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Sun J, Dong J, Gao L, Zhao YQ, Moon H, Scott SL. Catalytic Upcycling of Polyolefins. Chem Rev 2024. [PMID: 39151127 DOI: 10.1021/acs.chemrev.3c00943] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/18/2024]
Abstract
The large production volumes of commodity polyolefins (specifically, polyethylene, polypropylene, polystyrene, and poly(vinyl chloride)), in conjunction with their low unit values and multitude of short-term uses, have resulted in a significant and pressing waste management challenge. Only a small fraction of these polyolefins is currently mechanically recycled, with the rest being incinerated, accumulating in landfills, or leaking into the natural environment. Since polyolefins are energy-rich materials, there is considerable interest in recouping some of their chemical value while simultaneously motivating more responsible end-of-life management. An emerging strategy is catalytic depolymerization, in which a portion of the C-C bonds in the polyolefin backbone is broken with the assistance of a catalyst and, in some cases, additional small molecule reagents. When the products are small molecules or materials with higher value in their own right, or as chemical feedstocks, the process is called upcycling. This review summarizes recent progress for four major catalytic upcycling strategies: hydrogenolysis, (hydro)cracking, tandem processes involving metathesis, and selective oxidation. Key considerations include macromolecular reaction mechanisms relative to small molecule mechanisms, catalyst design for macromolecular transformations, and the effect of process conditions on product selectivity. Metrics for describing polyolefin upcycling are critically evaluated, and an outlook for future advances is described.
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Affiliation(s)
- Jiakai Sun
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106-9510, United States
| | - Jinhu Dong
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106-5080, United States
| | - Lijun Gao
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106-5080, United States
| | - Yu-Quan Zhao
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106-9510, United States
| | - Hyunjin Moon
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106-5080, United States
| | - Susannah L Scott
- Department of Chemistry and Biochemistry, University of California, Santa Barbara, California 93106-9510, United States
- Department of Chemical Engineering, University of California, Santa Barbara, California 93106-5080, United States
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2
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Twagirayezu G, Cheng H, Irumva O, Nizeyimana JC, Nizeyimana I, Bakunzibake P, Uwimana A, Birame CS. A critical review and analysis of plastic waste management practices in Rwanda. ENVIRONMENTAL SCIENCE AND POLLUTION RESEARCH INTERNATIONAL 2024:10.1007/s11356-024-34572-4. [PMID: 39126583 DOI: 10.1007/s11356-024-34572-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/12/2023] [Accepted: 07/24/2024] [Indexed: 08/12/2024]
Abstract
Plastic products are now essential commodities, yet their widespread disposal leads to environmental and human health effects, particularly in developing nations. Therefore, developing nations require comprehensive studies to assess the current state of plastic and plastic waste production to enhance plastic waste management practices. This review analyzes the import and export of plastic and the production of plastic waste in Rwanda, aiming to improve waste management practices. This review used open-access papers, reports, and websites dealing with plastic waste management. In this review, 58 articles from the Web of Science and 86 from other search engines were consulted to write this review. The findings revealed that the daily estimated plastic waste produced per person ranges between 0.012 and 0.056 kg. The estimated amount of plastic waste generated per person per year in Rwanda could be between 4.38 and 20.44 kg. Plastic waste accounts for between 1 and 8% of the total municipal solid waste produced per person per day in the country, which ranges from 219 to 255.5 kg. The average annual amount of imported plastics could reach 568.2881 tons, whereas the average quantity of exported plastics could reach 103.7414 tons. This shows that plastic management practices have not yet adopted technically advanced or improved practices, which should concern efforts to protect our environment. This study suggests approaches that can vastly improve plastic waste management and potentially open massive opportunities for the people of Rwanda.
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Affiliation(s)
- Gratien Twagirayezu
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550002, Guizhou, China
- University of Chinese Academy of Sciences, Beijing, 100049, People's Republic of China
| | - Hongguang Cheng
- State Key Laboratory of Environmental Geochemistry, Institute of Geochemistry, Chinese Academy of Sciences, Guiyang, 550002, Guizhou, China.
| | - Olivier Irumva
- School of Science and Engineering, Tongji University, Shanghai, 200092, P. R. China
| | - Jean Claude Nizeyimana
- University of Chinese Academy of Sciences, Beijing, 100049, People's Republic of China
- CAS Key Laboratory of Urban Pollutant Conversion of Urban Environment and Health, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China
| | | | - Philippe Bakunzibake
- School of Environmental and Municipal Engineering, Lanzhou Jiaotong University, Lanzhou, 730070, China
| | - Abias Uwimana
- College of Science and Technology, University of Rwanda, P. O. Box 3900, Kigali, Rwanda
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3
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Pu M, Fang C, Zhou X, Wang D, Lin Y, Lei W, Li L. Recent Advances in Environment-Friendly Polyurethanes from Polyols Recovered from the Recycling and Renewable Resources: A Review. Polymers (Basel) 2024; 16:1889. [PMID: 39000744 PMCID: PMC11244063 DOI: 10.3390/polym16131889] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2024] [Revised: 06/25/2024] [Accepted: 06/27/2024] [Indexed: 07/17/2024] Open
Abstract
Polyurethane (PU) is among the most universal polymers and has been extensively applied in many fields, such as construction, machinery, furniture, clothing, textile, packaging and biomedicine. Traditionally, as the main starting materials for PU, polyols deeply depend on petroleum stock. From the perspective of recycling and environmental friendliness, advanced PU synthesis, using diversified resources as feedstocks, aims to develop versatile products with excellent properties to achieve the transformation from a fossil fuel-driven energy economy to renewable and sustainable ones. This review focuses on the recent development in the synthesis and modification of PU by extracting value-added monomers for polyols from waste polymers and natural bio-based polymers, such as the recycled waste polymers: polyethylene terephthalate (PET), PU and polycarbonate (PC); the biomaterials: vegetable oil, lignin, cashew nut shell liquid and plant straw; and biomacromolecules: polysaccharides and protein. To design these advanced polyurethane formulations, it is essential to understand the structure-property relationships of PU from recycling polyols. In a word, this bottom-up path provides a material recycling approach to PU design for printing and packaging, as well as biomedical, building and wearable electronics applications.
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Affiliation(s)
- Mengyuan Pu
- School of Mechanical and Precision Instrument Engineering, Xi’an University of Technology, Xi’an 710048, China; (M.P.); (D.W.)
