Surface Complexation and Dynamic Transport Modeling of Arsenic Removal on Adsorptive Media

166 Pages·2010·2.08 MB·English

Arsenic Water Technology Partnership

Surface Complexation and Dynamic
Transport Modeling of Arsenic Removal on
Adsorptive Media
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Surface Complexation and Dynamic
Transport Modeling of Arsenic Removal on
Adsorptive Media

Prepared by:
Gerald E. Speitel Jr., Lynn E. Katz, Chia-Chen Chen, and Shannon Stokes
University of Texas at Austin, Department of Civil, Architectural and
Environmental Engineering, 1 University Station, Austin, TX 78712-0273

and
Paul Westerhoff and Pedram Shafieian
Arizona State University, Department of Civil and Environmental Engineering,
Tempe, AZ 85287-5306

Jointly Sponsored by:
Water Research Foundation
6666 West Quincy Avenue, Denver CO 80235-3098

and

U.S. Department of Energy
Washington, D.C. 20585-1290

Published by:

WERC, a Consortium for Water Research Foundation
Environmental Education and
Technology Development at
New Mexico State University
U NM DINÉ
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MS MIM
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SANDIALOSALAMOS A CONSOANRTDIU TMEC FHONRO ELNOVGIRYO DNEVMEELNOTPAML EENDTUCATION
DISCLAIMER

This study was jointly funded by the Water Research Foundation and Sandia National
Laboratories (SNL) under Agreement No. FI061030711 through the Arsenic Water Technology
Partnership. The comments and views detailed herein may not necessarily reflect the views of
the Water Research Foundation, its officers, directors, affiliates or agents, or the views of SNL
and the Arsenic Water Technology Partnership. The mention of trade names for commercial
products does not represent or imply the approval or endorsement of Water Research Foundation
or SNL. This report is presented solely for informational purposes.

Copyright 2010
By Water Research Foundation
and Arsenic Water Technology Partnership

All Rights Reserved

Printed in the U.S.A.
CONTENTS

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

LIST OF FIGURES .................................................................................................................. ix

FOREWORD ............................................................................................................................ xv

ACKNOWLEDGMENTS ........................................................................................................ xvii

EXECUTIVE SUMMARY ...................................................................................................... xix

CHAPTER 1: INTRODUCTION ............................................................................................ 1

CHAPTER 2: DATABASE DEVELOPMENT ...................................................................... 3
Selection of Literature ................................................................................................... 3
Organization of Database .............................................................................................. 5

CHAPTER 3: MATERIALS AND METHODS ..................................................................... 9
Adsorbents .................................................................................................................... 9
Adsorbent Preparation for Batch Test ............................................................... 9
Adsorbent Characterization .............................................................................. 10
Potentiometric Titrations .................................................................................. 16
Analytical Methods ....................................................................................................... 17
Batch Adsorption Experiments ..................................................................................... 18
Preliminary Experiments to Determine Equilibration Kinetics and Bicarbonate
Effects ................................................................................................... 18
Single-Solute Adsorption Experiments ............................................................. 19
Multi-Solute Adsorption Experiments .............................................................. 22
Short Bed Adsorber Tests (SBAs) ................................................................................ 29
Rapid Small Scale Column Tests (RSSCTs) ................................................................ 30

CHAPTER 4: ADSORPTION EQUILIBRIUM EXPERIMENTS AND MODELING ......... 33
Diffuse Layer Model Description ................................................................................. 33
Estimation of DLM Surface Protolysis Constants ........................................................ 34
Single Solute Equilibria and DLM Model Calibration ................................................. 36
Single Solute Isotherm Data ............................................................................. 36
Model Calibration Overview ............................................................................ 37
AsO 3- Adsorption ................................................................................. 39
4
VO 3- Adsorption .................................................................................. 40
4
Si Adsorption ........................................................................................ 40
Ca2+ Adsorption .................................................................................... 41
E33 Single Solute Equilibria ............................................................................. 41
GFH Single Solute Equilibria ........................................................................... 47
GTO Single Solute Equilibria ........................................................................... 51
Multi-Solute Equilibria and DLM Predictions ............................................................. 55
v
As(V)/V(V) Bi-Solute Equilibria and DLM Predictions ................................. 55
As(V)/Si Bi-Solute Equilibria and DLM Predictions ....................................... 59
As(V)/Ca2+ Bi-Solute Equilibria and DLM Predictions ................................... 63
As(V)/Ca2+/Si Tri-Solute Equilibria and DLM Predictions .............................. 70
Summary ....................................................................................................................... 74

CHAPTER 5: CONTINUOUS FLOW COLUMN TESTS ..................................................... 75
Effect of Adsorbent Media Packed Bed Depth ............................................................. 75
Comparison of E33, GFH And GTO Media ................................................................. 77
Influence of Water Chemistry on As(V) Breakthrough ................................................ 78
Summary ....................................................................................................................... 83

