废弃塑料快递袋作为一种新兴且广泛存在的塑料垃圾，具有数量庞大、组成复杂、环境风险高等特点。因此，高效降解废弃塑料快递袋备受关注。目前，传统回收技术存在原料要求高、反应温度高、二次污染等问题，因此需要开发应用广泛、绿色且环保的回收技术。超临界流体因其高反应活性和无污染性而被视为一种绿色环保的处理方法。然而，目前对于废弃塑料快递袋在超临界流体中的分解转化规律尚不明确。本论文通过构建超临界水降解(Supercritical water degradation, SCWD)，超临界水部分氧化(Supercritical water partial oxidation, SCWPO)，超临界水氨体系(Supercritical water + ammonia, SCWA)将废弃塑料快递袋高效绿色处理并对其分解转化规律进行探索。同时也研究了废弃塑料快递袋与低阶煤两者在超临界水+乙醇体系(Supercritical water + ethanol, SCWE)下协同共液化的规律与特征。本论文的研究内容与结论如下：

(1) SCWD和SCWPO处理废弃塑料快递袋的分解特性比较研究。开发出两种处理手段(SCWD和SCWPO)均可高效分解废弃塑料快递袋，并且能获得高值且易于分离的油产品(蜡和液体油)。在450 ℃下的转化率均超过95%。SCWPO处理废弃塑料快递袋获得的转化率高于SCWD。蜡(塑料基体聚乙烯分解所得)和液态油(塑化剂和阻燃剂分解所得)的产率和组分均有所差异，425 ℃下，SCWD处理废弃塑料快递袋获得42.08%的蜡产率，30.25%的液体油产率，蜡产品主要包括长链烯烃和少量烷烃、醇类等。SCWPO处理废弃塑料快递袋获得34.49%的蜡产率和37.43%的液体油产率。由于过氧化氢的部分氧化作用，蜡主要由长链烷烃组成。两种工艺产生的液体油成分相似，以塑化剂分解产生的酚类和芳香化合物为主。此外，SCWD和SCWPO转化产物的最大区别在于SCWD有利于长链烯烃的生成，而SCWPO有利于生成与工业石蜡组成相似的长链烷烃。

(2) SCWA处理废弃塑料快递袋的转化研究。基于(1)存在的问题：反应产物的选择性低、反应温度较高以及未考虑各因素相互作用。通过构建了临界温度更低的SCWA，并引入响应面优化法对所有实验条件进行了优化。由于NH₃及其构成的碱性环境的高反应性，对优化和调节分解产物的分布具有积极作用。通过响应面法优化的最佳工艺参数为：440.5 ℃，90 min，氨的质量分数(C_NH3) = 4.8 wt%。同时，废弃塑料快递袋转化率和碳酸钙回收率分别为99.10%和98.85%。NH₃或NH₃诱导的碱性介质可以促进超临界水体系中废弃塑料快递袋中主要成分聚乙烯分解过程中的β-断裂，并导致产物中长链烯烃含量的增加。NH₃的亲核活性导致塑料添加剂邻苯二甲酸二(2-乙基己基)(Di-2-ethylhexyl phthalate, DEHP)和双酚A(Bisphenol A, BPA)转化产生苯胺化合物，有效抑制了超临界水过程中的其他副反应发生。

(3) 废弃塑料快递袋与低阶煤在SCWE体系中协同共液化的研究。针对(1)和(2)实验中仅对一种废弃物进行资源转化并考虑到目前低阶煤的低利用率，通过构建SCWE体系对废弃塑料快递袋和低阶煤进行共液化处理，实现二者高值转化同时进行。高温和低水醇比有利于共液化转化。在425 ℃、60 min、水醇比 = 1:1 mL/mL、塑煤比 = 1:1 g/g时，最大总转化率达到85.11%。与此同时，在高温范围内(375-425 ℃)，废弃塑料快递袋和低阶煤共液化在SCWE中表现出正协同效应，而在低温范围内(325-350 ℃)则表现出负协同效应。在375 ℃以上，固体残渣与原煤相比，含氧量少，含碳量多，热值高，富含甲基和亚甲基结构，因此可被作为一种优质的固体燃料。在400 ℃时，反应后的油产品主要成分是碳氢化合物和酚类，主要来源于塑料和低阶煤的分解转化。因此，废弃塑料快递袋与低阶煤共液化可同时实现塑料废弃物的降解和低阶煤升级，并获得高品质的油产品作为精细化工的中间原料。

