Contents
Preface
Foreword
Chapter 1 Occurrence and Pollution Control of PBDEs 1
1.1 Occurrence of PBDEs 2
1.1.1 Physiochemical properties of PBDEs 2
1.1.2 Legislation of PBDEs 4
1.1.3 History of PBDEs production 6
1.1.4 The release of PBDEs 7
1.1.5 Toxicity of PBDEs 10
1.2 PBDE pollution in the environment 11
1.2.1 Air pollution 11
1.2.2 Water pollution 13
1.2.3 Soil pollution 15
1.2.4 Sediment pollution 17
1.2.5 Biological uptake 18
1.2.6 Human exposure 21
1.3 PBDE prevention and control techniques 23
1.3.1 Chemical methods 23
1.3.2 Biological methods 55
1.4 Main points of interest in this book 58
1.4.1 The mechanism of degradation of PBDEs by pyrolysis 58
1.4.2 The mechanism of degradation of PBDEs by chemical and photochemical methods 60
1.4.3 The mechanism of degradation of PBDEs by selected bacteria 63
1.4.4 The application of physiochemical methods for degradation of PBDEs in surfactant solution 64
Chapter 2 Transformation of PBDEs Under High Temperature 66
2.1 Formation of brominated products from PBDE pyrolysis 67
2.1.1 Effect of pyrolysis temperature 67
2.1.2 Formation mechanisms of PBDFs 69
2.1.3 Formation mechanisms of PBDDs 72
2.1.4 Formation of polybromobenzenes 76
2.2 Formation of chloro-bromo-mixed products from PBDE pyrolysis 79
2.2.1 Formation of PBCDEs 80
2.2.2 Formation of PBCDD/Fs 87
2.2.3 Formation of other products 89
2.2.4 Formation mechanism of PBCDD/Fs 90
Chapter 3 Degradation of PBDEs by Single Zero-valent Metals and Bimetals 97
3.1 Degradation of PBDEs by zero-valent zinc 98
3.1.1 Characterization of zinc powder 98
3.1.2 Debromination of BDE-47 by zinc 98
3.1.3 Effect of pH on the debromination of BDE-47 by zinc 99
3.1.4 Relationships between molecular properties and reaction rate constants 101
3.1.5 The debromination pathway of BDE-47 by zinc 103
3.1.6 Using the SOMO of PBDE anions to predict debromination pathways by e-transfer mechanism 105
3.2 Debromination of PBDEs by n-ZVI and n-ZVI/Pd particles 108
3.2.1 Debromination pathways of PBDEs by n-ZVI and n-ZVI/Pd particles 110
3.2.2 Debromination of PBDEs in a palladium-H2 system 112
3.2.3 Predicting the dominant debromination pathway (e-transfer or H-transfer) of PBDEs 114
3.2.4 Explanation for why Mulliken charges can be used to predict debromination pathways 116
3.3 Debromination of PBDEs in various iron-based bimetallic systems 117
3.3.1 Characterization of different bimetallic particles 118
3.3.2 Influence of metal catalysts on reaction rates for BDE-47 reduction 119
3.3.3 Debromination of BDE-47 in metal-H2 systems 122
3.3.4 Debromination pathways of BDE-47 in various bimetallic systems 123
3.3.5 Debromination pathways of BDE-47 in NaBH4-metal systems 126
3.4 Debromination of PBDEs by zero-valent zinc (ZVZ) and ZVZ-based bimetal (Pd/ZVZ) 130
3.4.1 Characterization of different particles 130
3.4.2 Influence of loading rate of catalysts on reaction rates for BDE-47 debromination 131
3.4.3 The degraded reaction of lightly substituted BDEs in ZVZ and Pd/ZVZ systems 133
3.4.4 Debromination pathway of BDEs in the two materials 135
3.4.5 The different influence on reaction rate of BDE-47 with varied pH in ZVZ and Pd/ZVZ systems 137
Chapter 4 Degradation of PBDEs by UV Light 139
4.1 Debromination behavior of PBDEs by UV light 139
4.1.1 Degradation kinetics of BDE isomers in pure methanol 139
4.1.2 Debromination pathways of BDE-47 and using Mulliken charges to predict them 142
4.1.3 Effect of water content in the degradation of PBDEs 147
4.1.4 Debromination pathways of BDE-47 in different organic solvents 151
4.2 Generation of PBDFs during photolysis of PBDEs under UV light 153
4.2.1 Degradation of PBDEs without an ortho-bromine substituent 154
4.2.2 Degradation of BDEs with one ortho-bromine substituent 156
4.2.3 Degradation of BDEs with two ortho-bromine substituents 158
4.2.4 The photochemical reaction of PBDFs 162
4.2.5 The effect of solvents on the formation of PBDFs during the photolysis of PBDEs 164
4.2.6 Insights into the mechanism of formation of PBDFs from the photolysis of PBDEs using computational chemistry 169
4.3 Photodegradation of decabrominated diphenyl ether in soil suspensions 177
4.3.1 BDE-209 photodegradation in soil suspensions 178
4.3.2 The effect of HA on BDE-209 photodegradation in soil suspensions 180
4.3.3 The effects of metal ions on BDE-209 photodegradation in soil suspensions 181
4.3.4 The products of BDE-209 degradation in soil suspensions 183
Chapter 5 Degradation Behavior of PBDEs by Metal-doped TiO2 187
5.1 Preparation and characterization of four metal-doped TiO2 nanocomposites 188