CHAPTER 6: MODELING OF PACKED-BED ADSORBERS ............................................ 85
Description of Mass Transport Models for Porous Adsorbents .................................... 85
HSDM-“Fouling” Model .............................................................................................. 866
Selection of Model Inputs ................................................................................. 86
Validation of AdDesignSTM Model Parameters ................................................ 88
Empirical Fouling Model Parameterization ...................................................... 89
Modeling Arsenic Breakthrough for Groundwaters Using the Fouling Model with
AdDesignSTM ........................................................................................ 92
HSDM/DLM Model...................................................................................................... 94
Modeling Single-Component Arsenic RSSCTs ................................................ 94
Modeling Multicomponent Arsenic RSSCTs ................................................... 96
Summary ....................................................................................................................... 98

CHAPTER 7: CONCLUSIONS .............................................................................................. 99
Adsorption Equilibria and DLM Modeling .................................................................. 99
Preliminary Experiments for Surface Characterization and Equilibration Time 99
Single-solute Adsorption .................................................................................. 99
Multi-solute Adsorption .................................................................................... 100
Packed Bed Modeling ................................................................................................... 101
Freundlich-Based Modeling Approach ............................................................. 101
DLM Based Modeling Approach ...................................................................... 101

APPENDIX A: SUPPLEMENTAL INFORMATION REGARDING DLM EQUILIBRIUM
MODELING ................................................................................................................. 103

APPENDIX B: HSDM/DLM USER’S GUIDE ...................................................................... 121

REFERENCES ......................................................................................................................... 125

ABBREVIATIONS .................................................................................................................. 1367

vi
TABLES
Table 2.1 Studies included in the database ............................................................................. 4
Table 3.1 Reported properties of adsorbents ......................................................................... 10
Table 3.2 Surface site density (SSD) values used to model adsorption on ferrihydrite ......... 13
Table 3.3 Surface site density (SSD) values used to model adsorption on goethite (α-FeOOH)
................................................................................................................................. 14
Table 3.4 Estimates of surface area and surface site density .................................................. 16
Table 3.5 Analytical methods, containers, preservations, and holding times ......................... 17
Table 3.6 Single Solute arsenate pH adsorption edge surface coverages (µmol/g) corresponding
to 100 percent removal from solution. .................................................................... 23
Table 3.7 Trisolute experimental conditions........................................................................... 24
Table 3.8 Summary of bisolute experimental conditions ....................................................... 25
Table 4.1 Summary of DLM Surface Parameters based on the tritium exchange derived site
density ..................................................................................................................... 35
Table 4.2 Summary of DLM Surface Parameters based on the MAA derived site density ... 35
Table 4.3 Equilibrium constants using MAA based site density ............................................ 39
Table 4.4 Equilibrium constants using tritium exchange based site density .......................... 40
Table 5.1 Summary of Influent Water Quality Conditions Considered for RSSCTs with E33
Media ...................................................................................................................... 79
Table 5.2 Freundlich isotherm parameters (K, 1/n) and goodness of fit (R2) for 10 Day
f
adsorption As(V) experiments with E33 and influent water from RSSCT experiments
(Table 5.1) ............................................................................................................... 79
Table 6.1 Summary of Pore Surface Diffusion Model (PSDM) Parameters, Units and Selected
Values for AdDesignSTM ........................................................................................ 87
Table 6.2 Fouling Model Parameters (for Equation 6.1) for RSSCTs with E33 Media (1/n = 0.3
and K = 16 at pH 8.3) ............................................................................................ 90
0
Table 6.3 Summary of DLM Parameters for HSDM/DLM for E33 ....................................... 95
Table 6.4 Summary of Vanadium DLM Parameters for HSDM/DLM .................................. 97
vii
Table A.1 Aqueous Complexation Reactions .......................................................................... 103
Table B.1 Description of Inputs to HSDM/DLM .................................................................... 121