- School of Printing, Packaging Engineering and Digital Media Technology, Xi’an University of Technology, Xi’an 710048, China; (Y.L.); (W.L.)
| | - Changqing Fang
- School of Mechanical and Precision Instrument Engineering, Xi’an University of Technology, Xi’an 710048, China; (M.P.); (D.W.)
- School of Printing, Packaging Engineering and Digital Media Technology, Xi’an University of Technology, Xi’an 710048, China; (Y.L.); (W.L.)
| | - Xing Zhou
- School of Mechanical and Precision Instrument Engineering, Xi’an University of Technology, Xi’an 710048, China; (M.P.); (D.W.)
- School of Printing, Packaging Engineering and Digital Media Technology, Xi’an University of Technology, Xi’an 710048, China; (Y.L.); (W.L.)
| | - Dong Wang
- School of Mechanical and Precision Instrument Engineering, Xi’an University of Technology, Xi’an 710048, China; (M.P.); (D.W.)
- School of Printing, Packaging Engineering and Digital Media Technology, Xi’an University of Technology, Xi’an 710048, China; (Y.L.); (W.L.)
| | - Yangyang Lin
- School of Printing, Packaging Engineering and Digital Media Technology, Xi’an University of Technology, Xi’an 710048, China; (Y.L.); (W.L.)
| | - Wanqing Lei
- School of Printing, Packaging Engineering and Digital Media Technology, Xi’an University of Technology, Xi’an 710048, China; (Y.L.); (W.L.)
| | - Lu Li
- Key Laboratory of Auxiliary Chemistry and Technology for Chemical Industry, Ministry of Education, Shaanxi University of Science and Technology, Xi’an 710021, China;
- Shaanxi Collaborative Innovation Center of Industrial Auxiliary Chemistry and Technology, Shaanxi University of Science and Technology, Xi’an 710021, China
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4
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Nordahl SL, Scown CD. Recommendations for life-cycle assessment of recyclable plastics in a circular economy. Chem Sci 2024; 15:9397-9407. [PMID: 38939149 PMCID: PMC11206198 DOI: 10.1039/d4sc01340a] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2024] [Accepted: 05/21/2024] [Indexed: 06/29/2024] Open
Abstract
Technologies that enable plastic circularity offer a path to reducing waste generation, improving environmental quality, and reducing reliance on fossil feedstocks. However, life-cycle assessment (LCA) methods commonly applied to these systems fall far short of capturing the full suite of advantages and tradeoffs. This perspective highlights inconsistencies in both the research questions and methodological choices across the growing body of LCA literature for plastics recycling. We assert that conducting LCAs on the basis of tonnes of waste managed vs. tonnes of recycled plastics yields results with fundamentally different conclusions; in most cases, analyses of recyclable plastics should focus on the unit of recycled product yielded. We also offer straightforward paths to better approach LCAs for recycling processes and plastics in a circular economy by rethinking study design (metrics, functional unit, system boundaries, counterfactual scenarios), upstream assumptions (waste feedstock variability, pre-processing requirements), and downstream assumptions (closed-loop vs. open-loop systems, material substitution). Specifically, we recommend expanding to metrics beyond greenhouse gases by including fossil carbon balances, net diversion of waste from landfill, and quantity of avoided plastic waste leakage to the environment. Furthermore, we highlight the role that plastic waste plays as a problematic contaminant in preventing greater diversion of all wastes to recycling, energy recovery, and composting, suggesting that plastics may hold a shared responsibility for the system-wide greenhouse gas emissions that occur when mixed wastes are landfilled.
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Affiliation(s)
- Sarah L Nordahl
- Energy Technologies Area, Lawrence Berkeley National Laboratory 1 Cyclotron Road Berkeley CA 94720 USA
| | - Corinne D Scown
- Energy Technologies Area, Lawrence Berkeley National Laboratory 1 Cyclotron Road Berkeley CA 94720 USA
- Joint BioEnergy Institute 5885 Hollis Street Emeryville CA 94608 USA
- Biosciences Area, Lawrence Berkeley National Laboratory 1 Cyclotron Road Berkeley CA 94720 USA
- Energy & Biosciences Institute, University of California Berkeley CA 94720 USA
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5
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Taxeidis G, Nikolaivits E, Nikodinovic-Runic J, Topakas E. Mimicking the enzymatic plant cell wall hydrolysis mechanism for the degradation of polyethylene terephthalate. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 356:124347. [PMID: 38857840 DOI: 10.1016/j.envpol.2024.124347] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/20/2024] [Revised: 06/06/2024] [Accepted: 06/07/2024] [Indexed: 06/12/2024]
Abstract
Plastic pollution presents a global challenge, impacting ecosystems, wildlife, and economies. Polyethylene terephthalate (PET), widely used in products like bottles, significantly contributes to this issue due to poor waste collection. In recent years, there has been increasing interest in plant biomass-degrading enzymes for plastic breakdown, due to the structural and physicochemical similarities between natural and synthetic polymers. Filamentous fungi involved in hemicellulose degradation have developed a complex mode of action that includes not only enzymes but also biosurfactants; surface-active molecules that facilitate enzyme-substrate interactions. For this reason, this study aimed to mimic the mechanism of biomass degradation by repurposing plant cell wall degrading enzymes including a cutinase and three esterases to cooperatively contribute to PET degradation. Surfactants of different charge were also introduced in the reactions, as their role is similar to biosurfactants, altering the surface tension of the polymers and thus improving enzymes' accessibility. Notably, Fusarium oxysporum cutinase combined with anionic surfactant exhibited a 2.3- and 1.6-fold higher efficacy in hydrolyzing amorphous and semi-crystalline PET, respectively. When cutinase was combined with either of two ferulic acid esterases, it resulted in complete conversion of PET intermediate products to TPA, increasing the overall product release up to 1.9- fold in presence of surfactant. The combination of cutinase with a glucuronoyl esterase demonstrated significant potential in plastic depolymerization, increasing degradation yields in semi-crystalline PET by up to 1.4-fold. The approach of incorporating enzyme cocktails and surfactants emerge as an efficient solution for PET degradation in mild reaction conditions, with potential applications in eco-friendly plastic waste management.
