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Clark R, Shaver MP. Depolymerization within a Circular Plastics System. Chem Rev 2024; 124:2617-2650. [PMID: 38386877 PMCID: PMC10941197 DOI: 10.1021/acs.chemrev.3c00739] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/10/2023] [Revised: 01/18/2024] [Accepted: 02/08/2024] [Indexed: 02/24/2024]
Abstract
The societal importance of plastics contrasts with the carelessness with which they are disposed. Their superlative properties lead to economic and environmental efficiency, but the linearity of plastics puts the climate, human health, and global ecosystems at risk. Recycling is fundamental to transitioning this linear model into a more sustainable, circular economy. Among recycling technologies, chemical depolymerization offers a route to virgin quality recycled plastics, especially when valorizing complex waste streams poorly served by mechanical methods. However, chemical depolymerization exists in a complex and interlinked system of end-of-life fates, with the complementarity of each approach key to environmental, economic, and societal sustainability. This review explores the recent progress made into the depolymerization of five commercial polymers: poly(ethylene terephthalate), polycarbonates, polyamides, aliphatic polyesters, and polyurethanes. Attention is paid not only to the catalytic technologies used to enhance depolymerization efficiencies but also to the interrelationship with other recycling technologies and to the systemic constraints imposed by a global economy. Novel polymers, designed for chemical depolymerization, are also concisely reviewed in terms of their underlying chemistry and potential for integration with current plastic systems.
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Affiliation(s)
- Robbie
A. Clark
- Department
of Materials, School of Natural Sciences, University of Manchester, Manchester M13 9PL, United
Kingdom
- Sustainable
Materials Innovation Hub, Henry Royce Institute, University of Manchester, Manchester M13 9PL, United
Kingdom
| | - Michael P. Shaver
- Department
of Materials, School of Natural Sciences, University of Manchester, Manchester M13 9PL, United
Kingdom
- Sustainable
Materials Innovation Hub, Henry Royce Institute, University of Manchester, Manchester M13 9PL, United
Kingdom
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Jiang M, Wang X, Xi W, Yang P, Zhou H, Duan J, Ratova M, Wu D. Chemical catalytic upgrading of polyethylene terephthalate plastic waste into value-added materials, fuels and chemicals. THE SCIENCE OF THE TOTAL ENVIRONMENT 2024; 912:169342. [PMID: 38123093 DOI: 10.1016/j.scitotenv.2023.169342] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Revised: 11/18/2023] [Accepted: 12/11/2023] [Indexed: 12/23/2023]
Abstract
The substantial production of polyethylene terephthalate (PET) products, coupled with high abandonment rates, results in significant environmental pollution and resource wastage. This has prompted global attention to the development of rational strategies for PET waste treatment. In the context of renewability and sustainability, catalytic chemical technology provides an effective means to recycle and upcycle PET waste into valuable resources. In this review, we initially provide an overview of strategies employed in the thermocatalytic process to recycle PET waste into valuable carbon materials, fuels and typical refined chemicals. The effect of catalysts on the quality and quantity of specific products is highlighted. Next, we introduce the development of renewable-energy-driven electrocatalytic and photocatalytic systems for sustainable PET waste upcycling, focusing on rational catalysts, innovative catalytic system design, and corresponding underlying catalytic mechanisms. Moreover, we discuss advantages and disadvantages of three chemical catalytic strategies. Finally, existing limitations and outlook toward controllable selectivity and yield enhancement of value-added products and PET upvaluing technology for scale-up applications are proposed. This review aims to inspire the exploration of waste-to-treasure technologies for renewable-energy-driven waste management toward a circular economy.
