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Amodio L, López J, Souza A, Cueto J, Hernando H, Pizarro P, Serrano D. Simultaneous removal of brominated and chlorinated species during the production of oils by e-waste plastics catalytic hydropyrolysis. JOURNAL OF HAZARDOUS MATERIALS 2024; 465:133357. [PMID: 38157819 DOI: 10.1016/j.jhazmat.2023.133357] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 12/15/2023] [Accepted: 12/21/2023] [Indexed: 01/03/2024]
Abstract
The production of added-value chemicals via pyrolysis of plastic wastes, such as those from electrical and electronic equipment (WEEE), needs addressing their usual contamination with halogens (mainly Br and Cl). This work compares the conversion via pyrolysis and hydropyrolysis of a real WEEE plastic, having a complex composition, in two different reactor configurations: down-flow (DF) and up-flow (UF). Likewise, the effects of incorporating a Pd/Al2O3 catalyst and using two different pressures (1 and 6 bar) have been assessed. With the DF mode, pyrolysis at 1 bar leads to an oil yield above 80 wt% and a total halogen content of about 600 ppm (vs 1600 ppm in the water-washed WEEE plastic). Under DF catalytic hydropyrolysis at 6 bar, this high oil yield is maintained while its dehalogenation degree is improved (142 ppm). Operating with the up-flow configuration, under 6 bar and H2 presence, leads to some reduction in the oil yield (about 70 wt%) but significantly decreases the oil halogen content (55 ppm Cl and total elimination of Br). These results have been related to the slower pyrolysis and longer residence time in the thermal zone of the UF configuration, which favours the halogen-trapping effect of the char fraction, and the pressure-enhanced hydrodehalogenation activity of the catalyst. This study highlights the environmental benefits of the proposed process, emphasizing the lower halogen content in the resulting oils and promoting a more sustainable approach to plastic waste valorisation.
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Affiliation(s)
- Lidia Amodio
- Thermochemical Processes Unit, IMDEA Energy, Avda. Ramón de la Sagra 3, Móstoles, Madrid 28935, Spain; Chemical and Environmental Engineering Group, Rey Juan Carlos University, Móstoles, Madrid, Spain
| | - Julio López
- Thermochemical Processes Unit, IMDEA Energy, Avda. Ramón de la Sagra 3, Móstoles, Madrid 28935, Spain; Chemical and Environmental Engineering Group, Rey Juan Carlos University, Móstoles, Madrid, Spain
| | - Adriana Souza
- Thermochemical Processes Unit, IMDEA Energy, Avda. Ramón de la Sagra 3, Móstoles, Madrid 28935, Spain
| | - Jennifer Cueto
- Thermochemical Processes Unit, IMDEA Energy, Avda. Ramón de la Sagra 3, Móstoles, Madrid 28935, Spain
| | - Héctor Hernando
- Thermochemical Processes Unit, IMDEA Energy, Avda. Ramón de la Sagra 3, Móstoles, Madrid 28935, Spain
| | - Patricia Pizarro
- Thermochemical Processes Unit, IMDEA Energy, Avda. Ramón de la Sagra 3, Móstoles, Madrid 28935, Spain; Chemical and Environmental Engineering Group, Rey Juan Carlos University, Móstoles, Madrid, Spain
| | - David Serrano
- Thermochemical Processes Unit, IMDEA Energy, Avda. Ramón de la Sagra 3, Móstoles, Madrid 28935, Spain; Chemical and Environmental Engineering Group, Rey Juan Carlos University, Móstoles, Madrid, Spain.
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Ma C, Kumagai S, Saito Y, Yoshioka T, Huang X, Shao Y, Ran J, Sun L. Recent Advancements in Pyrolysis of Halogen-Containing Plastics for Resource Recovery and Halogen Upcycling: A State-of-the-Art Review. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:1423-1440. [PMID: 38197317 DOI: 10.1021/acs.est.3c09451] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2024]
Abstract
Plastic waste has emerged as a serious issue due to its impact on environmental degradation and resource scarcity. Plastic recycling, especially of halogen-containing plastics, presents challenges due to potential secondary pollution and lower-value implementations. Chemical recycling via pyrolysis is the most versatile and robust approach for combating plastic waste. In this Review, we present recent advancements in halogen-plastic pyrolysis for resource utilization and the potential pathways from "reducing to recycling to upcycling" halogens. We emphasize the advanced management of halogen-plastics through copyrolysis with solid wastes (waste polymers, biomass, coal, etc.), which is an efficient method for dealing with mixed wastes to obtain high-value products while reducing undesirable substances. Innovations in catalyst design and reaction configurations for catalytic pyrolysis are comprehensively evaluated. In particular, a tandem catalysis system is a promising route for halogen removal and selective conversion of targeted products. Furthermore, we propose novel insights regarding the utilization and upcycling of halogens from halogen-plastics. This includes the preparation of halogen-based sorbents for elemental mercury removal, the halogenation-vaporization process for metal recovery, and the development of halogen-doped functional materials for new materials and energy applications. The reutilization of halogens facilitates the upcycling of halogen-plastics, but many efforts are needed for mutually beneficial outcomes. Overall, future investigations in the development of copyrolysis and catalyst-driven technologies for upcycling halogen-plastics are highlighted.
