Retention and Transport of Arsenic in Soils

214 Pages·2017·1.4 MB·English

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LSU Doctoral Dissertations Graduate School
2006
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Hua Zhang
Louisiana State University and Agricultural and Mechanical College
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Zhang, Hua, "Retention and Transport of Arsenic in Soils" (2006). LSU Doctoral Dissertations. 3194.
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RETENTION AND TRANSPORT OF ARSENIC IN SOILS

A Dissertation

Submitted to the Graduate Faculty of the
Louisiana State University and
Agricultural and Mechanical College
in partial fulfillment of the
requirement for the degree of
Doctor of Philosophy

in

The Department of Agronomy and Environmental Management

by
Hua Zhang
B.S., HuaZhong Agricultural University, 1999
M.S., Chinese Academy of Sciences, 2002
December, 2006
ACKNOWLEDGEMENTS

At this opportunity the author wishes to express his most sincere gratitude and
appreciation to Dr. H.M. Selim, Caldwell Endowed Professor of Soils, for his valuable guidance
and genuine interest as research advisor and chairman of the examination committee. Deep
appreciation is also extended to other members of the committee, Dr. Donald D. Adrian, Dr.
Ronald D. DeLaune, Dr. Jim J. Wang, Dr. William Blanford, and Dr. Nan D. Walker for their
support and constructive suggestions.
I wish to thank the Department of Agronomy and Environmental Management for the
wonderful experience I have had during my study period. I also would like to express my
appreciation for my fellow graduate students: Brain Naquin, and Lixia Liao, for their help and
friendship. I would like to thank Jackie Prudente for her ICP expertise. Thank all student workers
who have spent time with me, especially the late Elizabeth Thompson, you will always be
remembered.
Funding for this research was supported by the Louisiana AgriculturalExperiment Station
and the Department of Environmental Quality (DEQ), Section 319.
I would like to acknowledge my wife, Xueli Gao for her patience and understanding. I
would like to give my final thanks to my parents for their support throughout my life.
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TABLE OF CONTENTS

ACKNOWLEDGEMENTS............................................................................................................ii

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

LIST OF FIGURES.....................................................................................................................viii

ABSTRACT..................................................................................................................................xii

CHAPTER
1. INTRODUCTION......................................................................................................................1
1.1 Statement of Problem............................................................................................................2
1.2 Objectives.............................................................................................................................2
1.3 References.............................................................................................................................3

2. ARSENIC IN SOILS: A REVIEW.............................................................................................4
2.1. Introduction..........................................................................................................................4
2.2. Environmental Toxicity of Arsenic.....................................................................................4
2.3. Arsenic in Soils....................................................................................................................6
2.3.1 Background Concentrations.......................................................................................6
2.3.2 Arsenic Sources.........................................................................................................6
2.3.2 Soil Arsenic Regulations..........................................................................................10
2.3.4 Chemical Speciation................................................................................................11
2.4. Adsorption-Desorption of Arsenic in Soils........................................................................12
2.4.1 Adsorption Mechanisms..........................................................................................12
2.4.2 Adsorption Envelopes..............................................................................................17
2.4.3 Adsorption Isotherms...............................................................................................19
2.4.4 Competing Anions...................................................................................................21
2.4.5 Kinetic Adsorption-Desorption................................................................................24
2.5. Dissolution – Precipitation.................................................................................................28
2.5.1 Disslution of Primary Minerals................................................................................28
2.5.2 Reductive Disslution of Metal Oxides.....................................................................29
2.5.3 Coprecipiation and Surface Precipitation with Metal Oxides..................................31
2.5.4 Precipitation with Sulfides.......................................................................................32
2.6. Reduction-Oxidation..........................................................................................................32
2.6.1 Theromodynamics....................................................................................................33
2.6.2 Oxidation by Metal Oxides......................................................................................34
2.6.3 Reduction by Sulfides..............................................................................................35
2.6.4 Biotransformation....................................................................................................35
2.6.5 Kinetics of Arsenic Reduction-Oxidation in Soils...................................................36
2.7. Transport of Arsenic under Dynamic Flow Condition......................................................37
2.8. Movement of Arsenic in Field...........................................................................................41
2.9. Remediation of Arsenic Contaminated Soils.....................................................................44
2.10. Summary..........................................................................................................................46
2.11. References........................................................................................................................47
iii
3. KINETICS OF ARSENATE ADSORPTION-DESORPTION IN SOILS..............................59
3.1 Introduction.........................................................................................................................59
3.2 Materials and Methods........................................................................................................62
3.3 Multireaction Model...........................................................................................................65
3.4 Results and Discussion.......................................................................................................67
3.4.1 Nonlinear Sorption Isotherms..................................................................................67
3.4.2 Adsorption Kinetics.................................................................................................73
3.4.3 Desorption Hysteresis and Binding Phases..............................................................75
3.4.4 Multireaction Modeling...........................................................................................77
3.5 Summary and Conclusions.................................................................................................82
3.6 References...........................................................................................................................85

