Electrodialysis and Water Reuse (eBook)

Preface 6
Contents 7
307669_1_En_1_Chapter_OnlinePDF 9
1 Introduction 9
2 General Aspects of Membrane Separation Processes 11
Abstract 11
2.1…Water and Wastewater Treatment for Reuse 11
2.2…Membrane Separation Processes 13
2.3…Electrodialysis as an Alternative for Reverse Osmosis 15
References 16
3 General Aspects of Electrodialysis 18
Abstract 18
3.1…Introduction 18
3.2…Assembling an Electrodialysis System 20
3.2.1 Membranes 22
3.2.2 Spacers 22
3.2.3 Electrodes and Electrode Reactions 23
3.3…Fouling and Scaling in Electrodialysis 24
3.4…Electrodialysis Reversal 26
3.5…Evaluation of the Process Efficiency 27
3.5.1 Percent Extraction 27
3.5.2 Current Efficiency 27
3.6…Electrodialysis Process Costs 28
References 29
4 Electrodialysis Control Parameters 31
Abstract 31
4.1…Membrane Permselectivity and Transport Number 31
4.2…Concentration Polarization and Limiting Current Density 33
4.3…Phenomena Accompanying Concentration Polarization 35
4.3.1 Water Dissociation and Exaltation Effects 35
4.3.2 Gravitational Convection 36
4.3.3 Electro-Convection 36
4.4…Chronopotentiometry 37
4.4.1 Principle 37
4.4.2 Applications 39
4.4.2.1 Limiting Current Density 39
4.4.2.2 Transport Number of Ions Through the Membrane 39
4.4.2.3 Heterogeneity of Membranes. Conductive and Non-conductive Regions 40
4.4.2.4 Fouling by Organic Molecules and Mineral Deposits 40
4.4.2.5 Side Effects Associated with Concentration Polarization 41
4.4.2.6 Transport Properties for Bipolar Membranes 42
References 42
5 Ionic Membranes 46
Abstract 46
5.1…Membrane Materials 47
5.1.1 Polymer Intrinsically Conducting (PICs) Membranes 47
5.1.1.1 Membranes Obtained by In Situ Polymerization 47
5.1.1.2 Membrane Obtained Through PICs and Conventional Polymer Mixture 48
5.1.1.3 Membrane Obtained by Interpenetrating Polymer Nets 49
5.2…Membrane Characterization 50
5.2.1 Heterogeneous Ion Exchange Membranes 51
5.2.2 Homogeneous Ion Exchange Membrane 51
5.2.3 Special Membranes 52
5.3…Membrane Properties 52
5.3.1 Permselectivity of Membranes 53
5.3.2 Mechanical Properties of Membranes 53
5.3.3 Chemical Stability of Membranes 53
5.3.4 Electrical Resistance of Membranes 54
5.3.5 Ion Exchange Capacities of Membranes 54
5.4…Electrodialysis Membranes 55
5.4.1 Preparation of Homogeneous Ion Exchange Membranes 59
5.4.2 Preparation of Heterogeneous Ion Exchange Membranes 62
References 62
6 Electrodialysis in Water Treatment 67
Abstract 67
6.1…Introduction 67
6.2…Water Quality 68
6.3…Conventional Drinking Water Treatment System 69
6.4…Membrane Processes Applied to Drinking Water Production 71
6.5…Electrodialysis Applied to the Desalination and Purification of Brackish Water 72
6.6…Electrodialysis Aapplied to Nitrate Contaminated Potable Water 75
6.7…Concluding Remarks 77
References 77
7 Electrodialysis Treatment of Refinery Wastewater 80
Abstract 80
7.1…Water Use and Wastewater Generation in Refineries 81
7.2…Conventional Wastewater Treatment in Refineries 81
7.2.1 Preliminary Treatment 81
7.2.2 Primary Treatment 82
7.2.3 Secondary Treatment 83
7.3…Electrodialysis to Process Water Production 83
7.4…Comparison of Electrodialysis Reversal and Reverse Osmosis 84
7.5…Water Pretreatment for Electrodialysis Reversal 87
7.6…Energy Consumption 89
7.7…Operational Control and Maintenance 90
7.8…Concluding Remarks 91
References 92
8 Electrodialysis Treatment of Tannery Wastewater 94
Abstract 94
8.1…Introduction 94
8.2…Generation of Effluents in Tanneries 95
8.3…Tannery Wastewater Characteristics 95
8.4…Conventional Tannery Wastewater Treatment 97
8.5…Electrodialysis to Process Wastewater 98
8.6…Concluding Remarks 100
References 101
9 Electrodialysis Treatment of Phosphate Solutions 103
Abstract 103
9.1…Introduction 103
9.2…The use of Phosphate Solutions in the Metal-Mechanics Industry 104
9.3…Conventional Phosphate Wastewater Treatment 105
9.4…Electrodialysis in the Water Purification Process 106
9.5…Fouling and Scaling in Phosphating Wastewater Treatment 108
9.6…Concluding Remarks 109
References 110
10 Electrodialysis for the Recovery of Hexavalent Chromium Solutions 112
Abstract 112
10.1…Introduction 112
10.2…The Use of Hexavalent Chromium in the Electroplating Processes 113
10.3…Characteristics and Contaminants of Hexavalent Chromium Solutions 113
10.4…Conventional Treatment of Hexavalent Chromium Solutions 114
10.5…Electrodialysis for the Recovery of Water and Chromium Solutions 115
10.6…Concluding Remarks 117
References 118
11 Electrodialysis Treatment of Metal-Cyanide Complexes 120
Abstract 120
11.1…Introduction 121
11.2…The Transport of Metal Cyanide Complexes Through Ion Exchange Membranes 122
11.3…Solutions of Zinc Cyanide Complexes 123
11.4…The Transport of Zinc Cyanide Complexes Through Ion Exchange Membranes 124
11.5…Solutions of Cadmium Cyanide Complexes 127
11.6…The Transport of Cadmium Cyanide Complexes Through Ion Exchange Membranes 128
11.7…Influence of the Presence of Other Metallic Ions (Copper, Iron, Chromium) 130
11.8…Concluding Remarks 131
References 131
12 Electrodialysis Treatment of Nickel Wastewater 133
Abstract 133
12.1…Introduction 134
12.2…The Use of Nickel in Electroplating Processes 134
12.3…Conventional Nickel Wastewater Treatment 135
12.4…Electrodialysis for Water and Nickel Recovery 135
12.5…Concluding Remarks 142
References 142