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Affiliation(s)
- Chuan Ma
- Key Laboratory of Low-grade Energy Utilization Technologies and Systems, Ministry of Education, School of Energy and Power Engineering, Chongqing University, Chongqing 400044, China
| | - Shogo Kumagai
- Graduate School of Environmental Studies, Tohoku University, 6-6-07 Aoba, Aramaki-aza, Aoba-ku, Sendai, Miyagi 980-8579, Japan
| | - Yuko Saito
- Graduate School of Environmental Studies, Tohoku University, 6-6-07 Aoba, Aramaki-aza, Aoba-ku, Sendai, Miyagi 980-8579, Japan
| | - Toshiaki Yoshioka
- Graduate School of Environmental Studies, Tohoku University, 6-6-07 Aoba, Aramaki-aza, Aoba-ku, Sendai, Miyagi 980-8579, Japan
| | - Xin Huang
- Key Laboratory of Low-grade Energy Utilization Technologies and Systems, Ministry of Education, School of Energy and Power Engineering, Chongqing University, Chongqing 400044, China
| | - Yunlin Shao
- Key Laboratory of Low-grade Energy Utilization Technologies and Systems, Ministry of Education, School of Energy and Power Engineering, Chongqing University, Chongqing 400044, China
| | - Jingyu Ran
- Key Laboratory of Low-grade Energy Utilization Technologies and Systems, Ministry of Education, School of Energy and Power Engineering, Chongqing University, Chongqing 400044, China
| | - Lushi Sun
- State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology, Wuhan 430074, China
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Zhang Y, Zhou C, Liu Y, Qu J, Ali Siyal A, Yao B, Dai J, Liu C, Chao L, Chen L, Wang L. The fate of bromine during microwave-assisted pyrolysis of waste printed circuit boards. WASTE MANAGEMENT (NEW YORK, N.Y.) 2024; 173:160-171. [PMID: 37992535 DOI: 10.1016/j.wasman.2023.11.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/18/2023] [Revised: 10/20/2023] [Accepted: 11/13/2023] [Indexed: 11/24/2023]
Abstract
Bromine control is imperative for efficient treatment and products utilization during pyrolysis of waste printed circuit boards (WPCBs). This study investigated Br-species in products from microwave-assisted auger pyrolysis of WPCBs, and discussed synergetic evolution mechanisms, release kinetics and thermodynamics of Br-containing pollutants with different kinds of mineral species (alkaline earth, alkali, and transition metals). Results indicated that heavy Br-containing volatiles release (e.g., brominated phenols) was dominated at 320-520 °C. Brominated phenols released Br* to react with small-molecule groups to form light Br-containing products (e.g., HBr, CH3Br, and CH3CH2Br) at >520 °C. K2CO3 efficiently suppressed Br-containing pollutants emissions (∼50% reduction) and promoted bromine fixation in char (∼33.49% increase). With K2CO3 addition, bromine evolution mechanism is largely dehydrobromination and neutralization reactions when bromine bonds with aliphatic carbon with an adjacent aliphatic hydrogen. Negatively charged oxygen of K2CO3 attacks bromine and causes C-Br scission when bromine bonds with CH3* or aromatic carbon. The chemical reaction models (CRM3-CRM5) are best fitted with bromine evolution and the activation energy of WPCBs-KC reached the lowest (149.83-192.19 kJ/mol). Furthermore, bromine control strategy in WPCBs pyrolysis products toward environmental and economic sustainability were suggested, which created less environmental impact and maximum resource recovery.
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Affiliation(s)
- Yingwen Zhang
- State Key Laboratory of Organic-Inorganic Composites, College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Chunbao Zhou
- State Key Laboratory of Organic-Inorganic Composites, College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029, China.
| | - Yang Liu
- State Key Laboratory of Organic-Inorganic Composites, College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Junshen Qu
- State Key Laboratory of Organic-Inorganic Composites, College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Asif Ali Siyal
- State Key Laboratory of Organic-Inorganic Composites, College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Bang Yao
- State Key Laboratory of Organic-Inorganic Composites, College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Jianjun Dai
- State Key Laboratory of Organic-Inorganic Composites, College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029, China.
| | - Chenglong Liu
- State Key Laboratory of Organic-Inorganic Composites, College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Li Chao
- State Key Laboratory of Organic-Inorganic Composites, College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Lei Chen
- State Key Laboratory of Organic-Inorganic Composites, College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Long Wang
- Systematic Engineering Center, JIHUA Group Co., Ltd., Beijing 100070, China
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Mistry C, Surya DV, Potnuri R, Basak T, Kumar PS, Rao CS, Gautam R, Sridhar P, Choksi H, Remya N. Effective electronic waste valorization via microwave-assisted pyrolysis: investigation of graphite susceptor and feedstock quantity on pyrolysis using experimental and polynomial regression techniques. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023:10.1007/s11356-023-30661-y. [PMID: 38038921 DOI: 10.1007/s11356-023-30661-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2023] [Accepted: 10/20/2023] [Indexed: 12/02/2023]
Abstract
Waste printed circuit board (WPCB) was subjected to microwave-assisted pyrolysis (MAP) to investigate the energy and pyrolysis products. In MAP, pyrolysis experiments were conducted, and the effects of WPCB to graphite mass ratio on three-phase product yields and their compositions were analyzed. In addition, the role of the initial WPCB mass (10, 55, and 100 g) and susceptor loading (2, 22, and 38 g) on the quality of product yield was also evaluated. By using design of experiments, the effects of graphite susceptor addition and WPCB feedstock quantity was investigated. A significant liquid yield of 38.2 wt.% was achieved at 38 g of graphite and 100 g of WPCB. Several other operating parameters, including average heating rate, pyrolysis time, microwave energy consumption, specific microwave power used, and product yields, were optimized for the MAP of WPCB. Pyrolysis index (PI) was calculated at the blending of fixed quantity WPCB (100 g) and various graphite quantities in the following order: 2 g (21) > 20 g (20.4) > 38 g (19.5). The PI improved by increasing the WPCB quantity (10, 55, and 100 g) with a fixed quantity of graphite. This work proposes the product formation and new reaction pathways of the condensable compounds. GC-MS of the liquid fraction from the MAP of WPCBs without susceptor resulted in the generation of phenolic with 46.1% relative composition. The addition of graphite susceptor aided in the formation of phenolic and the relative composition of phenolics was found to be 83.6%. The area percent of phenol increased from 42.8% (without susceptor) to 78.6% (with susceptor). Without a susceptor, cyclopentadiene derivative was observed in a very high composition (~ 31 area %).
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Affiliation(s)
- Chintan Mistry
- Department of Petroleum Engineering, School of Energy Technology, Pandit Deendayal Energy University, Gandhinagar, 382426, India
| | - Dadi Venkata Surya
- Department of Chemical Engineering, Pandit Deendayal Energy University, Gandhinagar, 382426, India.
| | - Ramesh Potnuri
- Department of Chemical Engineering, National Institute of Technology Karnataka, Surathkal, 575025, India
| | - Tanmay Basak
- Department of Chemical Engineering, Indian Institute of Technology Madras, Chennai, 600036, India
| | - Pandian Siva Kumar
- Department of Petroleum Engineering, School of Energy Technology, Pandit Deendayal Energy University, Gandhinagar, 382426, India
| | - Chinta Sankar Rao
- Department of Chemical Engineering, National Institute of Technology Karnataka, Surathkal, 575025, India
| | - Ribhu Gautam
- Clean Combustion Research Center, King Abdullah University of Science and Technology, 23955, Thuwal, Saudi Arabia
| | - Palla Sridhar
- Department of Chemical Engineering, Indian Institute of Petroleum and Energy, Visakhapatnam, 530003, India
| | - Himanshu Choksi
- Department of Chemical Engineering, Pandit Deendayal Energy University, Gandhinagar, 382426, India
| | - Neelancherry Remya
- School of Infrastructure, Indian Institute of Technology Bhubaneswar, Bhubaneswar, 752050, India
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Hu D, Zeng X, Lin Y, Chen Y, Chen W, Jia Z, Lin J. High Value-Added Reutilization of Waste-Printed Circuit Boards Non-Metallic Components in Sustainable Polymer Composites. Molecules 2023; 28:6199. [PMID: 37687027 PMCID: PMC10489137 DOI: 10.3390/molecules28176199] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2023] [Revised: 08/16/2023] [Accepted: 08/21/2023] [Indexed: 09/10/2023] Open
Abstract
The reutilization non-metallic components from a waste-printed circuit board (WPCB) has become one of the most significant bottlenecks in the comprehensive reuse of electronic wastes due to its low value and complex compositions, and it has received great attention from scientific and industrial researchers. To effectively address the environmental pollution caused by inappropriate recycling methods, such as incineration and landfill, extensive efforts have been dedicated to achieving the high value-added reutilization of WPCB non-metals in sustainable polymer composites. In this review, recent progress in developing sustainable polymer composites based on WPCB non-metallic components was systematically summarized. It has been demonstrated that the WPCB non-metals can serve as a promising reinforcing and functional fillers to significantly ameliorate some of the physical and chemical properties of polymer composites, such as excellent mechanical properties, enhanced thermal stability, and flame retardancy. The recovery strategies and composition of WPCB non-metals were also briefly discussed. Finally, the future potentials and remaining challenges regarding the reutilization of WPCB non-metallic components are outlined. This work provides readers with a comprehensive understanding of the preparation, structure, and properties of the polymer composites based on WPCB non-metals, providing significant insights regarding the high value-added reutilization of WPCB non-metals of electronic wastes.