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Affiliation(s)
- George Taxeidis
- Industrial Biotechnology & Biocatalysis Group, Biotechnology Laboratory, School of Chemical Engineering, National Technical University of Athens, Heroon Polytechniou 9, Zografou, 15772, Athens, Greece
| | - Efstratios Nikolaivits
- Industrial Biotechnology & Biocatalysis Group, Biotechnology Laboratory, School of Chemical Engineering, National Technical University of Athens, Heroon Polytechniou 9, Zografou, 15772, Athens, Greece
| | - Jasmina Nikodinovic-Runic
- Eco-Biotechnology & Drug Development Group, Laboratory for Microbial Molecular Genetics and Ecology, Institute of Molecular Genetics and Genetic Engineering, University of Belgrade, 11000, Belgrade, Serbia
| | - Evangelos Topakas
- Industrial Biotechnology & Biocatalysis Group, Biotechnology Laboratory, School of Chemical Engineering, National Technical University of Athens, Heroon Polytechniou 9, Zografou, 15772, Athens, Greece.
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6
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Chea JD, Ruiz-Mercado GJ, Smith RL, Meyer DE, Gonzalez MA, Barrett WM. Material Flow Analysis and Occupational Exposure Assessment in Additive Manufacturing End-of-Life Material Management. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2024; 58:9000-9012. [PMID: 38710661 DOI: 10.1021/acs.est.4c01562] [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: 05/08/2024]
Abstract
Additive manufacturing (AM) offers a variety of material manufacturing techniques for a wide range of applications across many industries. Most efforts at process optimization and exposure assessment for AM are centered around the manufacturing process. However, identifying the material allocation and potentially harmful exposures in end-of-life (EoL) management is equally crucial to mitigating environmental releases and occupational health impacts within the AM supply chain. This research tracks the allocation and potential releases of AM EoL materials within the US through a material flow analysis. Of the generated AM EoL materials, 58% are incinerated, 33% are landfilled, and 9% are recycled by weight. The generated data set was then used to examine the theoretical occupational hazards during AM EoL material management practices through generic exposure scenario assessment, highlighting the importance of ventilation and personal protective equipment at all stages of AM material management. This research identifies pollution sources, offering policymakers and stakeholders insights to shape pollution prevention and worker safety strategies within the US AM EoL management pathways.
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Affiliation(s)
- John D Chea
- Oak Ridge Institute for Science and Education, Hosted by Office of Research & Development, US Environmental Protection Agency, Cincinnati, Ohio 45268, United States
| | - Gerardo J Ruiz-Mercado
- Office of Research & Development, US Environmental Protection Agency, Cincinnati, Ohio 45268, United States
- Chemical Engineering Graduate Program, Universidad del Atlántico, Puerto Colombia 080007, Colombia
| | - Raymond L Smith
- Office of Research & Development, US Environmental Protection Agency, Cincinnati, Ohio 45268, United States
| | - David E Meyer
- Office of Research & Development, US Environmental Protection Agency, Cincinnati, Ohio 45268, United States
| | - Michael A Gonzalez
- Office of Research & Development, US Environmental Protection Agency, Cincinnati, Ohio 45268, United States
| | - William M Barrett
- Office of Research & Development, US Environmental Protection Agency, Cincinnati, Ohio 45268, United States
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7
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Monegro R, Graham SR, Steele J, Robertson ML, Henderson JA. Hands-On Activity Illustrating the Sorting Process of Recycled Waste and Its Role in Promoting Sustainable Solutions. JOURNAL OF CHEMICAL EDUCATION 2024; 101:1899-1904. [PMID: 38764940 PMCID: PMC11097386 DOI: 10.1021/acs.jchemed.3c01128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/04/2023] [Revised: 02/20/2024] [Accepted: 02/22/2024] [Indexed: 05/21/2024]
Abstract
Effective recycling is not merely a matter of collecting waste; it also requires meticulous categorization to maximize the potential for reusing material and minimizing waste sent to landfills. Education and awareness of the sorting and recycling process bottlenecks need to be emphasized and extended beyond higher educational contexts (e.g., in multiple stages of educational pathways, such as middle or high school). Hence, this project introduces a hands-on plastic sorting activity where students use recycled waste to be sorted based on their physical properties. Several tools were provided to perform the separation, such as water, sieves, magnets, and manual/visual separation while considering the time and cost associated with each tool. The activity was evaluated by pre- and post-evaluations based on Likert-scale and open-ended questions grouped in several categories related to the sorting process. In several categories, we observed that the activity enhanced student knowledge (e.g., general sorting understanding), while in other categories, there was no growth. From open-ended questions, students expressed an understanding of how to sort recycled waste and an appreciation for the trade-offs in developing sorting solutions. This activity effectively enhanced students' awareness of the sorting process of recycled waste. It lays the foundation for future inquiry and outreach project design.
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Affiliation(s)
- Ronard
Herrera Monegro
- William
A. Brookshire Department of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas 77204, United States
| | - Savannah R. Graham
- William
A. Brookshire Department of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas 77204, United States
| | - Jaiah Steele
- Texas
A&M College of Engineering, College
Station, Texas 77843, United States
| | - Megan L. Robertson
- William
A. Brookshire Department of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas 77204, United States
| | - Jerrod A. Henderson
- William
A. Brookshire Department of Chemical and Biomolecular Engineering, University of Houston, Houston, Texas 77204, United States
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8
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Zhuo Y, He J, Li W, Deng J, Lin Q. A review on takeaway packaging waste: Types, ecological impact, and disposal route. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2023; 337:122518. [PMID: 37678737 DOI: 10.1016/j.envpol.2023.122518] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/25/2023] [Revised: 08/31/2023] [Accepted: 09/04/2023] [Indexed: 09/09/2023]
Abstract
Rapid economic growth and urbanization have led to significant changes in the world's consumption patterns. Accelerated urbanization, the spread of the mobile Internet, and the increasing pace of work globally have all contributed to the demand for the food takeaway industry. The rapid development of the takeaway industry inevitably brings convenience to life, and with it comes great environmental pressure from waste packaging materials. While maintaining the convenience of people's lives, further reducing the environmental pollution caused by takeaway packaging materials and promoting the recycling and reuse of takeaway packaging waste need to attract the attention and concern of the whole society. This review systematically and comprehensively introduces common takeaway food types and commonly used packaging materials, analyzes the impacts of discarded takeaway packaging materials on human health and the ecological environment, summarizes the formulation and implementation of relevant policies and regulations, proposes treatment methods and resourceful reuse pathways for discarded takeaway packaging, and also provides an outlook on the development of green takeaway packaging. Currently, only 20% of waste packaging materials are recycled worldwide, and there is still a need to develop more green takeaway packaging materials and continuously improve relevant policies and regulations to promote the sustainable development of the takeaway industry. The review is conducive to further optimizing the takeaway packaging management system, alleviating the environmental pollution problem, and providing feasible solutions and technical guidance for further optimizing takeaway food packaging materials and comprehensive utilization of resources.
