Contents List of figures ix List of tables xix Foreword xxi Acknowledgement xxiii Abbreviations xxv 1.Background introduction 1 1.1 Current situation and hazards of plastic waste 1 1.1.1 Pollution to the natural environment 2 1.1.2 A threat to human health 4 1.1.3 Cause a waste of resources 5 1.2 Traditional treatment methods6 1.2.1 Landfill treatment 7 1.2.2 Mechanical recovery 7 1.2.3 Incineration method 8 1.2.4 Thermal decomposition 8 1.3 Supercritical water technology 9 1.3.1 Supercritical water characteristics 9 1.3.2 Resource utilization of waste plastics in supercritical water 10 References 20 2.Analysis of types of plastics 29 2.1 Introduction to raw materials 29 2.1.1 Polycarbonate plastic 29 2.1.2 Polypropylene plastic 29 2.1.3 Acrylonitrile butadiene styrene plastic 29 2.1.4 Polyethylene terephthalate plastic 31 2.1.5 High-impaa polystyrene plastic 31 2.1.6 Polystyrene plastic 31 2.1.7 Polyethylene plastic 32 2.1.8 Urea��formaldehyde plastic 32 2.1.9 Circuit board 32 2.1.10 Lignite 33 2.1.11 Soda lignin 33 2.1.12 Artificial seawater 33 2.1.13 Formic add and hydrochloric acid solvent 33 2.2 Material characterization 34 2.2.1 Elemental and proximate analysis 34 2.2.2 Thermogravimetric analysis 34 2.3 Experimental bench 40 2.3.1 Quartz tube reactor 40 2.3.2 Batch kettle reactor 41 2.4 Product analysis 42 2.4.1 Gas phase products 42 2.4.2 Liquid phase products 43 2.4.3 Solid phase products 45 References 46 3.Resource utilization of thermoplastics in supercritical water 47 3.1 Gasification 47 3.1.1 Experimental investigation on gasification characteristics of polycarbonate microplastics in supercritical water 47 3.1.2 Experimental study on gasification performance of polypropylene plastics in supercritical water 58 3.1.3 Experimental investigation on in-situ hydrogenation induced gasification characteristics of acrylonitrile butadiene styrene microplastics in supercritical water 74 3.1.4 Experimental investigation on gasification characteristics of polyethylene terephthalate microplastics in supercritical water 85 3.1.5 Experimental investigation on gasification characteristics of high impact polystyrene plastics in supercritical water 99 3.2 Liquefaction 110 3.2.1 Hydrothermal liquefaction of polycarbonate plastics in sub-/supercritical water and an exploration of reaction pathways 110 3.3 Liquefaction reaction pathways exploration 123 3.3.1 Liquefaction kinetics of polycarbonate 126 3.4 Carbon dioxide fixation 141 3.4.1 In the supercritical water/C02 environment 141 3.4.2 In C02 environment 147 3.5 Coordinated treatment of pollutants 157 3.5.1 Hydrogen/methane production from supercritical water gasification of lignite coal with plastic waste blends 157 3.5.2 Cogasification of plastic wastes and soda lignin in supercritical water 169 3.6 Preparation of hydrophobic materials 182 3.6.1 Hydrophobic behavior 183 3.6.2 Microstructure 186 3.6.3 Functional groups 191 References 193 4.Resource utilization of thermosetting plastics in supercritical water 201 4.1 Hydrogen-rich syngas production by gasification of urea��formaldehyde plastics in supercritical water 201 4.1.1 Effect of reaction temperature 201 4.1.2 Effect of reaction time 202 4.1.3 Effect of feedstock mass fraction 203 4.1.4 Effect of reaction pressure 204 4.1.5 Compared with the polystyrene plastics 205 4.1.6 Reaction analysis 207 4.1.7 Kinetic study 207 4.1.8 Conclusions 209 4.2 Resource utilization of circuit boards 210 4.2.1 Effect of reaction temperature 210 4.2.2 Effect of the reaction time 215 4.2.3 Effect of feedstock concentration 219 4.2.4 Effect of additive 220 4.2.5 Conclusion 222 References 223 5.Development prospects for resource utilization of waste plastics 227 5.1 Necessity of recycling waste plastics 227 5.1.1 Biodiversity conservation 228 5.1.2 Maintaining soil fertility 229 5.1.3 Saving resources 231 5.2 Comprehensive treatment countermeasures of waste plastics 232 5.2.1 Policy 232 5.2.2 General situation of domestic and foreign waste plastic treatment 237 5.2.3 Existing shortcomings 239 5.2.4 Improvement measures 240 5.3 Prospect of waste plastics treatment with supercritical water 242 5.3.1 Existing problems 243 5.3.2 Future development direction 244 References 245 Index 249 List of figures Figure 1.1 Global annual production of plastic.1 Figure 1.2 The transfer of microplastic in different environments.3 Figure 1.3 The formation and influence of microplastic in the ocean.3 Figure 1.4 Main treatment methods for waste plastic.6 Figure 2.1 Chemical structure of(A)BPA;(B)DPC;(C)PC.BPA��bisphenol A;30 DPC��diphenyl carbonate;PC��polycarbonate. Figure 2.2 Molecular structure of ABS plastic here.ABS��acrylonitrile butadiene styrene.30 Figure 2.3 Chemical structure of polyethylene terephthalate(PET).31 Figure 2.4 Molecular structure of HIPS plastic.HIPS��high-impact polystyrene.31 Figure 2.5 Molecular structure of PS plastic.PS��polymer synthesized.32 Figure 2.6 Chemical structures of(A)hydroxymethylurea;(B)1��3-32 bishydroxym