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Affiliation(s)
- Dechao Hu
- School of Materials Science and Hydrogen Energy, Foshan University, Foshan 528000, China; (D.H.)
| | - Xianghong Zeng
- School of Materials Science and Hydrogen Energy, Foshan University, Foshan 528000, China; (D.H.)
| | - Yinlei Lin
- School of Materials Science and Hydrogen Energy, Foshan University, Foshan 528000, China; (D.H.)
| | - Yongjun Chen
- Key Lab of Guangdong High Property and Functional Macromolecular Materials, School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, China
| | - Wanjuan Chen
- School of Materials Science and Hydrogen Energy, Foshan University, Foshan 528000, China; (D.H.)
| | - Zhixin Jia
- Key Lab of Guangdong High Property and Functional Macromolecular Materials, School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, China
| | - Jing Lin
- Research Center of Flexible Sensing Materials and Devices, School of Applied Physics and Materials, Wuyi University, Jiangmen 529020, China
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Chen Y, Ke Y, Liang S, Hu J, Hou H, Yang J. Enhanced bromine fixation and tar lightweighting in co-pyrolysis of non-metallic fractions of waste printed circuit boards with Bayer red mud. WASTE MANAGEMENT (NEW YORK, N.Y.) 2023; 162:72-82. [PMID: 36948115 DOI: 10.1016/j.wasman.2023.03.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2022] [Revised: 02/12/2023] [Accepted: 03/09/2023] [Indexed: 06/18/2023]
Abstract
A co-pyrolysis process for non-metallic fractions (NMFs) from WPCBs with Bayer red mud (RM) is proposed to upgrade pyrolysis products in this study. High bromine fixation efficiency was realized, and higher content of lightweight pyrolysis tar was obtained. The mechanism of catalytic pyrolysis and simultaneous bromine fixation of NMFs by RM was investigated by experiments and theoretical calculations. The three inorganic components of Fe2O3, CaCO3 and Al2O3 in RM played key roles in the catalytic pyrolysis of NMFs, and their order of catalytic debromination effect was CaCO3 > Fe2O3 > Al2O3. By adding 15 wt% RM, the pyrolysis solid residue could fix 89.55 wt% bromine, compared with 35.42 wt% of NMFs without adding RM, due to the formation of FeBr2 and CaBr2 from Fe2O3 and CaCO3 in RM, respectively. Tar lightweighting was realized by reducing the energy barrier of the direct decomposition of tetrabromobisphenol A (TBBPA) in NMFs. The order of effect of the three key components on the tar lightweighting was Fe2O3 > Al2O3 > CaCO3. The content of lightweight tar in the tar obtained by catalytic pyrolysis of NMFs with 15 wt% RM was 44.29% higher than that in the tar obtained by direct pyrolysis of NMFs. This work provides a theoretical guidance for the low-cost and eco-friendly recycling of e-wastes by co-pyrolysis with RM.
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Affiliation(s)
- Ye Chen
- School of Environmental Science & Engineering, Huazhong University of Science and Technology (HUST), 1037 Luoyu Road, Wuhan, Hubei 430074, China; Hubei Provincial Engineering Laboratory for Disposal and Recycling Technology of Solid Waste, Huazhong University of Science and Technology (HUST), 1037 Luoyu Road, Wuhan, Hubei 430074, China
| | - Yan Ke
- School of Environmental Science & Engineering, Huazhong University of Science and Technology (HUST), 1037 Luoyu Road, Wuhan, Hubei 430074, China; Hubei Provincial Engineering Laboratory for Disposal and Recycling Technology of Solid Waste, Huazhong University of Science and Technology (HUST), 1037 Luoyu Road, Wuhan, Hubei 430074, China
| | - Sha Liang
- School of Environmental Science & Engineering, Huazhong University of Science and Technology (HUST), 1037 Luoyu Road, Wuhan, Hubei 430074, China; Hubei Provincial Engineering Laboratory for Disposal and Recycling Technology of Solid Waste, Huazhong University of Science and Technology (HUST), 1037 Luoyu Road, Wuhan, Hubei 430074, China.
| | - Jingping Hu
- School of Environmental Science & Engineering, Huazhong University of Science and Technology (HUST), 1037 Luoyu Road, Wuhan, Hubei 430074, China; Hubei Provincial Engineering Laboratory for Disposal and Recycling Technology of Solid Waste, Huazhong University of Science and Technology (HUST), 1037 Luoyu Road, Wuhan, Hubei 430074, China
| | - Huijie Hou
- School of Environmental Science & Engineering, Huazhong University of Science and Technology (HUST), 1037 Luoyu Road, Wuhan, Hubei 430074, China; Hubei Provincial Engineering Laboratory for Disposal and Recycling Technology of Solid Waste, Huazhong University of Science and Technology (HUST), 1037 Luoyu Road, Wuhan, Hubei 430074, China
| | - Jiakuan Yang
- School of Environmental Science & Engineering, Huazhong University of Science and Technology (HUST), 1037 Luoyu Road, Wuhan, Hubei 430074, China; Hubei Provincial Engineering Laboratory for Disposal and Recycling Technology of Solid Waste, Huazhong University of Science and Technology (HUST), 1037 Luoyu Road, Wuhan, Hubei 430074, China; State Key Laboratory of Coal Combustion, Huazhong University of Science and Technology (HUST), 1037 Luoyu Road, Wuhan, Hubei 430074, China
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Liu J, Zhan L, Xu Z. Debromination with Bromine Recovery from Pyrolysis of Waste Printed Circuit Boards Offers Economic and Environmental Benefits. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2023; 57:3496-3504. [PMID: 36794988 DOI: 10.1021/acs.est.2c06448] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/18/2023]
Abstract
Bromine is an important resource that is widely used in medical, automotive, and electronic industries. Waste electronic products containing brominated flame retardants can cause serious secondary pollution, which is why catalytic cracking, adsorption, fixation, separation, and purification have gained significant attention. However, the bromine resources have not been effectively reutilized. The application of advanced pyrolysis technology could help solve this problem via converting bromine pollution into bromine resources. Coupled debromination and bromide reutilization during pyrolysis is an important field of research in the future. This prospective paper presents new insights in terms of the reorganization of different elements and adjustment of bromine phase transition. Furthermore, we proposed some research directions for efficient and environmentally friendly debromination and reutilization of bromine: 1) precise synergistic pyrolysis should be further explored for efficient debromination, such as using persistent free radicals in biomass, polymer hydrogen supply, and metal catalysis, 2) rematching of Br elements and nonmetal elements (C/H/O) will be a promising direction for synthesizing functionalized adsorption materials, 3) oriented control of the bromide migration path should be further studied to obtain different forms of bromine resources, and 4) advanced pyrolysis equipment should be well developed.