4. MODELING THE TRANSPORT AND RETENTION OF ARSENIC(V) IN SOILS............88
4.1 Introduction.........................................................................................................................88
4.2 Material and Methods.........................................................................................................90
4.3 Results and Discussion.......................................................................................................94
4.3.1 Kinetic Sorption.......................................................................................................94
4.3.2 Tracer Breakthrough Curves....................................................................................98
4.3.3 Arsenate Breakthrough Curves..............................................................................100
4.3.4 Multireaction Transport Modeling.........................................................................101
4.3.5 Inverse MRM Modeling........................................................................................103
4.4 Summary and Conclusions...............................................................................................110
4.5 References.........................................................................................................................111

5. COMPETITIVE SORPTION KINETICS OF ARSENATE AND PHOSPHATE IN SOILS113
5.1 Introduction.......................................................................................................................113
5.2 Material and Methods.......................................................................................................115
5.3 Results and Discussion.....................................................................................................116
5.3.1 Adsorption Isotherms.............................................................................................116
5.3.2 Competitive Adsorption.........................................................................................118
5.3.3 Adsorption Kinetics...............................................................................................122
5.3.4 Desorption and Sequential Extraction...................................................................126
5.3.5 Selectivity Coefficients..........................................................................................128
5.3.6 Multi-reaction Modeling........................................................................................130
5.4 Summary and Concluions.................................................................................................132
5.5 References.........................................................................................................................133

6. MODELING ARSENATE-PHOSPHATE RETENTION AND TRANSPORT IN SOILS: A
MULTI-COMPONENT APPROACH.......................................................................................136
6.1 Introduction.......................................................................................................................136
6.2 Model Formulation...........................................................................................................138
6.3 Materials and Methods......................................................................................................142
6.4 Results and Discussion.....................................................................................................143
6.4.1 Competitive Sorption Isotherms............................................................................143
6.4.2 Sorption Kinetics...................................................................................................145
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6.4.3 Multi-Component Retention Kinetics....................................................................147
6.4.4 Breakthrough Curves.............................................................................................155
6.4.5 Transport Modeling...............................................................................................163
6.5 Summary and Conclusions...............................................................................................167
6.6 References.........................................................................................................................168

7. COLLOID MOBILIZATION AND ARSENITE TRANSPORT IN SOIL COLUMNS.......170
7.1 Introduction.......................................................................................................................170
7.2 Material and Methods.......................................................................................................173
7.2.1 X-ray Diffraction...................................................................................................173
7.2.2 Miscible Displacement Experiments.....................................................................174
7.2.3 Sequential Extraction.............................................................................................175
7.3 Results...............................................................................................................................175
7.3.1 Soil Characteristics................................................................................................175
7.3.2 Arsenite Transport.................................................................................................177
7.3.3 Arsenic Retention in Soils.....................................................................................181
7.3.4 Mobilization of Colloidal Particles........................................................................181
7.3.5 Release of Fe and Al..............................................................................................184
7.4 Discussion.........................................................................................................................187
7.4.1 Colloid Mobilization..............................................................................................187
7.4.2 Release of Fe Oxides under Anarobic Condition..................................................189
7.4.3 Arsenite Transport.................................................................................................191
7.4.4 Environmental Implications...................................................................................192
7.5 Summary and Conclusions...............................................................................................192
7.6 References.........................................................................................................................193

8. SUMMARY AND CONCLUSIONS.....................................................................................196

VITA...........................................................................................................................................200
v
LIST OF TABLES

