Li-Zhi Huang , Jingjing Lin , Weiguo Chen , Wei Wang , Yitao Dai , Ivan P. Pozdnyakov , Bingbing Hu
{"title":"紫外/小分子单羧酸体系生成二氧化碳阴离子自由基用于氯代烷烃还原脱氯","authors":"Li-Zhi Huang , Jingjing Lin , Weiguo Chen , Wei Wang , Yitao Dai , Ivan P. Pozdnyakov , Bingbing Hu","doi":"10.1016/j.jes.2024.12.025","DOIUrl":null,"url":null,"abstract":"<div><div>The persistence of chlorinated alkanes in aquatic environments poses significant health risks due to its biotoxicity and high volatility, which contributes to both water and air pollution. This study investigates the efficacy of carbon dioxide radical anion (CO<sub>2</sub>•<sup>−</sup>) mediated advanced reduction processes (ARPs) for the reductive dechlorination of chlorinated alkanes using small molecular monocarboxylic acids (SMAs) under UV irradiation. The study focused on formic acid (HCOOH), acetic acid (CH<sub>3</sub>COOH), and propionic acid (CH<sub>3</sub>CH<sub>2</sub>COOH) to generate CO<sub>2</sub>•<sup>−</sup>, revealing that UV/HCOOH system exhibits a notably high chloroform (CF) degradation efficiency of 97.8 % in 90 min. Kinetic studies indicated a linear relationship between the HCOOH concentrations and the observed reaction rate constants (<em>k</em><sub>obs</sub>), demonstrating that CO<sub>2</sub>•<sup>−</sup> production is crucial for CF degradation. Electron paramagnetic resonance spectroscopy identified CO<sub>2</sub>•<sup>−</sup> and hydroxyl radicals (HO•) as the active species, with the former playing a predominant role in CF degradation. The study also explored the influence of carbon chain length in SMAs on CF degradation, finding that longer chains decrease the degradation efficiency, potentially due to reduced UV activation. A higher reaction rate constant (<em>k</em><sub>obs</sub>) under acidic conditions, with a marked decrease in efficiency as the pH exceeds 3.7, where HCOO<sup>−</sup> becomes predominant. This study enhances our understanding of CO<sub>2</sub>•<sup>−</sup> mediated ARPs and explores potential applications in environmental remediation, providing insights into the pathways and mechanisms of CF degradation. The UV/SMAs systems offer advantages for practical applications, such as milder reaction conditions and higher efficiency compared to traditional methods.</div></div>","PeriodicalId":15788,"journal":{"name":"Journal of Environmental Sciences-china","volume":"158 ","pages":"Pages 50-59"},"PeriodicalIF":6.3000,"publicationDate":"2024-12-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":"{\"title\":\"Generation of carbon dioxide anion radical by UV/small molecular monocarboxylic acid system for reductive dechlorination of chlorinated alkanes\",\"authors\":\"Li-Zhi Huang , Jingjing Lin , Weiguo Chen , Wei Wang , Yitao Dai , Ivan P. Pozdnyakov , Bingbing Hu\",\"doi\":\"10.1016/j.jes.2024.12.025\",\"DOIUrl\":null,\"url\":null,\"abstract\":\"<div><div>The persistence of chlorinated alkanes in aquatic environments poses significant health risks due to its biotoxicity and high volatility, which contributes to both water and air pollution. This study investigates the efficacy of carbon dioxide radical anion (CO<sub>2</sub>•<sup>−</sup>) mediated advanced reduction processes (ARPs) for the reductive dechlorination of chlorinated alkanes using small molecular monocarboxylic acids (SMAs) under UV irradiation. The study focused on formic acid (HCOOH), acetic acid (CH<sub>3</sub>COOH), and propionic acid (CH<sub>3</sub>CH<sub>2</sub>COOH) to generate CO<sub>2</sub>•<sup>−</sup>, revealing that UV/HCOOH system exhibits a notably high chloroform (CF) degradation efficiency of 97.8 % in 90 min. Kinetic studies indicated a linear relationship between the HCOOH concentrations and the observed reaction rate constants (<em>k</em><sub>obs</sub>), demonstrating that CO<sub>2</sub>•<sup>−</sup> production is crucial for CF degradation. Electron paramagnetic resonance spectroscopy identified CO<sub>2</sub>•<sup>−</sup> and hydroxyl radicals (HO•) as the active species, with the former playing a predominant role in CF degradation. The study also explored the influence of carbon chain length in SMAs on CF degradation, finding that longer chains decrease the degradation efficiency, potentially due to reduced UV activation. A higher reaction rate constant (<em>k</em><sub>obs</sub>) under acidic conditions, with a marked decrease in efficiency as the pH exceeds 3.7, where HCOO<sup>−</sup> becomes predominant. This study enhances our understanding of CO<sub>2</sub>•<sup>−</sup> mediated ARPs and explores potential applications in environmental remediation, providing insights into the pathways and mechanisms of CF degradation. The UV/SMAs systems offer advantages for practical applications, such as milder reaction conditions and higher efficiency compared to traditional methods.