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Ragu Prasath A, Selvam K, Sudhakar C. Biodegradation of low-density polyethylene film by Bacillus gaemokensis strain SSR01 isolated from the guts of earthworm. Environ Geochem Health 2024; 46:159. [PMID: 38592645 DOI: 10.1007/s10653-024-01925-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2023] [Accepted: 02/20/2024] [Indexed: 04/10/2024]
Abstract
In recent years, low-density polyethylene (LDPE) has emerged as an essential component of the routine tasks that people engage in on a daily basis. However, over use of it resulted in environmental buildup that contaminated aquatic habitats and human health. Biodegradation is the most effective way for controlling pollution caused by synthetic plastic waste in a sustainable manner. In the present study, the LDPE degrading bacterial strain was screened from gut of Earthworms collected from plastic waste dumped area Mettur dam, Salem district, Tamil Nadu, India. The LDPE degrading bacterial strain was screened and identified genotypically. The LDPE degrading Bacillus gaemokensis strain SSR01 was submitted in NCBI. The B. gaemokensis strain SSR01 bacterial isolate degraded LDPE film after 14 days of incubation and demonstrated maximum weight loss of up to 4.98%. The study of deteriorated film using attenuated total reflection-Fourier transform infrared revealed the presence of a degraded product. The degradation of LDPE film by B. gaemokensis strain SSR01 was characterized by field-emission scanning electron microscopy analysis for surface alterations. The energy dispersive X-ray spectroscopy test confirmed that the broken-down LDPE film had basic carbon reduction. The present study of LDPE flim biodegradation by B. gaemokensis strain SSR01 has acted as a suitable candidate and will help in decreasing plastic waste.
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Affiliation(s)
- Arunagiri Ragu Prasath
- Department of Biotechnology, Mahendra Arts and Science College (Autonomous), Kalippatti, Namakkal, Tamil Nadu, 637 501, India
| | - Kandasamy Selvam
- Department of Biotechnology, Mahendra Arts and Science College (Autonomous), Kalippatti, Namakkal, Tamil Nadu, 637 501, India.
| | - Chinnappan Sudhakar
- Department of Biotechnology, Mahendra Arts and Science College (Autonomous), Kalippatti, Namakkal, Tamil Nadu, 637 501, India
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Sbarberi R, Magni S, Boggero A, Della Torre C, Nigro L, Binelli A. Comparison of plastic pollution between waters and sediments in four Po River tributaries (Northern Italy). Sci Total Environ 2024; 912:168884. [PMID: 38042177 DOI: 10.1016/j.scitotenv.2023.168884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2023] [Revised: 11/23/2023] [Accepted: 11/23/2023] [Indexed: 12/04/2023]
Abstract
The monitoring of plastic contamination in freshwaters is still pioneering in comparison with marine environments, and few studies analyzed the distribution of these pollutants in both aqueous and bottom compartments of continental waters. Therefore, the aim of this study was the comparison of plastic pollution in both waters and sediments of four Po River tributaries (Ticino, Adda, Oglio and Mincio Rivers), which outflow from the main Italian sub-alpine Lakes, in order to establish the strengths and weaknesses of both matrices. The main results pointed out a heterogeneous plastic contamination, with the lowest values in Ticino (0.9 ± 0.5 plastics/m3 in waters and 6.8 ± 4.5 plastics/kg dry weight - d.w. - in sediments) and the highest in Mincio (62.9 ± 53.9 plastics/m3 in waters and 26.5 ± 13.3 plastics/kg d.w in sediments), highlighting a plastic amount in sediments four times higher than waters. Plastic pollution, mainly due to microplastics, was associated principally to a domestic input in both waters and sediments of Ticino and Adda Rivers, as well as in sediments of Oglio, while an industrial pollution was found in waters and sediments of Mincio and Oglio waters. Our data clearly highlighted as the monitoring of both matrices provide complementary information for a holistic risk assessment of these emerging contaminants in freshwaters: the aqueous matrix provides an instantaneous picture of contamination, while sediments the history of pollution.
