It has recently been discovered that HFPO-TA (a processing aid in the production of fluoropolymers) has high levels of bioaccumulation and biotoxicity. Hydrated electrons (e) have been proposed to be potent nucleophiles that may decompose PFAS. Unlike previous studies in which the generation of e was often restricted to anaerobic or highly alkaline environments, in this study, we applied the UV/SO/I process under mild conditions of neutrality, low source chemical demand, and open-air, which achieved effective degradation (81.92 %, 0.834 h) and defluorination (48.99 %, 0.312 h) of HFPO-TA. With I as the primary source of e, SO acting as an I regenerator and oxidizing substances scavenger, UV/SO/I outperformed others under mild circumstances. The e were identified as the main active species by quenching experiments and electron paramagnetic resonance (EPR). During degradation, the first site attacked by e was the ether bond (C6-O7), followed by the generation of HFPO-DA, TFA, acetic and formic acid. Degradation studies of other HFPOs have shown that the defluorination of HFPOs was accompanied by a clear chain-length correlation. At last, toxicological experiments confirmed the safety of the process. This study updated our understanding of the degradation of newly PFASs and the application of e mediated photoreductive approaches under mild conditions.

中文翻译：

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新型六氟环氧丙烷低聚酸在温和条件下通过紫外线/亚硫酸盐/碘化物有效脱氟：机制和生态毒性


最近发现HFPO-TA（含氟聚合物生产中的加工助剂）具有高水平的生物蓄积性和生物毒性。水合电子 (e) 被认为是可以分解 PFAS 的有效亲核试剂。与之前的研究不同，e的产生通常局限于厌氧或高碱性环境，在本研究中，我们在中性、低化学源需求和露天的温和条件下应用了UV/SO/I工艺，实现了HFPO-TA 的有效降解（81.92 %，0.834 h）和脱氟（48.99 %，0.312 h）。由于 I 作为 e 的主要来源，SO 作为 I 再生剂和氧化物质清除剂，UV/SO/I 在温和条件下优于其他物质。通过猝灭实验和电子顺磁共振（EPR）鉴定出e是主要活性物质。在降解过程中，e攻击的第一个位点是醚键（C6-O7），随后生成HFPO-DA、TFA、乙酸和甲酸。其他 HFPO 的降解研究表明，HFPO 的脱氟伴随着明显的链长相关性。最后，毒理学实验证实了该工艺的安全性。这项研究更新了我们对新型 PFAS 的降解以及温和条件下 e 介导的光还原方法的应用的理解。