As an emerging and widespread plastic waste, waste plastic express bags are characterized by large quantity, complex composition and high environmental risk. Therefore, there is an urgent need for efficient degradation of waste plastic express bags. Currently, traditional recycling technologies suffer from high raw material requirements, high reaction temperatures and secondary pollution, and thus the need to develop widely used, green and environmentally friendly recycling technologies. Supercritical fluid is considered as a green treatment method for its high reactivity and non-polluting nature. However, the decomposition and conversion pattern of waste plastic express bags in supercritical fluids is still unclear. In this thesis, the supercritical water degradation (SCWD), supercritical water partial oxidation (SCWPO), supercritical water + ammonia (SCWA) systems were established for the efficient green treatment of waste plastic express bags. Meanwhile, the patterns and characteristics of synergistic co-liquefaction between waste plastic express bags and low-rank coal in supercritical water + ethanol (SCWE) was also investigated. The contents and conclusions of this thesis are as follows:

(1) Comparative study on decomposition characteristics of waste plastic express bags treated by SCWD and SCWPO. Both treatments (SCWD and SCWPO) were developed to efficiently decompose waste plastic express bags and to obtain high-value and easily separable oil products (waxes and liquid oils). At 450 ℃, their conversion ratio both exceeded 95%, but the conversion ratio obtained by SCWPO treatment of waste plastic express bags was higher than that obtained by SCWD. the yield and components of wax (the decomposition of plastic matrix) and liquid oil (the decomposition of plastic additives) were different, and at 425 ℃, SCWD treatment of waste plastic express bags obtained a wax yield of 42.08% and a liquid oil yield of 30.25%. The wax products mainly included long-chain alkenes and small amounts of alkanes and alcohols. 34.49% wax yield and 37.43% liquid oil yield were obtained by SCWPO treatment of waste plastic express bags. Due to the partial oxidation of hydrogen peroxide, the waxes consisted mainly of long-chain alkanes. The composition of the liquid oil produced by both processes was similar, dominated by phenolic and aromatic compounds produced by the decomposition of plasticizers. In addition, the major difference between SCWD and SCWPO conversion products is that SCWD favors the production of long-chain alkenes, while SCWPO favors the production of long-chain alkanes with similar composition to industrial paraffins.

(2) Research on conversion of waste plastic express bags treated by SCWA. Based on the problems of (1): low selectivity of the reaction, high reaction temperature and failure to consider the interaction of factors. The whole experiment was optimized by building SCWA with lower critical temperature and introducing Response Surface Methodology. Due to the high reactivity of NH₃ and its basic medium, it has a positive effect on optimizing and regulating the distribution of decomposition products. The optimal process parameters optimized by the response surface methodology were: 440.5 ℃, 90 min, and ammonia mass fraction (C_NH3) = 4.8 wt%. Meanwhile, the conversion ratio of waste plastic express bags and the recovery ratio of calcium carbonate were 99.10% and 98.85%, respectively. NH₃ or NH₃ induced alkaline medium can facilitate β-scission during polyethylene decomposition in supercritical water processes and lead to an increase in the content of long-chain alkenes. The nucleophilic of NH₃ led to an increase in the content of the plastic additive di(2-ethylhexyl) phthalate and bisphenol A conversion to produce aniline, effectively inhibiting other side reactions occurring in the supercritical water process.

(3) Research on the synergistic co-liquefaction of waste plastic express bags and low-rank coal in the SCWE system. For the experiments in (1) and (2), only one kind of waste was converted into resources and considering the current low utilization value of low-rank coal, therefore, the co-liquefaction treatment of waste plastic express bags and low-rank coal was carried out by constructing SCWE system to achieve the synergistic high-value conversion of both. Higher temperature and lower water-ethanol ratio are favorable for co-liquefaction conversion. The maximum total conversion reached 85.11% at 425 ℃, 60 min, water-ethanol ratio = 1:1 mL/mL and plastic-coal ratio = 1:1 g/g. Meanwhile, during the high temperature range (375-425 ℃), the co-liquefaction of waste plastic express bags and low-rank coal exhibited a positive synergistic effect in SCWE, while during the low temperature range (325-350 ℃), it showed a negative synergistic effect. Above 375 ℃, the solid residue contains less oxygen, more carbon, higher heat value, and rich in methyl and methylene structures compared to raw coal, and thus can be used as a high-quality solid fuel. At 400 ℃, the main components of the oil product after the reaction are hydrocarbons and phenols. The hydrocarbons and phenols are mainly derived from the decomposition and conversion of plastics and low-rank coal. Therefore, co-liquefaction of waste plastic express bags and low-rank coal can achieve waste degradation and low-rank coal upgrading, and obtain high-quality oil products as intermediate raw materials for fine chemicals.

[1] Rochman C M, Browne M A. Classify plastic waste as hazardous[J]. Nature, 2013, 494: 169-171.

[2] Häußler M, Eck M, Rothauer D, et al. Closed-loop recycling of polyethylene-like materials[J]. Nature, 2021, 590(7846): 423-427.

[3] 吴谊平. 城镇塑料生活垃圾智能精细分类关键技术研究[D]. 南昌大学, 2020.

[4] Rahimi A, García J M. Chemical recycling of waste plastics for new materials production[J]. Nature Reviews Chemistry, 2017, 1(6): 46-47.

