasis of this work was on understanding the
chemodynamics (e.g., solubility, sorption, and transport) of such complex mixtures.
Experimental and theoretical analyses presented focus on: (1) liquid-liquid
partitioning behavior of aromatic hydrocarbons between environmentally relevant
organic immiscible liquids (OILs) and water; and (2) the solubility and sorption of
HIOCs by soils from completely miscible-organic solvent/water mixtures.
149


49
Also included in Figure 2-8 are the confidence intervals for both the measured and
predicted concentrations. Measured concentration errors were estimated from the
standard deviations observed in triplicate analyses of the aqueous phase; confidence
intervals with arrows reflect limits of detection. Similarly, the errors associated with
the predicted values were estimated from the standard deviations obtained from
triplicate analyses of the neat diesel fuel, i.e., the determination of Cdf. The
confidence intervals given for the predicted Cw in Figure 2-8 did not include errors
incurred in estimating MWd( or pdf. Overall, the correspondence between measured
and predicted equilibrium aqueous phase concentrations shown in Figure 2-8 is to
be very good.
Assessment of Deviations from Ideal Behavior for Equilibrium Conditions
The relationship between Kd and S¡ assumed previously (el 2-6) was based on
the simplifying assumption of ideal behavior (i.e.,y0* = 1 and yw* = Yw)- Several
factors may cause deviations from the assumed ideal behavior for diesel-water
partitioning of PAHs. For example, negative deviations from the ideal line could
result from the presence of surfactants or emulsions or sufficient nonideality, while
positive deviations can be expected if equilibrium has not been reached, and
apparent deviations (positive or negative) can result from uncertainty in parameter
estimation.
For a mixture which is complex in composition and behaves in a "nonideal"
fashion, the partition coefficient (Kd) between an organic liquid and an aqueous
phase can be related to the aqueous solubility of the pure liquid (S) in the following


124
(uniformly ring-labeled) with a specific activity of 13.3 mCi/mmol, purchased from
Sigma Chemical Co., with a reported purity of >98%.
Table 5-1. List of various chemical and physical properties of solvents.
Parameter Acetone Acetonitrile DMSO Methanol l,4Dioxane
Boiling Point (C)a
56
81.6
189
64.96
101.2
log Kowb
-0.24
-0.34
-2.03
-0.82
-0.42
Density (g/mL)a
0.788
0.786
1.101
0.792
1.03
Hildebrand Solubility b
Parameter (MPa'1 /2)
20.2
24.3
24.5
29.6
20.5
Surface Tension (dyne/cm)1
*26.3
29.6
43.5
24
36.2
Hydrogen Bond Donor0
0
na!
0
24.6
NA
Hydrogen Bond Acceptor0
27.12
18.27
28.2
49.2
NA
Viscosity (mN s m'2) a
0.34
0.375
2
0.54
1.2
Refractive Index*
1.35
1.34
1.48
1.33
1.422
Dielectric constant*
20.7
37.5
47
32.7
2.2
Dipole moment (D)a
2.88
2.7
3.9
1.66
Ej-OO) (kcal/mole)b
42.2
45.6
45
55.4
36
Donor No. (kcal/mole)d
17
14.1
29.8
19
14.8
Acceptor No. (kcal/mole)b
12.5
18.9
19.3
41.5
10.8
oe
3
2.74
2.96
2.25
3.3g
pKa s (Benzoic Acid)h
18.2
20.7
8.7
8.96
NA
a Dean (1972); b Reichardt (1990); c Yalkowsky, 1985;d Marcus, 1984;e NA
means not available; f Estimated by a log-linear regression of solubility versus
volume fraction cosolvent (fc=0 to 0.8) with a force fit through the aqueous
solubility; g estimated by adding the difference observed between o values for
anthracene in DMSO/water and 1,4-dioxane/water solutions (Pinal et al., 1990) to
the an value for benzoic acid in DMSO/water solutions; Ludwig et al., 1986;' Not
Available


log K
40
7
6
5
4
-6 -5.5 -5 -4.5 -4 -3.5 -3
log [S{ moles/L]
Figure 2-5. Comparison of measured tar-water partition coefficients (K^) and
predictions based on Raoults law, for ID# 7N(A) and ID# 9(B) coal
tars collected by EPRI.


19
In addition, the different propensities of the cosolvent and water to solvate both the
solute and the sorbent will be important in understanding the sorption of HIOCs.
The existence of codisposal sites, implementation of cosolvents in remediation
schemes, and the development of alcohol-based fuels further warrants a better
understanding of the behavior of HIOCs in complex solvent mixtures.
Emphasis of this work was on understanding the solubility and sorption of
HOCs in multi-phasic mixtures, and of HIOCs in complex miscible-solvent/water
mixtures. The liquid-liquid partitioning behavior of aromatic hydrocarbons between
environmentally relevant organic immiscible liquids (OILs) and water was
investigated. The applicability of Raoults law was assessed by measuring and
compiling partitioning data from several multi-component OILs, and the UNIFAC
model was utilized to estimate the likely nonidealities resulting from interactions
between components in these complex OILs. These results are discussed in Chapter
2. For the partitioning of HIOCs from binary miscible-cosolvent/water mixtures, the
role of solute hydrophobicity and acidity, solvent type, and pH on the sorption of
organic acids by a surface soil from mixed solvents was investigated. These studies
included (1) sorption of several organic acids from methanol/water solutions
(Chapter 3), (2) sorption of benzoic acid and PCP as a function of pH at several
fixed methanol/water compositions (Chapter 4), and (3) benzoic acid sorption from
additional binary mixtures of water and cosolvents with a wide range in solvent
properties, as well as, sorption of several substituted carboxylic acids from
methanol/water solutions (Chapter 5). The observed sorption of these HIOCs was
assessed in terms of cosolvent-enhanced solubility, cosolvent-induced speciation, as
well as specific and nonspecific solvent association mechanisms.


51
log VQ (see Eq. 2-8). The single data point represents a possible value for a solute
partitioning between a hypothetical nonideal mixture and water. Note that the
magnitude of deviation from the ideal line is given by the last two terms on the right
hand side ofEq. (2-8) plus an error term, e, representing experimental uncertainty.
Figure 2-9. Schematic representation of the ideal behavior (Raoults law) and
nonideality in liquid-liquid partitioning.
Application of the UNIFAC model for assessing the potential for nonideality
is presented for a gasoline, diesel fuel, and coal tar. Using the UNIFAC model,
activity coefficients (y0*) of several aromatic compounds were estimated for an
unleaded gasoline simulated to represent the relative compositions (see inset in
Figure 2-10) reported in Cline et al. (1991).


se (jug/mL)
105
Figure 4-2. Representative isotherms for benzoic acid in (A) aqueous solutions;
(B) fc=0.1; and (C) fc=0.9 buffered at several pH values.


33
Table 2-2. Range of properties observed
for eight coal tars (EPRI,
1993).
Phvsical Properties:
Ranee
Elemental Analysis:
Raneef%)
Ash
0-50%
Carbon
43-90
Water Content
0-30%
Hydrogen
2-7
TOC a
40-90%
Nitrogen
<0.5-1
Viscosity15
34-6,600 cps (40C)
Oxygen
1-33%
Density'
1.06-1.43 g/mL (24C)
Sulfur
0.4-4%
MW d
230-7806 g/mole
Cyanide
< 1-580 mg/kgh
< 1-150 mg/kg1
Organic Compounds
Ranee (mg/kg)
Metals Analvsis
Range (mg/kg)
monocyclics
13-25,300
Arsenic
3-23
polycyclic:
Beryllium
<1
2 & 3 rings
6,800-218,000
Cadmium
<1-4
> 3 rings
12,000-110,000
Lead
1-930
NPAHsf
70-1,000
Nickel
2-74
SPAHsg
0-4,000
Selenium
<1-5
Pitch
Vanadium
6-230
Chromium
< 1-230
a Total Organic Carbon; b Test Methods ASTM D445 and D88; c Test Methods
ASTM D70, D369, or D1429; d Average molecular weight determined using vapor
pressure osmometry; e Exception: asphaltene-like tar 1600 g/mole; f Nitrogen
polyaromatic hydrocarbons; g Sulfur polyaromatic hydrocarbons; h Determined using
EPA Method 4500;1 Determined using EPA Method 9010.


109
to that observed in aqueous solutions, and was well described by Eq. (4-1) (Figure
4-6). In neat methanol, however, PCP sorption increased with increasing pH (Figure
4-6) similar to that observed for benzoic acid at fc>0.75. The cosolvency curve for
PCP in neat methanol also begins to decrease at a higher pH (pHapp>6) similar to
that observed for benzoic acid in high methanol fractions. The decrease, however,
begins at pHapp much smaller than the pKa of PCP (8.45) in neat methanol.
Comparisons of (pHapp-pKa) and the pKa values given in Figure 4-5, shows that the
initial decrease in sorption of benzoic acid at high fc values also begins at pHapp > 6.
This phenomenon does not appear to happen in aqueous solutions or at lower
methanol contents; therefore, it can only be attributed to solvent-sorbent interactions.
2 4 6 8 10
pH app
Figure 4-5. Sorption of PCP by Webster soil buffered at different pH values in
methanol/water solutions of fc=0.75 and 1.0.
In reversed-phase liquid chromatography (RPLC), high ionic strength buffers
(> 0.05 M) are used to adjust the pH of the mobile phase, thus limiting the amount


139
Similar observations in methanol/water and in DMSO/water solutions (i.e.,
magnitude of sorption and large deviations from Eq. (3-6) predictions) leads to a
search for some common solvent property that may explain such behavior. However,
upon reviewing various solvent parameters summarized by Reichardt (1990)(see
Table 5-1 for a partial listing), a unique bulk solvent property could not be found
which explains the similarity or dissimilarity observed in the shape of the sorption
curves observed between different cosolvents. For example, acetone, acetonitrile,
DMSO, and 1,4-dioxane are all dipolar aprotic solvents, whereas, methanol is an
amphiprotic solvent. Of the aprotic solvents, DMSO is the solvent with a relatively
high polarizability (as reflected in a high refractive index) and a high dielectric
constant (ej which may explain the dissimilarity observed with DMSO relative to the
other aprotic solvents. However, this does not explain why similar sorption behavior
was observed with methanol, since methanol has a lower refractive index then any
of the solvents and a es whose value is between that of acetone and acetonitrile. In
terms of hydrogen bonding characteristics of the pure solvent as exhibited by
hydrogen bond donor and acceptor numbers, only methanol can act as a hydrogen
bond donor; however, methanol, DMSO, and acetone have a large ability to accept
hydrogen bonds.
The inability to identify a single solvent property responsible for the varying
behavior observed for the different solvent/water solutions suggest the contribution
of some interaction not expressed by any one bulk solvent property. This suggests
that: (1) although both methanol and DMSO have the same macroscopic effect on


logK
39
Figure 2-4. Comparison of measured tar-water partition coefficients (K^) and
predictions based on Raoults law, for ID # 5(A) and ID# 7(B) coal
tars.


22
point is that a mixture can be complex in composition without being complex in
behavior and vice versa.
To assess the extent of groundwater contamination and the long-term
environmental impacts from land disposal or spill sites containing multi-phasic
wastes, it is necessary to characterize the total amounts released and the release rates
of HOCs from the waste matrix. The properties of an organic mixture complex only
in composition are determined by the properties of its pure components and their
concentrations in the mixture. This implies that the chemicals of interest behave
ideally in the matrix containing them. Under these conditions Raoults law would
suggest that the concentration in the aqueous phase of a chemical is proportional to
the mole fraction of the chemical in the organic phase.
This chapter will focus on the use of equilibrium theory to characterize the
total amounts of PAHs released from organic liquid wastes. Coal-tar/water partition
coefficients for several PAHs were measured from several coal tars spanning a wide
range in physical and chemical properties. To estimate aqueous-phase concentrations
of PAHs in equilibrium with coal tar, the utility of applying Raoults law convention
for activity coefficients in conjunction with supercooled liquid solubilities for PAHs
that are crystalline in their pure form will be assessed. Although the majority of this
chapter is on coal tar wastes, a reassessment of diesel fuel/water and gasoline/water
partitioning data will also be presented including the use of the UNIFAC
(UNIQUAC functional group activity coefficient) model to estimate the likely
nonidealities resulting from interactions between components in these complex
organic liquids.


56
Summary
Release of aromatic hydrocarbons from an immiscible organic liquid waste is
governed primarily by solubility phenomena. In assessing the likelihood of soil and
water contamination from complex organic wastes (e.g.,gasoline, diesel fuel, and coal
tar), it is incorrect to assume that PAH concentrations in groundwater would be
equal to the corresponding aqueous solubilities of the pure compounds. Such an
assumption usually leads to considerable over-predictions of the PAH concentrations
likely to be found in groundwater.
According to the model based on Raoults law, the concentration of an
organic constituent in the aqueous phase in equilibrium with an "ideal" organic
mixture is proportional to the mole fraction of that constituent in the organic phase.
An experimental evaluation of a model based on ideal behavior was presented for
the partitioning of aromatic hydrocarbons from diesel fuel and coal tar into water,
and the results compared to data reported earlier for gasoline/water and motor
oil/water partitioning. The diesel fuel/water and tar/water partitioning of several
PAHs, all solids in their standard state, was well described within a factor of four for
diesel fuels, and within a factor of two for coal tars by employing supercooled liquid
solubilities and assuming ideal behavior. Good agreement between the observed
partitioning of several PAHs and UNIFAC model calculations for a simulated
gasoline, diesel fuel, and coal tar further suggests that the extent of deviations from
ideal behavior may be relatively small.
Agreement between the model predictions based on Raoults law and
measured liquid-liquid partitioning data for several aromatic hydrocarbons is not to
be taken as evidence that such compositionally-complex organic liquid wastes are


Ill
solutions by Lee et al. (1991), where sorption for both species decreased with
increasing fc,and the RPLC data shown in Figure 4-6B, benzoate sorption increased
with methanol content. Based on the almost one to one inverse correlation between
the slopes from regression of neutral benzoic acid and benzoate data, and assuming
the individual processes were additive, sorption would be expected to be
approximately constant over the fc range regressed. If the slopes were exactly
proportional, then the two lines would intersect at fc=0.5;however, slight differences
in the absolute values of the two slopes yields an intersection at fc of approximately
0.6.
From the slope of the neutral benzoic acid methanol/water sorption data
(nan=l-32) and the an value of 2.25 for benzoic acid methanol/water solubility data
(Yalkowsky, 1985), an equals 0.8 which is midway between the two of the Eq. (3-6)
predictions given in Figure 3-6. Recall from Chapter 3 that none of the estimated
parameters were sufficient to predict the magnitude of sorption observed at fc>0.4
(assuming no methanol enhancement of benzoate solubility, i.e.,ai~0) (See Figure
3-3). From the data in Figure 4-6 and predictions given in Figure 3-3, we can deduce
that the enhanced sorption of benzoic acid primarily results from some additional
sorption mechanism of benzoate. However, in neat methanol, neutral benzoic acid
may also contribute significantly to the enhance sorption. Note that positive
deviations from log-linear behavior were observed at fc>0.75and particularly in neat
methanol (Figure 4-5). Similar deviations were noted for PCP sorption (see Figure
3-6), but to a lesser extent.


144
values for the ionized (i) and neutral (n) species are shown in Table 5-5 along with
the pH measurements of the aqueous solutions after equilibration and aqueous
ionization constants (pKa w) for comparison. The difference between measured Kow ¡
and Kown values becomes increasingly larger with increasing acidity. An attempt to
correlate measured Kow values and pKa values with the sorption profiles observed in
solvent/water solutions for these carboxylic acids follows.
Table 5-5. The logarithms of the octanol/water partition coefficients (log Kow) for
both the neutral (subscript n) and ionized (subscript i) species of
several substituted carboxylic acids.
Compound
PKa,w
log Kow na
pHb
log Kow i
benzoic acid
4.2a
2.00
5.0
1.10
2-naphthoic acid
4.6a
3.34
6.1
1.48
9-anthroic acid
3.65a
3.5
5.4
1.27
o-chlorobenzoic acid
2.94a
2.16
4.4
0.67
m-chlorobenzoic acid
3.84a
2.79
5.3
1.52
p-chlorobenzoic acid
4.a
2.73
5.6
1.27
2,4-dichlorobenzoic acid
2.85b
2.98
4.5
0.65
2,5-dichlorobenzoic acid
2.61b
2.98
5.6
0.75
2,6-dichlorobenzoic acid
1.49b,c
2.35
4.0
-0.14
2,4,6-trichlorobenzoic acid
1.24b,c
3.07
4.6
-0.05
8 pH of aqueous solution < 0.45 after equilibration.
b pH of aqueous solution for ionized species (basic) after equilibration.