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Affiliation(s)
- Riccardo Sbarberi
- Department of Biosciences, University of Milan, Via Celoria 26, 20133 Milan, Italy
| | - Stefano Magni
- Department of Biosciences, University of Milan, Via Celoria 26, 20133 Milan, Italy.
| | - Angela Boggero
- National Research Council - Water Research Institute (CNR-IRSA), Corso Tonolli 50, 28922 Verbania Pallanza, Italy
| | - Camilla Della Torre
- Department of Biosciences, University of Milan, Via Celoria 26, 20133 Milan, Italy
| | - Lara Nigro
- Department of Biosciences, University of Milan, Via Celoria 26, 20133 Milan, Italy
| | - Andrea Binelli
- Department of Biosciences, University of Milan, Via Celoria 26, 20133 Milan, Italy
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Hu Y, Li M, Zhou N, Yuan H, Guo Q, Jiao L, Ma Z. Catalytic stepwise pyrolysis for dechlorination and chemical recycling of PVC-containing mixed plastic wastes: Influence of temperature, heating rate, and catalyst. Sci Total Environ 2024; 908:168344. [PMID: 37951271 DOI: 10.1016/j.scitotenv.2023.168344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 10/27/2023] [Accepted: 11/03/2023] [Indexed: 11/13/2023]
Abstract
The viability of pyrolysis technology for chemical recycling of plastics is challenged by the presence of PVC in real-world mixed plastic wastes. This study aims to investigate catalytic stepwise pyrolysis as a pretreatment step to remove chlorine from PVC-containing plastic wastes prior to further processing. TG-FTIR and Py-GCMS analysis as well as experiments on a lab-scale pyrolysis system were conducted to study the influence of key processing parameters on the pretreatment including temperature, heating rate, and catalysts. Py-GCMS results indicated 300 °C to be the best pretreatment temperature in terms of balancing Cl removal and avoidance of organochloride formation. Metal oxides, i.e., CaO and Fe2O3, mainly acted as adsorbents of HCl gases with little cracking effect, and their adsorption effects are positively correlated with alkalinity. ZSM-5 catalysts promoted the release of HCl, and the dechlorination effect was more pronounced with ZSM-5 of higher acidity. In contrast, in the lab-scale pyrolysis system, 350 °C pretreatment achieved the highest HCl generation ratio, i.e., 43.60 %. The addition of zeolite catalyst significantly reduced the content of organochloride in the pyrolysis oil in contrast to the performance of metal oxides, but also absorbed most HCl instead of promoting HCl release as in Py-GCMS tests. Mass balance analyses revealed that the majority of chlorine was retained in the solid residues following the catalytic stepwise pyrolysis process, with the notable exception of Fe2O3. ZSM-5(25) catalyst combined with 350 °C pretreatment temperature and 550 °C final pyrolysis achieved the lowest chlorine content in the pyrolysis oil, i.e., 20 ppm, among different process conditions.
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Affiliation(s)
- Yanjun Hu
- Institute of Thermal and Power Engineering, Zhejiang University of Technology, Liuhe Road 288#, 310023 Hangzhou, China; Zhejiang Carbon Neutral Innovation Institute, Zhejiang University of Technology, Chaowang Road 18#, 310024 Hangzhou, China
| | - Mingzhe Li
- Institute of Thermal and Power Engineering, Zhejiang University of Technology, Liuhe Road 288#, 310023 Hangzhou, China
| | - Nan Zhou
- Institute of Thermal and Power Engineering, Zhejiang University of Technology, Liuhe Road 288#, 310023 Hangzhou, China.
| | - Hao Yuan
- Institute of Thermal and Power Engineering, Zhejiang University of Technology, Liuhe Road 288#, 310023 Hangzhou, China
| | - Qianqian Guo
- Institute of Thermal and Power Engineering, Zhejiang University of Technology, Liuhe Road 288#, 310023 Hangzhou, China
| | - Long Jiao
- Institute of Thermal and Power Engineering, Zhejiang University of Technology, Liuhe Road 288#, 310023 Hangzhou, China
| | - Zengyi Ma
- State Key Laboratory of Clean Energy Utilization, Zhejiang University, 310013 Hangzhou, China
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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] [What about the content of this article? (0)] [Affiliation(s)] [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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