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Affiliation(s)
- Yu Zhuo
- National Engineering Research Center of Rice and Byproduct Deep Processing, Hunan Province Key Laboratory of Edible forestry Resources Safety and Processing Utilization, College of Food Science and Engineering, Central South University of Forestry and Technology, Changsha, 410004, Hunan, China
| | - JinTao He
- National Engineering Research Center of Rice and Byproduct Deep Processing, Hunan Province Key Laboratory of Edible forestry Resources Safety and Processing Utilization, College of Food Science and Engineering, Central South University of Forestry and Technology, Changsha, 410004, Hunan, China
| | - Wen Li
- National Engineering Research Center of Rice and Byproduct Deep Processing, Hunan Province Key Laboratory of Edible forestry Resources Safety and Processing Utilization, College of Food Science and Engineering, Central South University of Forestry and Technology, Changsha, 410004, Hunan, China; Hunan Provincial Engineering Technology Research Center of Seasonings Green Manufacturing, Changsha, 410004, China; College of Food Science and Engineering, Nanjing University of Finance and Economics/Collaborative Innovation Center for Modern Grain Circulation and Safety, Nanjing, 210023, Jiangsu, China.
| | - Jing Deng
- National Engineering Research Center of Rice and Byproduct Deep Processing, Hunan Province Key Laboratory of Edible forestry Resources Safety and Processing Utilization, College of Food Science and Engineering, Central South University of Forestry and Technology, Changsha, 410004, Hunan, China
| | - QinLu Lin
- National Engineering Research Center of Rice and Byproduct Deep Processing, Hunan Province Key Laboratory of Edible forestry Resources Safety and Processing Utilization, College of Food Science and Engineering, Central South University of Forestry and Technology, Changsha, 410004, Hunan, China; Hunan Provincial Engineering Technology Research Center of Seasonings Green Manufacturing, Changsha, 410004, China; College of Food Science and Engineering, Nanjing University of Finance and Economics/Collaborative Innovation Center for Modern Grain Circulation and Safety, Nanjing, 210023, Jiangsu, China
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9
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Nordahl SL, Baral NR, Helms BA, Scown CD. Complementary roles for mechanical and solvent-based recycling in low-carbon, circular polypropylene. Proc Natl Acad Sci U S A 2023; 120:e2306902120. [PMID: 37934823 PMCID: PMC10655212 DOI: 10.1073/pnas.2306902120] [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: 04/26/2023] [Accepted: 09/05/2023] [Indexed: 11/09/2023] Open
Abstract
Plastic recycling presents a vexing challenge. Mechanical recycling offers substantial greenhouse gas emissions savings relative to virgin plastic production but suffers from degraded aesthetic and mechanical properties. Polypropylene, one of the most widely used and lowest-cost plastics, features methyl pendants along the polymer backbone, rendering it particularly susceptible to declining properties, performance, and aesthetics across a succession of mechanical recycles. Advanced processes, such as solvent-assisted recycling, promise near-virgin quality outputs at a greater energy and emissions footprint. Mechanical and advanced recycling are often presented as competing options, but real-world plastic waste streams are likely to require preprocessing regardless of whether they are routed to an advanced process. This study quantifies the life-cycle greenhouse gas implications of multiple recycling strategies and proposes a system in which mechanical and solvent-assisted recycling can be leveraged together to boost recycling rates and satisfy demand for a wider range of product applications. Polypropylene can be recovered from mixed-plastic bales produced at material recovery facilities and processed through mechanical recycling, with a varying fraction sent for further upgrading via solvent-assisted recycling to produce material approved for food packaging and other higher-quality applications. The resulting mechanically recycled rigid polypropylene reduces life-cycle greenhouse gas emissions by 80% relative to the same quantity of virgin material, while the upgraded higher-quality material achieves GHG savings of 30%.
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Affiliation(s)
- Sarah L. Nordahl
- Energy Analysis and Environmental Impacts Division, Lawrence Berkeley National Laboratory, Berkeley, CA94720
- Department of Civil and Environmental Engineering, University of California, Berkeley, CA94720
| | - Nawa R. Baral
- Joint BioEnergy Institute, Emeryville, CA94608
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA94720
| | - Brett A. Helms
- Joint BioEnergy Institute, Emeryville, CA94608
- The Molecular Foundry, Lawrence Berkeley National Laboratory, Berkeley, CA94720
- Materials Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA94720
- Chemical Sciences Division, Lawrence Berkeley National Laboratory, Berkeley, CA94720
| | - Corinne D. Scown
- Energy Analysis and Environmental Impacts Division, Lawrence Berkeley National Laboratory, Berkeley, CA94720
- Joint BioEnergy Institute, Emeryville, CA94608
- Biological Systems and Engineering Division, Lawrence Berkeley National Laboratory, Berkeley, CA94720
- Energy and Biosciences Institute, University of California, Berkeley, CA94720
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10
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Zhu C, Yang L, Chen C, Zeng G, Jiang W. Metal-free recycling of waste polyethylene terephthalate mediated by TBD protic ionic salts: the crucial role of anionic ligands. Phys Chem Chem Phys 2023; 25:27936-27941. [PMID: 37830243 DOI: 10.1039/d3cp03590e] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2023]
Abstract
The structure-activity relationships of 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD) based protic ionic salts for polyethylene terephthalate (PET) glycolysis by ethylene glycol (EG) were comprehensively investigated through theoretical prediction and experimental verification. The proton capture ability of the anionic ligand from EG is positively correlated with the activity of the catalyst, as the generation of EG- was crucial for the chain breaking reaction via nucleophilic attack on the carbonyl group. Furthermore, density functional theory calculations demonstrated that the HTBD cation and anionic ligands work in a cooperative manner in the PET glycolysis reaction, where the ligands abstract a proton from EG to generate EG- and provide a proton to produce the bis(hydroxyalkyl)terephthalate (BHET) product. The rate-determining step is the nucleophilic attack step, where the Gibbs energy barriers (ΔG≠) increase in the order of 29.7 kcal mol-1 (HTBD-OAc) < 30.2 kcal mol-1 (HTBD-CH3CH2COO) < 31.4 kcal mol-1 (HTBD-HCOO) < 35.7 kcal mol-1 (HTBD-CH3COCOO) < 36.9 kcal mol-1 (HTBD-NO3). This is confirmed from the experimental results that the BHET yields decrease in the order of 84.8% (HTBD-OAc) > 82.4% (HTBD-CH3CH2COO) > 80.2% (HTBD-HCOO) > 73.6% (HTBD-CH3COCOO) > 4.7% (HTBD-NO3). These findings offer valuable guidance for designing more efficient metal-free protic ionic salts, promoting sustainable PET recycling.
