Photodegradation of Hexafluoropropylene Oxide Trimer Acid under UV Irradiation

作     者：Chen Li Na Mi Zhanghao Chen Cheng Gu Chen Li;Na Mi;Zhanghao Chen;Cheng Gu

作者机构：State Key Laboratory of Pollution Control and Resource ReuseSchool of the EnvironmentNanjing UniversityNanjing 210023China 

出 版 物：《Journal of Environmental Sciences》 (环境科学学报（英文版）)

年 卷 期：2020年第32卷第11期

页      面：132-140页

核心收录：

学科分类：0830[工学-环境科学与工程（可授工学、理学、农学学位）] 082803[工学-农业生物环境与能源工程] 08[工学] 0828[工学-农业工程] 

基　　金：funded by the Chinese Academy of Engineering Consulting Project(No.2019-XZ-24) the National Key Re-search and Development Plans of Special Project for Site Soil(No.2018YFC1801002)。 

主　　题：HFPO-TA Photo-reductive Hydrated electrons Active hydrogen atoms Degradation pathway 

摘      要：As a novel alternative to traditional perfluoroalkyl substances(PFASs),including perfluorooctanoic acid(PFOA)and perfluorooctane sulfonate(PFOS),hexafluoroproplyene oxide trimer acid(HFPO-TA)has been detected worldwide in surface water.Moreover,recent researches have demonstrated that HFPO-TA has stronger bioaccumulation potential and higher hepatotoxicity than PFOA.To treat these contaminants e.g.PFOA and PFOS,some photochemical techniques by adding exogenous substances had been reported.However,there is still no report for the behavior of HFPO-TA itself under direct UV irradiation.The current study investigated the photo-transformation of HFPO-TA under UV irradiation in aqueous solution.After 72 hr photoreaction,75%degradation ratio and 25%defluorination ratio were achieved under ambient condition.Reducing active species,i.e.,hydrated electrons and active hydrogen atoms,generated from water splitting played dominant roles in degradation of HFPO-TA,which was confirmed by different effects of reaction atmospheres and quenching experiments.A possible degradation pathway was proposed based on the products identification and theoretical calculations.In general,HFPO-TA would be transformed into shorter-chain PFASs,including hexafluoropropylene oxide dimer acid(HFPODA),perfluoropropionic acid(PFA)and trifluoroacetate(TFA).This research provides basic information for HFPO-TA photodegradation process and is essential to develop novel remediation techniques for HFPO-TA and other alternatives with similar structures.