Room-temperature defluorination of PTFE and PFAS via sodium dispersion
Taichi Araki, Hibiki Ota, Yusuke Murata, Yuji Sumii, Jin Hamaura, Hiroaki Adachi, Takumi Kagawa, Hisao Hori, Jorge Escorihuela, Norio Shibata
Abstract
Polytetrafluoroethylene (PTFE) and other fluoropolymers are widely used because of their exceptional chemical resistance and thermal stability. However, their disposal poses a significant environmental challenge. Conventional methods for degrading PTFE either require high temperatures or rely on complex reagents and often neglect efficient fluorine recovery. Herein, we present an approach for the room-temperature defluorination of PTFE using sodium dispersion, enabling the conversion of PTFE into sodium fluoride (NaF) under mild conditions. This method not only eliminates the need for elevated temperatures, but also demonstrates high yields of fluoride ion recovery, reaching up to 97% under optimized conditions. We further extend the application of this method to non-polymer, per- and polyfluoroalkyl substances (PFAS), including perfluorononanoic acid (PFNA), perfluorooctanoic acid (PFOA), perfluorobutanesulfonic acid (PFBS) and trifluoroacetic acid (TFA), achieving similarly high yields of NaF with appropriate adjustments of the reaction time and reagent amounts. The disposal of PTFE and PFAS poses major environmental concerns. Here, the authors demonstrate their efficient defluorination at room temperature using sodium dispersion, converting these persistent pollutants into recoverable sodium fluoride.