Solar-driven defluorination via hydroxyl radical spillover for complete mineralization of organofluorine pollutants without fluoride byproducts.

Abstract

The recalcitrance of fluorinated organic pollutants-featuring robust Csp²-F and Csp³-F bonds-poses critical challenges to aquatic ecosystems due to their extreme persistence and bioaccumulation. Whereas current destruction strategies suffer from high energy consumption and non-selective, here we present a solar-powered mineralization strategy utilizing cerium oxide/mesoporous silica (CeO₂/mSiO₂) heterojunction photocatalysts for complete defluorination of organofluorine contaminants, including fluorinated e-waste, fluoro-antibiotics and perfluorinated surfactant. Under visible light irradiation, the optimized 5%CeO₂/mSiO₂ achieved 91.1 ± 3.2% octafluorobiphenyl (OFB) and 97.7 ± 2.8% fleroxacin (FLE) degradations within 6 h. Notably, the 'forever chemical' perfluorooctanesulfonic acid (PFOS) can be effectively destructed, achieving a maximum of 25.9 ± 2.7% reduction in 5 days under sunshine, outperforming parallel experiments conducted without a catalyst (~0%). This process notably avoids the evolution of fluoride ions. Theoretical calculations reveal that the removal of C-F bonds by photogenerated hydroxyl radical is thermodynamically superior to hydroxyl-mediated defluorination. This work establishes an energy-efficient paradigm for eradicating "forever chemicals" without secondary pollution, advancing sustainable water remediation technologies.