Complete Aqueous Defluorination of GenX (Hexafluoropropylene Oxide Dimer Acid Anion) by Pulsed Electrolysis with Polarity Reversal

Abstract

Per- and polyfluoroalkyl substances (PFAS) are extremely stable chemicals that are essential for modern life and decarbonization technologies. Yet PFAS are persistent pollutants that are harmful to human health. Hexafluoropropylene oxide dimer acid (GenX), a replacement for the PFAS chemical perfluorooctanoic acid, continues to pollute waterways. In this study, we report the complete defluorination of GenX through electrocatalysis in aqueous LiOH electrolytes, utilizing high surface area anodes consisting of pulsed laser in liquid synthesized [NiFe]-(OH)₂ nanocatalysts on hydrophilic carbon fiber paper. Additional experiments with industrial nickel–iron alloy demonstrated exceptional stability for >100 hours. Including a brief interval of reversed polarity in pulsed electrolysis and optimizing the pulse train sequence enabled the complete defluorination of GenX. Our facile approach employs only nonprecious materials, does not require bisulfate or other auxiliary chemical agents that are consumed, and thus provides a promising strategy for alleviating the environmental impact of PFAS pollutants.