Table 3.1 Selected physical and chemical properties of the studied soils....................................63
Table 3.2 Estimated Freundlich- and Langmuir- equation parameters (with standard error) for
arsenate adsorption at different reaction times.............................................................................70
Table 3.3 Fitted two-phase fully reversible MRM parameters (with standard error) for
adsorption and desorption kinetics of As(V) in soils....................................................................81
Table 3.4 Fitted three-phase reversible-irreversible MRM parameters (with standard error) for
adsorption and desorption kinetics of As(V) in soils....................................................................81
Table 4.1 Column soil physical parameters for As(V) and tritium miscible displacement
experiments for single and double pulses. Values of the dispersion coefficient were estimated
from tritium breakthrough results.................................................................................................93
Table 4.2 Comparison of the goodness-of-fit of a two-phase kinetic reversible and consecutive
irreversible model requires 3 parameters model formulation (M4 = k , k , and k ) for Olivier
1 2 3
soil.................................................................................................................................................95
Table 4.3 Comparison of parameters and goodness-of-fit determined from fitting eight different
MRM model formulations to kinetic adsorption data...................................................................96
Table 4.4 Root mean squared errors (RMSE) of predicted and optimized arsenate breakthrough
curves (BTCs) across all soil columns and eight different MRM formulations (M1-M8).........104
Table 5.1 Estimated Freundlich and SRS parameters for 24 h adsorption of arsenate and
phosphate....................................................................................................................................119
Table 5.2 Estimated MRM parameters for the kinetic adsorption of arsenate in the presence of
various concentrations of phosphate...........................................................................................131
Table 5.3 Estimated MRM parameters for the kinetic adsorption of phosphate in the presence of
various concentrations of arsenate..............................................................................................131
Table 6.1 Soil physical parameters for miscible displacement experiments. Values of the
dispersion coefficient were estimated from tritium breakthrough results..................................144
Table 6.2 Estimated single component MRM parameters (with standard errors) for adsorption
kinetics of arsenate and phosphate..............................................................................................148
Table 6.3 Estimated single component MRM parameters (with standard error) obtained from
nonlinear optimization with As(V) BTCs...................................................................................164
Table 7.1 Column soil physical parameters for miscible displacement experiments. Values of the
dispersion coefficient were estimated from tritium breakthrough results..................................176
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Table 7.2 XRD determined mineral composition of coarse (0.2-2 µm) and fine (<0.2µm)
fractions of sodium-dispersible clay (SDC) and water-dispersible clay (WDC) for Olivier and
Windsor soils..............................................................................................................................176
Table 7.3 Cumulative amount of As, Fe, and Al leached out and amount of As retained in soil
columns.......................................................................................................................................179
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LIST OF FIGURES
Figure 3.1 A schematic diagram of the multireaction transport model (MRM). Here C is
concentration in solution, S , S , S and S are the amounts sorbed on equilibrium, kinetic,
e k i s
consecutive and cucurrent irreversible sites, respectively, where K , k , k , k and k are the
e 1 2 3 s
respective rates of reactions..........................................................................................................66
Figure 3.2 Isotherms of arsenate adsorption on different soils. Symbols are for different reaction
times of 24, 72, 168, 336, and 504 h (from bottom to top). Solid curves depict results of curve-
fitting with Freundlich equation....................................................................................................69
Figure 3.3 Freundlich parameter N (top), coefficient K (middle), and Langmuir adsorption
F
maxima S (bottom) as a function of total amount of citrate-bicarbonate-dithionite (CBD)
max
extractable Fe and Al content.......................................................................................................72
Figure 3.4 Arsenate concentration in solution versus time during adsorption-desorption for
different soils. Symbols are for different initial concentrations (C ) of 5, 10, 20, 40, 80, and 100
o
mg L-1 (from bottom to top). Solid curves are two-phase MRM simulations using parameters
obtained from nonlinear optimization with adsorption data.........................................................74
Figure 3.5 Isotherms of arsenate desorption from different soils based on successive dilution