[5] Li N, Liu H, Cheng Z, et al. Conversion of plastic waste into fuels: A critical review[J]. Journal of Hazardous Materials, 2021, 424(Part B): 127460.

[6] 刘超, 张晓然, 刘俊峰. 塑料制品中微塑料的释放行为及在环境中的迁移规律研究进展[J]. 环境工程, 2022: 1-13.

[7] Wong S L, Ngadi N, Abdullah T, et al. Current state and future prospects of plastic waste as source of fuel: A review[J]. Renewable & Sustainable Energy Reviews, 2015, 50: 1167-1180.

[8] Abbas-Abadi M S. The effect of process and structural parameters on the stability, thermo-mechanical and thermal degradation of polymers with hydrocarbon skeleton containing PE, PP, PS, PVC, NR, PBR and SBR[J]. Journal of Thermal Analysis and Calorimetry, 2021, 143(4): 2867-2882.

[9] PlasticsEurope, Plastics—The facts (2015) an analysis of European latest plastics production[R]: Demand and Waste Dataplastics, 2016.

[10] Bahar T, Fusun I D, Mithat Z D. An evaluation of new values in economy and their impacts on future transformation in tourism[J]. Procedia Computer Science, 2019, 158: 1095-1102.

[11] 中国国家邮政局. 2019年邮政行业发展统计公报[R]. 北京, 2020.

[12] 中国国家邮政局. 2021年全国邮政管理工作会议在京召开[R]. 北京, 2021.

[13] 中国国家邮政局. 国家邮政局关于2021年上半年行业经济运行的通知[R]. 北京, 2021.

[14] Joerss M, Schroder J, Neuhaus F, et al. Parcel delivery: The future of last mile[M]. McKinsey & Company. 2016.

[15] Cai K, Xie Y, Song Q, et al. Identifying the status and differences between urban and rural residents' behaviors and attitudes toward express packaging waste management in Guangdong Province, China[J]. Science of the Total Environment, 2021, 797: 148996.

[16] Duan H, Song G, Qu S, et al. Post-consumer packaging waste from express delivery in China[J]. Resources, Conservation & Recycling, 2019, 144: 137-143.

[17] 王姿怡, 义艺, 孙锲. 快递包装的能耗现状及对策分析[J]. 包装工程, 2019, 40(3): 143-148.

[18] Alam O, Billahc M, Yajie D. Characteristics of plastic bags and their potential environmental hazards[J]. Resources, Conservation & Recycling, 2018, 132: 121-129.

[19] Halden R U. Plastics and health risks[J]. Annual Review of Public Health, 2010, 31: 179-194.

[20] 陈满英, 喻乔, 张太平. 土壤环境中微塑料污染及迁移转化规律研究进展[J]. 生态科学, 2021, 40(4): 202-211.

[21] 桑文静, 王晓霞, 王夏妹等. 土壤中微塑料的来源、赋存特征及迁移行为[J]. 生态与农村环境学报, 2021, 37(11): 1361-1367.

[22] Barnes D K, Galgani F, Thompson R C, et al. Accumulation and fragmentation of plastic debris in global environments[J]. Philosophical Transactions of the Royal Society B: Biological Sciences, 2009, 364(1526): 1985-1998.

[23] Gallo F, Fossi C, Weber R, et al. Marine litter plastics and microplastics and their toxic chemicals components: the need for urgent preventive measures[J]. Environmental Sciences Europe, 2018, 30(1): 13: 320-335.

[24] Paluselli A, Fauvelle V, Galgani F, et al. Phthalate release from plastic fragments and degradation in seawater[J]. Environmental Science & Technology, 2019, 53(1): 166-175.

[25] Xu Z, Xiong X, Zhao Y, et al. Pollutants delivered every day: Phthalates in plastic express packaging bags[J]. Journal of Hazardous Materials, 2020, 384: 121282.

[26] Mankidy R, Wiseman S, Ma H, et al. Biological impact of phthalates[J]. Toxicology Letters, 2013, 217: 50-58.

[27] Koelmans A A, Besseling E, Foekema E M. Leaching of plastic additives to marine organisms[J]. Environmental Pollution, 2014, 187: 49-54.

[28] Hermann F, Thomas K, Thomas O, et al. Occurrence of phthalates and bisphenol A and Fin the environment[J]. Water Research, 2002, 36: 1429-1438.

[29] 陈浮, 于昊辰, 卞正富等. 碳中和愿景下煤炭行业发展的危机与应对[J]. 煤炭学报, 2021, 46(6): 13: 1808-1820.

[30] Qi X, Guo P, Guo Y, et al. Understanding energy efficiency and its drivers: An empirical analysis of China’s 14 coal intensive industries[J]. Energy, 2020, 190: 116354.

[31] 杨雨濛, 刘建忠, 陈明义等. 低阶煤及其热解半焦的超细粉碎特性[J]. 煤炭学报, 2021, 46(11):3692-3698.