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Affiliation(s)
- Mingkun Jiang
- Key Laboratory of Green Chemical Engineering Process of Ministry of Education, Hubei Key Laboratory of Plasma Chemistry and New Materials, School of Materials Science and Engineering, Wuhan Institute of Technology, Wuhan 430205, Hubei, PR China
| | - Xiali Wang
- Key Laboratory of Green Chemical Engineering Process of Ministry of Education, Hubei Key Laboratory of Plasma Chemistry and New Materials, School of Materials Science and Engineering, Wuhan Institute of Technology, Wuhan 430205, Hubei, PR China
| | - Wanlong Xi
- Key Laboratory of Green Chemical Engineering Process of Ministry of Education, Hubei Key Laboratory of Plasma Chemistry and New Materials, School of Materials Science and Engineering, Wuhan Institute of Technology, Wuhan 430205, Hubei, PR China
| | - Peng Yang
- Key Laboratory of Green Chemical Engineering Process of Ministry of Education, Hubei Key Laboratory of Plasma Chemistry and New Materials, School of Materials Science and Engineering, Wuhan Institute of Technology, Wuhan 430205, Hubei, PR China
| | - Hexin Zhou
- Key Laboratory of Green Chemical Engineering Process of Ministry of Education, Hubei Key Laboratory of Plasma Chemistry and New Materials, School of Materials Science and Engineering, Wuhan Institute of Technology, Wuhan 430205, Hubei, PR China
| | - Junyuan Duan
- Key Laboratory of Green Chemical Engineering Process of Ministry of Education, Hubei Key Laboratory of Plasma Chemistry and New Materials, School of Materials Science and Engineering, Wuhan Institute of Technology, Wuhan 430205, Hubei, PR China
| | - Marina Ratova
- Faculty of Science and Engineering, Manchester Metropolitan University, Chester Street, Manchester M1 5GD, UK
| | - Dan Wu
- Key Laboratory of Green Chemical Engineering Process of Ministry of Education, Hubei Key Laboratory of Plasma Chemistry and New Materials, School of Materials Science and Engineering, Wuhan Institute of Technology, Wuhan 430205, Hubei, PR China.
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Bohre A, Jadhao PR, Tripathi K, Pant KK, Likozar B, Saha B. Chemical Recycling Processes of Waste Polyethylene Terephthalate Using Solid Catalysts. CHEMSUSCHEM 2023:e202300142. [PMID: 36972065 DOI: 10.1002/cssc.202300142] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 03/27/2023] [Accepted: 03/27/2023] [Indexed: 05/28/2023]
Abstract
Polyethylene terephthalate (PET) is a non-degradable single-use plastic and a major component of plastic waste in landfills. Chemical recycling is one of the most widely adopted methods to transform post-consumer PET into PET's building block chemicals. Non-catalytic depolymerization of PET is very slow and requires high temperatures and/or pressures. Recent advancements in the field of material science and catalysis have delivered several innovative strategies to promote PET depolymerization under mild reaction conditions. Particularly, heterogeneous catalysts assisted depolymerization of post-consumer PET to monomers and other value-added chemicals is the most industrially compatible method. This review includes current progresses on the heterogeneously catalyzed chemical recycling of PET. It describes four key pathways for PET depolymerization including, glycolysis, pyrolysis, alcoholysis, and reductive depolymerization. The catalyst function, active sites and structure-activity correlations are briefly outlined in each section. An outlook for future development is also presented.