5
In contrast, a mixture of benzene and n-octanol illustrates a system simple in
composition, yet nonideal in behavior. Deviations from Raoults law assuming ideal
behavior are evident in Figure 1-1B. Such deviations, however, are not surprising
when we consider the dissimilarity in the chemical nature of these two components.
Benzene is a hydrophobic aromatic compound while octanol is an alkane with a polar
functional group (-OH). The two illustrations given in Figure 1-1 were for
compositionally simple mixtures. However, in most environmental scenarios,
mixtures with a much larger number of constituents are of interest.
Deviations from ideal behavior can arise if the activity coefficient of the solute
in the organic phase is not unity and/or if the solute activity in the aqueous phase
is significantly impacted by the presence of other components. A number of
computational schemes are available to estimate various activity coefficients such that
liquid-liquid partitioning for nonideal mixtures can be evaluated. One of the most
frequently used models for this purpose is the UNIFAC (UNIQUAC Functional-
Group Activity Coefficient) model proposed by Prausnitz et al. 1980). This model
is based on the UNIQUAC model (Abrams and Prausnitz, 1975) and the solution-of-
group concept (Wilson and Deal, 1962). In this model, a mixture of different
chemicals is treated as a mixture of functional groups constituting the components
in the mixture. The interactions between functional groups in the mixture and the
likely nonidealities, resulting from such interactions, are calculated in order to
estimate the activity coefficient of a chemical for a specified phase. Calculations
based on the UNIFAC model require the values for group interaction parameters as
well as the mole fraction of each component in the mixture. The interaction


182
Zachara, J.M., C.C. Ainsworth, R.L. Schmidt, and C.T. Resch. 1988. Influence of
cosolvents on quinoline sorption by subsurface materials and clays. Journal
of Contaminant Hydrology, 1:343-364.
Zachara, J.M., C.C. Ainsworth, and S.C. Smith. 1990. The sorption ofN-
heterocyclic compounds on reference and subsurface smectite clay isolates.
Journal of contaminant Hydrology, 6:281-305.
Zhong, W.Z., A.T. Lemley, and R. J. Wagenet. 1986. Quantifying Pesticide
Adsorption and Degradation During Transport through Soil to
Groundwater. American Chemistry Society Symposium Series No. 315.
American Chemical Society, Washington, DC.


135
Trends in soil-solution pH (pHapp) measured in binary mixtures of water and
several organic cosolvents are shown in Figure 5-4. Decreases in pHapp with
increasing fc were observed for all solvents except DMSO. The actual decrease in
pHapp observed between aqueous solutions and fc=0.8were 0.3,0.8,0.9,and l.lpH
units for methanol, 1,4-dioxane, acetone, and acetonitrile, respectively. For
DMSO/water solutions, increases in pHapp of almost 2 pH units were observed going
from aqueous solutions to fc =0.8. At first, the accuracy ofpHapp may be questioned;
however, Rubino and Berryhill (1986) observed changes of only 0.5 pH units in their
measurements of 0.01 N HC1 in aqueous and 50/50 DMSO/water solutions using a
glass electrode similar to the one used in this study. Therefore, a majority of the
change observed in soil-suspension pH with DMSO/water solutions may be due to
a specific reaction of the solvent with the sorbent in which hydroxide ions are
released.
10
CL
CL
(0
X 7
CL
B
Methanol
A
Acetone
e
Acetonitrile
DMSO
*
1,4-Dloxane
-*]
o
0.2
Figure 5-4.
0.4 0.6 0.8
Volume Fraction Cosolvent, f
Trends in soil-solution pHapp measured in binary mixtures of water and
several organic cosolvents.


34
Similar compounds were found in all of the tars, but individual hydrocarbon
concentrations varied significantly from one MGP site to another. PAH
concentrations ranged from 7,000mg/kg to 220,000mg/kg, with various naphthalenes
as the dominant components. Several monocyclic aromatic hydrocarbons (e.g.,
benzene, toluene, ethylbenzene, and xylenes (BTEX), and styrene) were also present
in concentrations ranging from 13 to 25,300 mg/kg. Much smaller amounts of
nitrogen- and sulfur-containing aromatic hydrocarbons (e.g., carbazole and
dibenzothiophene) were also found.
It is important to recognize that less than 40% (on a mass basis) of the coal
tar constituents can be quantified (see Table 2-2) using common extraction and
chromatographic techniques. The unidentified tar fraction is often referred to as the
"pitch" for operational purposes. Current sophisticated analytical techniques still lack
the capability needed to identify most of the pitch constituents; however, their
general nature may be surmised based on coal composition (e.g.,Whitehurst et al.,
1980) or oil composition. A majority of the pitch constituents are aromatic
compounds with high molecular weights and low aqueous solubilities; thus, they may
not be of direct concern in terms of groundwater contamination. However, the
physical and chemical characteristics of the pitch may exert a strong influence on the
rates of release and the equilibrium partitioning of the more-soluble tar constituents
(e.g., BTEX, naphthalenes) that are of greater environmental concern. Also,
nitrogen- and sulfur-containing aromatic hydrocarbons present in coal tars may
impart nonideal behavior.


102
centrifugal force) using a Sorvall RT6000 centrifuge. After analysis, pH
measurements of the supernatant and/or the resuspended sample were made using
a Coming Model 130 or a Fisher Accumet Model 925 pH meter and an Ingold
micro-electrode (AgCl saturated 3 M KC1 filling solution).
Sorption isotherms consisted of data collected in duplicate at no fewer than
three concentrations. Most isotherm experiments were also repeated. Blanks
containing the solution matrix with and without soil were run along with the samples
to check for coelution of any peaks from the soil in the HPLC analysis or to obtain
an appropriate background count in the LSC analysis. In the case of the soil treated
to pH8, an unidentified peak eluted at the same retention time as benzoic acid;
therefore, the area response from this peak was subtracted from the known sample
peak. Samples were usually equilibrated by rotating for 16-24 hours. In control
studies where solutions decanted from a pre-equilibration of uncontaminated soil
with 20% methanol were spiked with appropriate solute concentrations, degradation
of benzoic acid was noted after 4 hours. Therefore, samples in solutions of fc<0.2
were equilibrated for a maximum of 2 hours; no differences were observed between
sorption coefficients measured after one and two hours of equilibration time.
Solute concentrations of nonradiolabeled samples and radiolabeled samples
were analyzed using previously described (Chapter 3) reversed-phase liquid
chromatography (RPLC) and liquid scintillation counting (LSC) techniques,
respectively, and sorption coefficients (K, mL/g) were estimated by difference from
initial and equilibrium solute concentration data (Chapter 3).


log (Kb/Kj
145
Figure 5-6. Normalized sorption coefficients, log (Kb/KJ, for the sorption of
selected substituted carboxylic acids by Webster soil as a function of
volume fraction methanol (fc).


170
Johnson, R.L., S.M. Brillante, L.M. Isabelle, J.E. Houck, and J.F. Pankow. 1985.
Migration of chlorophenolic compounds at the chemical waste disposal site
at Alkali Lake, Oregon. 2. Contaminant distributions, transport, and
retardation. Groundwater, 23:652-666.
Kaiser, K.L.E. and I. Valdmanis. 1982. Apparent octanol/water partition
coefficients of pentachlorophenol as a function of pH. Can. J. Chem.,
60:2104-2106.
Kan, A.T. and M.B. Tomson. 1990. Effect of pH and concentration on the
transport of naphthalene in saturated aquifer media. J. Contam. Hydrol.,
5:235-251.
Karger, Barry L., James N. LePage, and Nobuo Tanaka. 1980. Secondary
chemical equilibria in high-performance liquid chromatography. IN: High
Performance Liquid Chromatography. Advances and Perspectives. C.
Horvath (Ed.). Academic Press, Inc., New York, Vol. 1, pp. 128-131.
Karickhoff, S.W. 1981. Semi-empirical estimation of sorption of hydrophobic
pollutants on natural sediments and soils. Chemosphere, 10:833-846.
Karickhoff, S.W. 1984. Organic pollutant sorption in aquatic systems. J.
Hydraulic Eng., 110:707-735.
Karickhoff, S.W.,D.S. Brown, and T.A. Scott. 1979. Sorption of hydrophobic
pollutants on natural sediments. Water Research, 13:241-248.
Kearney, P.C. and D.D. Kaufman, 1976. Degradation and Mode of Action:
Volume 2, Marcel Dekker Inc., New York.
Kenega, E.E. and C.A.I. Goring. 1980. Relationship between water solubility, soil
sorption, octanol-water partitioning, and concentration of chemicals in
biota. IN: Aquatic Toxicology. J.G. Eaton, P.R. Parrish, and A.C.
Hendricks (Eds.) Special Technical Publication 707; American Society for
Testing of Materials: Philadelphia, PA, pp. 78-115.
Kirk-Othmer Encyclopedia of Chemical Technology. 1980. 3rd ed.; John Wiley &
Sons; New York. Vol. 11.
Kohl, R.A. and S.A. Taylor. 1961. Hydrogen bonding between the carbonyl group
and Wyoming bentonite. Soil Sci.,91:223-227.


log k log [Kfa mL/g]
112
Figure 4-6.
Sorption data obtained for neutral benzoic acid and benzoate as a
function of methanol content.


12
Data compiled from Kukowski (1989) and Jafvert (1990) for sorption of a variety
of organic acids by soils from aqueous solutions are shown in Figure 1-3. To
facilitate viewing of sorption data from different solute-sorbent combinations
simultaneously, the pH scale is referenced to the solutes pKa (i.e., pH-pKa) and
sorption is scaled to the solutes Kn and K¡ values as follows: (Kobs K¡)/(Kn K¡).
Values for Kn and K¡ were estimated in the sorption experiments where pH-pKa was
less than or greater than one (i.e., acid was predominately neutral or ionic,
respectively). Agreement of Eq. (1-2) with the measured data suggests that the
measured bulk soil-solution pH is representative of the pH seen by the solute, and
that Kn and K¡ are additive. Note that this does not infer a particular sorption
mechanism or that the mechanisms for the neutral and ionized species are the same.
For organic bases, sorption is affected by similar factors as for organic acids.
However, ion-exchange has been shown to be the controlling sorption mechanism for
organic bases even at pH values as much as two units greater than the solute pKa
(Zachara et al., 1987, 1990; Ainsworth et al., 1987; Beilin, 1993). Competitive
sorption between compounds has also been observed for organic cations (Zachara
et al., 1987; Felice et al., 1985) In contrast, for HOCs and neutral HIOCs
competition is minimal (Zachara et al., 1987; Karickhoff et al., 1979; Schwarzenbach
and Westall, 1981; Chiou et al., 1983; MacIntyre and deFur, 1985; Rao et al., 1986).
The predominance of ion-exchange in the sorption of organic bases suggests the use
of a sorption coefficient normalized to the cation exchange capacity of the sorbent
as a first approximation, analogous to the use of for describing sorption of HOCs.


173
May, W.E. 1980. "The solubility behavior of polycyclic aromatic hydrocarbons in
aqueous systems". IN: Petroleum in the Marine Environment. L. Petrakis
and F.T. Weiss (Eds.). American Chemical Society, Washington DC, Adv.
Chem. Series, No. 185, pp. 143-192.
McGinnis, G.D.,H. Borazjani, L.K. McFarland, D.F. Pope, and D.A. Strobel.
1989. Characterization and laboratory soil treatability studies for creosite
and pentachlorophenol sludges and contaminated soil. EPA/600/S2-
88/055. U.S. EPA, Ada, OK.
Miller, M.M.,P. Wasik, G.-L. Huang, W.-Y. Shiu, and D. Mackay. 1985.
Relationships between octanol-water partition coefficients and aqueous
solubility. Envir. Sci. Tech., 19:522-529.
Millner, G.C., R.C. James, and A.C. Nye. 1992. Human health-based soil cleanup
guidelines for diesel fuel No. 2. J. Soil Contam., 1:103-157.
Mingelgrin, U. and Z. Gerstl. 1983. Reevaluation of partitioning as a mechanism
of nonionic chemicals adsorption in soils. J. Envir. Qual., 12:1-11.
Morris, K.R.,R. Abramowitz, R. Pinal, P. Davis^T *S AU*3kowsky. 1988.
Solubility of aromatic pollutants in mixed solvents. Chemosphere, 17:285-
298.
Mrkvidakov, L. and S. Pokomy. 1985. On the reliability of molecular weight
determination by vapor phase osmometry. J. Appl. Polymer Sci., 30:1211-
1218.
Murray, M.R. and J.K. Hall. 1989. Sorption-desorption of dicamba and 3,6-
dichlorosalicylic acid in soils. J. Envir. Qual. 18(l):51-57.
Nelson, D.W. and L.E. Sommers. 1982. Total carbon, organic carbon, and organic
matter. IN: Methods of Soil Analysis, Part 2-Chemical and Microbiological
Properties, 2nd ed. A.L. Page, R.H. Miller, R.H.,and D.R. Kenndy (Eds.).
ASA and SSSA Publ., Madison, WI, Ch. 29, pp. 570-573.
Nicholls, P. H. and A. A. Evans. 1991. Sorption of ionisable organic compounds
by field soils. Part 2: Cations, bases, and zwitterions. Pesticide Sci.,
33:331-345.
Nkedi-Kizza, P., M.L. Brusseau, P.S.C.Rao, and A.G. Hornsby. 1989. Sorption
nonequilibrium during displacement of hydrophobic organic chemicals and
45Ca through soil columns with aqueous and mixed solvents. Envir. Sci.
Tech., 23:814-820.


4 IMPACT OF pH ON SORPTION OF BENZOIC ACID FROM
METHANOL/WATER SOLUTIONS 95
Introduction 95
Materials and Methods 98
Sorbents 98
Chemicals 99
Equilibrium Sorption Isotherms 101
Results and Discussion 103
Effects of pH on Benzoic Acid Sorption at fe<0.5 106
Effects of pHapp on Benzoic Acid Sorption at fc>0.75 107
Effects of pHapp on PCP Sorption at fc>0.75 108
Sorption of Neutral Benzoic Acid Relative to Benzoate .... 110
Soil-Solution pHapp 113
Effect of pH Treatments 113
Sorption Domains 114
Summary 119
5 IMPACT OF SOLUTE STRUCTURE AND ORGANIC COSOLVENT ON
THE SORPTION OF CARBOXYLIC ACIDS BY SOILS FROM MIXED
SOLVENTS 122
Introduction 122
Materials and Methods 123
Sorbents 123
Chemicals 123
Equilibrium Sorption Isotherms 125
Determination of Octanol-Water Partition Coefficients .... 126
Results and Discussion 127
Sorption of Benzoic Acid in Several Solvent-
Water Solutions 133
Sorption of Several Substituted Carboxylic Acids
in Methanol/Water Solutions 143
Summary 147
6 SUMMARY AND CONCLUSIONS 149
Complex Mixtures 149
Liquid -Liquid Partitioning 150
Sorption of Organic Acids 151
Conclusions 155
vii


162
(Table B-l continued)
VT
Meas.
n
o
H
Cha.t
C-A-.T
(mL)
pH
(M)
(M)
(M)
[HA]/[A-] pKaM
1.25
4.30
9.52E-03
5.00E-03
4.52E-03
1.11
4.34
1.30
4.34
9.51E-03
4.80E-03
4.71E-03
1.02
4.35
1.35
4.37
9.49E-03
4.60E-03
4.89E-03
0.94
4.34
1.40
4.40
9.47E-03
4.40E-03
5.07E-03
0.87
4.34
1.45
4.44
9.45E-03
4.20E-03
5.25E-03
0.80
4.34
1.50
4.48
9.43E-03
4.00E-03
5.43E-03
0.74
4.35
1.55
4.51
9.42E-03
3.80E-03
5.62E-03
0.68
4.34
1.60
4.55
9.40E-03
3.60E-03
5.80E-03
0.62
4.34
1.65
4.59
9.38E-03
3.40E-03
5.98E-03
0.57
4.34
1.70
4.63
9.36E-03
3.20E-03
6.16E-03
0.52
4.35
1.75
4.67
9.35E-03
3.00E-03
6.35E-03
0.47
4.34
1.80
4.71
9.33E-03
2.80E-03
6.53E-03
0.43
4.34
1.85
4.76
9.31E-03
2.60E-03
6.71E-03
0.39
4.35
1.90
4.81
9.29E-03
2.40E-03
6.89E-03
0.35
4.35
1.95
4.86
9.28E-03
2.20E-03
7.08E-03
0.31
4.35
2.00
4.91
9.26E-03
2.00E-03
7.26E-03
0.28
4.35
2.05
4.97
9.24E-03
1.80E-03
7.44E-03
0.24
4.35
Average pKa
M = 4.37
To correct for the effect of the solvent on the e.m.f. measurements, pH
measurements of 0.001 M HC1 aqueous solution was compared to the 0.001 M
HC1 in the appropriate mixed solvent. The difference was added to the average
pKaM value estimated from the titration. Each titration set was performed in
triplicate and the estimated pKaM values averaged. For the titration exemplified
above, there was no difference between the measured pH values of the 0.001 M
HC1 aqueous and mixed solvent solution (pH = 3.07).