[32] 胡彦勇, 张瑞, 郄晓彤等. 全生命周期下中国煤炭资源能源碳排放效率评价[J]. 中国环境科学, 2022, 42(6): 2942-2954.

[33] 王建国, 赵晓红. 低阶煤清洁高效梯级利用关键技术与示范[C]; 2012年可持续发展20年学术研讨会, 北京, 2012.

[34] Liu Z, Shi S, Li Y. Coal liquefaction technologies—Development in China and challenges in chemical reaction engineering[J]. Chemical Engineering Science, 2010, 65(1): 12-17.

[35] Mochida I, Okuma O, Yoon S H. Chemicals from direct coal liquefaction[J]. Chemical Reviews, 2014, 114(3): 1637-1672.

[36] Vasireddy S, Morreale B, Cugini A, et al. Clean liquid fuels from direct coal liquefaction: chemistry, catalysis, technological status and challenges[J]. Energy & Environmental Science, 2011, 4(2): 311-345.

[37] 戴重阳, 田宜水, 胡二峰等. 生物质与低阶煤共热解特性研究及其技术进展[J]. 太阳能学报, 2021, 42(12): 326-333.

[38] 汪寿建. 低阶煤清洁高效梯级利用关键技术及全产业链探讨[J]. 煤化工, 2017, 45(5): 18-24.

[39] Al-Salem S M, Lettieri P, Baeyens J. Recycling and recovery routes of plastic solid waste (PSW): A review[J]. Waste Management, 2009, 29(10): 2625-2643.

[40] Foundation E M. The New Plastics Economy: Rethinking the future of plastics - industry agenda[M]. World Economic Forum. 2016.

[41] Zhang G-H, Zhu J-F, Okuwaki A. Prospect and current status of recycling waste plastics and technology for converting them into oil in China[J]. Resources, Conservation and Recycling, 2007, 50(3): 231-239.

[42] Zhou C, Fang W, Xu W, et al. Characteristics and the recovery potential of plastic wastes obtained from landfill mining[J]. Journal of Cleaner Production, 2014, 80: 80-86.

[43] MacArthur E. Beyond plastic waste[J]. Science, 2017, 358(6365): 843-844.

[44] Jin K, Vozka P, Kilaz G, et al. Conversion of polyethylene waste into clean fuels and waxes via hydrothermal processing (HTP)[J]. Fuel, 2020, 273: 117726.

[45] PlasticsEurope, Plastics—The facts (2020) an analysis of European latest plastics production[R]: Demand and Waste Dataplastics, 2021.

[46] Lettieri P, Al-Salem S M. Thermochemical treatment of plastic solid waste[M]. Academic Press. 2011: 233-242.

[47] Queiroz A, Pedroso G B, Kuriyama S N, et al. Subcritical and supercritical water for chemical recycling of plastic waste[J]. Current Opinion in Green and Sustainable Chemistry, 2020, 25: 100364.

[48] Zia K M, Bhatti H N, Bhatti I A. Methods for polyurethane and polyurethane composites, recycling and recovery: A review[J]. Reactive and Functional Polymers, 2007, 67(8): 675-692.

[49] Al-Salem S M, Antelava A, Constantinou A, et al. A review on thermal and catalytic pyrolysis of plastic solid waste (PSW)[J]. Journal of Environmental Management, 2017, 197: 177-198.

[50] Al-Salem S M. Establishing an integrated databank for plastic manufacturers and converters in Kuwait[J]. Waste Management, 2009, 29(1): 479-484.

[51] Al-Salem S M, Lettieri P, Baeyens J. The valorization of plastic solid waste (PSW) by primary to quaternary routes: From re-use to energy and chemicals[J]. Progress in Energy and Combustion Science, 36(1): 103-129.

[52] Okan Aydin M, Aydin H M, Barsbay M. Current approaches to waste polymer utilization and minimization: A Review[J]. Journal of Chemical Technology & Biotechnology, 2019, 94: 8-21.

[53] Schlummer M, Fell T, Maurer A, et al. The role of chemistry in plastics recycling[J]. Kunststoffe international, 2020: 34-37.

[54] 赵爱之. 废弃塑料回收方法概述[J]. 塑料科技, 2020, 48(9): 123-126.

[55] Bora R R, Wang R, You F. Waste polypropylene plastic recycling toward climate change mitigation and circular economy: Energy, environmental, and technoeconomic perspectives[J]. ACS Sustainable Chemistry & Engineering, 2020, 8(43): 16350-16363.

[56] Zhao Y, Lv X, Ni H. Solvent-based separation and recycling of waste plastics: A review[J]. Chemosphere, 2018, 209: 707-720.

[57] Garcia J M, Robertson M L. The future of plastics recycling[J]. Science, 2017, 358(6365): 870.

[58] Mastellone M L. Thermal treatments of plastic wastes by means of fluidized bed reactors[D]. Second University of Naples, 1999.

