Complete defluorination of per- and polyfluoroalkyl substances — dream or reality?

The consensus of removing per- and polyfluoroalkyl substances (PFAS) from the environment is widely recognized and enlightened by the near-zero standards released from the U.S. Environmental Protection Agency in 2023. The only way to achieve the goal of zero fluoro-pollution is to fully defluorinate or mineralize PFAS, but current technologies only partially defluorinate a limited number of PFAS, which can lead to the creation of potentially more toxic short-chain intermediates. Therefore, we discuss herein the need to broaden the scope of tested PFAS, summarize the state-of-the-art degradation technologies, and provide perspectives to achieve complete defluorination. Besides fundamental knowledge gaps in defluorination reactions, technological gaps in the aspects of water matrix effects, pilot tests, and cost analysis also limit the application and comparison of different treatment technologies. This work would shed light on further research to find solutions in the complete defluorination of PFAS.