5.2 Mechanism of photocatalytic debromination of BDE-47 on TiO2 and metal-doped TiO2 190
5.2.1 Enhanced photocatalytic debromination of BDE-47 on TiO2 and metal-doped TiO2 191
5.2.2 Mechanistic discussion of debromination co-catalyzed by different metals 193
5.3 Environmental factors in the debromination of BDE-47 on metal-doped TiO2 197
5.3.1 The effect of oxygen on the debromination of BDE-47 on metal-doped TiO2 198
5.3.2 The discussion of the merits and demerits of each metal-doped TiO2 200
5.4 Photocatalytic degradation of other brominated flame retardants 205
Chapter 6 Microbial Degradation of PBDEs 209
6.1 Microbial screening and identification 210
6.1.1 Microbial screening 210
6.1.2 Identification of strain GYP4 212
6.1.3 Biodegradation of BDE-47 212
6.2 Rapid biodegradation of BDE-47 by strain GYP4 214
6.2.1 Effects of environmental factors 214
6.2.2 Probable metabolism pathways 218
6.2.3 The “viable but non-culturable” state of frozen GYP4 219
6.3 Effects of resuscitation-promoting factor on strain GYP4 222
6.3.1 Identification of Rpf extraction 223
6.3.2 Effects of Rpf on BDE-47 biodegradation 225
6.3.3 Characterization of strain GYP4 227
Chapter 7 Degradation of PBDEs by Advanced Oxidation Process—Feasibility of Thermally Activated Persulfate Method 236
7.1 Degradation kinetics of PBDE in TAP system 237
7.1.1 Effect of acetonitrile 237
7.1.2 Effect of PDS dosage and activation temperature 237
7.1.3 Effect of initial pH 240
7.2 Identification of reactive species 241
7.3 Identification of oxidation products 244
7.4 Oxidation mechanisms of BDE-47 in the TAP system 245
7.4.1 BDE-47 reactive site prediction 245
7.4.2 Possible reaction mechanisms of hydroxyl radical 248
7.4.3 Possible reaction mechanisms of sulfate radical 250
7.4.4 Possible single e-transfer reaction mechanisms 251
7.5 Degradation of other PBDEs in the TAP system 253
Chapter 8 Degradation of PBDEs in Surfactant Solutions 255
8.1 ZVI degradation of PBDEs in surfactant solutions 255
8.1.1 Preparation and characterization of Ag/Fe bimetals 256
8.1.2 Effect of different surfactants on BDE-47 degradation 257
8.1.3 Adsorption of the TX-100 onto n-Ag/Fe particles 259
8.1.4 Effects of different concentrations of TX-100 on BDE-47 degradation 260
8.1.5 PBDE product degradation by Ag/Fe 264
8.2 UV degradation of PBDEs in surfactant solutions 267
8.2.1 PBDE photodegradation in surfactant solutions 267
8.2.2 Effects of pH on PBDE photodegradation 272
8.2.3 The PBDE photodegradation products in surfactant micelles 273
8.2.4 The loss and products of surfactant solutions during UV treatment 285
8.2.5 The reuse of photo-treated surfactant solutions 289
8.2.6 Toxicity assessment of photo-treatment surfactant solutions 291
8.3 Effect of nitrate on the photo-treatment of PBDEs in surfactant solution 292
8.3.1 Effects of nitrate on BDE-15 photodegradation and loss of TX-100 293
8.3.2 Effects of nitrite 295
8.3.3 Effects of TX-100 on nitrate transformation 297
8.3.4 Effects of pH and dissolved oxygen 299
8.3.5 Effects of nitrate on the products of BDE-15 302
8.3.6 Effects of nitrate on products of TX-100 305
8.3.7 Toxicity assessment 314
8.4 Effect of ferric ion on the photo-treatment of PBDEs in surfactant solution 315
8.4.1 Effects of ferric iron on the photodegradation of BDE-47 and loss of Brij 35 316
8.4.2 Effects of Brij 35 on BDE-47 degradation and ferric ion transformation 319
8.4.3 Effects of pH, ferric species, and dissolved oxygen 320
8.4.4 The photoproducts of BDE-47 in Brij 35 containing Fe3+ during UV irradiation 324
8.4.5 The photoproducts of Brij 35 327
8.4.6 The mechanism of BDE-47 photodegradation in Fe3+-Brij 35 solution 332
8.5 Ag/TiO2 photocatalytic degradation of PBDEs in surfactant solution 334
8.5.1 Preparation and characterization of Ag/TiO2 334
8.5.2 TX-100 and BDE-47 adsorption on Ag/TiO2 336
8.5.3 Photocatalytic degradation of BDE-47 by Ag/TiO2 in TX-100 solution 338
8.5.4 Effects of TX-100 on BDE-47 photodegradation 340
8.5.5 The photoproducts of BDE-47 and the mechanism of Ag/TiO2 photolysis 344
8.5.6 The photostability of the photocatalyst and the selection of additives 348
8.6 Selective removal of PBDEs from soil washing effluent using molecularly imprinted polymers 350
8.6.1 Characterization of imprinted adsorbents 350
8.6.2 Adsorption of PBDEs on MIPS from surfactants 353
8.6.3 Selective removal of PBDEs 356
8.6.4 Effect of temperature and pH 359
8.6.5 Adsorption mechanism 360
8.6.6 Application of magnetic molecularly imprinted polymers 365
References 372