PVDF ‐Pyrolyzed Fluorine‐Doped TiO ₂ for Synergistic Adsorption‐Enhanced PFOA Photocatalysis

ABSTRACT Per‐ and polyfluoroalkyl substances (PFAS), notably perfluorooctanoic acid (PFOA), are persistent pollutants posing health risks via bioaccumulation and water mobility. While TiO ₂ photocatalysis for PFOA degradation is well‐reported, efficiency falters in dilute environments due to weak adsorption and rapid charge recombination. This study presents a novel hybrid approach with surface‐modified TiO ₂ designed to enhance PFOA adsorption while enabling simultaneous degradation. Fluorine‐doped TiO ₂ (F‐TiO ₂ ) was synthesized through cost‐effective, one‐step PVDF pyrolysis, promoting nanopores and hydrophobic interactions for PFOA enrichment alongside improved charge separation. UV–vis spectroscopy and UVC tests (254 nm, 1.59 mW/cm ² ) with sodium persulfate showed F‐TiO ₂ achieving ~92% PFOA removal at 700 mg/L (vs. ~58% for pristine TiO ₂ ), with nine‐fold faster kinetics (rate constant: 0.217 h ⁻¹ vs. 0.024 h ⁻¹ ; half‐life: ~3.2 h vs. ~28 h). IC analysis confirmed partial PFOA mineralization, with ~25 ppm F ⁻ detected after 16 h UV irradiation, indicating significant defluorination. Unlike noble‐metal or graphene variants, F‐TiO ₂ exploits fluorine for adsorption‐photocatalysis synergy, providing an economical, scalable PFAS remediation in low‐concentration waters. image