Arsenic Removal From Drinking Water By Electrocoagulation

............................................................................................................................. ii Acknowledgments ............................................................................................................ iv List of Tables ................................................................................................................... vii List of Figures ................................................................................................................. viii Chapter 1 ........................................................................................................................... 1 1.1 Background .......................................................................................................... 1 1.2 Objectives ............................................................................................................. 4 1.3 References ............................................................................................................ 5 Chapter 2 ........................................................................................................................... 7 2.1 Introduction .......................................................................................................... 9 2.2 Materials and Methods ....................................................................................... 11 2.2.1 Laboratory-scale Electrocoagulation Experiments ..................................... 11 2.2.2 Materials and Methods of the Field Study .................................................. 13 2.2.3 Analysis Methods........................................................................................ 15 2.3 Results and discussion ........................................................................................ 16 2.3.1 Production of Iron Oxide Coagulant ........................................................... 16 2.3.2 Effect of pH on As Removal ....................................................................... 19 2.3.3 Effect of Oxidization State on As Removal ................................................ 22 2.3.4 Effect of Initial As Concentrations on As Removal ................................... 24 2.3.5 Effect of Phosphate on As Removal ........................................................... 24 2.3.6 Effect of Silica on As Removal .................................................................. 26 2.3.7 Effect of Sulfate on As Removal ................................................................ 28 2.3.8 Results of the Field Study ........................................................................... 29 2.4 Conclusions ........................................................................................................ 31 2.5 Acknowledgments .............................................................................................. 31 2.6 References .......................................................................................................... 32 Chapter 3 ......................................................................................................................... 33 3.1 Introduction ........................................................................................................ 36 3.2 Materials and Methods ....................................................................................... 37 3.2.1 Electrocoagulation Experiments ................................................................. 37 3.2.2 Equilibrium Adsorption Experiments ......................................................... 38 3.2.3 Sampling Methods ...................................................................................... 39