CONTENTS
Foreword v
Preface vii
Acknowledgements \ ix
1.Arsenic in Groundwater and its Health Effects 1
Introduction 1
Health Hazards of Arsenic 2
Social Impact of Arsenicosis 4
Summary 5
References 5
2.Hydrogeochemistry of Arsenic-contaminated Water 9
Introduction 9
Arsenic Chemistry 10
Sources of Arsenic and Environmental Impacts 12
Physico-chemical Processes Involved in Arsenic Mobilization 14
World Scenario of Arsenic Pollution in Water 16
Groundwater Hydrochemistry 25
Scenario of Arsenic in Deep Groundwater (>150m) and
its Hydrogeochemistry 60
Summary 66
References 67
Bibliography 86
3. Arsenic Removal Processes and Advantages of the
Adsorption Process 89
Introduction 89
Oxidation 91
Chemical Coagulation-Precipitation and Electrocoagulation 91
Ion Exchange 92
Membrane Technology 92
Adsorption 93
Literature Review on Various Adsorbents used for
Arsenic Removal Studies 94
Prospect of Raw Laterite as an Arsenic Adsorbent 100 Treated/Modified Laterite as a Potential Arsenic Adsorbent 102
Organization of Experimental Work for Arsenic-Laterite System 104
Summary 106
References 106
Bibliography 115
4.Application of Raw Laterite as an Arsenic Adsorbent 117
Introduction 117
Experiment 119
Results and Discussion 126
Summary 126 186
5.Application of Acid-treated Laterite as an Arsenic Adsorbent 193
Introduction 193
Experiment and Methodology 194
Results and Discussion 197
Summary 216
References 217
Bibliography 219
6. Application of Acid-Base Treated Laterite as an Arsenic Adsorbent 221
Introduction 221
Materials and Analysis 222
Preparation of Acid-Base Treated Laterite and the Optimization of Treatment Process 224
Characterization of Treated Laterite 227
Chemical Reactions Involved during the Preparation of Treated Laterite 238
Batch Mode Arsenic Adsorption on Treated Laterite 240
Batch Kinetic Modelling of the Treated Laterite/Arsenic System 251
Adsorption of Arsenic Species in a Binary System 252
Effect of other Ions on As(III) and As(V) Adsorption F 255
Fixed-bed Column Study
256
Comparison of Adsorption Capacity of Treated Laterite
with other Adsorbents 264
Scale up for Preparation of Treated Laterite and Performance of Household Filter using Contaminated Groundwater 269
Leaching Study of Fresh Treated Laterite and
Arsenic Adsorbed Treated Laterite 272
Summary 274
References 275
Bibliography 279
7. Conclusions and Future Work 281
Index 285
About the Authors 289