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Affiliation(s)
- Chenxi Zhu
- State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing 210023, China.
| | - Linlin Yang
- Kuang Yaming Honors School, Nanjing University, Nanjing 210023, China
| | - Chenhui Chen
- State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing 210023, China.
| | - Guixiang Zeng
- Kuang Yaming Honors School, Nanjing University, Nanjing 210023, China
| | - Wei Jiang
- State Key Laboratory of Pollution Control and Resources Reuse, School of the Environment, Nanjing University, Nanjing 210023, China.
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11
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Cecon VS, Curtzwiler GW, Vorst KL. Evaluation of mixed #3-7 plastic waste from material recovery facilities (MRFs) in the United States. WASTE MANAGEMENT (NEW YORK, N.Y.) 2023; 171:313-323. [PMID: 37699294 DOI: 10.1016/j.wasman.2023.09.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2023] [Revised: 08/29/2023] [Accepted: 09/02/2023] [Indexed: 09/14/2023]
Abstract
Plastic recycling rates are still low in the United States (U.S.), with less than 10% of municipal solid waste (MSW) plastic being recycled. Most unrecycled plastics are identified by Resin Identification Codes (RIC) from #3-7, which are commonly destined for landfill or waste-to-energy facilities (WTE). Therefore, the composition and quality of outbound bales containing #3-7 plastics were assessed to understand the potential to increase recycling rates. Three bales were sourced from three different Material Recovery Facilities (MRFs) located in the United States. Each bale was manually sorted and characterized for quality and performance via multiple plastic characterization techniques. Considerable differences in bale composition were observed between MRFs, which correlated with the technology used by each MRF in the sorting process. The differences were substantial in the residual levels of poly(ethylene terephthalate) (PET) and high-density polyethylene (HDPE), which are highly desired for mechanical recycling processes and not expected in #3-7 plastics bales. Traditional recycling processes including washing, extrusion, and injection molding of the sorted material were employed prior to the physical, thermal, and molecular characterization. Despite differences in bale composition by plastic type, some polymer properties were similar across MRFs. This research suggests that landfill-diverted mixed plastic waste can be utilized in the mechanical recycling of currently unrecycled materials, as processes can be designed to work with consistent polymer properties. It also highlights the need to upgrade the sorting systems to prevent waste feedstocks, which can be recycled with current technologies, from contaminating other plastic streams or reach landfills.
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Affiliation(s)
- Victor S Cecon
- Polymer and Food Protection Consortium, Iowa State University, 536 Farmhouse Lane, Ames IA, 50011, USA; Department of Food Science and Human Nutrition, Iowa State University, 536 Farmhouse Lane, Ames IA, 50011, USA
| | - Greg W Curtzwiler
- Polymer and Food Protection Consortium, Iowa State University, 536 Farmhouse Lane, Ames IA, 50011, USA; Department of Food Science and Human Nutrition, Iowa State University, 536 Farmhouse Lane, Ames IA, 50011, USA
| | - Keith L Vorst
- Polymer and Food Protection Consortium, Iowa State University, 536 Farmhouse Lane, Ames IA, 50011, USA; Department of Food Science and Human Nutrition, Iowa State University, 536 Farmhouse Lane, Ames IA, 50011, USA.
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12
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Zhao ZY, Li WB, Wang PY, Tao HY, Zhou R, Cui JY, Zhang J, Tian T, Zhao XZ, Wang YB, Xiong YC. Farmers' participation into the recovery of waste agricultural plastic film: An application of the Theory of Planned Behavior. WASTE MANAGEMENT (NEW YORK, N.Y.) 2023; 169:253-266. [PMID: 37480740 DOI: 10.1016/j.wasman.2023.06.036] [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: 06/10/2022] [Revised: 06/25/2023] [Accepted: 06/30/2023] [Indexed: 07/24/2023]
Abstract
This study aims to address the lack of relevant researches in the field of waste recycling using the Theory of Planned Behavior (TPB). A village-scale social survey was conducted to investigate the degree of farmers' participation in a waste plastic film program, i.e. Old for New in northwest China. The program required farmers to recycle plastic film residues in exchange for new films. Survey results showed that 67.5% of farmers accepted the program, yet only 14.5% of them actually participated. Logistic regression analysis was used to analyze questionnaire data and identify the factors that significantly affected farmers' recycling behavior. Principal component and weight analysis further showed that farmers' participation was mainly influenced by their attitudes (p < 0.01), with a relative weight (RW) of 46.3%. Yet, subjective norms (p < 0.1) and perceived behavior control (p < 0.1) had less effect on the degree of participation, and their RWs were 4.2% and 4.1% only, respectively. Moreover, the RW of plastic film usage characteristics and household characteristics reached up to 13.2% and 6.4%, respectively. Interestingly, environmental awareness (β = 0.083) and compulsory environmental education (β = 0.130) as surface factors strongly affected the farmers' adoption and response, with the RW of 25.7%. As such, the extended TPB model was established to analyze the participation behavior of farmers for stronger explanatory power. This study highlighted a promising strategy based on TPB for waste plastic film recycling and similar environmental management practices.
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Affiliation(s)
- Ze-Ying Zhao
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Ecology, Lanzhou University, Lanzhou 730000, China
| | - Wen-Bo Li
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Ecology, Lanzhou University, Lanzhou 730000, China
| | - Peng-Yang Wang
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Ecology, Lanzhou University, Lanzhou 730000, China
| | - Hong-Yan Tao
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Ecology, Lanzhou University, Lanzhou 730000, China
| | - Rui Zhou
- School of Ecology and Environmental Science, Yunnan University, Kunming 650091, China
| | - Jin-Ying Cui
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Ecology, Lanzhou University, Lanzhou 730000, China
| | - Jian Zhang
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Ecology, Lanzhou University, Lanzhou 730000, China
| | - Tao Tian
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Ecology, Lanzhou University, Lanzhou 730000, China
| | - Xu-Zhe Zhao
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Ecology, Lanzhou University, Lanzhou 730000, China
| | - Yi-Bo Wang
- Gansu Key Laboratory of Resource Utilization of Agricultural Solid Wastes, Tianshui Normal University, Tianshui 741000, China
| | - You-Cai Xiong
- State Key Laboratory of Herbage Improvement and Grassland Agro-ecosystems, College of Ecology, Lanzhou University, Lanzhou 730000, China.