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Affiliation(s)
- Jiangshan Liu
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Lu Zhan
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Zhenming Xu
- School of Environmental Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
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Li C, Xia H, Liu C, Zeng K, Zhang L. Analysis of the effect of heating rate on pyrolysis kinetics and product composition of copper-containing waste circuit boards. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2023; 30:33075-33089. [PMID: 36471150 DOI: 10.1007/s11356-022-24524-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/2022] [Accepted: 11/28/2022] [Indexed: 06/17/2023]
Abstract
Pyrolysis is a cost-effective and environmentally benign method for recycling organic waste, which can be converted into high-energy gases and oils. Pyrolysis technology was employed in this study to recycle copper-containing discarded circuit board material and recover copper, glass fibers, and gases and oils with high calorific values. Thermogravimetric analyses (TGA), Fourier transform infrared spectroscopy (FTIR), and gas chromatography-mass spectrometry (GC-MS) were used to evaluate pyrolyses of copper-containing waste circuit board materials conducted at different heating rates (5, 10, 20, and 40 °C/min), and the resulting volatiles were studied in detail. The effects of heating rate on the kinetics and activation energies for pyrolyses of copper-containing waste circuit boards were also investigated by using the Coats-Redfern (C-R) method. The TGA curves and FTIR spectra did not differ significantly for different heating rates, and the main functional groups identified with the FTIR results were O-H, C = C, aromatic benzene, substituted benzene, and C-Br. Additionally, GC-MS analyses showed that the heating rate had a great influence on the pyrolysis products formed; the phenol content decreased with increasing heating rate, and the highest content was realized at 5 ℃/min. Energy dispersive spectroscopy (EDS) analyses showed that bromine was removed from the solid phase products during pyrolysis, while copper was effectively enriched in the feedstock. This indicated that pyrolysis can be used to recover copper-containing waste circuit boards.
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Affiliation(s)
- Chunyu Li
- Faculty of Metallurgy and Energy Engineering, Kunming University of Science and Technology, Kunming, 650093, Yunnan, China
- Yunnan Provincial Key Laboratory of Intensification Metallurgy, Kunming University of Science and Technology, Kunming, 650093, Yunnan, China
- Key Laboratory of Unconventional Metallurgy, Ministry of Education, Kunming, 650093, Yunnan, China
- State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, Kunming University of Science and Technology, Kunming, 650093, Yunnan, China
| | - Hongying Xia
- Faculty of Metallurgy and Energy Engineering, Kunming University of Science and Technology, Kunming, 650093, Yunnan, China.
- Yunnan Provincial Key Laboratory of Intensification Metallurgy, Kunming University of Science and Technology, Kunming, 650093, Yunnan, China.
- Key Laboratory of Unconventional Metallurgy, Ministry of Education, Kunming, 650093, Yunnan, China.
- State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, Kunming University of Science and Technology, Kunming, 650093, Yunnan, China.
| | - Chengfei Liu
- Faculty of Metallurgy and Energy Engineering, Kunming University of Science and Technology, Kunming, 650093, Yunnan, China
- Yunnan Copper Co., Ltd, Kunming, 650000, China
| | - Kangqing Zeng
- Faculty of Metallurgy and Energy Engineering, Kunming University of Science and Technology, Kunming, 650093, Yunnan, China
- Yunnan Provincial Key Laboratory of Intensification Metallurgy, Kunming University of Science and Technology, Kunming, 650093, Yunnan, China
- Key Laboratory of Unconventional Metallurgy, Ministry of Education, Kunming, 650093, Yunnan, China
- State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, Kunming University of Science and Technology, Kunming, 650093, Yunnan, China
| | - Libo Zhang
- Faculty of Metallurgy and Energy Engineering, Kunming University of Science and Technology, Kunming, 650093, Yunnan, China
- Yunnan Provincial Key Laboratory of Intensification Metallurgy, Kunming University of Science and Technology, Kunming, 650093, Yunnan, China
- Key Laboratory of Unconventional Metallurgy, Ministry of Education, Kunming, 650093, Yunnan, China
- State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, Kunming University of Science and Technology, Kunming, 650093, Yunnan, China
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9
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Lin KH, Tsai JH, Lan CL, Chiang HL. The effect of microwave pyrolysis on product characteristics and bromine migration for a non-metallic printed circuit board. WASTE MANAGEMENT (NEW YORK, N.Y.) 2022; 153:147-155. [PMID: 36096042 DOI: 10.1016/j.wasman.2022.08.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/16/2022] [Revised: 08/17/2022] [Accepted: 08/29/2022] [Indexed: 06/15/2023]
Abstract
At present, it is necessary to carry out environmentally friendly treatment of non-metallic fractions (NMFs) of waste printed circuit board (WPCB) to improve resource utilization. NMFs of WPCB are pyrolyzed by microwave heating to determine the effect of different operating conditions on the characteristics of pyrolysis products. The results show that yields for residue, oil and gas are 59.03-67.63, 7.10-28.46 and 4.86-33.88 wt%. A high temperature promotes a decrease in oil yield and an increase in non-condensable gas yield. An increase in the NaOH dose results in a more significant cracking of the oil to gas. Increasing the concentration of NaOH increases the mass fraction of the total Br in residues (from 23.62 to 86.94 %), so the addition of NaOH is beneficial to the fixation of Br. A kinetics study shows that there are two thermal decomposition regions (398-625 K and 675-925 K), and NaOH-catalyzed pyrolysis reduces the activation energy to 18.91 and 31.95 kJ mol-1, respectively. The formation of Br-containing substances in the pyrolysis oil and gas can be inhibited if the bromine fixation in pyrolysis residue increases. NaOH-catalyzed pyrolysis can reduce bromine and also reduce energy recovery efficiency. This pyrolysis process still requires further research to improve the recovery of energy and valuable materials.