129
Table 5-4. Parameters for linear and Freundlich fits to the isotherm data for
substituted benzoic acids in methanol/water solutions.
Solvent
fc
Kd(mL/g)
K/mLW)
NSEa
Benzoic acidb
0
0.12
0.07
1.100.06
0.1
0.11
0.13
0.890.21
0.2
0.09
0.04
1.240.06
0.4
0.15
0.09
1.170.02
0.5
0.2
0.12
1.160.05
0.6
0.30
0.26
1.050.12
0.75
0.56
0.37
1.160.05
0.8
0.82
1.33
0.850.03
0.9
1.69
2.5
0.860.04
1.0
4.98
8.13
0.790.01
Anthroic acid
0
2.58
4.37
0.7110.02
0.2
1.98
2.35
0.9110.08
0.4
1.20
2.28
0.6710.10
0.6
1.17
2.35
0.6610.05
1
5.79
8.00
0.7910.01
Naphthoic acid
0
5.16
9.83
0.5810.03
0.2
3.26
6.35
0.6410.05
0.4
2.17
3.67
0.7410.08
0.6
1.60
2.35
0.8210.05
0.8
1.99
2.81
0.8410.02
1.0
9.91
11.72
0.7710.02
(Table 5-4 continued)


113
Soil-solution pHapp
The substantial deviation from the log-linear model in neat methanol was
attributed to sorption of neutral benzoic acid based on the assumption that pHapp was
an adequate estimator of the soil-solution pH. Recall from Chapter 3 that the
differences between measured pH (pHapp) and the calculated pH of 0.001 N HC1 in
methanol/water solutions (5) were negligible for fc<0.8. For fc=0.8,0.9,and 1.0,5
values of approximately 0.1,0.4, and 2.3 pH units were observed, respectively. If we
applied similar corrections to the pHapp measured for the soil solutions, the fraction
of benzoic acid that is neutral is only affected in the neat methanol solutions. In
neat methanol, the corrected pH (9) is approximately the same as the measured pKa
(8.95) for benzoic acid, thus, 0n=i~O.5(e.g.,pHKpKa). The point shown for neutral
benzoic acid at fc = l in Figure 4-6 is, therefore, really representative of a 50/50
mixture of neutral and ionized benzoic acid. This would offer an explanation for the
apparent deviation at fc = l from the relationship observed between neutral benzoic
acid sorption and volume fraction methanol at fc<0.9. Eventhough their is some
uncertainty about the pH and pKa measurements at fc>0.9,the magnitude of benzoic
acid sorption observed in methanol/water (0.01 N CaClj) solutions is also greater
than that predicted by Eq. (3-6) at lower fc values where this uncertainty is small.
Effect of pH Treatments
The potential for the pH treatments of the soil to significantly change other
soil properties must be considered. As previously noted, there was no measurable
change in the OC content with treatment; however, a change in speciation of the


ionized and neutral forms of the carboxylic acids log Kow values were also measured
for use as indicators of relative hydrophobicities. Correlation of the sorption profiles
for the different substituted acids with indices of acidity and hydrophobicity will be
attempted. A hypothesis for the enhanced sorption of carboxylic acids in the
presence of methanol will be deduced by assimilating the results already discussed
in Chapters 3 and 4 with those presented in this chapter.
Materials and Methods
Sorbents
The sorbent used in this study was a sample of Webster silty clay loam (Typic
Haplaquoll) from Iowa, similar in sand, silt, and clay contents to the soil sample
described in Chapter 3 and 4. The organic carbon (OC) content was slightly higher
(3.12%) and the soil-solution pH in 0.01 N CaCl2 was lower (5.8). The soil was
air-dried and passed through a 2 mm sieve prior to use.
Chemicals
The organic solvents and organic acids used in this study are listed in Tables
5-1 and 5-2, respectively, along with selected physical and chemical properties.
Solvents were purchased from either J.T. Baker (high purity, HPLC grade) or Aldrich
Chemical Co. (purity >99%), and used without further preparation with the
exception of octanol. Benzoic acid was purchased from Fisher Scientific (purity
>99%) and all other crystalline compounds were purchased from Aldrich Chemical
Co. (purity of >99%). Some of the benzoic acid experiments employed 14C material
123


76
were measured using a Coming Model 130 pH meter and a Fisher Scientific or
Orion combination micro-electrode (AgCl saturated 3 M KC1 filling solution)
following equilibration and analysis of the sample. For suspensions of Webster silty
clay loam in methanol/water solutions with a background electrolyte of 0.01 N CaCl2,
changes in the measured pH (pHxapp) of less than 0.5 pH units were observed going
from aqueous to methanol solutions. Recall that a change () of over 2 pH units
were previously noted for solutions going from aqueous to methanol solutions. This
prompts questions regarding (1) the interactions between the liquid junction
potentials arising from the solvent and soil medium; and (2) the effect of methanol
on the activity of hydronium ions on the soil surface. Given the difficulty of
answering such questions at this time, pHxapp will be used in combination with pK/
to estimate solute speciation.
Solubility Experiments
Experimental techniques described by Pinal et al. (1990) were employed to
measure benzoic acid solubility in methanol/water solutions that were either acidified
with 0.01 M HC1 or made basic with 0.3 N NaOH. These data were compared to
solubilities obtained by Yalkowsky (1985) without additions of an acid or a base.
Solute concentrations were analyzed using reversed-phase liquid chromatography
(RPLC) techniques. The RPLC system consisted of a ternary solvent pump (LDC
Milton Roy Model CM4000, Eldex Model 9600, or Gilson Model 302), a Waters
Radial Compression Column with a C-18 cartridge, a UV detector (Gilson Model
115 or Waters Model 490), and a Waters Intelligent Sample Processor (Model 710B
or 715). The composition of the mobile phase (acetonitrile/methanol/water; pH2


APPENDICES
A SUPERCOOLED LIQUID SOLUBILITIES 156
B SAMPLE pKa DETERMINATION 159
REFERENCES 164
BIOGRAPHICAL SKETCH 183
viii


69
The success of Eq. (3-6) in describing sorption of organic acids is predicated
on the ability to measure (or define) the ionization constant (pKa) and pH in the
solutions of interest. Defining pKa and pH is fairly straightforward for aqueous
systems; however, various complications must be considered for mixed solvent
systems. The pH of an aqueous solution is thermodynamically defined as the
negative logarithm of the hydrogen ion activity (aH+)
(3-8)
pH -log aH. -log yh<[H1
where Yh+ and [H+] are the hydrogen activity coefficient and concentration,
respectively. Experimentally, an electrometric method is usually employed (e.g.,pH
meter) where the determination of pH is based on the measurement of the
electromotive forces (e.m.f.)of standard aqueous buffer solutions. Therefore, the pH
of an unknown solution (pHx) can be determined by
or at T=298,
pH % PHs +
(flr In 10/JO
(3-9)
pH pH + hoh (3-10)
1 s 0.06
where Ex and Es are the e.m.f. values of the solutions, R and F are the gas and
Faradays constants, respectively, and T is absolute temperature. Not shown in Eq.
(3-9) are the potentials that arise from the liquid junction and the standard potential
of the glass electrode. The difference in these potentials between the standard and


176
Rao, P.S.C.and R.E. Jessup. 1983. Sorption and movement of pesticides and
other toxic substances in soils. IN: Chemical Mobility and Reactivity in Soil
Systems. D.W. Nelson, K.K. Tanji. and D.E.Elrick (Eds.). American Society
of Agronomy and Soil Science Society of American Special Publication No.
11. American Society of Agronomy, Madison, WI, pp. 183-201.
Rao, P.S.C.,and L.S.Lee. 1988. Sorption of organic chemicals by soils from
multi-solvent and multi-sorbate mixtures. IN: Health and Environmental
Research on Complex Organic Mixtures. R.H. Gray, E.K. Chess, P.J.
Mellinger, R.G. Riley, and D.L. Springer (Eds.). DOE 62 Symposium
Series. 24th Hanford Life Sciences Symposium, Battelle, Washington, pp.
457-471.
Rao, P.S.C.,L.S. Lee, P.Nkedi-Kizza, and S.H. Yalkowsky. 1989. Sorption and
transport of organic pollutants at waste disposal sites. IN: Toxic Organic
Chemicals in Porous Media. Z. Gerstl, Y. Chen, U. Mingelgrin, and B.
Yaron (Eds.) Springer-Verlag, Berlin, Germany, pp. 176-192.
Rao, P.S.C.,L.S. Lee, and R. Pinal. 1990. Cosolvency and sorption of
hydrophobic Organic chemicals. Envir. Sci. Tech., 24:647-654.
Rao, P.S.C.and P. Nkedi-Kizza (Eds.). 1987. Development and testing of
protocol for selecting the principal hazardous constituents (PHCs in a
waste stream). Progress Completion Report, CRff 811035. U.S.
Environmental Protection Agency.
Rao, P.S.C.,P. Nkedi-Kizza, and J.M. Davidson. 1986. IN: Land Treatment: A
Hazardous Waste Management Alternative, Water Research Symp. Series
13, Austin, TX. pp. 63-72.
Rao, P.S.C.,R. D. Rhue, C.T. Johnston, and R.A. Ogwada. 1988. Sorption of
Selected Volatile Organic Constituents of Jet FUels and Solvents on
Natural Sorbents from Gas- and Solution-Phases. Project Completeion
Report, ESL-TR-02. U.S. Air Force.
Rhue, R. D. and W.H. Reve. 1990. Exchange capacity and adsorbed-cation
charge as affected by chloride and perchlorate. Soil Sci. Soc. Amer. J.,
54:705-708.
Reichardt, K. 1990. Soil spacial variability and symbiotic nitrogen fixation by
legumes. Soil Sci., 150(3):579-587.
Reick, C.E. and R.D. Carringer. 1977. Effect of n,n-diallyl dichloroacetamide on
EPTC degradation. ABS PAP ACS, 173(Mar20):71.


60
Figure 3-1. Schematic representaton of cosolvency plots for solutes with a range
of log Kow values.
For an acidic fluorescent dye (Rhodamine WT) in binary mixtures of
methanol/water and acetone/water at cosolvent fractions above 30%, sorption was
observed to increase even though at lower cosolvent fractions (< 30%) sorption
appeared to follow an inverse log-linear relationship (Soerens and Sabatini, 1992).
Previous use of Rhodamine WT as a surface and groundwater tracer prompted an
investigation on the potential use of this dye as a tracer in alternative fuel research
(i.e.,alcohol-based fuels). In soil thin-layer chromatography (TLC) studies (Hassett
et al., 1981), the herbicide dicamba (3,6-dichloro-2-methoxybenzoic acid) moved with
the solvent front in both aqueous and 50/50 (v/v) ethanol/water solutions, but was
strongly retained by soil with neat ethanol as the mobile phase.


Partition coefficients for several HOCs were either measured or compiled from
the literature for a wide range of OILs (e.g.,gasoline, diesel fuel, motor oil, and coal
tar). The use of the UNIFAC (UNIQUAC Functional Group Activity Coefficient)
model to estimate the likely nonidealities resulting from interactions between
components in these complex OILs is also presented. Both the UNIFAC simulations
and the observed OIL-water partition coefficients suggest that nonideality is
sufficiently small. Thus, the use of Raoults law convention for activity coefficients
in conjunction with super-cooled liquid solubilities was considered adequate in
assessing the partitioning of HOCs between several OILs and water.
The role of solute hydrophobicity and acidity, solvent type, and pH on the
sorption of organic acids by a surface soil from mixed solvents was investigated.
Predictions of a model that incorporated effects of cosolvent-enhanced solubility and
cosolvent-suppressed speciation were compared to measured data. Sorption of
neutral benzoic acid was observed to decrease with increasing methanol content,
while benzoate sorption increased. Effects of specific solvent and solute properties
were investigated by measuring (1) benzoic acid sorption from additional binary
mixtures of water and cosolvents with a wide range in solvent properties and (2)
sorption of several substituted carboxylic acids from methanol/water solutions. Of the
different solute-solvent conbinations investigated, enhanced sorption by soils was only
observed with carboxylic acids in the presence of methanol or dimethylsulfoxide
(DMSO). It was postulated that enhanced sorption resulted from hydrogen-bonding
interactions combined with the formation of heterogeneous solvation shells about the
solute and the sorbent.
xiv


142
The term solvation refers to the surrounding of each dissolved molecule (or
sorbent functional groups) by a shell of solvent molecules which are bound to some
degree (i.e.,long enough to experience the its translational movements) (Reichardt,
1990). Preferential or selective solvation comes about when more than one solvent
is present and the composition of the solvent shell around a solute (or sorbent) is
different than the composition of the bulk solution. Preferential solvation is a result
of differences in the free energy of solvation (AGMlv) for a given solute and is
induced by both nonspecific and specific solute-solvent interactions. Nonspecific
solute-solvent associations are caused by a dielectric enrichment in the solvent shell
of ions or dipolar molecules, and causes for specific solute-solvent associations
include hydrogen-bonding or electron pair donating/accepting interactions
(Reichardt, 1990). The preferential solvation of Ag+ by acetonitrile in
acetonitrile/water solutions is an example of specific solute-solvent associations
resulting from electron pair donation (Strehlow and Koepp, 1958). Water molecules
preferentially solvate both Ca+2 and Cl" ions in methanol/water solutions as a result
of electrostatic interactions causing a dielectric enrichment phenomena in the solvent
shell (i.e.,solvation sheath is enriched with the solvent of highest dielectric constant)
(Schneider and Strehlow, 1962). Given the heterogeneity of both an organic acid and
soil organic matter (i.e., mixture of hydrophobic and polar regions) it is not
unreasonable to infer heterogeneity in the solvation shell about both solute and the
sorbent (soil organic matter). In addition, preferential orientation of the molecules
in the solvation shells are also expected. Selective solvation and preferential


log [K b, mL/g]
88
Volume Fraction Methanol, %
Figure 3-6. Measured and predicted sorption by Webster soil of (A)
pentachlorophenol, and (B) benzoic acid as a function of volume
fraction methanol (fc).


4-4. Sorption of benzoic acid by Webster soil buffered at different pH values in
methanol/water solutions of fc=0.75,0.8,and 0.9 108
4-5. Sorption of PCP by Webster soil buffered at different pH values in
methanol/water solutions of fc=0.75 and 1.0 109
4-6. Sorption data obtained as a function of pH and methanol content, for neutral
benzoic acid and benzoate 112
4-7. Isotherm data for benzoic acid on (A) A1203, Al(OH)3, and SAz-1 (pH8);
and (B) Pahokee muck (pH7) along with linear and Freundlich fits 117
5-1. Representative isotherms for benzoic acid in (A) acetone/water;
(B) acetonitrile/water; (C) DMSO/water; and (D) 1,4-dioxane/water
solutions 131
5-2. Representative isotherms for (A) anthroic acid; (B) 2-chlorobenzoic acid (C)
2.4-dichlorobenzoic acid; and (D) 2,4,6-trichlorobenzoic acid in various
methanol/water solutions 132
5-3. (A) Benzoic acid solubility data where Sb and Sw are solubilities in the binary
solution and water, respectively; and (B) benzoic sorption data with Webster
soil in binary mixtures of water and several organic cosolvents as a function
of volume fraction cosolvent (fc) 134
5-4. Trends in pHapp of soil-suspensions in binary mixtures of water and several
organic cosolvents 135
5-5. Measured and predicted (Eq. 3-6) sorption of benzoic acid by Webster soil
from (A) acetone/water; (B) acetonitrile/water; (C) DMSO/water; and (D)
1.4-dioxane/water solutions as a function of volume fraction cosolvent (f])38
5-6. Normalized sorption coefficients, log (K,,/!1^), for the sorption of selected
substituted carboxylic acids by Webster soil as a function of volume fraction
methanol (fc) 145
5-7. Correlation between benzoic acid sorption in neat methanol (log KMe0H) and
the log Kow values for both the ionized (i) and neutral (n) forms of the
substituted carboxylic acids 146
A-l. Schematic representation of the steps involved in the thermodynamic cycle for
producing a hypothetical supercooled liquid from a crystal solute 157
Xll


57
indeed ideal mixtures. Rather, the assumption of ideal behavior might suffice for
practical considerations in providing first-order estimates for maximum PAH
concentrations likely to be found in groundwater leaving an area contaminated with
residual OILs. Several site-specific hydrogeologic factors might lead to significant
mass transfer constraints for solute partitioning. Such factors include: random
spatial variability in aquifer hydraulic properties, the patterns of residual fuel
entrapment, and the source of fuel contamination (e.g.,surface spill versus subsurface
leaks). Under nonequilibrium mass transfer conditions, the concentrations of organic
constituents detected in groundwater are likely to be smaller than those estimated
using the equilibrium approach presented here. In contrast, larger concentrations
might be observed in the presence of surfactants, emulsifiers, or cosolvents.


