Degradation and mechanism of hexafluoropropylene oxide dimer acid by thermally activated persulfate in aqueous solutions
Degradation and mechanism of hexafluoropropylene oxide dimer acid by thermally activated persulfate in aqueous solutions
复制标题
水溶液中热活化过硫酸盐降解六氟环氧丙烷二聚酸及其机理
DOI：
10.1016/j.chemosphere.2021.131720
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发表时间：
2021
期刊：
影响因子：
8.8
通讯作者：
Hong Chen
中科院分区：
文献类型：
--
作者：
Xiaoyan Ding;Xin Song;Xing Chen;Da Ding;Chang Xu;Hong Chen
六氟环氧丙烷二聚酸（HFPO-DA）是全氟辛酸（PFOA）的替代品，在世界范围内的环境介质中经常被检测到。据报道，HFPO-DA的毒性与PFOA相当或更高，并且更难降解。在这项研究中，HFPO-DA的有效降解实现了热活化过硫酸盐（TAP）系统，但在现场的共污染物的影响可能是显着的。通过实验和密度泛函理论（DFT）计算相结合的方法，提出了HFPO-DA的降解途径。超高效液相色谱-四极杆-飞行时间-质谱（UPLC-Q-TOF-MS）鉴定了稳定的中间体CF 3CF 2COO-和CF 3COO-。HFPO-DA降解过程的不同步骤中发生了电子转移、脱羧、抽氢、以H2O为催化剂的HF消除和水解等反应，-COO-是被SO 4自由基dot-攻击的起始氧化位点。此外，用大肠杆菌对HFPO-DA在TAP系统中的降解进行了急性毒性评价，结果表明HFPO-DA被降解到对大肠杆菌生长无不良影响的水平。大肠杆菌，并且没有更多的有毒中间体形成。总的来说，这项工作提供了深入了解HFPO-DA污染的TAP系统的降解。
Hexafluoropropylene oxide dimer acid (HFPO-DA), an alternative of perfluorooctanoic acid (PFOA), has been detected frequently in environmental media worldwide. It has been reported that HFPO-DA is equal to or more toxic than PFOA, as well as more recalcitrant to degradation. In this study, the efficient degradation of HFPO-DA was achieved by the thermally activated persulfate (TAP) system, but the influence of co-contaminants in the field can be significant. The degradation pathways of HFPO-DA were proposed through an integrated approach of experiment and density functional theory (DFT) calculations. CF3CF2COO−and CF3COO−, were the stable intermediates identified by ultra-performance liquid chromatography-quadrupole-time-of-flight-mass spectrometry (UPLC-Q-TOF-MS). Electron transfer, decarboxylation, H abstraction, HF elimination using H2O as a catalyst and hydrolysis occurred in different steps of HFPO-DA degradation process, with –COO−as the initial oxidative site attacked by SO4radical dot−. In addition, the acute toxicity assessment for HFPO-DA degradation in the TAP system performed byEscherichia colisuggested that HFPO-DA was degraded to a level having no adverse effect on the growth ofE. coli, and no more toxic intermediates were formed. Overall, this work provides insights for the degradation of HFPO-DA contamination by the TAP system.