[59] Mulakkal M C, Castillo A, Taylor A C, et al. Advancing mechanical recycling of multilayer plastics through finite element modelling and environmental policy[J]. Resources, Conservation and Recycling, 2021, 166: 105371.

[60] Chen H, Wan K, Zhang Y, et al. Waste to wealth: Chemical recycling and chemical upcycling of waste plastics for a great future[J]. ChemSusChem, 2021, 14(19): 4123-4136.

[61] Fagnani D E, Tami J L, Copley G, et al. 100th anniversary of macromolecular science viewpoint: Redefining sustainable polymers[J]. ACS Macro Letters, 2020, 10: 41-53.

[62] 李明丰, 蔡志强, 邹亮等. 中国石化废旧塑料化学回收与化学循环技术探索[J]. 中国塑料, 2021, 35(8): 64-76.

[63] Huang J, Veksha A, Foo T, et al. Upgrading waste plastic derived pyrolysis gas via chemical looping cracking–gasification using Ni−Fe−Al redox catalysts[J]. Chemical Engineering Journal, 2022: 135580.

[64] Rahimi S, Rostamizadeh M. Novel Fe/B-ZSM-5 nanocatalyst development for catalytic cracking of plastic to valuable products[J]. Journal of the Taiwan Institute of Chemical Engineers, 2021, 118: 131-139.

[65] Hussein Z A, Shakor Z M, Alzuhairi M, et al. Thermal and catalytic cracking of plastic waste: a review[J]. International Journal of Environmental Analytical Chemistry, 2021, 15: 1-18.

[66] Dwivedi U, Naik S N, Pant K K. High quality liquid fuel production from waste plastics via two-step cracking route in a bottom-up approach using bi-functional Fe/HZSM-5 catalyst[J]. Waste Management, 2021, 132: 151-161.

[67] Li C, Zhuang H, Hsieh L, et al. PAH emission from the incineration of three plastic wastes[J]. Environment International, 2001, 27: 61-67.

[68] Takayuki S, Akio Y, Katami T. Dioxin formation from waste incineration[J]. Reviews of Environmental Contamination and Toxicology, 2007, 190: 1-41.

[69] Agraniotis M, Koumanakos A, Doukelis A, et al. Investigation of technical and economic aspects of pre-dried lignite utilization in a modern lignite power plant towards zero CO2 emissions[J]. Energy, 2012, 45(1): 134-141.

[70] Jeon D, Kang T, Kim H, et al. Investigation of drying characteristics of low rank coal of bubbling fluidization through experiment using lab scale[J]. Science China Technological Sciences, 2011, 54(7): 1680-1683.

[71] Wang W-C. Laboratory investigation of drying process of Illinois coals[J]. Powder Technology, 2012, 225: 72-85.

[72] Rao Z, Zhao Y, Huang C, et al. Recent developments in drying and dewatering for low rank coals[J]. Progress in Energy and Combustion Science, 2015, 46: 1-11.

[73] Zhao P, Zhong L, Zhu R, et al. Drying characteristics and kinetics of Shengli lignite using different drying methods[J]. Energy Conversion and Management, 2016, 120: 330-337.

[74] Top S, Akgün M, Kıpçak E, et al. Treatment of hospital wastewater by supercritical water oxidation process[J]. Water Research, 2020, 185: 116279.

[75] Xu Y, Zhang Y, Zhang G, et al. Low temperature pyrolysates distribution and kinetics of Zhaotong lignite[J]. Energy Conversion and Management, 2016, 114: 11-19.

[76] Yang H, Li S, Fletcher T H, et al. Simulation of the evolution of pressure in a lignite particle during pyrolysis[J]. Energy & Fuels, 2014, 28(5): 3511-3518.

[77] 初茉, 高晶晶. 褐煤低温热解提质试验研究[J]. 煤炭科学技术, 2012, 40(10): 95-99.

[78] 迟姚玲, 李术元, 岳长涛等. 昭通褐煤及其低温热解产物的性质研究[J]. 石油大学学报：自然科学版, 2005, 29(2): 101-107.

[79] 欧阳创. 超临界水氧化法处理有机污染物研究[D]. 上海交通大学, 2013.

[80] 王炫. 近临界水中自身碱催化有机反应的研究[D]. 华东师范大学, 2006.

[81] Zhu N-M, Wang C-F, Zhang F-S. An integrated two-stage process for effective dechlorination of polychlorinated biphenyls in subcritical water in the presence of hydrogen donors[J]. Chemical Engineering Journal, 2012, 197: 135-142.

[82] 刘颖. 亚(超)临界水中的烃自由基反应[D]. 华东理工大学, 2012.

[83] 李世斌, 夏晓彬, 秦强等. 超临界水氧化处理核电厂润滑油的实验研究[J]. 核技术, 2021, 44(7): 91-98.

[84] 林春绵, 潘志彦. 超临界氧化技术在有机废水处理中的应用[J]. 浙江化工, 1996, 27(2): 16-20.

