Rapid photo-reductive destruction of hexafluoropropylene oxide trimer acid (HFPO-TA) by a stable self-assembled micelle system of producing hydrated electrons

Abstract

Herein, we developed a self-assembled micelle system to decompose/defluorinate HFPO-TA (an alternative perfluoroalkyl substances (PFASs)) under ambient conditions by using three hydroxyphenylacetic acids (2-HPA, 3-HPA, 4-HPA) as hydrated electron precursors under UV irradiation, and using cationic surfactant cetyl trimethyl ammonium bromide (CTAB) to construct the micelle structure. The formed HPAs/CTAB/HFPO-TA micelles were well characterized. All the three micelle systems could efficient destruct HFPO-TA, while 2-HPA/CTAB/HFPO-TA self-assembled micelle showed the best stability under a wide pH range from 4 to 10 attributing to its tighter micelle structure and lower surface charge density. Moreover, natural organic matter (<10 mg L-1) plays little inhibition for the 2-HPA/CTAB/HFPO-TA system. This novel ternary micelle system not only maintains the high efficiency under the conditions of oxygen enrichment, but also keeps well performance in varied pH conditions. The high decomposition/defluorination efficiency and anti-interference capability of the 2-HPAs/CTAB/HFPO-TA micelle system make it a promising technology for treating the PFASs contaminating wastewater.