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Affiliation(s)
- Kuo-Hsiung Lin
- Department of Environmental Engineering and Science, Fooyin University, Kaohsiung 831301, Taiwan
| | - Jiun-Horng Tsai
- Department of Environmental Engineering, National Cheng Kung University, Tainan 701401, Taiwan; Research Center for Climate Change and Environment Quality, National Cheng Kung University, Tainan 701401, Taiwan
| | - Chen-Laun Lan
- Department of Environmental Engineering and Science, Fooyin University, Kaohsiung 831301, Taiwan
| | - Hung-Lung Chiang
- Department of Safety Health and Environmental Engineering, National Yunlin University of Science and Technology, Yunlin 640301, Taiwan
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10
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Faraji F, Golmohammadzadeh R, Pickles CA. Potential and current practices of recycling waste printed circuit boards: A review of the recent progress in pyrometallurgy. JOURNAL OF ENVIRONMENTAL MANAGEMENT 2022; 316:115242. [PMID: 35588669 DOI: 10.1016/j.jenvman.2022.115242] [Citation(s) in RCA: 18] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2022] [Revised: 04/22/2022] [Accepted: 05/04/2022] [Indexed: 06/15/2023]
Abstract
Over the last few decades, a substantial amount of e-waste including waste printed circuit boards (WPCBs) has been produced and is accumulating worldwide. More recently, the rate of production has increased significantly, and this trend has raised some serious concerns regarding the need to develop viable recycling methods. The presence of other materials in the WPCBs, such as ceramics and polymers, and the multi-metal nature of WPCBs all contribute to the increased complexity of any recycling process. Among the viable techniques, pyrometallurgy, with the inherent ability to process the waste independent of its composition, is a promising candidate for both rapid and large-scale treatment. In the present study, firstly, the principles of the pyrometallurgical methods for WPCB recycling are discussed. Secondly, the different unit operations of thermochemical pretreatment including incineration, pyrolysis, and molten salt processing are reviewed. Thirdly, the smelting processes for the recovery of metals from WPCBs, as well as the issues surrounding slag formation and subsequent treatment are explained. Fourthly, alternative methods for the recovery of polymers and ceramics, in addition to metal recycling, are elucidated. Fifthly, emission control techniques and the potential for energy recovery are evaluated.
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Affiliation(s)
- Fariborz Faraji
- The Robert M. Buchan Department of Mining, Queen's University, Kingston, ON, K7L 3N6, Canada.
| | - Rabeeh Golmohammadzadeh
- Department of Chemical Engineering, Monash University, Clayton, Victoria, 3800, Australia; Institute for Frontier Materials, Deakin University, Geelong, Victoria 3200, Australia
| | - Christopher A Pickles
- The Robert M. Buchan Department of Mining, Queen's University, Kingston, ON, K7L 3N6, Canada.
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11
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Shi SX, Jiang SQ, Nie CC, Li B, Chang HH, Zhu XN. Innovative method for removing bromine in waste printed circuit boards: Ultrafine milling and porous media loaded debromination agent. ADV POWDER TECHNOL 2022. [DOI: 10.1016/j.apt.2022.103662] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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12
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Liu S, Hou X, Yu C, Pan X, Ma J, Liu G, Zhou C, Xin Y, Yan Q. Integration of wastewater treatment units and optimization of waste residue pyrolysis conditions in the brominated phenol flame retardant industry. J IND ENG CHEM 2022. [DOI: 10.1016/j.jiec.2022.07.051] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
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13
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Liu J, Wang H, Zhang W, Wang T, Mei M, Chen S, Li J. Mechanistic insights into catalysis of in-situ iron on pyrolysis of waste printed circuit boards: Comparative study of kinetics, products, and reaction mechanism. JOURNAL OF HAZARDOUS MATERIALS 2022; 431:128612. [PMID: 35259695 DOI: 10.1016/j.jhazmat.2022.128612] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 02/26/2022] [Accepted: 02/28/2022] [Indexed: 06/14/2023]
Abstract
Pyrolysis is a potential recovery method for waste printed circuit boards (WPCBs), but the organic brominated products are toxic and hazardous. Iron has been used as a catalyst for debromination from pyrolysis oil, but the effects of in-situ iron on WPCBs pyrolysis is still not well understood. Herein, the pyrolysis mechanism for laminates of PCBs in the absence and presence of iron was studied via analyzing pyrolysis characteristics, kinetics, and products. According to the thermogravimetry experiments, pyrolysis of all samples could be divided into four stages, and iron accelerated the pyrolysis reaction by decreasing the activation energy as calculated using the Starink method. Volatiles released during the heating process were continuously determined by TG-FTIR-MS, and products generated at different pyrolysis temperatures were collected and characterized. The obtained results exhibited that iron promoted the generation of gaseous products and facilitated the conversion of organic bromides to inorganic bromides. Therefore, retaining iron was beneficial to energy saving and environmental protection for WPCBs pyrolysis. In addition, the decomposition mechanisms of brominated epoxy resin with and without iron were proposed. This work would contribute to the improvement and application of WPCBs pyrolysis technology.
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Affiliation(s)
- Jingxin Liu
- School of Environmental Engineering, Wuhan Textile University, Wuhan 430073, China; Engineering Research Centre for Clean Production of Textile Dyeing and Printing, Ministry of Education, Wuhan Textile University, Wuhan 430073, China
| | - Hanlin Wang
- School of Environmental Engineering, Wuhan Textile University, Wuhan 430073, China
| | - Wenjuan Zhang
- School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China; Department of Materials Engineering, The University of British Columbia, Vancouver, BC V6T 1Z4, Canada.