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13
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Ng KWJ, Lim JSK, Gupta N, Dong BX, Hu CP, Hu J, Hu XM. A facile alternative strategy of upcycling mixed plastic waste into vitrimers. Commun Chem 2023; 6:158. [PMID: 37500812 PMCID: PMC10374618 DOI: 10.1038/s42004-023-00949-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2023] [Accepted: 07/03/2023] [Indexed: 07/29/2023] Open
Abstract
Chemical depolymerization has been identified as a promising approach towards recycling of plastic waste. However, complete depolymerization may be energy intensive with complications in purification. In this work, we have demonstrated upcycling of mixed plastic waste comprising a mixture of polyester, polyamide, and polyurethane through a reprocessable vitrimer of the depolymerized oligomers. Using poly(ethylene terephthalate) (PET) as a model polymer, we first demonstrated partial controlled depolymerization, using glycerol as a cleaving agent, to obtain branched PET oligomers. Recovered PET (RPET) oligomer was then used as a feedstock to produce a crosslinked yet reprocessable vitrimer (vRPET) despite having a wide molecular weight distribution using a solventless melt processing approach. Crosslinking and dynamic interactions were observed through rheology and dynamic mechanical analysis (DMA). Tensile mechanical studies showed no noticeable decrease in mechanical strength over multiple repeated melt processing cycles. Consequently, we have clearly demonstrated the applicability of the above method to upcycle mixed plastic wastes into vitrimers and reprocessable composites. This work also afforded insights into a potentially viable alternative route for utilization of depolymerized plastic/mixed plastic waste into crosslinked vitrimer resins manifesting excellent mechanical strength, while remaining reprocessable/ recyclable for cyclical lifetime use.
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Affiliation(s)
- Kok Wei Joseph Ng
- School of Material Science and Engineering, Nanyang Technological University, Nanyang Avenue, 639798, Singapore, Singapore
| | - Jacob Song Kiat Lim
- Temasek Laboratories, Nanyang Technological University, 50 Nanyang Drive, 637553, Singapore, Singapore
| | - Nupur Gupta
- School of Material Science and Engineering, Nanyang Technological University, Nanyang Avenue, 639798, Singapore, Singapore
| | - Bing Xue Dong
- School of Material Science and Engineering, Nanyang Technological University, Nanyang Avenue, 639798, Singapore, Singapore
| | - Chun-Po Hu
- Nanyang Environment and Water Research Institute, Nanyang Technological University, 637141, Singapore, Singapore
| | - Jingdan Hu
- School of Material Science and Engineering, Nanyang Technological University, Nanyang Avenue, 639798, Singapore, Singapore
| | - Xiao Matthew Hu
- School of Material Science and Engineering, Nanyang Technological University, Nanyang Avenue, 639798, Singapore, Singapore.
- Temasek Laboratories, Nanyang Technological University, 50 Nanyang Drive, 637553, Singapore, Singapore.
- Nanyang Environment and Water Research Institute, Nanyang Technological University, 637141, Singapore, Singapore.
- Rolls-Royce@NTU Corporate Lab, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore, Singapore.
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14
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Olafasakin O, Ma J, Bradshaw SL, Aguirre-Villegas HA, Benson C, Huber GW, Zavala VM, Mba-Wright M. Techno-Economic and life cycle assessment of standalone Single-Stream material recovery facilities in the United states. WASTE MANAGEMENT (NEW YORK, N.Y.) 2023; 166:368-376. [PMID: 37210960 DOI: 10.1016/j.wasman.2023.05.011] [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: 01/11/2023] [Revised: 04/30/2023] [Accepted: 05/07/2023] [Indexed: 05/23/2023]
Abstract
Material Recovery Facilities (MRFs) are crucial players in achieving a circular economy. MRFs receive complex waste streams and separate valuable recyclables from these mixtures. This study conducts techno-economic analysis (TEA) to estimate the net present value (NPV) and life cycle assessment (LCA) to estimate different environmental impacts of a commercial scale standalone, single-stream MRF to assess the economic feasibility and environmental impacts of recovering valuable recyclables from an MRF processing 120,000 tonnes per year (t/y). The TEA employs a discounted cash flow rate of return (DCFROR) analysis over a 20-year facility lifetime, along with a sensitivity analysis on the impact of different operating and economic parameters. Results show that the total fixed cost of building the MRF facility is $23 MM, and the operating cost is $45.48/tonne. The NPV of the MRF can vary from $3.57 MM to $60 MM, while 100-year global warming potential can range from 5.98 to 8.53 kg carbon dioxide equivalents (CO2-eq) per tonne of MSW. We have also found that MSW composition (arising from regional effects) significantly impacts costs, 100-year global warming potential, and other impact categories such as acidification potential, eutrophication potential, ecotoxicity, ozone depletion, photochemical oxidation, carcinogenic effects, and non-carcinogenic effects. Sensitivity and uncertainty analysis indicate that waste composition and market prices significantly impact the profitability of the MRF, and the waste composition mostly impacts global warming potential. Our analysis also indicates that facility capacity, fixed capital cost, and waste tipping fees are vital parameters that affect the economic viability of MRF operations.
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Affiliation(s)
- Olumide Olafasakin
- Department of Mechanical Engineering, Iowa State University, Ames, IA 50010, United States
| | - Jiaze Ma
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, WI, United States
| | - Sabrina L Bradshaw
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, WI, United States
| | | | - Craig Benson
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, WI, United States
| | - George W Huber
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, WI, United States
| | - Victor M Zavala
- Department of Chemical and Biological Engineering, University of Wisconsin-Madison, Madison, WI, United States
| | - Mark Mba-Wright
- Department of Mechanical Engineering, Iowa State University, Ames, IA 50010, United States; Bioeconomy Institute, Iowa State University, Ames, IA 50010, United States.
