Chen Zhanghao, Dong Ruochen, Wang Xinhao, Huang Liuqing, Qiu Longlong, Zhang Ming, Mi Na, Xu Min, He Huan, Gu Cheng
State Key Laboratory of Pollution Control and Resource Reuse, School of Environment, Nanjing University, Nanjing 210023, P. R. China.
Department of Environmental Engineering, College of Biology and the Environment, Nanjing Forestry University, Nanjing 210037, P. R. China.
Environ Sci Technol. 2024 Feb 8. doi: 10.1021/acs.est.3c08453.
Perfluoroalkyl substances (PFAS) are a class of persistent organic pollutants known as "forever chemicals". Currently, the hydrated electron-based advanced reduction process (ARP) holds promise for the elimination of PFAS. However, the efficiency of ARP is often challenged by an oxygen-rich environment, resulting in the consumption of hydrated electron source materials in exchange for the high PFAS decomposition efficiency. Herein, we developed a ternary system constructed by indole and isopropyl alcohol (IPA), and the addition of IPA significantly enhanced the PFOA degradation and defluorination efficiency in the presence of low-concentration indole (<0.4 mM). Meanwhile, opposite results were obtained with a higher amount of indole (>0.4 mM). Further exploring the molecular mechanism of the reaction system, the addition of IPA played two roles. On one hand, IPA built an anaerobic reaction atmosphere and improved the yield and utilization efficiency of hydrated electrons with a low concentration of indole. On the other hand, IPA suppressed the attraction between indole and PFOA, thus reducing the hydrated electron transfer efficiency, especially with more indole. In general, the indole/PFAS/IPA system significantly improved the PFAS destruction efficiency with a small amount of hydrated electron donors, which provided new insights for development of simple and efficient techniques for the treatment of PFAS-contaminated wastewater.
全氟烷基物质（PFAS）是一类被称为“永久化学物质”的持久性有机污染物。目前，基于水合电子的高级还原过程（ARP）有望用于消除PFAS。然而，ARP的效率常常受到富氧环境的挑战，导致水合电子源材料被消耗，以换取高PFAS分解效率。在此，我们开发了一种由吲哚和异丙醇（IPA）构建的三元体系，在低浓度吲哚（<0.4 mM）存在下，IPA的添加显著提高了全氟辛酸（PFOA）的降解和脱氟效率。同时，当吲哚含量较高（>0.4 mM）时，得到了相反的结果。进一步探索反应体系的分子机制，IPA的添加起到了两个作用。一方面，IPA营造了厌氧反应氛围，提高了低浓度吲哚条件下水合电子的产率和利用效率。另一方面，IPA抑制了吲哚与PFOA之间的吸引力，从而降低了水合电子转移效率，尤其是在吲哚含量较高时。总体而言，吲哚/PFAS/IPA体系用少量水合电子供体显著提高了PFAS的破坏效率，为开发处理受PFAS污染废水的简单高效技术提供了新的见解。