[85] Čolnik M, Knez Ž, Škerget M. Sub- and supercritical water for chemical recycling of polyethylene terephthalate waste[J]. Chemical Engineering Science, 2021, 233: 116389.

[86] Hatakeyama K, Kojima T, Funazukuri T. Chemical recycling of polycarbonate in dilute aqueous ammonia solution under hydrothermal conditions[J]. Journal of Material Cycles and Waste Management, 2013, 16(1): 124-130.

[87] Jin H, Bai B, Wei W, et al. Hydrothermal liquefaction of polycarbonate (pc) plastics in sub-/supercritical water and reaction pathway exploration[J]. ACS Sustainable Chemistry & Engineering, 2020, 8(18): 7039-7050.

[88] Genta M, Goto M, Sasaki M. Heterogeneous continuous kinetics modeling of PET depolymerization in supercritical methanol[J]. The Journal of Supercritical Fluids, 2010, 52(3): 266-275.

[89] Chen W-T, Jin K, Linda Wang N-H. Use of supercritical water for the liquefaction of polypropylene into oil[J]. ACS Sustainable Chemistry & Engineering, 2019, 7(4): 3749-3758.

[90] Watanabe M, Hirakoso H, Sawamoto S, et al. Polyethylene conversion in supercritical water[J]. Journal of Supercritical Fluids, 1998, 13(1-3): 247-252.

[91] Bai B, Jin H, Fan C, et al. Experimental investigation on liquefaction of plastic waste to oil in supercritical water[J]. Waste Management, 2019, 89: 247-253.

[92] Saha N, Banivaheb S, Toufiq Reza M. Towards solvothermal upcycling of mixed plastic wastes: Depolymerization pathways of waste plastics in sub- and supercritical toluene[J]. Energy Conversion and Management, 2022, 13: 100158.

[93] Zhao P, Yuan Z, Zhang J, et al. Supercritical water co-liquefaction of LLDPE and PP into oil: properties and synergy[J]. Sustainable Energy & Fuels, 2021, 5(2): 575-583.

[94] Liu Y, Fan C, Zhang H, et al. The resource utilization of ABS plastic waste with subcritical and supercritical water treatment[J]. International Journal of Hydrogen Energy, 2019, 44(30): 15758-15765.

[95] Wang W, Bai B, Wei W, et al. Hydrogen-rich syngas production by gasification of Urea-formaldehyde plastics in supercritical water[J]. International Journal of Hydrogen Energy, 2021, 46(71): 35121-35129.

[96] Kershaw J R. Extraction of Victorian Brown coals with supercritical water[J]. Fuel Processing Technology, 1986, 13(2): 111-124.

[97] Aida T M, Sato T, Sekiguchi G, et al. Extraction of Taiheiyo coal with supercritical water–phenol mixtures[J]. Fuel, 2002, 81(11): 1453-1461.

[98] Zhao Y, Zhang M, Cui X, et al. Converting lignite to caking coal via hydro-modification in a subcritical water–CO system[J]. Fuel, 2016, 167: 1-8.

[99] Ali A, Zhao C. Direct liquefaction techniques on lignite coal: A review[J]. Chinese Journal of Catalysis, 2020, 41(3): 375-389.

[100] Liu F-J, Gasem K A M, Tang M, et al. Enhanced liquid tar production as fuels/chemicals from Powder River Basin coal through CaO catalyzed stepwise degradation in eco-friendly supercritical CO2/ethanol[J]. Energy, 2020, 191: 116563.

[101] Onsri K. Co-liquefaction of coal and used tire in supercritical water[J]. Energy and Power Engineering, 2010, 02(2): 95-102.

[102] Yang R, Yu C, Wu Y, et al. Production of liquid fuel via coliquefaction of coal and dunaliella tertiolecta in a sub-/supercritical water–ethanol system[J]. Energy & Fuels, 2013, 27(5): 2619-2627.

[103] Li W, Peng C. Development of first-stage co-liquefaction of Chinese coal with waste plastics[J]. Chemical Engineering and Processing, 2004, 43(2): 145-148.

[104] Mott R A, Spooner C E. The calorific value of carbon in coal: The Dulong relationship[J]. Fuel in science and practice, 1940, 19: 242-251.

[105] Gong Y, Wang S, Xu H, et al. Partial oxidation of landfill leachate in supercritical water: Optimization by response surface methodology[J]. Waste Management, 2015, 43: 343-352.

[106] Turkay B, Dıncer F I, Dincer M Z. An Evaluation of new values in economy and their impacts on future transformation in tourism[J]. Procedia Computer Science, 2019, 158: 1095-1102.

[107] Xu Z, Xiong X, Zhao Y, et al. Pollutants delivered every day: Phthalates in plastic express packaging bags and their leaching potential[J]. Journal of Hazardous Materials, 2019, 384: 121282.