</div></div>\",\"PeriodicalId\":15788,\"journal\":{\"name\":\"Journal of Environmental Sciences-china\",\"volume\":\"158 \",\"pages\":\"Pages 50-59\"},\"PeriodicalIF\":6.3000,\"publicationDate\":\"2024-12-26\",\"publicationTypes\":\"Journal Article\",\"fieldsOfStudy\":null,\"isOpenAccess\":false,\"openAccessPdf\":\"\",\"citationCount\":\"0\",\"resultStr\":null,\"platform\":\"Semanticscholar\",\"paperid\":null,\"PeriodicalName\":\"Journal of Environmental Sciences-china\",\"FirstCategoryId\":\"93\",\"ListUrlMain\":\"https://www.sciencedirect.com/science/article/pii/S1001074224005904\",\"RegionNum\":2,\"RegionCategory\":\"环境科学与生态学\",\"ArticlePicture\":[],\"TitleCN\":null,\"AbstractTextCN\":null,\"PMCID\":null,\"EPubDate\":\"\",\"PubModel\":\"\",\"JCR\":\"Q1\",\"JCRName\":\"ENVIRONMENTAL SCIENCES\",\"Score\":null,\"Total\":0}","platform":"Semanticscholar","paperid":null,"PeriodicalName":"Journal of Environmental Sciences-china","FirstCategoryId":"93","ListUrlMain":"https://www.sciencedirect.com/science/article/pii/S1001074224005904","RegionNum":2,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"ENVIRONMENTAL SCIENCES","Score":null,"Total":0}
Generation of carbon dioxide anion radical by UV/small molecular monocarboxylic acid system for reductive dechlorination of chlorinated alkanes
The persistence of chlorinated alkanes in aquatic environments poses significant health risks due to its biotoxicity and high volatility, which contributes to both water and air pollution. This study investigates the efficacy of carbon dioxide radical anion (CO2•−) mediated advanced reduction processes (ARPs) for the reductive dechlorination of chlorinated alkanes using small molecular monocarboxylic acids (SMAs) under UV irradiation. The study focused on formic acid (HCOOH), acetic acid (CH3COOH), and propionic acid (CH3CH2COOH) to generate CO2•−, revealing that UV/HCOOH system exhibits a notably high chloroform (CF) degradation efficiency of 97.8 % in 90 min. Kinetic studies indicated a linear relationship between the HCOOH concentrations and the observed reaction rate constants (kobs), demonstrating that CO2•− production is crucial for CF degradation. Electron paramagnetic resonance spectroscopy identified CO2•− and hydroxyl radicals (HO•) as the active species, with the former playing a predominant role in CF degradation. The study also explored the influence of carbon chain length in SMAs on CF degradation, finding that longer chains decrease the degradation efficiency, potentially due to reduced UV activation. A higher reaction rate constant (kobs) under acidic conditions, with a marked decrease in efficiency as the pH exceeds 3.7, where HCOO− becomes predominant. This study enhances our understanding of CO2•− mediated ARPs and explores potential applications in environmental remediation, providing insights into the pathways and mechanisms of CF degradation. The UV/SMAs systems offer advantages for practical applications, such as milder reaction conditions and higher efficiency compared to traditional methods.
期刊介绍:
The Journal of Environmental Sciences is an international journal started in 1989. The journal is devoted to publish original, peer-reviewed research papers on main aspects of environmental sciences, such as environmental chemistry, environmental biology, ecology, geosciences and environmental physics. Appropriate subjects include basic and applied research on atmospheric, terrestrial and aquatic environments, pollution control and abatement technology, conservation of natural resources, environmental health and toxicology. Announcements of international environmental science meetings and other recent information are also included.