46
estimate maximum Cw values, the eight coal tars investigated were assumed to be
representative of coal tars that might be found at any site in the United States. The
maximum concentrations of the PAHs investigated based on the data compiled for
the eight coal tars, are given in Table 2-3 along with the ratios of Cw to Sw. Note
that the maximum Cw expected is the crystal aqueous solubility for anthracene,
chrysene, and benzo(a)anthracene.
Table 2-3. Maximum Cw values for several PAHs based on the data compiled for
eight coal tars.
Compound
Sw
(mg/L)
Maximum
C a
v-'w
Cw/Sw
Naphthalene
32
14b
0.44
1 -methylnaphthalene
27
2
0.05
2-methylnaphthalene
26
1.4
0.05
Acenapthylene
3.93
0.5
0.13
Acenapthene
3.42
0.3
0.1
Fluorene
1.9
0.3
0.16
Phenanthrene
1.0
0.4
0.3
Anthracene
0.07
Sw
1.0
Fluoranthene
0.27
0.01
0.4
Pyrene
0.16
0.1
0.5
Benzo (a) anthracene
0.0057
Sw
1.0
Chrysene
0.006
Sw
1.0
Benzo(a)pyrene
0.0038
0.001
0.3
T=25C
Result from data compiled for seven of the eight coal tars; data for one tar
resulted in a prediction of 26 mg/L.


44
shown in Figure 2-7 for the laboratory-measured concentrations represent the
standard errors calculated from replicate averages. An arrowhead on an error bar
indicates that the lower bound approached the limit of detection. For the predicted
concentrations, the error bars shown in Figure 2-7 were estimated from the standard
errors calculated from the replicate average of M¡. Also given in Figure 2-7 is the
ideal line (i.e., 1:1 correlation) with the corresponding factor-of-two tolerance
intervals.
-4 -3-2-1012
Measured [log (Cw mg/L)]
Figure 2-7. Comparison of laboratory-measured aqueous-phase concentrations
(Cw) with those predicted on the basis of Raoults law for eight coal
tars.


178
Schellenberg, K., C. Leunberger, and R.P. Schwarzenbach. 1984. Sorption of
chlorinated phenols by natural sediments and aquifer materials. Envir. Sci.
Tech., 18:652-657.
Schneider, V.H. and H. Strehlow. 1962. Uber auswahlende solvation von ionen in
losungsmittelgemisehen. II, Z. Phys. Chem. (Frankfurt), 49:309-314.
Schoenmakers, Peter J., Sylvie van Molle, Carmel M.G. Hayes and Louis G.M.
Uunk. 1991. Effects of pH in reversed-phase liquid chromatography.
Analytica Chimica Acta, 250:1-19.
Schwarzenbach, R.P. and J.C. Westall. 1981. Transport of nonpolar organic
compounds from surface water to groundwater: Laboratory sorption
studies. Envir. Sci. Tech., 15:1360-1367.
Schwarzenbach, R.P. and J.C. Westall. 1985. Sorption of hydrophobic trace
organic compounds in groundwater systems. Water Sci. Tech., 17:39-55.
Seip, H. M.,J. Alstad, G. E. Carlberg, K. Martinsen, and R. Skaane. 1986.
Measurement of mobility of organic compounds in soil. The Sci. Total
Envir., 50:87-101.
Sergeant, E.P. and B. Dempsey. 1979. Ionisation Constants of Organic Acids in
Aqueous Solution. Pergamon Press, Oxford.
Shoemaker, D.P.,C.W. Garland, J.I. Steinfeld, and J.W. Nibler. 1980.
Experiments in Physical Chemistry, 4th ed. McGraw-Hill Book Co. New
York.
Shorten, C.V. and A.W. Elzerman. 1989. Desorption of phenanthrene in coal
contaminated sediments: Effect of organic cosolvents on release kinetics.
Envir. Sci. Tech. (In Review).
Skjold, S.,B. Kolbe, J. Gmehling, and P. Ramussen. 1979. Vapor-liquid equilibria
by UNIFAC group contribution. Revision and extension. Ind. Eng. Chem.
Process Des. Den. Sci. Technol., 19:522-529.
Soerens, Thomas S. and David A. Sabatini. 1992. Cosolvency effects on sorption
ofRhodamine WT. IN: Tracer Hydrology, 131-134.
Sposito, G. 1981. The operational definition of the zero point of charge in soils.
Soil Sci. Soc. Am. J., 45:292-297.


CHAPTER 1
INTRODUCTION
Environmental contamination problems at most industrial waste disposal sites
or spill sites commonly involve wastes consisting of complex mixtures of organic and
inorganic chemicals. Complex mixtures are defined here as those systems comprising
multiple organic solutes and multiple solvents. The solute mixtures of interest might
consist of various combinations of nonpolar or hydrophobic organic chemicals
(HOCs) and hydrophobic ionogenic organic chemicals (HIOCs). The solvent may
be a mixture of water and one or more organic cosolvents (either completely or
partially miscible in water). Solvent mixtures of interest may consist of water and
cosolvents in a single, homogeneous liquid phase, or multi-phases that form at least
two distinct liquid phases. The behavior of such mixtures is not well understood
because the primary chemodynamic properties have usually been characterized in
aqueous solutions which are simple in composition relative to many waste mixtures
found at or near disposal/spill sites. Several researchers have made considerable
efforts during the past decade to investigate the primary processes (e.g.,solubility,
sorption, transport) governing the environmental dynamics of organic chemicals in
complex mixtures.
The release and migration of organic constituents from a waste disposal/spill
source will produce a contaminant plume, either in the vadose zone or in the
saturated zone or both. The contaminant plume composition will vary with time and
1


25
Taking logarithms of both sides ofEq. (2-5), it is evident that the inverse relationship
between log Kd and log S¡ results in a unit negative slope and an intercept that is
dependent upon the molar volume of the organic phase (i.e.,MW0/ pj:
(MW \
log Kd -log S¡ log (2-6)
k p j
Derivation of Eq. (2-6) was based on a choice of the pure liquid solute as the
standard state. Most of the PAHs investigated in this study are solids in their pure
form; therefore, the hypothetical supercooled liquid solubilities of the solid solutes
must be employed. The supercooled liquid solubility (S) of a solute at a given
temperature can be calculated directly from the solutes measured heat of fusion
(AHf) and melting point (T^ (Yalkowsky, 1980), or alternately can be estimated by
assuming a constant entropy of fusion (aS^aH/TJ for the PAHs of interest
(Yalkowsky, 1979; Martin et al., 1979) (see Appendix A).
Application of Raoults Law for Gasoline. Motor Oil, and Diesel Fuel
The utility of the relationship defined by Eq. (2-6) was successfully
demonstrated for several gasolines by Cline et al. (Cline et al., 1991) for several
monocyclic aromatic hydrocarbons (MAHs). Gasoline is composed of several
branched-chain paraffins, cycloparaffins, alkanes, aromatic compounds, and small
amounts of various additives. Results presented by Cline et al. (1991) revealed that
although gasoline is complex in composition, MAH partitioning into water behavior
was essentially ideal. None of these MAHs exhibit crystalline structure in their pure
form which is common to most PAHs. Chen (1993) investigated the applicability of


18
solubility does increase with increasing fc; thus, a decrease in sorption is expected.
Fu and Luthy (1986b) observed an inverse log-linear behavior in the sorption by
three different soils of naphthol, quinoline, and dichloroaniline in methanol/water
and acetone/water solutions up to 50% by volume. Similar behavior was observed
by Zachara et al. (1986) for quinoline sorption by a natural clay isolate and
montmorillonite in the same binary mixtures. However, for the sorption of an
ionizable fluorescent dye (Rhodamine WT) from binary mixtures of methanol/water
and acetone/water, Soerens and Sabatini (1992) observed adherence to the log-linear
model only for cosolvent fractions less than 30%, while at higher fractions sorption
increased.
For hydrophobic, ionogenic organic compounds (HIOCs), several factors (e.g.,
speciation, soil-solution pH, sorbent-surface pH, charge, ionic strength, ionic
composition, multiple solutes) make predicting sorption from a single parameter
difficult due to additional mechanisms that must be considered. As discussed
previously, prediction of HIOC sorption by soils from aqueous solutions is already
complicated due to the potential for a variety of different sorption mechanisms.
Prediction of HIOC sorption from mixed solvents is further confounded by a number
of indirect effects resulting from cosolvent-induced phenomena occurring either in
the solution phase or on the sorbent. For example, for an organic acid in solvents
of low dielectric constants (e.g., methanol, acetone, dimethylsulfoxide) an alkaline
shift in the solute pKa results in an increase in the fraction of neutral species.
Similar impacts on the ionization of sorbent functional groups and subsequent solute-
sorbent interactions must also be considered. Also, the impact of cosolvent-water
interactions that have been considered negligible in predicting the chemodynamic
behavior of HOCs may become important when assessing the behavior of HIOCs.


169
Hesleitner, P., N. Kallay, and E. Matijevic. 1991. Adsorption of solid/liquid
interfaces. 6. The effect of methanol and ethanol on the ionic equilibria at
the hematite/water interface. Langmuir, 7:178-184.
Hess, R.E. and R.A. Plane. 1964. A raman spectrophotometric comparison of
interionic association in aqueous solutions of metal nitrates, sulfates, and
perchlorates. Inorg. Chem., 3:769-770.
Hingston, F.J. 1981. A review of anion adsorption. IN: Adsorption of Inorganics at
the Solid-Liquid Interface. M.A. Anderson and A.J. Rubin. (Eds.). Ann
Arbor SCi.,Ann arbor, MI.
Horvath, C. 1973. High performance ion-exchange chromatography with narrow-
bore columns: rapid analysis of nucleic acid constituents at the
subnanomole level. Methods Biochem. Anal., 21:79-154.
Horvath, D., W. Melander, and I. Molnar. 1976. Solvophobic interactions in
liquid-
chromatography with nonpolar stationary phases. J. Chromat., 125(1): 129-
156.
Horvath, C., W. Melander, and I. Molnar. 1977. Liquid chromatography of
ionogenic substances with nonpolar stationary phases. Anal. Chem.,
49:142-154.
Humburg, N.E.,E.R. Hill, L.M. Kitchen, S.R. Colby, R.G. Lynn, W.J. McAvoy,
and R. Prasad. Herbicide Handbook of the Weed Science Society of
America, 6th ed. Weed Sci. Soc. Amer., Champaign, IL.
IFAS, 1974 University of Florida, Institute of Food and Agricultural Sciences.
Characterization Data for Selected Florida Soils, Soil Sceince Research
Report 74-1.
Jafvert, C.T. 1990. Sorption of organic acid compounds to sediments: Initial
model development. Envir. Toxic, and Chem., 9:1259-1268.
Jandera, P. and J. Churacek. 1973. Ion exchange chromatography of carboxylic
acids. J. Chromat., 86:351-421.
Johnson, C.A. and J.C. Westall. 1990. Effect of pH and KC1 Concentration on
the Octanol-water Distribution of Methylanilines. Envir. Sci. Tech., 24:869-
875.


17
where K is the equilibrium sorption coefficient (mL/g), a is an empirical constant
for describing solvent-sorbent interactions, and the subscript b stands for binary
mixed solvent.
An extensive amount of data has shown that in binary mixed solvents, HOC
solubility increases and sorption decreases in a log-linear manner as the volume
fraction of the organic cosolvent increases (Rao et al., 1985,1986,1989,1990; Nkedi-
Kizza et al., 1985, 1987, 1989; Woodbum et al., 1986; Fu and Luthy, 1986a,b;
Yalkowsky 1985, 1987; Rubino and Yalkowsky, 1985, 1987a,b,c; Walters and
Guiseppi-Ellie, 1988). These experimental findings are consistent with the predictions
of both the UNIFAC model and the log-linear cosolvency model. Also, for the
sorption of HOCs, solvent-solute interactions as described by solubility are found to
predominate such that the impact of solvent-sorbent interactions has been considered
minor. However, for solutes containing specific functional groups, the impact of the
cosolvent on the sorbent may have considerable impact.
Hydrophobic Ionizable Organic Chemicals (HIPCs)
For hydrophobic ionogenic compounds (HIOCs) of environmental interest,
data on solubility, sorption, and transport in mixed solvents are limited. However,
pharmaceutical literature contains solubility data for several drugs spanning a wide
polarity range. Yalkowsky and Roseman (1981) observed that as solute polarity
increases relative to the solvent, the solubilization curves become increasingly more
parabolic in shape until an inverse relationship occurs (i.e.,decreased solubility with
cosolvent additions). Such behavior is explained on the basis of the solute-solute and
solute-cosolvent interactions.
The sorption of HIOCs from mixed solvents has received little research
attention to date. For several HIOCs of environmental relevance (log Kow > 1.0),


86
PCP was either completely ionized or completely neutral. The values for ¡ and
were adjusted for differences in the OC content of the Webster soil used in the
two studies (i.e.,K=Koc OC).
Benzoic acid sorption decreased with the addition of methanol up to fc<0.2,
but then increased with fc thereafter (Figure 3-6B). Eq. (3-6) was applied to the
benzoic acid data using four reasonable parameter sets to investigate if this behavior
was mostly due to changes in speciation with methanol additions. For all cases, the
sorption coefficient for benzoate (K^) was measured at pH = 6.9; Kn w was
estimated by measuring the at pH = 3.0 and applying Eq. (3-4); and an was
estimated by regressing benzoic acid solubility data in methanol/water solutions (data
in fc=0to 0.8; Yalkowsky, 1985). Two values for a¡ were used. In one case, cr¡ was
set equal to zero as suggested by the solubility data (Figure 3-4), and in the second
case, ol was set equal to 0.65 as estimated from the initial portion of the log
versus fc curve (i.e.,fc < 0.2) where benzoic acid remained > 99% ionized. For two
parameter sets, solvent-sorbent interactions were ignored (an=a¡=l) while in the
remaining two parameter sets an average a value of 0.5 observed by Fu and Luthy
(1986b) for several solute, soil, and solvent combinations was used as an initial
estimate of solvent-sorbent interactions. In all cases, Eq. (3-6) failed to adequately
predict the magnitude of sorption observed for benzoic acid at higher methanol
contents (Figure 3-6B). Similar sorption data were observed for dicamba (data not
shown). Model parameters were estimated for the dicamba sorption data in a
manner analogous to the calculations for benzoic acid with similar results.


