Microbial Electrochemical and Fuel Cells (eBook)

Front Cover 1
Microbial Electrochemical and Fuel Cells: Fundamentals and Applications 4
Copyright 5
Contents 6
Contributors 10
Woodhead Publishing Series in Energy 12
Part One: The workings of microbial fuel cells 18
Chapter 1: An introduction to microbial fuel cells 20
1.1. Introduction 20
1.2. Fuel cells 21
1.2.1. Cell voltage 22
1.2.2. Mass transport and concentration effects 24
1.2.3. Figures of merit 25
1.3. Biological FCs 26
1.3.1. Types of biological FCs 27
1.4. The MFC 28
1.4.1. Anode microbial behavior 29
1.4.2. MFCs without mediators 31
1.4.2.1. Performance indicators 31
1.4.3. MFC bacteria 34
1.4.4. MFC materials and operating conditions 35
1.4.5. Applications of MFCs 38
1.5. Biological enzyme FC 41
1.6. Conclusions 42
References 43
Chapter 2: Electrochemical principles and characterization of bioelectrochemical systems 46
2.1. Introduction 46
2.2. Electrochemical principles 47
2.2.1. Electrochemical thermodynamics and cell potential 47
2.2.2. Electrochemical kinetics 52
2.2.2.1. Electrochemical reaction model of kinetics 52
2.2.3. Mass transport and electrochemical reactions 56
2.3. Voltammetric electrochemical methods 58
2.3.1. Linear sweep voltammetry 59
2.3.2. Cyclic voltammetry 60
2.3.3. CV for the study of microbial electron transfer 62
2.3.4. Voltammetry in the presence of donor substrates 63
2.4. Rotating disk and ring-disk electrodes 66
2.4.1. Rotating ring-disk electrode 68
2.4.2. RDE and RRDE used in biological fuel cells 69
2.5. Electrochemical impedance spectroscopy 69
2.5.1. Polarization resistance 72
2.5.2. Warburg impedance 74
2.5.2.1. EIS for MFCs 75
2.6. Chronoamperometry 76
2.7. Square wave voltammetry 78
2.8. Differential pulse voltammetry 79
2.9. Other techniques 79
References 80
Chapter 3: Electron transfer mechanisms in biofilms 84
3.1. Introduction 84
3.2. Mechanisms for delivering electrons to an anode 90
3.2.1. Direct electron transfer in biofilms on anodes 91
3.2.2. Mediated electron transfer 96
3.2.2.1. Self-secreted mediators 97
3.2.2.2. Cell membrane modifications to enhance electron transfer 98
3.3. Mechanisms for electron uptake from cathodes 99
3.3.1. Extracellular electron uptake mechanisms of the model electrogens G. sulfurreducens and S. oneidensis 101
3.3.2. Extracellular electron uptake mechanisms of oxygen- and nitrate-reducing bacteria 102
3.3.2.1. Oxygen-reducing bacteria on cathodes 102
3.3.2.2. Nitrate-, nitrite-, and nitrous oxide-removing bacteria on cathodes 105
3.3.3. Extracellular electron uptake mechanisms of hydrogen-producing, methanogenic, and acetogenic microorganisms 105
3.3.3.1. Hydrogen-producing bacteria 105
3.3.3.2. Methanogenic archaea 106
3.3.3.3. Acetogenic bacteria 108
3.4. EET between microorganisms 109
3.4.1. Interspecies electron transfer 109
3.4.2. Electron transfer along ``cable´´ bacteria 112
3.5. Future trends and research needs 113
3.6. Conclusion 115
Acknowledgments 116
References 116
Part Two: Materials for microbial fuel cells and reactor design 132
Chapter 4: Anode materials for microbial fuel cells 134
4.1. Introduction 134
4.2. Anode materials 135
4.2.1. Carbon materials 135
4.2.2. Metal materials 138
4.2.3. Composite materials 140
4.2.4. Three-dimensional macroporous-based anode 141
4.3. Surface modification of MFC anode materials 142
4.3.1. Surface methods for anode modification 142
4.3.2. Anode modification with nanomaterials 145
4.3.2.1. Anode modification with carbon nanomaterials 145
4.3.2.2. Anode modification with metal or metal oxide 150
4.3.2.3. Anode modification with polymers 152
4.3.2.4. Anode modification with composite materials 155
4.4. Conclusions and future perspective 161
References 163
Chapter 5: Membranes and separators for microbial fuel cells 170
5.1. Introduction 170
5.2. Cell separators 172
5.2.1. Diaphragms and porous polymer membranes 172
5.2.2. Semipermeable membranes: ion-exchange membranes 173
5.3. Transport processes in membranes and diaphragms 175
5.3.1. Ion transport processes 175
5.3.2. Ion-exchange membranes and the transport of ions 176
5.4. Membranes for microbial fuel cells 178
5.4.1. Ion-exchange membranes 178
5.4.1.1. Cation-exchange membranes 178
5.4.1.2. Anion-exchange membranes 182
5.4.2. Membrane requirements in MFCs 185
5.4.3. Ion and mass transfer processes across ion-exchange membranes in MFCs 185
5.4.3.1. Cation transport 186
5.4.3.2. Anion transfer 187
5.4.4. Porous separators 189
5.4.5. Membrane electrode assemblies 190
5.5. Future trends 192
References 193
Chapter 6: Cathodes for microbial fuel cells 196
6.1. Introduction 196
6.2. Redox reactions for MFCs 196
6.3. The oxygen reduction mechanism 200
6.3.1. ORR in metal electrodes 201