| | - Teng Wang
- School of Environmental Engineering, Wuhan Textile University, Wuhan 430073, China; Engineering Research Centre for Clean Production of Textile Dyeing and Printing, Ministry of Education, Wuhan Textile University, Wuhan 430073, China
| | - Meng Mei
- School of Environmental Engineering, Wuhan Textile University, Wuhan 430073, China; Engineering Research Centre for Clean Production of Textile Dyeing and Printing, Ministry of Education, Wuhan Textile University, Wuhan 430073, China
| | - Si Chen
- School of Environmental Engineering, Wuhan Textile University, Wuhan 430073, China; Engineering Research Centre for Clean Production of Textile Dyeing and Printing, Ministry of Education, Wuhan Textile University, Wuhan 430073, China
| | - Jinping Li
- School of Environmental Engineering, Wuhan Textile University, Wuhan 430073, China; Engineering Research Centre for Clean Production of Textile Dyeing and Printing, Ministry of Education, Wuhan Textile University, Wuhan 430073, China
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14
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Ma C, Kumagai S, Saito Y, Kameda T, Yoshioka T. An integrated utilization strategy of printed circuit boards and waste tire by fast co-pyrolysis: Value-added products recovery and heteroatoms transformation. JOURNAL OF HAZARDOUS MATERIALS 2022; 430:128420. [PMID: 35149505 DOI: 10.1016/j.jhazmat.2022.128420] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/21/2021] [Revised: 01/31/2022] [Accepted: 02/02/2022] [Indexed: 06/14/2023]
Abstract
Fast co-pyrolysis has been suggested as a promising technique to solve the environmental issues and simultaneously recover value-added products from polymer wastes. However, to date, no studies have focused on fast co-pyrolysis of printed circuit boards (PCB) and waste tire (WT). Therefore, we comprehensively investigated the fast co-pyrolysis of PCB and WT using pyrolysis-gas chromatography/mass spectrometry. The results show that an increase in temperature during fast pyrolysis improved the interactions between the PCB and WT pyrolyzates, increasing the formation of aliphatic and aromatic compounds. The formation of p-cymene was greatly induced by the isomerization and dehydrogenation reactions of D-limonene. Co-pyrolysis reduced the formation of brominated phenols and benzothiazole from PCB and WT pyrolysis, respectively, whereas promoted the interactions between Br- and S/N-containing radicals, concentrating them into heavy compounds. Increasing the temperature enhanced the release of heteroatom compounds. The findings suggest that debromination of PCB achieved via dehydrogenation of WT pyrolysis provoked secondary reactions of olefins and interactions of heteroatom radicals. The major products were accurately predicted by different fitting models using response surface methodology, indicating the synergistic interactions during co-pyrolysis. The results were beneficial for optimizing the experimental parameters to obtain the maximum yield of desired products.
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Affiliation(s)
- Chuan Ma
- Graduate School of Environmental Studies, Tohoku University, 6-6-07 Aoba, Aramaki-aza, Aoba-ku, Sendai, Miyagi 980-8579, Japan.
| | - Shogo Kumagai
- Graduate School of Environmental Studies, Tohoku University, 6-6-07 Aoba, Aramaki-aza, Aoba-ku, Sendai, Miyagi 980-8579, Japan; Division for the Establishment of Frontier Sciences of Organization for Advanced Studies, Tohoku University, 2-1-1 Katahira, Aoba-ku, Sendai 980-8577, Japan.
| | - Yuko Saito
- Graduate School of Environmental Studies, Tohoku University, 6-6-07 Aoba, Aramaki-aza, Aoba-ku, Sendai, Miyagi 980-8579, Japan
| | - Tomohito Kameda
- Graduate School of Environmental Studies, Tohoku University, 6-6-07 Aoba, Aramaki-aza, Aoba-ku, Sendai, Miyagi 980-8579, Japan
| | - Toshiaki Yoshioka
- Graduate School of Environmental Studies, Tohoku University, 6-6-07 Aoba, Aramaki-aza, Aoba-ku, Sendai, Miyagi 980-8579, Japan
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15
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Tian S, Li B, He H, Liu X, Wen X, Zhang Z. Fabrication and Mechanical Properties of High-Durability Polypropylene Composites via Reutilization of SiO2 In-Situ-Synthesized Waste Printed Circuit Board Powder. Polymers (Basel) 2022; 14:polym14051045. [PMID: 35267868 PMCID: PMC8914678 DOI: 10.3390/polym14051045] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2022] [Revised: 02/24/2022] [Accepted: 03/02/2022] [Indexed: 02/04/2023] Open
Abstract
This paper focuses on the characterization of the physico-chemical properties, surface modification, residual copper content and in situ hybrid inorganic particle modification of polypropylene (PP) composites reinforced by waste printed circuit board powder (WPCBP). A series of WPCBP/SiO2 hybrids (TSW) were prepared by a sol–gel method at different pH values. Characterization results revealed the in situ generation of SiO2 on the surface of WPCBP, and showed that with an increase in pH value, the size of SiO2 particles increased gradually and the copper content decreased in the TSW powder. The mechanical properties, oxidation induction time (OIT) and thermal properties of PP composites were improved by reinforcement with TSW, which might be ascribed to the formation of serrated interfaces. This work not only develops a powerful method to enhance the properties of PP/WPCBP composites, but also provides an environmentally sustainable approach to the high-added-value reutilization of WPCBP.
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Affiliation(s)
- Shenghui Tian
- Provincial and Ministerial Co-Constructive of Collaborative Innovation Center for MSW Comprehensive Utilization, School of Metallurgy and Materials Engineering, Chongqing University of Science and Technology, Chongqing 401331, China; (S.T.); (X.L.); (X.W.)
- Key Lab of Guangdong Province for High Property and Functional Macromolecular Materials, School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, China;
| | - Baixue Li
- Key Lab of Guangdong Province for High Property and Functional Macromolecular Materials, School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, China;
| | - Hui He
- Key Lab of Guangdong Province for High Property and Functional Macromolecular Materials, School of Materials Science and Engineering, South China University of Technology, Guangzhou 510640, China;
- Correspondence:
| | - Xinlu Liu
- Provincial and Ministerial Co-Constructive of Collaborative Innovation Center for MSW Comprehensive Utilization, School of Metallurgy and Materials Engineering, Chongqing University of Science and Technology, Chongqing 401331, China; (S.T.); (X.L.); (X.W.)
| | - Xin Wen
- Provincial and Ministerial Co-Constructive of Collaborative Innovation Center for MSW Comprehensive Utilization, School of Metallurgy and Materials Engineering, Chongqing University of Science and Technology, Chongqing 401331, China; (S.T.); (X.L.); (X.W.)
| | - Zuolu Zhang
- Quality Inspection and Measurement Department, Tangshan Wenfeng Special Steel Co., Ltd., Tangshan 063299, China;
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16
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Yu H, Qu J, Liu Y, Yun H, Li X, Zhou C, Jin Y, Zhang C, Dai J, Bi X. Co-pyrolysis of biomass and polyvinyl chloride under microwave irradiation: Distribution of chlorine. THE SCIENCE OF THE TOTAL ENVIRONMENT 2022; 806:150903. [PMID: 34653460 DOI: 10.1016/j.scitotenv.2021.150903] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 09/26/2021] [Accepted: 10/06/2021] [Indexed: 06/13/2023]
Abstract
Co-pyrolysis of sophora wood (SW) and polyvinyl chloride (PVC) was conducted in a microwave reactor at different temperatures and different mixing ratios, and the transformation and distribution of chlorine in pyrolysis products were investigated. Microwave pyrolysis is a simple and efficient technique with better heating uniformity and process controllability than conventional heating. Compared with PVC pyrolysis, the addition of SW significantly reduced CO2 yield and greatly increased the yield of CO. The yield and quality of pyrolysis oil were effectively improved by SW, and the content of chlorine-containing compounds in the oil was suppressed to <1% at low temperatures (<550 °C). Co-pyrolysis of SW and PVC reduced the chlorine emissions from 59.07% to 28.09% and promoted the retention of chlorine in char (from 0.33% to 4.72%). Cellulose, hemicellulose, and lignin were co-pyrolyzed with PVC to investigate their effects on chlorine distribution. The experiments demonstrated that lignin had the most significant effects on reducing gas phase chlorine emission and achieving chlorine immobilization, and chlorine mainly existed in the form of sodium chloride in the char of lignin-PVC co-pyrolysis. Hence co-pyrolysis of lignocellulosic biomass and PVC provides a practical pathway for utilization of PVC waste in an environmentally friendly manner, realizing efficient chlorine retention and significantly reducing chlorine-related emissions.