136
To assess the presence or absence of specific solvent interactions among the
different cosolvents, Eq. (3-6) was employed in a similar manner as previously
applied to the data for sorption of organic acids from methanol/water solutions
(Chapter 3). Recall that Eq. (3-6) was a first attempt to incorporate cosolvency
phenomena in terms of solubility and cosolvent-induced speciation effects in order
to explain the observed sorption. The organic cosolvents used in this study vary in
their cosolvency power (see Figure 5-4 and a values in Table 5-1) and in their impact
on conditional ionization constants (pKa) (see Table 5-1). Of the parameters needed
to apply Eq. (3-6), K^, n and 1*^, ¡ were the same as used previously for benzoic acid
in Chapter 3; apparent pH values (pHapp) were used to estimate soil-solution pH; oa
values were obtained from solubility data as given in Table 5-1; an an value of 0.8
was used as previously estimated from the benzoic acid sorption and solubility data
measured in methanol/water solutions (Chapter 4) was used; and a¡CT¡ was set equal
to zero.
The pKa values were estimated using a the following modified Bom equation,
Ne2 J_
RT rH
-)(- ) + pKaw A
e, Gw
(5-1)
where N is Avogadros number; e is the electronic charge; R is the gas constant; T
is temperature; rH and rA are the radii of hydronium and organic ion, respectively;
e8 and ew are the cosolvent and water dielectric constants, respectively; and A is an
estimate for nonelectrostatic medium effects. The dielectric constant needed at each


LIST OF FIGURES
1-1. Comparison of measured and calculated (Raoults law) aqueous solubilities
in binary mixtures of benzene-toluene (A) and benzene-octanol (B). Data
from: Sanemesa et al. (1987) 6
1-2. Measured and predicted sorption of flumetsulam by several soils normalized
to organic carbon content plotted as a function of pH. (Data form Fontaine
et al., 1991) 11
1-3. Normalized sorption coefficients for several organic acids plotted as a function
of pH-pKa. [Data from Kukowski (1989) and Jafvert (1990)] 13
2-1. log Kdw values plotted versus log S, for eight PAHs along with the ideal line
(solid line) calculated form Eq. (2-6) for each diesel fuel 29
2-2. Comparison of measured tar-water partition coefficients (K^) and predictions
based on Raoults law for ID# 1(A) and ID# 2 (B) coal tars 37
2-3. Comparison of measured tar-water partition coefficients (K^) and predictions
based on Raoults law, for ID# 3(A) and ID# 4(B) coal tars 38
2-4. Comparison of measured tar-water partition coefficients (K^) and predictions
based on Raoults law, for ID# 5(A) and ID# 7(B) coal tars 39
2-5 Comparison of measured tar-water partition coefficients (K^) and predictions
based on Raoults law, for ID# 7N(A) and ID# 9(B) coal tars collected by
EPRI 40
2-6. Comparison of measured tar-water partition coefficients (K^) reported in the
literature and predictions based on Raoults law. Literature source as
indicated 42
2-7. Comparison of laboratory-measured aqueous-phase concentrations (Cw) with
those predicted on the basis of Raoults law for eight coal tars 44
2-8. Comparison of laboratory-measured aqueous-phase concentrations (Cw,^g/L)
with those predicted on the basis of Raoults law for four diesel fuel. . 48
x


63
< water < DMSO < acetonitrile. The fact that larger titers in DMSO and
acetonitrile were required was attributed to (1) pH-dependent sites for which a
quantitative endpoint was not obtained in aqueous media due to the acidic properties
of water, and (2) increased surface acidity in organic solvents. Loeppert et al. (1986)
also observed an increase acidity of montmorillonite in acetonitrile and
dimethylformamide. No apparent changes were observed in surface acidity with neat
methanol (Loeppert et al., 1979). Similar conclusions were made by Hesleitner et
al. (1991), who noted that addition of methanol (fc < 0.5) caused no apparent change
in the surface charge density of a hematite surface (iron oxide) or in the point of
zero charge which coincided with the isoelectric point.
Cosolvent-enhanced formation of ion-pairs with positive charges on the
sorbent surface may cause an increase in sorption of organic acids with addition of
an organic cosolvent even if solubility increases. As previously mentioned, Hesleitner
et al. (1991) observed no changes in the total surface charge of hematite in the fe
range investigated (fc < 0.5), but noted a pronounced decrease in electrokinetic
potentials with increasing methanol fractions (i.e., effective surface charge was
lowered). They attributed the decrease in electrokinetic permittivity to an
enhancement of counterion association with the surface charged groups. This
counterion association could include both the formation of outer-sphere complexes
by bridging of the carbonyl to the solvent (water and/or cosolvent) coordinated on
the exchange cation (Farmer and Russell, 1967) and inner-sphere complexation by
hydrogen bonding of the carbonyl group with protonated hydroxyls on the surface


118
Kummert and Stumm (1980) have extensively investigated the surface
complexation of organic acids by aluminum oxides from aqueous solutions. As
discussed in Chapter 3, ion-pair formation is enhanced upon addition of a solvent of
lower dielectric constant. Likewise, complexation of an organic acid with structural
metal cations may also be enhanced. To specifically assess the role of aluminum and
iron oxides from a natural material in the presence of methanol and in the absence
of organic matter, sorption of benzoic acid by sandy aquifer material (sampled from
the Canadian Forces Base Borden in southern Ontario, Canada) was measured in
several methanol/water solutions. Comparing sorption of benzoic acid between the
Borden aquifer material and the Webster soil may help assess the role of metal
oxides on the sorption of benzoic acid. The Borden material has been well
characterized by Ball et al. (1990) (CEC of 0.7cmol(+)/kg, specific surface area by
N2BET of0.5m2/g). Substantial quantities of iron and aluminum oxides are present
in the Borden material as coatings on the sand grains. Elemental analysis for this
material was done in a similar manner as that for the untreated Webster soil.
Relative to the Webster silty loam, this soil had 2, 3, and 4 times higher
concentrations of K, Na, and Ca, respectively, and approximately the same amounts
of Fe and Al; however, this particular subsample had only 0.02% OC content.
Benzoic acid sorption by the Borden material increased from less than 0.005 mL/g
to approximately 0.1 mL/g with fc increasing from 0.2 to 0.8. At similar pHapp values
( *7), sorption by Webster soil at fc=0.8was an order of magnitude higher (factor
of 10), suggesting that the solute-solvent interaction with organic matter or organic


146
Normalized sorption coefficients, log (Kb/K^), for the sorption of selected
substituted carboxylic acids by Webster soil plotted as a function of volume fraction
methanol (fc) are shown in Figure 5-6. A tabulated form of this data and the
Freundlich fits were given previously in Table 5-3. Sorption profiles for all the
carboxylic acids investigated are similar to that observed for benzoic acid in
methanol/water and DMSO/water solutions. Correlations of log KMe0H, log K^and
pKa w with log Kow nare extremely poor (^<0.35),whereas similar correlations to log
Kow iare much improved (^>0.75). Shown in Figure 5-7 is the correlation between
log KMeOH and the log Kow values for both the ionized and neutral forms of the acids.
Substantially better correlations observed with Kow i values supports the argument that
the carboxylate is the predominate species responsible for the enhanced carboxylic
acid sorption by soils from methanol/water solutions.
Figure 5-7. Correlation between benzoic acid sorption in neat methanol (log
KMe0H) log Kow values for both the ionized (i) and neutral (n)
forms of the substituted carboxylic acids.


110
of organic modifier that may be used. Problems with buffer precipitation begin to
occur at about 75% volume fraction of organic modifiers (i.e., methanol, acetonitrile)
typically used RPLC. However, sorption studies presented here were conducted with
soils prepared at different pH values such that buffers were not needed to achieve
various pH values. Also the ionic strength of the solutions employed were maintained
at 0.01 N with CaCl2 which is much less than the ionic strengths of the solutions
typically used in RPLC. However, to verify that the observed sorptive behavior was
not due to a precipitation reaction, radiolabelled benzoic acid experiments analogous
to those described for soils were conducted using 250 xM glass beads in fc=0.9
solutions in the 3 to 9 pH range. No measurable sorption by the glass beads was
observed, suggesting that artifacts due to precipitation were not present.
Sorption of Neutral Benzoic Acid Relative to Benzoate
From the sorption data obtained as a function of pH and methanol content,
separate cosolvency curves can be characterized for neutral benzoic acid and
benzoate. Sorption coefficients for neutral benzoic acid and benzoate at various
methanol contents were obtained from the sorption experiments where pHapp was at
least one pH unit below or above the pKa\ The compiled data are shown in Figure
4-6A along with slopes and lines estimated from regressing log Kb and fc data for
neutral benzoic acid (0 at fc = l was obtained from Figure 3-6; [pHapp -pKJ > 2). Also shown in Figure 4-6
is a similar plot for the benzoic acid retention data by RPLC supports.
Unlike the sorption data obtained for neutral and ionized PCP in methanol/water


CHAPTER 2
EQUILIBRIUM PARTITIONING OF POLY AROMATIC HYDROCARBONS
FROM ORGANIC IMMISCIBLE LIQUIDS INTO WATER
Introduction
Background
Environmental contamination problems at most industrial waste disposal sites
or spill sites commonly involve the presence of an immiscible organic phase
constituting a multi-phasic waste with multiple components. Of great concern is the
transport of organic constituents from these wastes resulting in contamination of soil
and water. Near the source of contamination where a separate organic phase is
present, solubility is the primary process controlling the release of organic chemicals
to the aqueous phase. Therefore, an understanding of the solubility (or partitioning)
of polyaromatic hydrocarbons (PAHs) from a complex liquid such as those suggested
is essential in predicting contaminant release.
Over the last few years efforts have been made to measure the partitioning
of PAHs from environmentally relevant organic liquid wastes such as gasoline, motor
oil, diesel fuel, and coal tar. Coal tars are among the most complex organic liquid
wastes and comprise a large number of hydrocarbons spanning a broad spectrum of
molecular weights. The concentrations of individual constituents in coal tars vary
significantly from one manufacturing gas plant (MGP) site to another. The
20


114
organic matter groups is expected. The CEC for the soil treated at the lowest pH
was significantly lower than that observed for the other soils [30 cmol(+)/kg
compared to 40 cmol(+)/kg]. A decrease in CEC with decreasing pH is expected
for charge that originates from constant potential surfaces represented by organic
matter; however, this soil also contains almost 30% clay (predominately
montmorillonite) which is responsible for a substantial portion of the measured CEC.
Overall the CEC is not considered a significant parameter in predicting the behavior
of organic acids; however, this does suggest that washing the soils with an acidic
solution may have dissolved some of the soil constituents (i.e, silica, aluminum and
iron oxides, and related substituents). The elemental analysis given in Table 4-2 for
the treated soils could suggest that dissolution of soil constituents did occur with the
soil treated at the lowest pH having the lowest elemental concentrations. However,
this trend may not be significant given the small soil sample size and the large
dilution factors used in the analysis. Also, trends within each element (metals or
silica) are approximately the same further suggesting that the observed differences
are due to experimental errors. Note that even if substantial changes did occur to
the soil with treatment, the impact of these changes appear to be a function of fc.
Sorption Domains
Horvath et al. (1977) showed that hydrophobic interaction play a dominant
role in determining interaction energies between both HOCs and HIOCs and
reversed-phase chromatographic supports; however, sorption of benzoic acid by soils
from methanol/water solutions were not predictable by only considering hydrophobic


94
Sorption of PCP was adequately characterized by combining the log-linear cosolvency
model for predicting cosolvency effects with the model demonstrated by Lee et al.
(1990) for describing speciation effects. For carboxylic acids, the magnitude of
sorption observed in methanol/water solutions could not be predicted. Inclusion of
cosolvent-induced changes in pKa and the uncertainty of the formation and exchange
of charged ion-pairs suggest that deviations from Eq. (3-6) predictions may be due
to other types of solvent-driven complexation reactions (e.g., hydrogen bonding,
cation- and water-bridging). Inaccurate assessments of the observed deviations from
Eq. (3-6) due to the potential errors associated with measuring soil-solution pH in
mixed solvents should also not be excluded.
Further research is needed to better understand the influence of ionic
equilibria on the sorption of organic acids in solvent/water solutions. This warranted
an investigation of the impact of pH within a given solvent/water fraction on the
sorption of benzoic acid by Webster soil. In addition, the apparent contradiction
between the insignificant impact of increasing CaCl2 concentrations on benzoic acid
sorption versus the differences observed between Ca++-and K+ saturated Webster
soil warrants a preliminary assessment of benzoic acid sorption by various sorbents
from aqueous and methanol solutions. Both the impact of ionic equilibria and
elucidation of the sorption process will be presented in the next chapter.


28
Table 2-1. Selected physico-chemical properties for the PAHs investigated.
Compound
Melting8
Point
(C)
Molecular
Weight8
(g/mole)
s b
(mg/L)
log S,d
Naphthalene
80.2
128.2
32
-3.05
1 -methylnaphthalene
-22
142.2
27a
-3.72*
2-methylnaphthalene
34
142.2
26c
-3.62
Acenaphthylene
82
152.2
3.93
-4.02
Acenaphthene
93
154.2
3.42
-3.98
Fluorene
116.5
166.2
1.9
-4.03
Phenanthrene
100
178.2
1.0
-4.5
Anthracene
216.3
178.2
0.07
-4.49
Fluoranthene
107
202
0.27
-5.19
Pyrene
150
202
0.16
-4.85
Chrysene
254
228.2
0.006
-5.29
Benzo(a)anthracene
156
228.2
0.0057
-6.29
Benzo(a)pyrene
179
252
0.0038
-6.28
a Verschuren (1983);b Crystal solubility at 25C (Little, 1981) unless stated otherwise;
c Miller et al. (1985); d Supercooled liquid solubility (moles/L) calculated assuming
a constant ASf for PAHs; e liquid solute at standard state.


104
(Table 4-3 continued)
fc
PH
Kd(mL/g)
K^mLW)
NSE
0.10
6.9
0.11
0.13
0.890.21
8.4
0.098
0.07
1.130.28
0.50
3.9
0.55
5.4
0.30
5.62
0.28
0.14
1.210.02
6.9
0.20
0.12
1.160.05
7.9
0.24
0.17
1.130.11
0.75
4.0
0.22
5.12
0.50
0.30
1.150.08
5.5
0.47
0.57
0.930.04
5.8
0.71
6.15
0.67
1.0
0.860.04
6.2
0.66
6.7
0.63
6.8
0.56
0.37
1.160.05
6.83
0.53
6.9
0.50
0.31
1.150.04
7.2
0.57
0.84
0.870.07
7.9
0.54
8.2
0.45
0.26
1.160.18
0.8
4.78
0.32
0.54
0.840.06
5.3
0.59
0.51
1.00.18
6.6
0.81
1.32
0.850.02
7.8
0.55
0.25
1.260.05
6.6
1.088
0.78
1.130.24
5.45
0.58
0.81
0.800.05
6.2
0.82
0.77
1.100.10
7.1
0.78
0.96
0.930.02
8.3
0.67
0.77
0.950.04
0.9
3.6
.31
.5
0.790.05
3.9
0.46
4.75
0.85
1.81
0.740.04
5.13
1.05
5.3
1.23
2.76
0.700.05
5.8
1.52
6.58
1.86
2.21
0.940.02
6.7
1.70
2.50
0.860.03
7.8
1.45


65
log(Sc/Sw) a
(3-2)
log Kb log Kw a ofc
(3-3)
where S is solubility (mg/L), K is sorption coefficient (mL/g) with subscripts b, c,
and w referring to binary mixtures, pure cosolvent, and water, respectively; fc is
volume fraction cosolvent; a describes the cosolvency power of a solvent for a solute;
and a accounts for solvent-sorbent interactions.
Sorption of HIOCs is dependent on the formation of neutral and ionized
species, as determined by pH and the solute acid dissociation constant (pKa). For
many organic acids, the neutral species is sorbed more than its dissociated (anionic)
species, and the differences in the sorption coefficient values can be rather large.
Thus, the measured sorption coefficient for HIOCs is a strong function of pH and
conditional dissociation constants (pKa) of the solute in the solvent system of
interest. Lee et al. (1990) showed that the pH-dependence of pentachlorophenol
(PCP) sorption from aqueous solutions can be described by,
(3-4)
where
<$>n (1 + ioPa-rKyi
(3-5)


CHAPTER 4
IMPACT OF pH ON SORPTION OF BENZOIC ACID
FROM METHANOL/WATER SOLUTIONS
Introduction
Separation and analysis of hydrophobic ionizable organic compounds (HIOCs)
using liquid chromatography has been carried out almost exclusively by ion-exchange
columns (Jandera and Churacek, 1973; Horvath, 1973). As the use of reversed-phase
chromatographic (RPLC) supports increased exponentially, investigations on the
utility of RPLC supports in separation of HIOCs were initiated (Horvath et al.,
1976). In RPLC, the distribution of a compound is between a nonpolar stationary
phase (i.e., alkyl chains or rings chemically bonded to a silica gel support) and a
polar mobile phase composed of water plus organic modifiers (e.g., methanol or
acetonitrile). Consensus on the retention mechanism of hydrophobic organic
compounds (HOCs) by RPLC supports is that solute-solvent interactions dominate
(Horvath et al., 1976, 1977). However, the influence of ionic equilibria on HIOCs
behavior warranted investigations on the impact of pH on retention of HIOCs in
RPLC. With increasing volume fraction cosolvent (fc) and pH (buffered within 3 and
7), decreasing retention by RPLC supports has been reported for carboxylic acids
95


70
unknown solutions are assumed to be the same when the solution matrix is similar,
thus cancelling out in the (EX-EJ term.
Likewise, in mixed solvents (denoted by *), pH is thermodynamically defined
as
ph* -log Y;.[jn <3-n)
If standard mixed solvent buffers are employed, pH can be operationally defined as
follows:
pK pK +
K-K
0.06
(3-12)
It is usually expedient to employ readily available standard aqueous buffers in which
case Eq. (3-12) must be modified to estimate the pH of a solution in mixed solvents,
PH?P pH
K ~ Es
0.06
(3-13)
where pHapp is the measured pH of a mixed solvent solution relative to a standard
aqueous buffer solution. The differences in the liquid junction potential and the
standard potential of the glass electrode between mixed solvents and aqueous
solutions cannot be assumed to be the same and must be considered. However,
Gelsema et al. (1967) have shown that differences in the standard potentials of the
glass electrodes between mixed solvents and aqueous solutions are negligible. The


2-9. Schematic representation of the ideal behavior (Raoults law) and nonideality
in liquid-liquid partitioning 51
2-10. log values for several aromatic hydrocarbons resulting from UNIFAC
model calculations and the average loggw values experimentally determined by
Cline et al. (1991) plotted against log S[ values along with the ideal line based
on Raoults law 52
2-11. log Kdw values for several aromatic hydrocarbons resulting from UNIFAC
model calculations plotted against log S, values along with the ideal line based
on Raoults law 54
2-12. Comparison of measured and predicted tar-water partition coefficients for
several PAHs: Raoults law (solid line) and UNIFAC model (solid
triangle) 55
3-1. Schematic representation of cosolvency plots for solutes with a range of log
Kow values 60
3-2. Example cosolvency curves that may be predicted by the use of various
parameters in Eq. (3-6) 68
3-3. Effect of methanol content on the pKa of benzoic acid and
pentachlorophenol 82
3-4. Solubility (Sb) of benzoic acid in methanol/water solutions 82
3-5. Representative sorption isotherms for (A) pentachlorophenol, (B) benzoic
acid, and (C) dicamba, on Webster soil in various methanol/water
solutions 87
3-6. Measured and predicted sorption by Webster soil of (A) pentachlorophenol,
and (B) benzoic acid as a function of volume fraction methanol (fc). ... 88
4-1. Retention data for benzoic acid as a function of pHapp at different methanol
fraction (v/v) by RPLC 96
4-2. Representative isotherms for benzoic acid in (A) aqueous solutions; (B)
fc=0.1; and (C) fc=0.9 buffered at several pH values 105
4-3. Sorption of benzoic acid by Webster soil buffered at different pH values in
methanol/water solutions of fc<0.5 107
xi


134
2.5
Benzoic Acid Solubility
2 -
£ifl.5
-Q
CO
O 1
y 'JB /
';/ X"
/
.X V*
X"
-Q-
.^A-~
..j0-
_A-A_
y'
acetone
a
acetonitrile
A
DMSO
methanol
)
"'El
0.2
0.4
0.6
0.8
Figure 5-3. (A) Benzoic acid solubility data where Sb and Sware solubilities in the
binary solution and water, respectively; and (B) benzoic sorption data
with Webster soil in binary mixtures of water and several organic
cosolvents as a function of volume fraction cosolvent (fc).


