H-driven degradation of PFAS in the gas/liquid interface using electrochemistry configuration of cold plasma

Plasma water treatment has emerged as a powerful technology capable of abate perfluoroalkyl substances (PFAS) in water matrices. With the electrochemical configuration and cathodic polarity, the electrified plasma/liquid interface (EPLI) not only produces in-situ hydrated electrons ( ) that readily react with PFAS, but also produced radicals in the plasma effluent. This study uses chemical reaction networks (CRN) to investigate the chemical pathways of PFAS degradation by EPLI-induced , allowing for a direct comparison with the bench experiments of Stratton et al. (Environ. Sci. Technol. 2017, 51, 3, 1643) and Alam et al. (Chemical Engineering Journal, 2024, 489, 151349). The computational results indicate that Perfluorooctanoic Acid (PFOA) degradation by EPLI-induced has a Faradaic efficiency of less than 0.01% given the typically low concentration of PFOA in water matrices, meaning that the majority of engages with water reduction, generating gaseous hydrogen. EPLI-induced alone cannot account for the energy efficiency observed in bench experiment of Stratton et al. and Alam et al., suggesting the presence of other plasma-induced radicals. This work evaluates the gas-phase H radical as crucial for degrading PFOA at the gas/liquid interface, which is created by the plasma effluent in contact with the water matrix. This work paves the way for construct effective plasma-based industrial reactors to degrade PFAS, suggesting the formation of radical-H in the plasma effluent as a key parameter to be optimized.