Micelle-Mediated Hydrated Electron Capture Enables Efficient C-F Bond Activation and PFAS Mineralization.

Per- and polyfluoroalkyl substances (PFAS) present a major challenge in environmental remediation due to their extreme persistence and resistance to conventional chemical treatments. While recent advances in reductive approaches using hydrated electrons (eaq-) have shown promise for C-F bond activation, most require high photosensitizer loadings, suffer from poor electron utilization, and lack compatibility with diverse PFAS structures. Here, we report a micellar photocatalytic system using the cationic surfactant cetyltrimethylammonium bromide (CTAB) under UV irradiation to enhance eaq- utilization for PFAS degradation. A diverse range of legacy and emerging PFAS compounds containing sulfonate (-SO3-), carboxylate (-CO2-), hydrocarbon (-C2H2-), and ether (-O-) moieties, were completely degraded with fewer than four C-F bonds remaining in transformation products. Characterization revealed strong interactions between CTAB and PFAS, which spontaneously formed positively charged cationic-anionic micelles even at low concentrations. These micelles act as nanoreactors, trapping eaq- from the bulk phase, suppressing geminate recombination, and facilitating direct electron transfer to PFAS molecules. A comprehensive degradation pathway was identified, involving micellization, electron trapping, PFAS activation, and downstream radical-mediated reactions that lead to further destruction. The UV/CTAB system demonstrated sustained performance across multiple treatment cycles and exhibited resilience to oxygen and common aqueous cocontaminants. These findings reveal that efficient utilization of eaq-, rather than their abundance, governs C-F bond activation and PFAS degradation. This approach enables integrated PFAS separation and mineralization while establishing a framework for designing scalable, photosensitizer-free redox systems.