121
The effect of solvent structure and solute-solvent interactions on
equilibrium and rate constants are poorly understood. The problem begins with an
inadequate understanding of water structure (Eisenberg and Kauzmann, 1969), and
is further complicated by the addition of an organic cosolvent. How then may we
begin to understand and interpret solvent-sorbent interactions, and solute-sorbent
interactions in the presence of a cosolvent? The differences observed in the sorptive
behavior of HOCs, phenolic compounds, and carboxylic acids in soil-mixed solvent
solutions suggests that different solutes should be used to probe solvent-sorbent
interactions. The use of different organic cosolvents, given the same solute, may also
help to recognize, and possibly understand, the specificity of these solvent-sorbent
interactions. Therefore, an investigation of the effect of solute structure for
carboxylic acids (e.g., acidity and hydrophobicity) on sorption by soil in
methanol/water solutions was initiated along with similar studies for benzoic acid
using several solvents varying in a wide range of properties. These data are
presented in the next chapter.


120
Several explanations were proposed for the observed trends in data for
sorption of organic acids by soils from mixed solvents. The enhanced retention of
benzoic acid by soils upon addition of methanol appears to be due to some sorption
involving benzoate and Ca+2. Additional mechanisms did not to be invoked to
explain benzoic acid retention by RPLC supports from methanol/water solutions
where the buffer counterion was Na+ reflecting the importance of the cation in the
retention process and/or the increased functionality of soil surfaces. Although the
formation and exchange of positively-charged ion pairs is plausible, a preliminary
assessment of several sorbents suggested the role of additional sorption mechanisms
especially those equally impacted by cation-type. The use other types of cosolvents
with similar or lower dielectric constants may help to further elucidate the plausibility
of this ion-pairing phenomenon, since it is correlated to the decrease in the
electropermittivity of a solvent (Reichardt, 1990).
The magnitude of benzoic acid sorption measured for the various sorbents
also suggests that the predominate sorbent fraction of interest still may be organic
matter as conceptualized for HOCs. For the sorption of HOCs, the hydrophobic
attributes of soil organic matter are presumed to be of greatest importance in
retention by soils consistent with the many correlations observed between the
retention of HOCs by soils and hydrophobic RPLC. Such results support the need
to consider attributes other than the hydrophobic nature of organic matter, and
specific solvent-sorbent interactions to explain the enhanced sorption of benzoic acid
by soils.


119
matter-clay matrix is predominant over than that with the metal oxides. Note,
however, that the sorption coefficients reported here are in units of mL/g.
Comparison of benzoic acid sorption normalized to surface area (N2 BET) for the
two materials would be closer in magnitude given that the Webster soil probably has
ten times more surface area than the Borden aquifer material.
Summary
The impact of changes in soil-solution pH within a given solvent/water
fraction was investigated to better differentiate and elucidate the roles of the ionized
and neutral species on the overall sorption of carboxylic acids by soils. Sorption of
benzoic acid by a silty clay loam was measured from several methanol/water
solutions buffered at different pH values. Sorption of neutral benzoic acid was
observed to decrease with increasing fc in methanol/water solutions with 0.01 N
CaCl2, while benzoate sorption increased. This resulted in the sorption of benzoic
acid decreasing with increasing pH at fc<0.5,while sorption increased with increasing
pH at fe>0.75. A similar increase with increasing pH was observed for PCP in neat
methanol, whereas PCP sorption decreased with pH fc=0.75as observed in aqueous
solutions. However, retention of both neutral and ionized benzoic acid by RPLC
supports decreased with increasing methanol contents. Mobile phases buffered with
solutions containing monovalent counter ions were employed in the RPLC analysis,
whereas Ca+2 dominated the soil systems investigated indicating the importance of
the cation-type in the sorption process.


101
Table 4-2. Chemical characteristics of benzoic acid and pentachlorophenol
(PCP).
Solubility pKa
Solute
MW1
(g/mole)
lQg Kow,n
Water
Methanol
Water Methanol
PCP
266.4
5.01
14a
VSC
4.74 8.45
Benzoic Acid
122.1
1.87
3,000b
360,000b
4.22 8.96
a Verschuren
(1983); b Yalkowsky EPA report;
c Very Soluble (Dean, 1985);
d Measured.
Equilibrium Sorption Isotherms
Equilibrium sorption isotherms were measured using the batch-equilibration
method (Rao et al., 1990). The vials used for this study were 5-mL (1 dram) screw
cap borosilicate glass autosampler vials with teflon-lined septa inserts. Amber vials
were employed to minimize photolysis. Mass to volume ratios ranged from 2:3 to 1:2
to achieve sorption of about 50% of the chemical added. All methanol/water
solutions used had a 0.01 N CaCl2 matrix. Initial solution concentrations applied to
the soils in the equilibration studies ranged from 5 to 45 qg/mL and 0.25 to 3 /ig/mL
for benzoic acid and PCP, respectively. All sorption isotherms were measured at
room temperature (22 2C). Following equilibration, the solution and solid phases
were separated by centrifuging the soil samples at approximately 300 RCF (relative


3
transformations could decrease contaminant concentrations. Thus, high
concentrations of multiple contaminants are less likely to be found as the distance
from the source increases. Nevertheless, it is possible that these contaminant
concentrations may be higher than the standards set by regulatory agencies.
Partitioning from Multi-phasic Liquids
An understanding of solubility (or partitioning) of HOCs from complex OILs
is essential for predicting organic contaminant release from mixtures such as fuels
(e.g., gasoline, diesel, kerosene) and industrial wastes (coal tar, creosote). The
properties of an organic mixture complex only in composition are determined by the
properties of its pure components and their concentrations in the mixture. This
implies that the chemicals of interest behave ideally in the matrix containing them.
Under these conditions, the concentration in the aqueous phase of a chemical is
proportional to the mole fraction of the chemical in the organic phase corresponding
to Raoults law. With the stated assumptions, the concentrations of a chemical in the
aqueous phase in contact with a complex mixture can be predicted using the
following simplified expression based on Raoults law:
Cw-x0S1 (1-1)
where Cw is the chemicals concentration (moles/L) in the aqueous phase in
equilibrium with the organic phase, St is the aqueous solubility (moles/L) of the pure
liquid chemical, and xQ is the mole fraction of the chemical in the organic phase. The
derivation of Eq. (1-1) was based on the pure liquid chemical as the standard state.


4
Many components of interest are solid in their pure form at standard state; however,
Eq. (1-1) can be extended to solid solutes by employing hypothetical super-cooled
liquid solubilities (Sscl).
Raoults law is applicable to a vast number of mixtures of organic chemicals
and its use in predicting aqueous phase concentrations in contact with a complex
organic mixture is invaluable. These mixtures may be considered complex based on
the number of chemicals that constitute the mixture. On the other hand, complexity
of a mixture can be defined by considering how the properties of the mixture deviate
from some "ideal" behavior, regardless of the number of components. The former
view corresponds to a mixture being complex in composition, whereas the latter
implies complexity in behavior. The important point is that a mixture can be complex
in composition without being complex in behavior and vice versa.
In general terms, structurally similar chemicals are likely to form "ideal"
mixtures, and solubility of such mixtures can then be estimated using Raoults law.
A simple example of the application of Raoults law is shown in Figure 1-1A for a
mixture of two structurally similar compounds, benzene and toluene. The pure
aqueous compound solubilities of benzene and toluene are 23.1 and 5.60mmol/L,
respectively. Note that the pure compound solubilities are observed only in the
absence of the second component (i.e.,only when xQ= 0 or 1). The concentration
of either compound in the mixture is attenuated by the presence of the other. The
excellent agreement between the measured results and those predicted from Raoults
law (lines) clearly exemplifies the role of mole-fraction on solubility.


174
Nkedi-Kizza, P.,P.S.C.Rao, and A.G. Hornsby. 1985. Influence of organic
cosolvent on sorption of hydrophobic organic chemicals by soils. Envir. Sci.
Tech., 19:975-979.
Nkedi-Kizza, P.,P.S.C.Rao, and A.G. Hornsby. 1987. The influence of organic
cosolvents on leaching of hydrophobic organic chemicals through soils.
Envir. Sci. Tech., 21:1107-1111.
OConnor, J.T.,M.M. Ghosh, S.K. Baneiji, K. Piontek, E. Aguado, and T.M.
Prakash. 1989. Organic groundwater contamination evaluation and
prediction (in review).
Okuda,I., L.S. Lee, and P.S.C.Rao. 1991. Dissolution and desorption of
polyaromatic hydrocarbons from nonaqueous phase liquid wastes. IN:
American Chemical Society, Division of Environmental Chemistry,
Preprints of Papers Presented at the 201st National Meeting, Atlanta, GA.
April 14-19, Vol. 31, No. 1:467-469.
Ou, L.T.,D.F. Rothwell, and M.V. Mesa. 1985. Soil sterilization by 2450 MHz
microwave radiation. Soil Crop Sci. Soc. Fla. Proc., 44:77-80.
Pal, A., S.K. Maity, and S.C.Lahari. 1983. Free energies of transfer of ions from
solubility and conductometric measurements. J. Indian Chem. Soc.,
LX: 640-642.
Palmer, C.D. and W. Fish. 1992. Chemical Enhancements to Pump-and-treat
Remediation. Ground Water Issue. EPA/540/S-92/001. Office of Solid
Waste and Emergency Response, U.S. Environmental Protection Agency,
Washington, DC.
Parks, G.A.. 1967. Aqueous surface chemistry of oxides and complex oxide
minerals. Isoelectric point and zero point of charge. IN: Equilibrium
Concepts in Natural Water Systems. Adv. in Chem. Series no. 67. W.
Stumm (Ed.). American Chemical Society, Washington, DC, pp. 94-103.
Patterson, R.J. and H.M. Liebscher. 1987. Laboratory simulation of
pentachlorophenol/ phenate behavior in an alluvial aquifer. Water Pollut.
Res. J. Canada, 22:147-155.
Perrin, D.D., B. Dempsey and E.P. Serjeant. 1981. pKa Prediction for Organic
Acids and Bases. Chapman and Hall Ltd., London, Great Britain.


32
Results and Discussion
Coal Tar Composition
The coal tars used in this study were received from META Environmental, Inc.
Various physical and chemical properties of these coal tars had been characterized
(EPRI, 1993), including density, viscosity, water and ash content, average molecular
weight, elemental and organic analysis. The ranges observed for these properties in
terms of percentages or concentrations are summarized in Table 2-2.
The viscosity of the coal tars ranged from approximately 34 cps to 6600 cps
(40C), with the coal tar consistency varying from thin liquids (ID# 1,4, and 5) to
thick liquids (ID# 7) and from soft (ID# 3 and 9) to sticky (ID# 2) "taffy-like"
materials. Coal tar viscosity will generally increase with aging and decrease with
temperature. Some coal tars had high ash contents, suggesting the presence of other
solids. For example, coal tar ID# 7N had a high content (37%) of what appeared
to be sand and silt. The PAH concentrations for this coal tar were corrected to
represent the mass of PAH present per actual mass of coal tar. For the remaining
coal tars an occasional rock or pellet was found, which was easily removed prior to
experimentation.
Water content of the thin liquid coal tars was small (<1% mass basis). For
the more viscous coal tars, reported water contents were as high as 30% (mass basis);
however, high molecular weights and densities for these coal tars strongly suggests
that these high water contents were in actuality a sampling artifact. It appears that
water may have been trapped as a separate liquid phase within the taffy-like matrix
of the coal tar.


153
attributed to any single bulk solvent property. This suggests that: (1) although both
methanol and DMSO have the same macroscopic effect on sorption of benzoic acid,
sorption is driven by two completely different mechanisms; or (2) in the presence of
water, one of the two solvents acquires a property common to the other solvent.
There was spectroscopic evidence found in the literature supporting the formation
of DMSO (H20)2 complexes and subsequent hydrogen-bonding interactions.
To investigate solute-sorbent interactions, sorption of several substituted
carboxylic acids by Webster soil from methanol/water solutions was measured.
Comparisons between sorption coefficients observed in neat methanol (KMeOH) and
water (1^), and aqueous ionization constants (pKa w) with octanol-water partition
coefficients (Kow) for both the ionized (i) and neutral (n) species showed that
substantially better correlations were obtained using Kow ¡ values. These results
further support the dominant role of benzoate in the cosolvent-enhanced sorption of
benzoic acid. However, the varied nature of the sorption profiles obtained from the
different solvent/water mixtures clearly demonstrates the solvent specificity of this
enhancement. In addition, the different trends observed between retention of
benzoate by Ca+2-saturated soils versus RPLC supports using mobile phases buffered
with monovalent counterions further support the significant role played by various
functional groups present in soil organic matter as well as demonstrate the
significance of electrolyte composition on sorption ofHIOCS. Therefore, enhanced
sorption appeared to be a function of specific solvent associations with both the
solute and the sorbent. It was deduced that hydrogen-bonding interactions coupled


30
Materials and Methods
Chemicals
For all the PAHs investigated (see Table 2-1) standards were purchased from
Aldrich Chemical Co. at > 98 % purity except for acenaphthene, which was available
only at 85% purity. Methylene chloride, the solvent used for the aqueous phase
extractions, was purchased from Fisher Scientific at Fisher grade Optima.
Batch Equilibration Technique
Approximately 0.3-0.5 g of coal tar were added to a glass centrifuge tube
(nominal volume 40 mL); enough electrolyte solution (0.01 N CaCy was added such
that no headspace remained; and tubes were closed with phenolic caps fitted with
Teflon-lined septa. Prior to sampling the coal tar for equilibration with an aqueous
phase, coal tars were rotated end-over-end at room temperature (23 2C) for 12-18
hours. The coal tar/water (0.01 N CaCy mixtures were then equilibrated for 3-7
days in the dark. Preliminary studies where samples were equilibrated for 1,3,5,
and 7 days showed no measurable differences in PAH concentrations after 3 days.
Following centrifugation (300 RCF for 30 minutes) of the equilibrated coal tar/water
mixtures, a portion of the aqueous phase (~25 mL) was quantitatively removed for
extraction with methylene chloride and subsequent concentration prior to analysis.
Due to the large masses of the compounds of interest present in the coal tar phase,
experimental artifacts from PAH sorption to the equilibration vessels were
considered negligible. To avoid volatilization losses and contamination of the
aqueous phase aliquot with the coal tar phase, the aqueous aliquot was removed
through the septa using a 50-mL Teflon-backed gas/liquid syringe equipped with a


175
Perrin, D.D. 1965. Dissociation Constants of Organic Bases in Aqueous Solution.
Butterworths, London.
Perrin, E.E. 1972 supplement. Dissociation Constants of Organic Bases in
Aqueous Solution. Butterworths, London.
Peters, C.A. 1992. Experimental evaluation and semi-empirical thermodynamic
modeling of coal tar dissolution in water-miscible solvents. Ph.D.
Dissertation, Carnegie Mellon, Pittsburgh.
Peters, R.A. 1931. Interfacial tension and hydrogen-ion concentration. Proc. Roy.
Soc. (London), A133:140-154.
Picel, K.C., V.C. Stamoudis, and M.S. Simmons. 1988. Distribution coefficients
for chemical components of a coal-oil/water system. Water Res., 22:1189-
1199.
Pinal, R. 1988. Estimation of Aqueous Solubility of Organic Compounds, Ph.D.
Dissertation, Univ. of Arizona, Tucson, AZ.
Pinal, R.,L.S.Lee, and P.S.C.Rao. 1991. Prediction of the solubility of
hydrophobic compounds on nonideal solvent mixtures. Chemosphere,
22:939-951.
Pinal, R., P.S.C.Rao, L.S.Lee, and P.V. Cline. 1990. Cosolvency of partially-
miscible organic solvents on the solubility of hydrophobic organic
chemicals. Envir. Sci. Tech., 24:639-647.
Popovych, O. and R.P.T. Tomkins. (1981) Nonaqueous Solution Chemistry, ohn
Wiley and Sons New York.
Prausnitz, J.M.,T.F. Anderson, E.A. Grens, C.A. Eckert, R. Hseieh, and J.P.
OConnell. 1980. Computer Calculations for Multicomponent Vapor-
Liquid and Liquid-Liquid Equilibria, rentice-Hall, Inc. Englewood Cliffs,
NJ.
Rao, P.S.C.,A.G. Hornsby, D.P. Kilcrease, and P. Nkedi-Kizza. 1985. Sorption
and transport of hydrophobic organic chemicals in aqueous and mixed
solvent systems: Model development and preliminary evaluation. J. Envir.
Qual., 14:376-383.