viii
FIGURES
Figure 2.1 Microsoft Access Database View ........................................................................ 6
Figure 2.2 Sample Microsoft Access Experiment Form ....................................................... 6
Figure 2.3 Sample Microsoft Access Experiment Table and Data Table ............................. 7
Figure 3.1 Effect of surface area on surface charge density determined from potentiometric
titration data for a) E33 (pH = 8.4), b) GFH (pH = 7.8) and c) GTO (pH =
PZC PZC PZC
4.5). Solid lines are calculated from known surface charge density relationships for
reference phases. .................................................................................................. 12
Figure 3.2 Tritium exchange data (replicate data are provided for each adsorbent) ............. 15
Figure 3.3 Kinetics of As adsorption on GFH at pH 7; Ionic Strength = 0.1 M ................... 18
Figure 3.4 Effects of allowing an additional 24 hours of equilibration time on As adsorption to
(a) E33, (b) GFH, and (c) GTO; Ionic Strength = 0.02 M; buffer = 0.01 M NaHCO
3
.............................................................................................................................. 21
Figure 3.5 Comparison of pH adsorption edges using 0.01 M NaHCO and bis-tris propane
3
buffer for As adsorption on E33. ......................................................................... 22
Figure 3.6 Effects of adding As and V sequentially on (a) As adsorption, and (b) V adsorption,
to E33. Total equilibration time was 72 hours; Ionic Strength = 0.02 M; buffer =
0.01 M NaHCO ................................................................................................... 26
3
Figure 3.7 Effects of adding As and V sequentially on (a) As adsorption, and (b) V adsorption,
to GFH. Total equilibration time was 72 hours; Ionic Strength = 0.02 M; buffer =
0.01 M NaHCO ................................................................................................... 27
3
Figure 3.8 Effects of adding As and V sequentially on (a) As adsorption, and (b) V adsorption,
GTO. Total equilibration time was 72 hours; Ionic Strength = 0.02 M; buffer = 0.01
M NaHCO ........................................................................................................... 28
3
Figure 3.9 Diagram of SBA and RSSCT packed columns. Glass beads are placed above and
below the packed columns to distribute inlet flows. Teflon fittings and tubing is
used with a positive displacement FMI pump drive and stainless steel pump head.
.............................................................................................................................. 31
Figure 4.1 Schematic of the electric double layer (EDL) used in the diffuse layer model ... 34
Figure 4.2 GFH DLM titration fit using MAA based site density ........................................ 36
Figure 4.3 Comparison of As(V) adsorption isotherms conducted at pH 8.5 (0.01M NaCl;
0.01M NaHCO ) .................................................................................................. 37
3
ix
Figure 4.4 Single solute As pH adsorption edges and model simulations for E33 Bayoxide in a
background of 0.01 M NaCl and 0.01 M NaHCO (DLM model calibration based
3
on MAA site density for E33). ............................................................................. 43
Figure 4.5 Ionic Strength comparisons of single solute As pH adsorption edges for E33
Bayoxide in a background of 0.01 M NaHCO . .................................................. 43
3
Figure 4.6 0.11 M Ionic Strength pH adsorption edge and DLM model predictions on E33
Bayoxide with a background of 0.01 M NaHCO and 0.1 M NaCl (site density
3
based on MAA). ................................................................................................... 44
Figure 4.7 Single solute V pH adsorption edges and DLM simulations for E33 Bayoxide in a
background of 0.01 M NaCl and 0.01 M NaHCO (site density based on MAA) 44
3
Figure 4.8 Single solute Si pH adsorption edges and DLM simulations for E33 Bayoxide in a
background of 0.01 M NaCl and 0.01 M NaHCO (site density based on MAA. 45
3
Figure 4.9 Single solute Ca2+ pH adsorption edges and DLM simulations for E33 Bayoxide in
a background of 0.01 M NaCl and 0.01 M Bis-tris propane; (a) site density based on
MAA, and (b) site density based on tritium exchange data. ................................ 46
Figure 4.10 Single solute As pH adsorption edges and model simulations for GFH in a
background of 0.01 M NaCl and 0.01 M NaHCO (DLM model calibration based
3
on MAA site density for GFH). ........................................................................... 47
Figure 4.11 Ionic Strength comparisons of single solute As pH adsorption edges for GFH in a
background of 0.01 M NaHCO . ......................................................................... 48
3
Figure 4.12 0.11 M ionic strength pH adsorption edge and DLM model predictions on GFH
with a background of 0.01 M NaHCO and 0.1 M NaCl (site density based on
3
MAA). .................................................................................................................. 48
Figure 4.13 Single Single solute V pH adsorption edges and DLM simulations for GFH in a
background of 0.01 M NaCl and 0.01 M NaHCO (site density based on MAA). 49
3
Figure 4.14 pH adsorption edges and DLM simulations for GFH in a background of 0.01 M
NaCl and 0.01 M NaHCO (site density based on MAA). .................................. 49
3
Figure 4.15 Single solute Ca2+ pH adsorption edges and DLM simulations for GFH in a
background of 0.01 M NaCl and 0.01 M Bis Tris Propane; (a) site density based on
MAA, and, (b) site density based on tritium exchange data. ............................... 50
Figure 4.16 Single solute As pH adsorption edges and model simulations for GTO in a
background of 0.01 M NaCl and 0.01 M NaHCO (DLM model calibration based
3
on MAA site density for GFH). ........................................................................... 53
Figure 4.17 Single Single solute V pH adsorption edges and DLM simulations for GTO in a
background of 0.01 M NaCl and 0.01 M NaHCO (site density based on MAA) 53
3
x