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Affiliation(s)
- Ashish Bohre
- Department of Chemical Engineering, Indian Institute of Technology Delhi, Delhi, 110016, India
- Biomass and Energy Management Division, Sardar Swaran Singh National Institute of Bio-energy Kapurthala, Punjab, 1440603, India
- Department of Catalysis and Chemical Reaction Engineering, National Institute of Chemistry, Hajdrihova 19, 1001, Ljubljana, Slovenia
| | - Prashant Ram Jadhao
- Department of Chemical Engineering, Indian Institute of Technology Delhi, Delhi, 110016, India
| | - Komal Tripathi
- Department of Chemical Engineering, Indian Institute of Technology Delhi, Delhi, 110016, India
| | - Kamal Kishore Pant
- Department of Chemical Engineering, Indian Institute of Technology Delhi, Delhi, 110016, India
| | - Blaž Likozar
- Department of Catalysis and Chemical Reaction Engineering, National Institute of Chemistry, Hajdrihova 19, 1001, Ljubljana, Slovenia
| | - Basudeb Saha
- RiKarbon, Inc., 550 S. College Ave, Newark, Delaware, DE 19716, USA
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Xu L, He Z, Zhang H, Wu S, Dong C, Fang Z. Production of aromatic amines via catalytic co-pyrolysis of lignin and phenol-formaldehyde resins with ammonia over commercial HZSM-5 zeolites. BIORESOURCE TECHNOLOGY 2021; 320:124252. [PMID: 33137639 DOI: 10.1016/j.biortech.2020.124252] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2020] [Revised: 10/07/2020] [Accepted: 10/08/2020] [Indexed: 06/11/2023]
Abstract
Aromatic amines could be produced from organic wastes via catalytic pyrolysis with ammonia that served not only as a carrier gas but also as a reactant. Aromatic amines of 14.2 C% with selectivity of 57.6% were obtained from phenol-formaldehyde resins via pyrolysis over commercial HZSM-5-3 zeolite (Si/Al ratio of 80) catalyst at 650 °C. Significant synergetic effects have been observed when lignin was added, which improved aromatic amines yield by 32.2% to 11.8 C% at the mixing weight ratio of lignin to PF resins of 1:1. HZSM-5-3 was slightly deactivated after 3 cycles with acid sites loss. Catalytic co-pyrolysis of plastics and biomass wastes is a fast and effective method to produce aromatic amines.
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Affiliation(s)
- Lujiang Xu
- Biomass Group, College of Engineering, Nanjing Agricultural University, No.40 Dianjiangtai Road, Nanjing 210031, China
| | - Zijian He
- Biomass Group, College of Engineering, Nanjing Agricultural University, No.40 Dianjiangtai Road, Nanjing 210031, China
| | - Huan Zhang
- Biomass Group, College of Engineering, Nanjing Agricultural University, No.40 Dianjiangtai Road, Nanjing 210031, China
| | - Shenghong Wu
- Biomass Group, College of Engineering, Nanjing Agricultural University, No.40 Dianjiangtai Road, Nanjing 210031, China
| | - Chengyu Dong
- Biomass Group, College of Engineering, Nanjing Agricultural University, No.40 Dianjiangtai Road, Nanjing 210031, China
| | - Zhen Fang
- Biomass Group, College of Engineering, Nanjing Agricultural University, No.40 Dianjiangtai Road, Nanjing 210031, China. http://biomass-group.njau.edu.cn/
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Selective Production of Terephthalonitrile and Benzonitrile via Pyrolysis of Polyethylene Terephthalate (PET) with Ammonia over Ca(OH)2/Al2O3 Catalysts. Catalysts 2019. [DOI: 10.3390/catal9050436] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
A series of Ca(OH)2/Al2O3 catalysts were synthesized for selectively producing N-containing chemicals from polyethylene terephthalate (PET) via catalytic fast pyrolysis with ammonia (CFP-A) process. During the CFP-A process, the carboxyl group in PET plastic was efficiently utilized for the selective production of terephthalonitrile and benzonitrile by controlling the catalysts and pyrolysis parameters (e.g. temperature, residence time, ammonia content). The best conditions were selected as 2% Ca(OH)2/γ-Al2O3 (0.8 g), 500 °C under pure ammonia with 58.3 C% terephthalonitrile yield and 92.3% selectivity in nitriles. In addition, 4% Ca(OH)2/ Al2O3 was suitable for producing benzonitrile. With catalyst dosage of 1.2 g, residence time of 1.87 s, pyrolysis temperature of 650 °C and pure ammonia (160 mL/min carrier gas flow rate), the yield and selectivity of benzonitrile were 30.4 C% and 82.6%, respectively. The catalysts deactivated slightly after 4 cycles.
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