{"title":"Catalytic pyrolysis of biodegradable plastic in CO2 atmosphere using MSW incinerator bottom ash for PLA monomer recovery","authors":"Shuting Fu , Doeun Choi , Jechan Lee","doi":"10.1016/j.jaap.2024.106839","DOIUrl":null,"url":null,"abstract":"<div><div>This study proposes a method for recovering value-added monomers from abandoned biodegradable plastics such as used biodegradable straws (UBSs) by utilizing a catalyst made of bottom ash generated from municipal solid waste (MSW) incinerators. The MSW-derived bottom ash (MSW-BA) catalyst primarily comprises alkaline metal oxides such as CaO (58.88 wt%). Thermogravimetric and single-shot pyrolysis analyses show that polylactic acid (PLA) monomers—lactide and lactic acid—are the main products of UBS pyrolysis. We conducted catalytic pyrolysis of UBS at 500 °C under different atmospheres (N<sub>2</sub> and CO<sub>2</sub>), with and without the MSW-BA catalyst. Compared with non-catalytic pyrolysis, the MSW-BA catalyst-based pyrolysis significantly increased the yield of PLA monomers in both N<sub>2</sub> and CO<sub>2</sub> environments. This is because the base sites present on the MSW-BA catalyst promoted the polymeric bond cleavage of PLA. The MSW-BA catalyst in CO<sub>2</sub> achieved the highest recovery yield of PLA monomers (20.84 wt% per feedstock mass basis), which was approximately 17.75 % higher than that during non-catalytic UBS pyrolysis. The base sites present on the MSW-BA catalyst promoted polymeric bond cleavage of PLA, and the base-catalyzed pyrolysis of PLA was enhanced by the more reactive cleavage of the bond linkages in the presence of CO<sub>2</sub>. The proposed approach not only reuses biodegradable plastic waste but also utilizes the MSW treatment byproducts.</div></div>","PeriodicalId":345,"journal":{"name":"Journal of Analytical and Applied Pyrolysis","volume":"183 ","pages":"Article 106839"},"PeriodicalIF":5.8000,"publicationDate":"2024-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Analytical and Applied Pyrolysis","FirstCategoryId":"92","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S0165237024004947","RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"CHEMISTRY, ANALYTICAL","Score":null,"Total":0}
引用次数: 0
Abstract
This study proposes a method for recovering value-added monomers from abandoned biodegradable plastics such as used biodegradable straws (UBSs) by utilizing a catalyst made of bottom ash generated from municipal solid waste (MSW) incinerators. The MSW-derived bottom ash (MSW-BA) catalyst primarily comprises alkaline metal oxides such as CaO (58.88 wt%). Thermogravimetric and single-shot pyrolysis analyses show that polylactic acid (PLA) monomers—lactide and lactic acid—are the main products of UBS pyrolysis. We conducted catalytic pyrolysis of UBS at 500 °C under different atmospheres (N2 and CO2), with and without the MSW-BA catalyst. Compared with non-catalytic pyrolysis, the MSW-BA catalyst-based pyrolysis significantly increased the yield of PLA monomers in both N2 and CO2 environments. This is because the base sites present on the MSW-BA catalyst promoted the polymeric bond cleavage of PLA. The MSW-BA catalyst in CO2 achieved the highest recovery yield of PLA monomers (20.84 wt% per feedstock mass basis), which was approximately 17.75 % higher than that during non-catalytic UBS pyrolysis. The base sites present on the MSW-BA catalyst promoted polymeric bond cleavage of PLA, and the base-catalyzed pyrolysis of PLA was enhanced by the more reactive cleavage of the bond linkages in the presence of CO2. The proposed approach not only reuses biodegradable plastic waste but also utilizes the MSW treatment byproducts.
期刊介绍:
The Journal of Analytical and Applied Pyrolysis (JAAP) is devoted to the publication of papers dealing with innovative applications of pyrolysis processes, the characterization of products related to pyrolysis reactions, and investigations of reaction mechanism. To be considered by JAAP, a manuscript should present significant progress in these topics. The novelty must be satisfactorily argued in the cover letter. A manuscript with a cover letter to the editor not addressing the novelty is likely to be rejected without review.