143
orientation of the solvent molecules in the solvation shell coupled with hydrogen
bonding interactions may be the mechanisms responsible for the enhanced sorption
of carboxylic acids by soils in methanol/water and DMSO/water solutions.
Sorption of Several Substituted Carboxylic Acids in Methanol/Water Solutions
From the foregoing discussion, it is clear that solvent structure plays a crucial
role in the relationship between sorption and volume fraction cosolvent (fc), but data
presented in Chapter 3 indicated that solute structure is also important. Chapter 3
investigations showed that sorption of benzoic acid increased with increasing
methanol fractions and was not predictable by incorporating cosolvent-enhanced
solubility and cosolvent-induced speciation effects (Eq. 3-6) which had prompted
further study. However, the sorption of several substituted phenols did decrease with
increasing methanol fractions in a predictable manner similar to that observed for
nonpolar hydrophobic organic chemicals. Carboxylic acids are generally more acidic
than phenols, as indicated by the lower pKa values, and have a greater propensity to
hydrogen bond. Therefore, the role of solute structure on sorption of carboxylic
acids by soils from solvent/water solutions was further investigated by measuring
sorption from methanol/water solutions of several carboxylic acids. The acids were
chosen by adding benzene rings or chlorine groups to benzoic acid resulting in
carboxylic acids with varying degrees of acidity (e.g.,pKa) and hydrophobicity (e.g.,
Kow).
First, the relative hydrophobicity of the ionized and neutral forms of the acids
was assessed by measuring octanol/water partition coefficients (Kow) of the various
carboxylic acids in acidic (pH< >pKa). The log Kow


35
Tar-Water Partitioning
The relative success in applying a model based on Raoults law convention for
gasolines (Cline et al., 1991), diesel fuels, and motor oil prompted the investigation
of whether ideal behavior could also be assumed for coal tars. Compared to
gasolines and diesel fuels, coal tars are compositionally more complex; thus, greater
deviations from ideal behavior might be expected. The assumption of ideal behavior
for coal tar is postulated here for practical expediency, since it reduces the number
of parameters needed to estimate PAH concentrations in groundwater. Ideal
behavior is not necessarily expected for such materials, but it is hoped that the
assumption will be adequate within a specified acceptance factor; a factor-of-two has
been chosen here to be adequate for field-scale applications. Experimental
measurements of tar-water partition coefficients are difficult, and are subject to
significant errors. Thus, experimental artifacts as a possible cause must be
eliminated before attributing nonideal behavior to a given coal tar or even to one or
more constituents within a coal tar. It is with this pragmatic perspective that we will
interpret tar-water partitioning data. The investigations of tar-water partitioning
involved analysis of data collected in this study for eight tars, analysis of published
data, and theoretical analysis of solute-solute interactions that might lead to nonideal
behavior.
Analysis of Laboratory Data
The tar-water partitioning data for the eight tars examined in this study are
presented in Figures 2-2 through 2-5. The logarithm of the average value and
the calculated standard deviations are shown along with the prediction based on Eq.


156
APPENDIX A
SUPERCOOLED LIQUID SOLUBILITIES
The derivation of Eq. (1-1) was based on the pure liquid chemical as the
standard state. Many components of interest are crystalline in their pure form at
standard state; however, Eq. (1-1) can be extended to solid solutes by employing
hypothetical supercooled liquid solubilities (Sscl ). Super-cooled liquid solubilities
cannot be determined directly; however, several estimation methods are available.
Supercooled liquid solubilities of solids can be best understood by examining
the steps and reviewing the properties responsible for the solubility of the solid.
First, unlike a liquid compound, the crystal structure of the solid must be destroyed
forming a super-cooled liquid (A in Figure 1-2). Then, a second step involving the
mixing of this hypothetical liquid with the solvent must occur as with a liquid
compound (B in Figure 1-2). Thermodynamically, step A involves only the
crystallinity properties of the solid (e.g.,the heats of fusion and the melting point),
whereas the mixing step (B) involves both the properties of the compound and the
solvent (e.g.,molecular dimensions and interactions). Step A can be interpreted as
the hypothetical melting of the compound at the temperature of interest (T) and can
be further simplified into three basic steps. The compound is heated from T to its
melting temperature (Tm) (Step 1), where it is melted at Tm (Step 2), followed by
bringing the compound back to the initial temperature of interest (T) without
returning it to the solid (Step 3).



PAGE 1

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7
Sorption from Aqueous Solutions
Most of the available data and theories for predicting sorption and transport
of organic chemicals may be successfully applied to predict contaminant behavior in
the far-field region (i.e., dilute aqueous solutions). The following section will
highlight the information available on equilibrium sorption of organic chemicals
relevant to this dissertation work.
Sorption is one of the dominant processes affecting the mobility of organic
contaminants in soils and groundwater. This process can be conceptualized either
as binding at a two-dimensional interface of the sorbent or as a partitioning into the
three-dimensional bulk of the sorbent. Several methods for estimating the magnitude
of sorption for organic contaminants have been developed based on the chemical and
physical properties of the srbate, the sorbent, and the solvent.
Hydrophobic Organic Compounds (HOCs)
Equilibrium sorption of hydrophobic organic compounds (HOCs) by soils and
sediments has been successfully predicted in many cases by the "solvophobic theory"
and the use of linear free energy relationships (LFER). Excellent log-log, linear
relationships have been reported between K^, the sorption coefficient normalized to
the fraction of organic carbon (OC) of the sorbent, and Kow, the octanol-water
partition coefficient for several HOCs (c.f.,Dzombak and Luthy, 1984; Karickhoff,
1981; 1984; Kenega and Goring, 1980). Linear relationships have also been found
between log Koc and solute hydrophobic surface area (HSA) (Dzombak and Luthy,
1984; Rao et al., 1985) and solute molecular connectivity (Sabljic, 1984; 1987). The


43
A decrease in the measured values would be anticipated for deviations
resulting from sufficient nonideality as observed in Figure 2-6A for the Rostad et al.
(1985) data. The expectation of the presence of nonideality resulting in negative
deviations for PAHs is based on work by Chiou and Schmedding (1982) and Chio et
al. (1985) where the activity coefficients of several PAHs were measured in water-
saturated octanol and mixtures of benzene and cyclohexane. In both cases, the
activity coefficient of a given PAH in the organic phase (yQ*) were found to be
greater than unity. Values of yQ* greater than unity will result in log KD values
smaller than those estimated assuming ideal behavior.
Predicting Aqueous-Phase PAH Concentrations
Coal Tars
The log versus log S; relationship observed for several coal tars (Figures
2-2 through 2-5) suggests that the application ofRaoults law and the assumption of
ideal behavior may be adequate to predict the concentration of PAHs in groundwater
(Cw) in contact with a coal-tar source. Equation (2-3) was used to estimate the
concentrations of several PAHs expected to be present in a groundwater in
equilibrium with a coal tar were estimated using Eq. (2-3) for the coal tars
investigated. The mole fraction of the PAH in the organic phase (xj needed in Eq.
(2-3) was approximated by the product of the mass fraction (mg/g) in the coal tar
and MWct (i.e.,Cw = M¡ MWct S¡). A log-log plot comparing predicted aqueous
concentrations (converted to commonly reported units of mg/L) and those measured
during the laboratory partitioning studies is shown in Figure 2-7. The error bars


82
V3
Cl
A-
-e

-A-
Benzoic Acid (This study)
Benzoic Acid (Pal et al., 1983)
Benzoic Acid (Bacarella et al., 1955)
Pentachlorophenol
0.2 0.4 0.6 0.8
Volume Fraction Methanol, f
* n

A
Figure 3-3. Effect of methanol content on the pKa of benzoic acid and
pentachlorophenol.
5.5
A
A
cn
ID
4.5m
W $
U)
O 4
3.51
3
0
a
Benzoic Acid (0.01 M HCI)
A Benzoic Acid (Yalkowsky, 1985)
Benzoic Acid (0.3 M NaOH)
0.2 0.4 0.6 0.8
Volume Fraction Cosolvent, f _
1
Figure 3-4. Solubility (Sb) of benzoic acid in methanol/water solutions.


75
mixed solvent was added to the pKa estimated from the titration curve (i.e.,
pKa=pKa + S). From 0 to 70% methanol, S values were negligible. At higher
methanol fractions, S values were approximately 0.1,0.4,and 2.3 for fe values of 0.8,
0.9 and 1.0, respectively. Similar results were obtained by De Ligny and Rehbach
(1960) for methanol/water solutions by comparing pH measured in aqueous standard
buffers (KC1 saturated solutions) and standard buffers prepared in the appropriate
mixed solvent using the method proposed by the National Bureau of Standards
(Bates et al., 1963). Therefore, the corrections needed to adjust the pKa determined
in mixed solvents relative to the use of aqueous standard buffers are only significant
at fc>0.9.
pH of Soil Suspensions in Mixed Solvents
When considering the measurement of pH in mixed solvent soil-suspensions,
problems in addition to those previously discussed for pH measurements in mixed
solvents arise. It has long been recognized that the ambiguity of measuring the pH
in aqueous soil solutions, and even more so in soil suspensions, is due to the inability
to accurately determine liquid junction potential differences between standard buffer
solutions (Ej J and soil-solutions (E¡ xs). Even with this ambiguity, the error in the
measured pH resulting from differences in the liquid junction potentials (Ej M Ej J
is usually assumed to be within 0.2 pH units for an aqueous soil-solution or dilute
soil-suspension given a background electrolyte concentration of approximately 0.01
N (Sposito, 1989).
In these studies, pH of the supernatant and/or the resuspended soil sample


11
where
4>n (1 + lop*-*)-1
(1-3)
and K is the measured distribution ratio for the sorbed- and solution-phase
concentrations; Koc =(K/OC); OC is the soil organic carbon content (mass fraction);
0n is the fraction of the neutral HIOC; and the subscripts n and i refer to neutral and
ionized species, respectively.
Sorption data compiled from the literature for several other organic acids
could be, in most cases, adequately described by Eq. (1-2). Shown in Figure 1-2 for
example, is reasonable predictions by Eq. (1-2) of OC normalized sorption of the
herbicide flumetsulam compiled from Fontaine et al. (1991) for several soils.
Figure 1-2. Measured and predicted sorption of flumetsulam by several soils
normalized to organic carbon content plotted as a function of pH.
(Data form Fontaine et al., 1991)


133
Sorption of Benzoic Acid in Several Solvent/Water Solutions
To investigate if specific solvent properties were responsible for the enhanced
sorption of benzoic acid observed upon addition of methanol, benzoic acid sorption
was measured in additional binary mixtures of water and several other organic
solvents spanning a wide range of solvent properties. Addition of any of the solvents
chosen will cause an increase in benzoic acid solubility relative to that in water.
Data for benzoic acid solubility in binary mixtures are available for all but 1,4-
dioxane/water solutions, and are shown in Figure 5-3A.
All the cosolvents chosen have dielectric constants lower than that of water;
therefore, in each case addition of a solvent would enhance the potential for ion
pairing. A summary of the sorption coefficients estimated from the batch
equilibration studies as a function of volume fraction cosolvent (fc) in different binary
mixtures is given in Figure 5-3B. Sorption of benzoic acid from DMSO/water
solutions is very similar in direction and magnitude to that observed in
methanol/water solutions. The remaining solvent/water mixtures (e.g., acetone,
acetonitrile, and 1,4-dioxane) all display a parabolic shaped curve with an apparent
sorption maximum at an approximate volume fraction of 0.4 to 0.5. The lack of
relationship between the observed sorption trends and the cosolvents dielectric
constant appears to discount the formation and exchange of positively charged ion-
pairs. Recall from Chapter 3 that this mechanism was proposed to explain the
differences in benzoic acid sorption by K+-versus Ca+-saturated Webster soil. These
results suggest the need to invoke alternate sorption mechanisms that may also be
impacted by cation-type such as cation- and water-bridging, and hydrogen bonding.


8
different slopes and intercepts found in these regression equations are predominantly
determined by the characteristics of a group of compounds (i.e., class, degree of
hydrophobicity, and structure), while the sorbent properties other than OC appear
to have only minor impact in most cases (Karickhoff, 1981,1984; Schwarzenbach and
Westall, 1985). The equations derived from LFER and experimental data obtained
for only a few sorbents provide reasonable predictions of HOC distribution in diverse
soil-water and sediment-water systems. However, the limitations of the concept
have been pointed out by a number of authors (e.g., Mingelgrin and Gerstl, 1983;
Green and Karickhoff, 1991; Gerstl, 1990). The two main concerns involve the
contribution of adsorption on mineral constituents and the possibility of site-specific
interactions between functional moieties of the solute and the sorbent.
Hydrophobic ionogenic organic compounds (HIPCs')
For hydrophobic, ionogenic organic compounds (HIOCs), several factors (e.g.,
speciation, soil-solution pH, sorbent-surface pH, charge, ionic strength, ionic
composition, multiple solutes) make predicting sorption from a single parameter
difficult due to additional mechanisms that must be considered. Several mechanisms
proposed in the literature for sorption of organic solutes from aqueous solutions
include: hydrophobic interactions; London-van der Waals or dispersion forces;
hydrogen bonding; cation and water bridging; cation and anion exchange; ligand
exchange; protonation; covalent bonding or chemisorption; and interlayer adsorption
(Koskinen and Harper, 1990). Hydrophobic interactions are driven by weak solute-
solvent interactions and the preference of an organic molecule to be near an organic


52
Figure 2-10. log Kgw values for several aromatic hydrocarbons resulting from
UNIFAC model calculations and the average logg,, values
experimentally determined by Cline et al. (1991) plotted against log S,
values along with the ideal line based on Raoults law.
The estimated y0* values were then used to predict log values (shown as solid
triangles in Figure 2-10) according to Eq. (2-8). UNIFAC model calculations for the
monocyclic aromatic compounds represented in Figure 2-10 (compounds 2-5) confirm
the experimental observations of Cline et al. (1991) that gasoline-water partition
coefficients of several liquid hydrocarbons can be approximated by assuming ideal