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15
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Veksha A, Wang Y, Foo JW, Naruse I, Lisak G. Defossilization and decarbonization of hydrogen production using plastic waste: Temperature and feedstock effects during thermolysis stage. JOURNAL OF HAZARDOUS MATERIALS 2023; 452:131270. [PMID: 36989781 DOI: 10.1016/j.jhazmat.2023.131270] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 03/16/2023] [Accepted: 03/21/2023] [Indexed: 06/19/2023]
Abstract
The replacement of natural gas with plastic-derived pyrolysis gas can defossilize H2 production, while subsequent capture, utilization and storage of carbon in a solid form can decarbonize the process. The objective of this study was to investigate H2 production from three types of plastics using a process comprising pyrolysis (600 °C) and thermolysis stages (1200-1500 °C). Depending on the plastic feedstock and thermolysis temperature, the laboratory-scale setup generated 1000-1350 mL/min product gas with H2 purity of 74.3-94.2 vol%. The recovery of 5-9 wt% molecular H2 per mass of plastics was achieved. Other products included solid residue (0.1-12 wt%) and oil (8-52 wt%) from the pyrolysis reactor, solid carbon (36-53 wt%) and gas impurities (2-16 wt%) from the thermolysis reactor. The purity of H2 gas was detrimentally influenced by polyethylene terephthalate in the feedstock due to the dilution of gas by CO. The decomposition of methane containing in the pyrolysis gas was the limiting reaction step during H2 production and improved at higher thermolysis temperature. Three solid carbon structures were formed during the thermolysis stage regardless of the plastic type: carbon black aggregates, carbon black aggregates coated with a layer of pyrolytic carbon and a carbon film on the inner reactor wall. Among the three types of carbon, the highest valorization potential was identified for carbon black aggregates. Plastic feedstock composition had little if any effect on carbon black properties, while high thermolysis temperature (1500 °C) reduced the particle sizes and increased the surface area of aggregates.
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Affiliation(s)
- Andrei Veksha
- Residues and Resource Reclamation Centre (R3C), Nanyang Environment and Water Research Institute, Nanyang Technological University, 637141, Singapore.
| | - Yuxin Wang
- Residues and Resource Reclamation Centre (R3C), Nanyang Environment and Water Research Institute, Nanyang Technological University, 637141, Singapore; Department of Mechanical Systems Engineering, Nagoya University, Tokai National Higher Education and Research, 464-8603, Japan
| | - Jun Wei Foo
- Residues and Resource Reclamation Centre (R3C), Nanyang Environment and Water Research Institute, Nanyang Technological University, 637141, Singapore
| | - Ichiro Naruse
- Institute of Materials and Systems for Sustainability, Nagoya University, Tokai National Higher Education and Research, 464-8601, Japan
| | - Grzegorz Lisak
- Residues and Resource Reclamation Centre (R3C), Nanyang Environment and Water Research Institute, Nanyang Technological University, 637141, Singapore; School of Civil and Environmental Engineering, Nanyang Technological University, 50 Nanyang Avenue, 639798, Singapore.
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16
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Belden E, Rando M, Ferrara OG, Himebaugh ET, Skangos CA, Kazantzis NK, Paffenroth RC, Timko MT. Machine Learning Predictions of Oil Yields Obtained by Plastic Pyrolysis and Application to Thermodynamic Analysis. ACS ENGINEERING AU 2023; 3:91-101. [PMID: 37096175 PMCID: PMC10119934 DOI: 10.1021/acsengineeringau.2c00038] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/20/2022] [Revised: 12/08/2022] [Accepted: 12/09/2022] [Indexed: 04/26/2023]
Abstract
Chemical recycling via thermal processes such as pyrolysis is a potentially viable way to convert mixed streams of waste plastics into usable fuels and chemicals. Unfortunately, experimentally measuring product yields for real waste streams can be time- and cost-prohibitive, and the yields are very sensitive to feed composition, especially for certain types of plastics like poly(ethylene terephthalate) (PET) and polyvinyl chloride (PVC). Models capable of predicting yields and conversion from feed composition and reaction conditions have potential as tools to prioritize resources to the most promising plastic streams and to evaluate potential preseparation strategies to improve yields. In this study, a data set consisting of 325 data points for pyrolysis of plastic feeds was collected from the open literature. The data set was divided into training and test sub data sets; the training data were used to optimize the seven different machine learning regression methods, and the testing data were used to evaluate the accuracy of the resulting models. Of the seven types of models, eXtreme Gradient Boosting (XGBoost) predicted the oil yield of the test set with the highest accuracy, corresponding to a mean absolute error (MAE) value of 9.1%. The optimized XGBoost model was then used to predict the oil yields from real waste compositions found in Municipal Recycling Facilities (MRFs) and the Rhine River. The dependence of oil yields on composition was evaluated, and strategies for removing PET and PVC were assessed as examples of how to use the model. Thermodynamic analysis of a pyrolysis system capable of achieving oil yields predicted using the machine-learned model showed that pyrolysis of Rhine River plastics should be net exergy producing under most reasonable conditions.
