Electron Beam-Based Remediation of PFAS-Contaminated Waters: Optimization, Mechanisms, and Application to Real...

Electron beam (e-beam) irradiation generates reactive oxidative and reductive species via water radiolysis, providing a powerful, chemical-free approach for degrading per- and polyfluoroalkyl substances (PFAS) in water. This study systematically evaluated the e-beam-mediated transformation of perfluorooctanoate (PFOA), perfluorooctanesulfonate (PFOS), and related PFAS under controlled conditions using a pulsed 10 MeV linear accelerator and commercial high-power systems. Unlike prior proof-of-concept studies, this work establishes quantitative dose-response relationships, kinetic models, and structure-reactivity trends across PFAS classes under environmentally realistic conditions. Near-complete destruction of PFOA and PFOS to inorganic fluoride and sulfate occurred at 100-200 kGy and 200-300 kGy, respectively, with highest removal (>99%) under alkaline (pH 13), low-oxygen (<5 mg L^-1 DO), and moderate dose-rate (≤1.2 kGy s^-1) conditions. Kinetic analyses indicated single-first-order behavior for PFOA (DT₅₀ = 6.2 s) and biphasic degradation for PFOS best described by a double-first-order-in-parallel model, implying two reactive sites for hydrated electron (e^-_aq) attack. Matrix tests using groundwater, wastewater, reverse osmosis reject water, and ion-exchange regenerant showed >95% total PFAS removal except in organic-rich RO reject water (∼50%). These findings define dose- and matrix-dependent thresholds and mechanisms for PFAS degradation, supporting e-beam irradiation as a scalable destructive remediation technology.