after the last adsorption step for different initial concentrations (C ) of 20, 40, 80, and 100 mg L-
o
1. The solid and dashed curves depict results of curve-fitting with Freundlich equation for 504 h
adsorption, and desorption isotherms, respectively......................................................................76
Figure 3.6 Recoveries of arsenic from desorption and sequential extractions as percentages of
total adsorption amounts for different soils. Different patterns illustrate arsenic distribution
among the following pools: P1 = desorbed during successive desorption, P2 = extracted with 1M
NaH PO , P3 = extracted with 0.2 M ammonium oxalate, and P4 = digested with 4 M HNO .
2 4 3
Different groups indicate initial concentrations (C ) of 5, 10, 20, 40, 80, and 100 mg L-1..........78
o
Figure 3.7 Arsenate sorbed versus time during adsorption-desorption for Olivier and Windsor
soils. Symbols are for initial concentrations (C ) of 5, 10, 20, 40, 80, and 100 mg L-1 (from
o
bottom to top). Solid curves are two-phase MRM simulations using parameters obtained from
nonlinear optimization with adsorption data.................................................................................83
Figure 3.8 Arsenate sorbed versus time during adsorption-desorption for Sharkey soil. Symbols
are for different initial concentrations (C ) of 5, 10, 20, 40, 80, and 100 mg L-1 (from bottom to
o
top). Solid curves are three-phase MRM simulations using parameters obtained from nonlinear
optimization with adsorption data.................................................................................................84
Figure 4.1 Tritium breakthrough curves for soils. Solid curves depict results of curve-fitting with
convection dispersion equation (CDE) for non-reactive solutes..................................................92
viii
Figure 4.2 Comparison of MRM model formulations M1-M8 for predicting As(V) breakthrough
curves for Olivier soil (top) and Windsor soil (bottom). Model parameters were those from the
batch kinetic experiment (Table 4.3)............................................................................................99
Figure 4.3 Comparison of MRM model formulations M1-M8 model for predicting As(V)
breakthrough curves for Olivier soil column 101. Model parameters were obtained using
nonlinear inverse modeling.........................................................................................................105
Figure 4.4 Comparison of MRM model formulations M1-M8 for predicting As(V) breakthrough
curves for Olivier soil column 102. Model parameters were obtained using nonlinear inverse
modeling.....................................................................................................................................106
Figure 4.5 Comparison of MRM model formulations M1-M8 for predicting As(V) breakthrough
curves for Windsor soil column 103. Model parameters were obtained using nonlinear inverse
modeling.....................................................................................................................................107
Figure 4.6 Comparison of MRM model formulations M1-M8 for predicting As(V) breakthrough
curves for Windsor soil column 104. Model parameters were obtained using nonlinear inverse
modeling.....................................................................................................................................108
Figure 4.7 Comparison of predictions and simulations using MRM model formulation M8 for
predicting As(V) breakthrough curves for Sharkey soil column 105.........................................109
Figure 5.1 Arsenate [As(V)] and phosphate (P) adsorption isotherms at 24 h of reaction for
Olivier, Sharkey, and Windsor soils. The lines depict results of curve-fitting with Freundlich
equation.......................................................................................................................................120
Figure 5.2 Competitive sorption between arsenate and phosphate at 24 h of reactions for Olivier,
Sharkey, and Windsor soils. The initial concentrations of arsenate were 0.13 mM...................121
Figure 5.3 Arsenate concentrations in solution as a function of reaction time during adsorption
on Olivier, Sharkey, and Windsor soils in the presence of various concentrations of phosphate.
The initial concentrations of arsenate were 0.13 mM. The initial concentrations of phosphate
were 0, 0.32, 1.3, and 3.2 mM. The lines depict results of MRM simulation.............................124
Figure 5.4 Phosphate concentrations in solution as a function of reaction time during adsorption
on Olivier, Sharkey, and Windsor soils in the presence of various concentrations of arsenate. The
initial concentration of phosphate was 0.32 mM. The initial concentrations of arsenate were 0,
0.13, and 1.3 mM. The lines depict results of MRM simulation................................................125
Figure 5.5 Recoveries of arsenic from desorption and sequential extractions for different soils.
Different patterns illustrate arsenic distribution among the following pools: P1 = desorbed during
successive desorption, P2 = extracted with 0.2 M ammonium oxalate, and P3 = digested with 4
M HNO . Different groups indicate different initial phosphate concentrations of 0, 0.32, 1.3, and
3
3.2 mM........................................................................................................................................127
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