[108] Shibamoto T, Yasuhara A, Katami T. Dioxin Formation from Waste Incineration[M]. Springer New York. 2007: 1-41.

[109] Ragaert K, Delva L, Van Geem K. Mechanical and chemical recycling of solid plastic waste[J]. Waste Management, 2017, 69: 24-58.

[110] Bai B, Liu Y, Zhang H, et al. Experimental investigation on gasification characteristics of polyethylene terephthalate (PET) microplastics in supercritical water[J]. Fuel, 2020, 262: 116630.

[111] Xiu F-R, Zhou K, Yu X, et al. Co-treatment of PVC and used LCD panels in low-temperature subcritical water: Enhanced dechlorination and mechanism[J]. Process Safety and Environmental Protection, 2021, 151: 10-19.

[112] Reig F B, Adelantado J V G, Moya Moreno M C M. FTIR quantitative analysis of calcium carbonate (calcite) and silica (quartz) mixtures using the constant ratio method. Application to geological samples[J]. Talanta, 2002, 58(4): 811-821.

[113] Zaman H U, Beg M D H. Effect of CaCO3 contents on the properties of polyethylene nanocomposites sheets[J]. Fibers and Polymers, 2014, 15(4): 839-846.

[114] Zhang X, Sun P, Yan T, et al. Water's phase diagram: From the notion of thermodynamics to hydrogen-bond cooperativity[J]. Progress in Solid State Chemistry, 2015, 43(3): 71-81.

[115] Xiu F-R, Qi Y, Zhang F-S. Leaching of Au, Ag, and Pd from waste printed circuit boards of mobile phone by iodide lixiviant after supercritical water pre-treatment[J]. Waste Management, 2015, 41: 134-141.

[116] Popov K V, Knyazev V D. Molecular dynamics simulation of C–C bond scission in polyethylene and linear alkanes: Effects of the condensed phase[J]. The Journal of Physical Chemistry A, 2014, 118(12): 2187-2195.

[117] Poutsma M L. Reexamination of the pyrolysis of polyethylene:  Data needs, free-radical mechanistic considerations, and thermochemical kinetic simulation of initial product-forming pathways[J]. Macromolecules, 2003, 36(24): 8931-8957.

[118] Arulmozhiraja S, Coote M L, Kitahara Y, et al. Is the bisphenol A biradical formed in the pyrolysis of polycarbonate[J]. The Journal of Physical Chemistry A, 2011, 115(19): 4874-4881.

[119] Zhao X, Korey M, Li K, et al. Plastic waste upcycling toward a circular economy[J]. Chemical Engineering Journal, 2022, 428: 131928.

[120] Fan W, Xu M, Dong X, et al. Considerable environmental impact of the rapid development of China's express delivery industry[J]. Resources, Conservation and Recycling, 2017, 126: 174-176.

[121] Mankidy R, Wiseman S, Ma H, et al. Biological impact of phthalates[J]. Toxicology Letters, 2013, 217(1): 50-58.

[122] Nouali M, Ghorbel E, Derriche Z. Phase separation and thermal degradation of plastic bag waste modified bitumen during high temperature storage[J]. Construction and Building Materials, 2020, 239: 117872.

[123] Hou L, Xi J, Liu J, et al. Biodegradability of polyethylene mulching film by two Pseudomonas bacteria and their potential degradation mechanism[J]. Chemosphere, 2022, 286: 131758.

[124] Taghavi N, Singhal N, Zhuang W-Q, et al. Degradation of plastic waste using stimulated and naturally occurring microbial strains[J]. Chemosphere, 2021, 263: 127975.

[125] Bai B, Wang W, Jin H. Experimental study on gasification performance of polypropylene (PP) plastics in supercritical water[J]. Energy, 2020, 191: 116527.

[126] Song Z, Xiu F-R, Qi Y. Degradation and partial oxidation of waste plastic express packaging bags in supercritical water: Resources transformation and pollutants removal[J]. Journal of Hazardous Materials, 2022, 423: 127018.

[127] Li K, Xu Z. Application of supercritical water to decompose brominated epoxy resin and environmental friendly recovery of metals from waste memory module[J]. Environmental Science & Technology, 2015, 49(3): 1761-1767.

[128] Xiu F-R, Li Y, Qi Y, et al. A novel treatment of waste printed circuit boards by low-temperature near-critical aqueous ammonia: Debromination and preparation of nitrogen-containing fine chemicals[J]. Waste Management, 2019, 84: 355-363.

[129] Liu X, Zhang W, Song Y, et al. Tracking asymmetric intramolecular vibrational redistribution of nitromethane[J]. Journal of Molecular Structure, 2021, 1226: 129342.

[130] Machyňáková A, Schneider M P, Khvalbota L, et al. A fast and inexpensive approach to characterize Slovak Tokaj selection wines using infrared spectroscopy and chemometrics[J]. Food Chemistry, 2021, 357: 129715.