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Affiliation(s)
- Hejie Yu
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering, State Key Laboratory of Organic-Inorganic Composites, College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Junshen Qu
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering, State Key Laboratory of Organic-Inorganic Composites, College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Yang Liu
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering, State Key Laboratory of Organic-Inorganic Composites, College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Huimin Yun
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering, State Key Laboratory of Organic-Inorganic Composites, College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Xiangtong Li
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering, State Key Laboratory of Organic-Inorganic Composites, College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Chunbao Zhou
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering, State Key Laboratory of Organic-Inorganic Composites, College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Yajie Jin
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering, State Key Laboratory of Organic-Inorganic Composites, College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Changfa Zhang
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering, State Key Laboratory of Organic-Inorganic Composites, College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029, China
| | - Jianjun Dai
- Beijing Advanced Innovation Center for Soft Matter Science and Engineering, State Key Laboratory of Organic-Inorganic Composites, College of Chemical Engineering, Beijing University of Chemical Technology, Beijing 100029, China.
| | - Xiaotao Bi
- Clean Energy Research Centre, The University of British Columbia, Vancouver, BC V6T 1Z3, Canada.
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17
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Altarawneh M. Temperature-dependent profiles of dioxin-like toxicants from combustion of brominated flame retardants. JOURNAL OF HAZARDOUS MATERIALS 2022; 422:126879. [PMID: 34411962 DOI: 10.1016/j.jhazmat.2021.126879] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/13/2021] [Revised: 07/22/2021] [Accepted: 08/09/2021] [Indexed: 06/13/2023]
Abstract
Literature provides detailed mechanisms underpinning the formation of a wide array of bromine (Br)-containing molecules with a prime focus on dioxin-like compounds. However, from a more applied point of view, the practical deployment of attained thermo-kinetic parameters remains inadequate in the absence of a robust kinetic model that connects bromine transformation at the molecular level with pertinent experimental observations. Herein and to fill in this gap, this study constructs a chemical kinetic model to account for the "homogenous gas phase" emission of Br-aromatic pollutants from the oxidative thermal decomposition of a monobromobenzene molecule (MBZ). The latter serves as a model compound for brominated flame retardants (BFRs) present in e-waste. The model consists of sub-mechanisms (that include reaction rate constants and thermochemical T-dependent functions) for HBr oxidation, combustion mechanism of C1-C6 species, bromine transformation, and synthesis of Br dioxin-like compounds. Reaction rate parameters were obtained for a large array of reactions that constitute the core of the model. For instance, the obtained activation energies for the initial pathways in the formation of brominated biphenyls reside in the range of ~15-45 kJ/mol. Considering oxidation of 5000 ppm MBZ in a plug flow reactor, the model reasonably predicts the temperature-dependent profiles (between 500 and 1200 °C at atmospheric pressure) of a few PBDD/Fs (i.e., polybrominated dibenzo-p-dioxins) isomers in reference to limited corresponding experimental measurements. Most Br dioxin-like compounds appear in the narrow temperature window of 600-1000 °C and achieve their highest abundance at molar yields in the range of 1.0-15 mmol/mol MBZ. A high load (100-120 mmol/mol MBZ) of brominated environmentally persistent free radicals (Br-EPFR) emerges and shifts from bromophenoxy radicals to bromocyclopentadienyl radicals around 700 °C. Oxidation of a 2-bromophenol molecule results in the formation of higher yields of Br-toxicants when compared with that of MBZ. The assembled model provides an informed hazards assessment into the potential emission inventories of Br-compounds in the gas phase at conditions encountered in real scenarios, such as open burning and primitive treatment of e-waste. Via an atomic-base understanding of the complex bromine chemistry and speciation, the model allows the underlying operational conditions that reduce the emission of Br-notorious pollutants to be surveyed and fine-tuned.
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Affiliation(s)
- Mohammednoor Altarawneh
- United Arab Emirates University, Department of Chemical and Petroleum Engineering, Sheikh Khalifa bin Zayed Street, Al-Ain 15551, United Arab Emirates.
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18
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Liu J, Jiang Q, Wang H, Li J, Zhang W. Catalytic effect and mechanism of in-situ metals on pyrolysis of FR4 printed circuit boards: Insights from kinetics and products. CHEMOSPHERE 2021; 280:130804. [PMID: 33965868 DOI: 10.1016/j.chemosphere.2021.130804] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 04/02/2021] [Accepted: 04/30/2021] [Indexed: 06/12/2023]
Abstract
Pyrolysis is a promising method for the recovery of waste printed circuit boards (WPCBs), but few researches have noticed the influence of in-situ metals. This study conducted a series of comparisons between metal-free leftover pieces (LP) and intact boards (IB), including pyrolysis characteristics, volatile emission, kinetics, and thermodynamic parameters. The thermo-gravimetry (TG) analyses indicated that both the samples presented predominant mass loss in narrow temperature intervals, and characteristic pyrolysis temperatures of IB were approximately 15 °C lower than those of LP. Dominant constituents in evolved gases were detected by Fourier-transform infrared spectrometry as CO2, phenol, bromophenol, ethers, ketones, and aldehydes, and metals accelerated the generation of light hydrocarbons and aromatic compounds. The activation energy and thermodynamic parameters were calculated and compared, and the results verified the presence of in-situ metals led to a lower energy barrier and higher reaction extent. Moreover, conversion behaviors of Cu, Fe, Sn, and Pb manifested the formation of metal bromides and implied the reduction of brominated volatiles. The obtained results confirmed the catalytic effect of in-situ metals on PCBs pyrolysis and their bromine fixation abilities. This study contributes to fundamental knowledge that can be used to guide the pyrolysis of WPCBs.
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Affiliation(s)
- Jingxin Liu
- School of Environmental Engineering, Wuhan Textile University, Wuhan, 430073, China; Engineering Research Centre for Clean Production of Textile Dyeing and Printing, Ministry of Education, Wuhan Textile University, Wuhan, 430073, China
| | - Qihao Jiang
- School of Environmental Engineering, Wuhan Textile University, Wuhan, 430073, China
| | - Hanlin Wang
- School of Environmental Engineering, Wuhan Textile University, Wuhan, 430073, China
| | - Jinping Li
- School of Environmental Engineering, Wuhan Textile University, Wuhan, 430073, China; Engineering Research Centre for Clean Production of Textile Dyeing and Printing, Ministry of Education, Wuhan Textile University, Wuhan, 430073, China
| | - Wenjuan Zhang
- School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing, 100083, China.