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Affiliation(s)
- Elizabeth
R. Belden
- Department
of Chemical Engineering, Worcester Polytechnic
Institute, 100 Institute Road, Worcester, Massachusetts01609, United States
| | - Matthew Rando
- Department
of Chemical Engineering, Worcester Polytechnic
Institute, 100 Institute Road, Worcester, Massachusetts01609, United States
| | - Owen G. Ferrara
- Department
of Chemical Engineering, Worcester Polytechnic
Institute, 100 Institute Road, Worcester, Massachusetts01609, United States
| | - Eric T. Himebaugh
- Department
of Chemical Engineering, Worcester Polytechnic
Institute, 100 Institute Road, Worcester, Massachusetts01609, United States
| | - Christopher A. Skangos
- Department
of Chemical Engineering, Worcester Polytechnic
Institute, 100 Institute Road, Worcester, Massachusetts01609, United States
| | - Nikolaos K. Kazantzis
- Department
of Chemical Engineering, Worcester Polytechnic
Institute, 100 Institute Road, Worcester, Massachusetts01609, United States
| | - Randy C. Paffenroth
- Department
of Mathematical Sciences, Worcester Polytechnic
Institute, 100 Institute Road, Worcester, Massachusetts01609, United States
- Department
of Computer Science, and Data Science Program, Worcester Polytechnic Institute, 100 Institute Road, Worcester, Massachusetts01609, United States
| | - Michael T. Timko
- Department
of Chemical Engineering, Worcester Polytechnic
Institute, 100 Institute Road, Worcester, Massachusetts01609, United States
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17
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Chea JD, Yenkie KM, Stanzione JF, Ruiz-Mercado GJ. A generic scenario analysis of end-of-life plastic management: Chemical additives. JOURNAL OF HAZARDOUS MATERIALS 2023; 441:129902. [PMID: 37155557 PMCID: PMC10125005 DOI: 10.1016/j.jhazmat.2022.129902] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/10/2023]
Abstract
Plastic growing demand and the increment in global plastics production have raised the number of spent plastics, out of which over 90% are either landfilled or incinerated. Both methods for handling spent plastics are susceptible to releasing toxic substances, damaging air, water, soil, organisms, and public health. Improvements to the existing infrastructure for plastics management are needed to limit chemical additive release and exposure resulting from the end-of-life (EoL) stage. This article analyzes the current plastic waste management infrastructure and identifies chemical additive releases through a material flow analysis. Additionally, we performed a facility-level generic scenario analysis of the current U.S. EoL stage of plastic additives to track and estimate their potential migration, releases, and occupational exposure. Potential scenarios were analyzed through sensitivity analysis to examine the merit of increasing recycling rates, using chemical recycling, and implementing additive extraction post-recycling. Our analyses identified that the current state of plastic EoL management possesses high mass flow intensity toward incineration and landfilling. Although maximizing the plastic recycling rate is a reasonably straightforward goal for enhancing material circularity, the conventional mechanical recycling method requires improvement because major chemical additive release and contamination routes act as obstacles to achieving high-quality plastics for future reuse and should be mitigated through chemical recycling and additive extraction. The potential hazards and risks identified in this research create an opportunity to design a safer closed-loop plastic recycling infrastructure to handle additives strategically and support sustainable materials management efforts to transform the US plastic economy from linear to circular.
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Affiliation(s)
- John D. Chea
- Department of Chemical Engineering, Henry M. Rowan College of Engineering, Rowan University, Glassboro, NJ 08028, USA
- Oak Ridge Institute for Science and Education, hosted by Office of Research & Development, US Environmental Protection Agency, Cincinnati, OH 45268, USA
| | - Kirti M. Yenkie
- Department of Chemical Engineering, Henry M. Rowan College of Engineering, Rowan University, Glassboro, NJ 08028, USA
| | - Joseph F. Stanzione
- Department of Chemical Engineering, Henry M. Rowan College of Engineering, Rowan University, Glassboro, NJ 08028, USA
| | - Gerardo J. Ruiz-Mercado
- Office of Research & Development, US Environmental Protection Agency, Cincinnati, OH 45268, USA
- Chemical Engineering Graduate Program, Universidad del Atlántico, Puerto Colombia 080007, Colombia
- Corresponding author at: Office of Research & Development, US Environmental Protection Agency, Cincinnati, OH 45268, USA. (G.J. Ruiz-Mercado)
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18
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Study of polyester degradation by sub/supercritical ethanol and enhancement of carbon dioxide. J Supercrit Fluids 2023. [DOI: 10.1016/j.supflu.2023.105837] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
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19
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Ullah R, Tsui MTK, Chow A, Chen H, Williams C, Ligaba-Osena A. Micro(nano)plastic pollution in terrestrial ecosystem: emphasis on impacts of polystyrene on soil biota, plants, animals, and humans. ENVIRONMENTAL MONITORING AND ASSESSMENT 2022; 195:252. [PMID: 36585967 DOI: 10.1007/s10661-022-10769-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/15/2022] [Accepted: 11/14/2022] [Indexed: 06/17/2023]
Abstract
Pollution with emerging microscopic contaminants such as microplastics (MPs) and nanoplastics (NPs) including polystyrene (PS) in aquatic and terrestrial environments is increasingly recognized. PS is largely used in packaging materials and is dumped directly into the ecosystem. PS micro-nano-plastics (MNPs) can be potentially bioaccumulated in the food chain and can cause human health concerns through food consumption. Earlier MP research has focused on the aquatic environments, but recent researches show significant MP and NP contamination in the terrestrial environments especially agricultural fields. Though PS is the hotspot of MPs research, however, to our knowledge, this systematic review represents the first of its kind that specifically focused on PS contamination in agricultural soils, covering sources, effects, and ways of PS mitigation. The paper also provides updated information on the effects of PS on soil organisms, its uptake by plants, and effects on higher animals as well as human beings. Directions for future research are also proposed to increase our understanding of the environmental contamination of PS in terrestrial environments.
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Affiliation(s)
- Raza Ullah
- Laboratory of Plant Molecular Biology and Biotechnology, Department of Biology, University of North Carolina Greensboro, Greensboro, NC, 27402, USA
| | - Martin Tsz-Ki Tsui
- Laboratory of Plant Molecular Biology and Biotechnology, Department of Biology, University of North Carolina Greensboro, Greensboro, NC, 27402, USA
- School of Life Sciences, The Chinese University of Hong Kong, Hong Kong SAR, Shatin, New Territories, China
| | - Alex Chow
- Biogeochemistry & Environmental Quality Research Group, Clemson University, Clemson, SC, 29442, USA
- Dep. of Environmental Engineering and Earth Sciences, Clemson University, Clemson, SC, 29634, USA
| | - Huan Chen
- Biogeochemistry & Environmental Quality Research Group, Clemson University, Clemson, SC, 29442, USA
- Dep. of Environmental Engineering and Earth Sciences, Clemson University, Clemson, SC, 29634, USA
| | - Clinton Williams
- USDA-ARS, US Arid Land Agricultural Research Center, Cardon Ln, Maricopa, AZ, USA
| | - Ayalew Ligaba-Osena
- Laboratory of Plant Molecular Biology and Biotechnology, Department of Biology, University of North Carolina Greensboro, Greensboro, NC, 27402, USA.
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20
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Chu M, Liu Y, Lou X, Zhang Q, Chen J. Rational Design of Chemical Catalysis for Plastic Recycling. ACS Catal 2022. [DOI: 10.1021/acscatal.2c01286] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Affiliation(s)
- Mingyu Chu
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou 215123, China
| | - Yu Liu
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou 215123, China
| | - Xiangxi Lou
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou 215123, China
| | - Qiao Zhang
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou 215123, China
| | - Jinxing Chen
- Institute of Functional Nano & Soft Materials (FUNSOM), Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices, Soochow University, Suzhou 215123, China
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