Perfluorooctanoic acid (PFOA), a synthetic persistent and bio-accumulative chemical, has raised global concerns. PFOA oxidation by advanced oxidation technology (AOPs) begins with decarboxylation, followed by CF 2 groups unzipping cycle and C–F cleavage. Since reactive radicals (even •OH) cannot initiate decarboxylation and abundant low-toxicity organics hinders decarboxylation, presents significant challenges for defluorination. We designed a functionalized high-index (201) TiO 2 photoanode (S-TiO 2,201 ) capable of molecular recognition and activation, which switches PFOA adsorption from carboxyl groups to preferential adsorption via the perfluoroalkyl backbone. This adsorption configuration selectively recognizes PFOA and accelerates decarboxylation via direct hole oxidation. In situ electron paramagnetic resonance (EPR) confirmed faster decarboxylation and •OH quantification showed hole utilization efficiency rising from 9.6 % to 39.3 % after functionalization. PFOA was selectively removed from 200 μg/L to 1.2 μg/L with 1000-fold humic acid interference. This work presents a strategy for efficient and selective PFOA removal by precisely modulating its adsorption configuration.
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 (CeO 2 /mSiO 2 ) heterojunction photocatalysts for complete defluorination of organofluorine contaminants, including fluorinated e-waste, fluoro-antibiotics and perfluorinated surfactant. Under visible light irradiation, the optimized 5%CeO 2 /mSiO 2 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.
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