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19
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Wang J, Jiang J, Sun Y, Meng X, Wang X, Ruan R, Ragauskas AJ, Tsang DCW. Heterogeneous Diels-Alder tandem catalysis for converting cellulose and polyethylene into BTX. JOURNAL OF HAZARDOUS MATERIALS 2021; 414:125418. [PMID: 33684816 DOI: 10.1016/j.jhazmat.2021.125418] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/24/2020] [Revised: 02/03/2021] [Accepted: 02/10/2021] [Indexed: 06/12/2023]
Abstract
Producing biomass-derived aromatic hydrocarbons via controllable Diels-Alder reactions is a promising approach to recover energy and chemicals from waste streams. A tandem Diels-Alder catalysis consisting of SAPO-34 and Fe/HZSM-5 (stacked catalysis or mixed catalysis) was evaluated for thermochemical conversion of cellulose and polyethylene blends into benzene, toluene, and xylenes (BTX). Aromatization catalyst type significantly affected the activity of tandem catalysis, and the BTX obtained from the HZSM-5 stacked catalysis was ~2.3 times higher than that of the USY stacked one. An introduction of Fe active promoters into HZSM-5 increased the Lewis to Brønsted acid sites molar ratio (L/B) from 0.4 to 4.1. The comparison between Fe/HZSM-5 stacked catalysis and parent HZSM-5 single catalysis indicated that the former was more effective for BTX production, obtaining a nearly two-fold increase in yield with a high selectivity of 82.8%. A close proximity between Fe/HZSM-5 and SAPO-34 in the mixed catalysis increased the BTX enhancement to 1.8. A synergistic effect was provided by the coordination of Lewis and Brønsted acid sites in the Fe/HZSM-5 mixed catalysts for facilitating BTX generation, achieving a maximum of 25.9% at a Fe/HZSM-5 to SAPO-34 mass ratio of 1:1 with a theoretical L/B of 7.2. This work provides a sustainable strategy to produce biomass-derived aromatic hydrocarbons.
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Affiliation(s)
- Jia Wang
- Jiangsu Co-Innovation Center for Efficient Processing and Utilization of Forest Resources, College of Chemical Engineering, Nanjing Forestry University, Longpan Road 159, Nanjing 210037, China; Jiangsu Province Key Laboratory of Biomass Energy and Materials, Institute of Chemical Industry of Forest Products, Chinese Academy of Forestry (CAF), No. 16, Suojin Five Village, Nanjing 210042, China
| | - Jianchun Jiang
- Jiangsu Co-Innovation Center for Efficient Processing and Utilization of Forest Resources, College of Chemical Engineering, Nanjing Forestry University, Longpan Road 159, Nanjing 210037, China; Jiangsu Province Key Laboratory of Biomass Energy and Materials, Institute of Chemical Industry of Forest Products, Chinese Academy of Forestry (CAF), No. 16, Suojin Five Village, Nanjing 210042, China.
| | - Yunjuan Sun
- Jiangsu Province Key Laboratory of Biomass Energy and Materials, Institute of Chemical Industry of Forest Products, Chinese Academy of Forestry (CAF), No. 16, Suojin Five Village, Nanjing 210042, China
| | - Xianzhi Meng
- Department of Chemical and Biomolecular Engineering, The University of Tennessee, Knoxville, TN 37996, USA
| | - Xiaobo Wang
- School of Environmental Science, Nanjing Xiaozhuang University, Nanjing 211171, China
| | - Roger Ruan
- Center for Biorefining and Department of Bioproducts and Biosystems Engineering, University of Minnesota, 1390 Eckles Ave., St. Paul, MN 55108, USA
| | - Arthur J Ragauskas
- Department of Chemical and Biomolecular Engineering, The University of Tennessee, Knoxville, TN 37996, USA; Center for Renewable Carbon, Department of Forestry, Wildlife and Fisheries, The University of Tennessee, Knoxville, TN 37996, USA; Biosciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, USA
| | - Daniel C W Tsang
- Department of Civil and Environmental Engineering, The Hong Kong Polytechnic University, Hung Hom, Kowloon, Hong Kong, China.
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20
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Wu Y, Liu G, Pan D, Yuan H, Li B. A new mechanism and kinetic analysis for the efficient conversion of inorganic bromide in waste printed circuit board smelting ash via traditional sulfated roasting. JOURNAL OF HAZARDOUS MATERIALS 2021; 413:125394. [PMID: 33607586 DOI: 10.1016/j.jhazmat.2021.125394] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Revised: 12/21/2020] [Accepted: 02/09/2021] [Indexed: 06/12/2023]
Abstract
The waste printed circuit board smelting ash (WPCB-SA) produced in the waste printed circuit board smelting process is a hazardous material that not only contains valuable metals, but also contains a large amount of toxic and harmful inorganic bromides. The utilization of metals has received considerable attention in previous studies, but the recovery of hazardous bromides requires further study. In this article, a new idea of converting inorganic bromine in WPCB-SA by traditional sulfated roasting is proposed. Debromination kinetics under simulated experimental conditions are discussed, and kinetic equations are established. The kinetic results show that during low-temperature sulfated roasting, the conversion of Br in CuBr and PbBr2 conforms to the chemical reaction diffusion model and diffusion control the product layer model, respectively. A possible reaction mechanism is also proposed. Our research shows that the conversion of Br in CuBr is divided into three processes: covalent bond decomposition, hydrogen ion form acid, copper ion form salt, and HBr oxidation conversion, whereas the conversion of Br in PbBr2 is divided into two processes: sulfuric acid ionization, lead ion form salt and HBr oxidation conversion. This work provides the theoretical basis for the improvement and application of inorganic bromide recovery technology in WPCB-SA.
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Affiliation(s)
- Yufeng Wu
- Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing 100124, PR China; Institute of Circular Economy, Beijing University of Technology, Beijing 100124, PR China.
| | - Gongqi Liu
- Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing 100124, PR China; Institute of Circular Economy, Beijing University of Technology, Beijing 100124, PR China
| | - De'an Pan
- Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing 100124, PR China; Institute of Circular Economy, Beijing University of Technology, Beijing 100124, PR China
| | - Haoran Yuan
- Guangzhou Institute of Energy Conversion, Chinese Academy of Sciences, Guangzhou 510640, PR China
| | - Bin Li
- Faculty of Materials and Manufacturing, Beijing University of Technology, Beijing 100124, PR China; Institute of Circular Economy, Beijing University of Technology, Beijing 100124, PR China
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