[131] Tziourrou P, Kordella S, Ardali Y, et al. Microplastics formation based on degradation characteristics of beached plastic bags[J]. Marine Pollution Bulletin, 2021, 169: 112470.

[132] Barhoum A, Rahier H, Abou-Zaied R E, et al. Effect of cationic and anionic surfactants on the application of calcium carbonate nanoparticles in paper coating[J]. ACS Applied Materials & Interfaces, 2014, 6(4): 2734-2744.

[133] Corchado J, Espinosa-Garcia J, Hu W-P, et al. Dual-level reaction-path dynamics (the III approach to VTST with semiclassical tunneling). Application to OH + NH3 → H2O + NH2[J]. Journal of physical chemistry, 1995, 99: 687-694.

[134] Ennis C P, Lane J R, Kjaergaard H G, et al. Identification of the water amidogen radical complex[J]. Journal of the American Chemical Society, 2009, 131(4): 1358-1359.

[135] Wang S, Jiao T, Zhang Y, et al. Recovery of paraffin from the filter cake used for paraffin decoloration in the Fischer-Tropsch synthetic process[J]. Fuel, 2022, 324: 124579.

[136] Amin A. A review on process conditions for optimum bio-oil yield in hydrothermal liquefaction of biomass[J]. Renewable and Sustainable Energy Reviews, 2011, 15(3): 1615-1624.

[137] Baloch H A, Nizamuddin S, Siddiqui M T H, et al. Co-liquefaction of synthetic polyethylene and polyethylene bags with sugarcane bagasse under supercritical conditions: A comparative study[J]. Renewable Energy, 2020, 162: 2397-2407.

[138] Wu X, Liang J, wu Y, et al. Co-liquefaction of microalgae and polypropylene in sub-/super-critical water[J]. RSC Advances, 2017, 7: 13768-13776.

[139] Seshasayee M S, Savage P E. Synergistic interactions during hydrothermal liquefaction of plastics and biomolecules[J]. Chemical Engineering Journal, 2021, 417: 129268.

[140] Bian C, Zhang R, Dong L, et al. Hydrogen/methane production from supercritical water gasification of lignite coal with plastic waste blends[J]. Energy & Fuels, 2020, 34(9): 11165-11174.

[141] Nonaka M, Hirajima T, Sasaki K. Upgrading of low rank coal and woody biomass mixture by hydrothermal treatment[J]. Fuel, 2011, 90(8): 2578-2584.

[142] Aziz M, Juangsa F, Kurniawan W, et al. Clean Co-production of H2 and power from low rank coal[J]. Energy, 2016, 116: 489-497.

[143] Li X, Song H, Wang Q, et al. Experimental study on drying and moisture re-adsorption kinetics of an Indonesian low rank coal[J]. Journal of Environmental Sciences, 2009, 21: S127-S130.

[144] Kou M, Zuo H, Ning X, et al. Thermogravimetric study on gasification kinetics of hydropyrolysis char derived from low rank coal[J]. Energy, 2019, 188: 116030.

[145] David Y, Baylon G, Pamidimarri S, et al. Screening of microorganisms able to degrade low-rank coal in aerobic conditions: Potential coal biosolubilization mediators from coal to biochemicals[J]. Biotechnology and Bioprocess Engineering, 2016, 22: 178-185.

[146] Kwon G, Park Y-K, Ok Y S, et al. Catalytic pyrolysis of low-rank coal using Fe-carbon composite as a catalyst[J]. Energy Conversion and Management, 2019, 199: 111978.

[147] Yu J, Jiang C, Guan Q, et al. Conversion of low-grade coals in sub-and supercritical water: A review[J]. Fuel, 2018, 217: 275-284.

[148] Cheng L, Zhang R, Bi J. Pyrolysis of a low-rank coal in sub- and supercritical water[J]. Fuel Processing Technology, 2004, 85(8): 921-932.

[149] Liu F-J, Gasem K A M, Tang M, et al. Mild degradation of Powder River Basin sub-bituminous coal in environmentally benign supercritical CO2-ethanol system to produce valuable high-yield liquid tar[J]. Applied Energy, 2018, 225: 460-470.

[150] Xiu F-R, Qi Y, Zhang F-S. Recovery of metals from waste printed circuit boards by supercritical water pre-treatment combined with acid leaching process[J]. Waste Management, 2013, 33(5): 1251-1257.

[151] Lu H-Y, Wei X-Y, Yu R, et al. Sequential thermal dissolution of huolinguole lignite in methanol and ethanol[J]. Energy & Fuels, 2011, 25: 2741-2745.

[152] Duan P, Jin B, Xu Y, et al. Co-pyrolysis of microalgae and waste rubber tire in supercritical ethanol[J]. Chemical Engineering Journal, 2015, 269: 262-271.

[153] Zeng R, Yang Y, Shen T, et al. Methanol oxidation using ternary ordered intermetallic electrocatalysts: A DEMS Study[J]. ACS Catalysis, 2019, 10: 770-776.