6.3.2. ORR at non-metal electrodes 205
6.3.2.1. Graphite and carbon 205
6.3.2.2. Carbon nanotubes 205
6.4. Hydrogen evolution mechanism 206
6.5. ORR cathode configuration in MFC 209
6.6. Non-precious metal cathodes 210
6.6.1. Cathodic materials and composites 210
6.6.2. Cathodic configurations 213
6.6.2.1. Plane cathodes 213
6.6.2.2. Packed cathodes 213
6.6.2.3. Tubular cathodes 213
6.6.2.4. Brush cathodes 214
6.6.3. Cathodic treatments 214
6.6.3.1. Cathodic coating 214
6.6.3.2. Cathodic surface treatment 215
6.7. Enzymatic cathodes 215
6.7.1. Typical enzymes at cathode 216
6.7.2. Major applications 217
6.7.2.1. Treatment 220
6.7.2.2. Product synthesis 220
6.7.3. Major challenges 221
6.8. Future trends 222
Acknowledgment 222
References 223
Chapter 7: Reactor design and scale-up 232
7.1. Introduction 232
7.2. Performance indicators for MFCs 233
7.2.1. Electrochemical performance indicators 234
7.2.2. System performance indicators 236
7.3. What governs the performance of MFCs 239
7.4. Determining the performance of MFCs 241
7.5. MFC architectures 245
7.6. Connectivity and control mechanisms 247
7.6.1. MFC connectivity and voltage reversal 248
7.7. MFC scale-up, application, and integration 252
7.8. Future trends 254
References 256
Part Three: Applications of microbial electrochemical and fuel cells 262
Chapter 8: Microbial fuel cells for wastewater treatment and energy generation 264
8.1. Wastewater treatment 264
8.2. Wastewater-energy-environment nexus 264
8.3. Energy requirements for wastewater treatment 266
8.4. Energy recovery in wastewater treatment systems 268
8.4.1. Energy recovery from wastewater sludge 269
8.4.1.1. Anaerobic digestion 269
8.4.1.2. Thermochemical processes 270
8.4.1.3. Other energy recovery options 271
8.5. Microbial fuel cells 271
8.5.1. Advantages of MFCs over other available options 273
8.5.2. Higher energy recovery via MFCs (energy recovery options from wastewater) 274
8.5.3. Principles of waste treatment via MFCs 275
8.5.4. Oxidation reduction reactions in MFCs 275
8.5.5. Critical operating parameters and components in MFCs 276
8.5.5.1. Critical operating parameters 276
8.5.5.2. Membrane versus membraneless MFCs 277
8.6. Organic removal in MFCs 277
8.6.1. MFCs with synthetic wastewater as substrates 277
8.6.2. MFCs with actual wastewater as substrates 278
8.6.3. Effect of process parameters 281
8.6.4. MFC integration with other processes 282
8.7. Algae biocathode for MFCs 283
8.8. Nitrogen removal in MFCs 285
8.9. Phosphorus removal in MFCs 288
8.10. Metals removal in MFCs 289
8.11. Source separation 291
8.11.1. Urine as energy source 291
8.11.2. Energy from human feces 292
8.12. Conclusions 292
Acknowledgments 293
References 293
Chapter 9: Microbial electrolysis cells for hydrogen production 304
9.1. Introduction 304
9.2. Advantages 306
9.3. Disadvantages 307
9.4. Role in the hydrogen economy 307
9.5. How to characterize an MEC 308
9.6. Rhetoric to reality? 312
9.7. Problems 329
9.8. Beyond hydrogen 331
9.9. Prospects for deployment of MEC 331
9.10. Conclusions: How to make MECs happen? 332
Further reading 333
References 333
Chapter 10: Resource recovery with microbial electrochemical systems 338
10.1. Introduction 338
10.2. Metal recovery 339
10.2.1. BES for metal recovery with abiotic cathode 340
10.2.2. Metal recovery with bioelectrodes 342
10.3. Nutrients removal and recovery 345
10.3.1. Nitrogen recovery with BES 346
10.3.2. Phosphorous removal and recovery 348
10.4. Converting CO2 to valuable chemicals 349
10.4.1. Electrochemical reduction of CO2 using BES 349
10.4.2. MES converting CO2 to valuable chemicals 351
10.5. Prospective 351
References 352
Chapter 11: Use of microbial fuel cells in sensors 358
11.1. An introduction to biosensors 358
11.2. Microbial biosensors 358
11.3. The use of microbial fuel cells as electrochemical sensor 359
11.4. Operation of the MFC sensor 360
11.5. MFC sensor design 363
11.6. MFCs as BOD sensors 364
11.7. Detection of toxicants in water by MFCs 368
11.8. Conclusions 370
References 370
Chapter 12: The practical implementation of microbial fuel cell technology 374
12.1. Introduction 374
12.2. Direct use of microbial fuel cells 375
12.2.1. Direct use of voltage behaviour: Sensing light patterns 375
12.2.2. Direct use of power 377
12.3. Implementing energy harvesting 380
12.3.1. Digital wristwatch 380
12.3.2. Mobile phone charging 381
12.3.3. Freshening the air 383
12.3.4. Process and bioprocess control 383
12.3.5. An array of LED lights powered by MFCs 386
12.3.6. Urine-powered smoke alarms 387
12.3.7. Urine-activated distress signal 388
12.4. Field trials 389
12.4.1. Wastewater treatment plant 389
12.4.2. Fuelled by urine 393
12.5. Conclusions 395
References 395
Index 398
Back Cover 411