150
Liquid-Liquid Partitioning
Partition coefficients for several HOCs were either measured or compiled
from the literature for a wide range of OILs. An experimental evaluation of a model
based on Raoults law was presented for the partitioning of aromatic hydrocarbons
from diesel fuel and coal tar into water, and the results compared to data reported
earlier for gasoline/water and motor oil/water partitioning. According to the model
based on Raoults law, the concentration of a constituent in the aqueous phase in
equilibrium with an "ideal" organic mixture is proportional to the mole fraction of
that constituent in the organic phase. Application of Raoults law convention for
activity coefficients with the assumption of ideal behavior and the use of supercooled
liquid solubilities was successful in describing the partitioning of several PAHs within
a factor of four for diesel fuels, and within a factor of two for coal tars. UNIFAC
(UNIQUAC Functional Group Activity Coefficient) model estimates of the likely
nonidealities resulting from interactions between components in a simulated gasoline,
diesel fuel, motor oil, and coal tar further suggested that the extent of deviations
from ideal behavior may be relatively small for these environmentally relevant OILs.
Agreement between the model predictions based on Raoults law and measured
liquid-liquid partitioning data is not to be taken as evidence that such compositionally
complex organic liquid wastes are indeed ideal mixtures, but rather as support for the
pragmatic assumption that ideal behavior might suffice for most practical
applications. Thus, first-order estimates of PAH concentrations likely to be found
in groundwater (assuming equilibrium) leaving an area contaminated with residual


59
competitive sorption) by soils from aqueous solutions has been documented (Felice
et al., 1985; Zachara et al., 1987; Rao and Lee, 1987); however, little attention has
been given to the behavior of HIOCs in solvent mixtures.
Pharmaceutical literature contains solubility data for several drugs spanning
a wide polarity range. As shown in Figure 3-1, Yalkowsky and Roseman (1981)
observed that as solute polarity increases relative to the solvent, cosolvency curves
become increasingly more parabolic in shape until an inverse relationship occurs (i.e.,
decreased solubility with cosolvent additions). Such behavior is explained on the
basis of the solute-solute and solute-cosolvent interactions. Therefore, for
compounds that exhibit a decrease in solubility with addition of a cosolvent (log Kow
< 1), sorption may increase with increasing cosolvent composition.
For the sorption of naphthol, quinoline, and dichloroaniline by three different
soils from methanol/water and acetone/water solutions up to 50% by volume, Fu
and Luthy (1986b) observed log-linear behavior inversely proportional to
corresponding solubility data (Fu and Luthy, 1986a) as observed with HOCs. Similar
behavior was observed by Zachara et al. (1986) for quinoline sorption by a natural
clay isolate and montmorillonite in binary mixtures of methanol or acetone and water
regardless if the protonated or neutral species predominated in solution. For these
HIOCs it appears that the cosolvent effect on sorption is dominated by solvation
forces (i.e., solubility) similar to that observed with HOCs even though sorption
mechanisms for HIOCs and HOCs are different (electrostatic and ion exchange
versus hydrophobic partitioning).


171
Koskinen, W.C.,and S.S.Harper. 1990. The retention process: mechanisms. IN:
Pesticides in the Soil Environment Processes, Impacys and Modeling, Soil
Sci. Soc. of Am. Book Series 2. pp. 51-78.
Koskinen, W.C.,G.A. OConnor, and H.H. Cheng. 1979. Characterization of
hysteresis in the desorption of 2,4,5-Tfrom soils. Soil Sci. Soc. Am. J.,
43:871-874.
Kukowski, H. 1989. Untersuchungen zur ad-und desorption ausgewahlter
chemikalien in boden. Ph.D. Dissertaion. Universitity of Kiel, Kiel,
Germany.
Kummert, R. and W.J. Stumm. 1980. The surface complexation of organic acids
on hydrous-A1203. Colloid and Interface Sci.,75:373-385.
Lambert, S.M. 1967. Functional relationship between sorption in soil and
chemical structure. J. Agri. Food Chem., 15:572-576.
Lane, B.F. and R.C. Loehr. 1992. Estimating the equilibrium aqueous
concentrations of polynuclear aromatic hydrocarbons in complex mixtures.
Envir. Sci. Tech., 26:983-990.
Lee, L.S.,C.A. Beilin, R. Pinal, and P.S.C.Rao. 1993a. Cosolvent effects on
sorption of organic acids by soils from mixed-solvents. Envir. Sci. Tech.,
27:165-171.
Lee, L.S.,P.S.C.Rao, and M.L. Brusseau. 1991. Nonequilibrium sorption and
transport of neutral and ionized chlorophenols. Envir. Sci. Tech., 25: 722-
729.
Lee, L.S.,P.S.C.Rao, M.L. Brusseau, and R.A. Ogwada. 1988. Nonequilibrium
sorption of organic contaminants during flow through columns of aquifer
materials. Envir. Toxicol, and Chem., 7:779-793.
Lee, L.S.,P.S.C.Rao, P. Nkedi-Kizza, and J.J. Delfino. 1990. Influence of solvent
and sorbent characteristics on distribution of pentachlorophenol in octanol-
water and soil-water systems. Envir. Sci. Tech., 24:654-661.
Leo, A.,C. Hansch, and D. Elkins. 1971. Partition coefficients and their uses.
Chem. Rev., 71:525-553.
Lewis, S. and I.D. Wilson. 1984. Factors affecting the ion-pair reversed-phase
thin-layer chromatography of organic acids on paraffin-coated and C18
bonded silica gel. J. Chromat., 312:133-140.


89
Discussion
Cosolvent effects on solubility and sorption of nonpolar organic solutes can
be readily predicted using the log-linear model, and most deviations from this model
can be explained by invoking water-cosolvent interactions (Pinal et al., 1991). In
contrast, prediction of sorption of ionizable organic solutes from mixed solvents is
confounded by a number of indirect effects resulting from cosolvent-induced
phenomenon occurring either in the solution phase or on the sorbent. The presence
of the neutral species of an ionizable organic solute is increasingly favored with
increasing cosolvent content (alkaline shift in the pKa), such that in a neat cosolvent
the amount of the ionized species present may be negligible. The cosolvency model
given by Eq. (3-6) accounts for such changes in speciation, but underestimated the
magnitude of carboxylic acid sorption from methanol-water; this suggests the
significance of other mechanisms.
Solute-solvent Interactions
Solution-phase interactions not considered in formulating Eq. (3-6) include
cosolvent-enhanced polymerization and ion-pairing. Polymerization of benzoic acid
in neat methanol could not be measured up to a concentration of 10 mg/mL.;
therefore, enhanced sorption arising from the former mechanism was discounted.
The formation of ion-pairs may be promoted by the addition of an organic cosolvent
to an aqueous solution resulting from a decrease in the dielectric constant of the
solution (Swarc, 1974); increase in pKa with fc is directly related to decreasing
dielectric constant. Even though the neutral form of the carboxylic acid is the


ACKNOWLEDGEMENTS
I want to thank my committee members Professor Suresh Rao, Dean Rhue,
Joe Delfino, Kirk Hatfield and John Zachara for support and helpful guidance
leading to the successful completion of this project. I especially want to thank Dr.
Rao for his continual contribution to both my personal and professional growth. The
exceptional role Dr. Rao has played as my chairman can be best summarized by his
most recently awarded title of Graduate Research Professor.
I thank my colleagues Dr. Arthur Hornsby, Ron Jessup, Lynn Wood, Dr. Mark
Brusseau, Dr. Ken Van Reese, Dr. Sam Traina, Cheryl Beilin, Denie Augustijn, Dong
Ping Dai, Itaru Okuda, and Dr. Peter Nkedi-Kizza for their assistance, support, and
friendship. Special thanks go to Cheryl Beilin for her assistance in the acid/base
titrations, Itaru Okuda for the UNIFAC simulations, Dr. Mary Collins and Dr. Ron
Kuehl for providing numerous subsamples of Webster soil from Iowa, Vicki Neary
for her technical assistance in the completion of the laboratory experiments, and
Candace Biggerstaff for her help in the preparation and submission of my final
draft.
It has been a pleasure to be affiliated with the Soil and Water Science
Department at the University of Florida through both employment and education,
m


128
Table 5-3. Parameters for linear and Freundlich fits to the isotherm data for
benzoic acid in several solvent/water solutions.
Solvent
fc
Kd(mL/g)
K10nL'W)
NSEa
Acetone
0.2
0.177
0.030
0.840.06
0.4
0.264
0.285
0.970.05
0.6
0.175
0.305
0.830.06
0.8
0.111
0.088
1.060.07
DMSO
0.2
0.239
0.732
0.660.02
0.25
0.256
0.57
0.750.05
0.4
0.296
0.455
0.870.03
0.5
0.385
0.515
0.900.05
0.6
0.507
0.724
0.880.04
0.75
0.845
0.872
0.870.03
0.8
0.872
1.267
0.870.03
Acetonitrile
0.2
0.173
0.263
0.880.06
0.25
0.167
0.153
l.OliO.ll
0.4
0.165
0.181
0.980.07
0.5
0.14
0.162
0.950.09
0.6
0.146
0.183
0.920.07
0.75
0.12
0.182
0.840.11
0.8
0.113
0.118
0.990.03
1,4-Dioxane
0.2
0.23
0.32
0.880.06
0.25
0.24
0.42
0.830.01
0.4
0.28
0.44
0.85 0.04
0.5
0.29
0.379
0.910.05
0.6
0.23
0.25
0.950.06
0.75
0.137
0.198
0.890.07
0.8
0.14
0.16
0.940.13
* Standard Error


CHAPTER
2
Results and Discussion 32
Coal Tar Composition 32
Tar-Water Partitioning 35
Analysis of Laboratory Data 35
Analysis of Literature Data 41
Predicting Aqueous-Phase PAH Concentrations 43
Coal Tars 43
Diesel Fuels 47
Assessment of Deviations from Ideal Behavior for
for Equilibrium Conditions 49
Summary 56
3 COSOLVENT EFFECTS ON SORPTION OF ORGANIC ACIDS BY SOILS
FROM METHANOL/WATER SOLUTIONS 58
Introduction 58
Theory 64
Materials and methods 72
Sorbents 72
Chemicals 72
Determination of Ionization Constants 74
pH of Soil Suspensions in Mixed Solvents 75
Solubility Experiments 76
Miscible Displacement Experiments 77
Equilibrium Sorption Isotherms 78
Results 79
pKa Measurements 79
Solubility 80
Miscible Displacement Studies 83
Batch Equilibration Studies 85
Effect of Solvent Addition 85
Discussion 89
Solute-solvent Interactions 89
Desorption Characterises 91
Estimation of pH by pHxapp 92
Summary 93
vi


115
interactions. To elucidate the sorption process of importance and get an indication
of what specific domains of the soil might be most significant, sorption of benzoic
acid by a range of sorbents was measured from aqueous and neat methanol solutions.
The following sorbents were utilized: Pahokee muck, Ca-montmorillonite (SAz-1),
A1203, and Al(OH)3 The SAz-1 was a reference clay obtained the clay depository
in Clay Bank, NE [CEC of 120 cmol(+)/kg and specific surface area by N2 BET of
100 m2/g (Rao et al., 1988)]; A1203 and Al(OH)3 were obtained from Fisher; and
Pahokee muck was sampled from Belleglade, Florida [CEC of 136 cmol(+)/kg, and
38% OC (IFAS, 1974)]. Sorption was measured over a similar benzoic acid
concentration range with a background electrolyte of 0.01 N CaCl2 as used previously
for the Webster soil experiments with a mass to volume ratio of two and a soil-
solution pH between 7 and 8. In aqueous solutions, either negligible or negative
sorption was observed by all sorbents at the measured pH. Similar results were
obtained for benzoic acid in aqueous solutions by Bailey et al. (1968) for Na- and H-
saturated montmorillonite; however, Carringer et al. (1975) was able to measure
some adsorption of benzoic acid onto Ca-saturated montmorillonite at pH=6.
In neat methanol, sorption increased for all sorbents with the muck having the
greatest sorption capacity at the pH investigated. Recall that in all the experiments
presented in this work, the neat methanol actually contained 0.05% water, and all
sorbents were air-dried, not oven dried. Estimates of the K values for the muck,
A1203, Al(OH)3, and SAz-1 were approximately 10, 0.8, 0.5, and 0.2 mL/g,
respectively. Isotherm data are shown in Figure 4-7 along with the linear and


log K
Volume Fraction Cosolvent, f
Figure 5-5. Measured and predicted (Eq. 3-6) sorption of benzoic acid by Webster soil from (A) acetone/water; (B)
acetonitrile/water; (C) DMSO/water; and (D) 1,4-dioxane/water solutions as a function of volume
fraction cosolvent (fc).
oo


85
Batch Equilibration Studies
Sorption of benzoic acid, dicamba, and PCP by Webster soil was measured
from several methanol/water solutions. Representative isotherms are shown in
Figure 3-5. Sorption isotherms were linear for PCP and dicamba in both aqueous
and mixed-solvent systems over the concentration range investigated. Sorption
isotherms for benzoic acid were slightly nonlinear, but a linear approximation of the
sorption coefficients (K) adequately described the data. The correlation coefficients
(r2) ranged between 0.95 and 1.0.
Effect of Solvent Addition
As noted previously, addition of an organic cosolvent to an aqueous solution
results in an increase in the pKa for organic acids. Changes in speciation become
significant at fc>0.5 as marked changes occur in the pKa values. In neat methanol,
the measured soil-solution pH for Webster soil ranged between 6.2 and 6.5;
therefore, essentially all the benzoic acid and PCP existed in the neutral form, while
20% to 30% of dicamba remained ionized.
The sorption coefficients estimated from batch equilibration studies of PCP
and benzoic acid are plotted in Figure 3-6 as a function of volume fraction methanol
(fc). Sorption of PCP in methanol/water systems was well described by the log-linear
model with speciation given by Eq. (3-6) (Figure 3-6A) except in neat methanol. Of
the required model parameters, bulk pH and pKa were measured; using Eq. (3-5); and a¡a¡, and ancjn were taken from Lee et al. (1990) where
sorption of PCP was measured as a function of fc while pH was maintained such that


9
surface; thus, strong inverse correlations are observed between and solubility of
HOCs. London-van der Waals forces result from correlations in the electron
movement between molecules that produce a small net electrostatic attraction.
Although small in magnitude (2-4 kJ/mol), these interactions are additive and have
been found to be significant for the sorption of large neutral polymeric solutes.
Hydrogen bonding interactions involve the electrostatic interaction between
protons and electronegative atoms, and can be stronger than dispersion forces (2-60
kJ/mol) (Kohl and Taylor, 1961;Stumm etal.,1980). Hydrogen-bonding interactions
may occur with both inorganic and organic surfaces, but for soils interactions with
organic matter are more important due to the abundance of carbonyl-type functional
groups (Sposito, 1984).
Cation bridging results if a polar organic functional group displaces a water
molecule from the primary hydration shell of an exchangeable cation (i.e.,formation
of an inner-sphere complex), whereas water bridging results when interaction occurs
without displacement of the hydrating water molecules (i.e., outer-sphere
complexation) (Farmer and Russell, 1967). The occurrence of cation bridging versus
water bridging will be a function of the heat of cation hydration, which varies with
cation size and charge (i.e.,charge density). For example, water bridging would be
preferred in a Ca+2-saturated sorbent due to its large negative heat of hydration
(AH=-377 kcal/mol) compared to a saturation with K+ (AH=-75 kcal/mol) (Bailey
et al., 1968).
Ion exchange involves the exchange of a cation or an anion for another ion
of similar charge at specific binding sites. Cation exchange is of much greater


21
manufacturing of gas from coal and oil for residential, commercial, and industrial use
in the late 1800s and early 1900s resulted in the production of large amounts of coal
tar wastes. Eng and Menzies (1985) reported that more than 11 billion gallons of
coal tar were generated in the U.S. during the period 1816-1947, but the disposition
of several billion gallons is unknown and remains unaccounted. In many cases, the
wastes were left on-site in pits or containers, placed in near by ponds or lagoons, or
taken to off-site areas for land disposal. Such practices resulted in contamination of
soils and groundwater at most former MGP sites. Hydrophobic organic chemicals
(HOCs) have been detected at former MGP sites, and are of particular concern due
to their potential carcinogenic nature (Guerin, 1978). Several of these compounds
have already been included on the U.S. EPA list of priority pollutants.
In the past, it has often been assumed that concentrations of organic
contaminant in the aqueous phase leaving a coal tar source would be equal to their
corresponding pure-compound aqueous solubilities. This may be a reasonable
estimate if the source of interest was composed of a single contaminant (e.g.,
trichloroethylene, tetrachloroethylene). However, most complex wastes (e.g.,coal tar,
diesel, gasoline) consist of mixtures of contaminants. These mixtures may be
considered complex based on the number of chemicals that constitute the mixture.
On the other hand, complexity of a mixture can be defined by considering how the
properties of the mixture deviate from some "ideal" behavior, regardless of the
number of components. The former view corresponds to a mixture being complex
in composition, whereas the latter implies complexity in behavior. The important