Hot topic: thermal treatment of per- and polyfluoroalkyl substances

Abstract

Per- and polyfluoroalkyl substances’ (PFAS) unique chemical properties define modern expectations of synthetic chemistry for diverse consumer products and industrial applications. That same chemistry becomes problematic at the end of PFAS-containing material life cycles. Safe disposal of PFAS is important to mitigate adverse human health and ecotoxicological effects. Thermal treatment is reported to be effective in defluorinating and mineralizing many PFAS. However, thermal technologies are energy-intensive and have the potential to create harmful by-products, including fluorinated products of incomplete combustion. In this work, we critically review recent advances in thermal treatment, focusing on mature technologies such as combustion and pyrolysis plus other promising options such as alkaline hydrothermal processes, sonolysis, and supercritical water oxidation. Furthermore, we propose that thermal treatment not be used as a sole method for PFAS destruction but as a treatment train component following the separation and concentration of PFAS from impacted environmental media.