The exceptional stability of C-F bonds renders PFAS highly persistent in aqueous environments, posing significant challenges for conventional treatment technologies. While plasma-based technologies show promise, their efficiency is often limited by poor gas–liquid mass transfer in bulk liquid. Here, an in-house constructed ultrasonic atomization–dielectric barrier discharge (UEN-DBD) system was developed to promote PFAS degradation under non-thermal plasma conditions. Ultrasonic atomization generated microdroplets, which promoted PFAS enrichment at the surface of microdroplets and facilitate interactions with plasma-generated reactive species. Using perfluorooctanoic acid (PFOA) and perfluorooctanesulfonate (PFOS) as model compounds, degradation behavior was evaluated over an initial concentration range of 0.01–1.0 ppm. At 0.01 ppm, degradation efficiencies of 96.06% for PFOA and 94.86% for PFOS were achieved within 5 min. Electron paramagnetic resonance (EPR) spectroscopy confirmed the formation of oxidative radicals (·OH) and suggested a mixed redox environment involving reactive species, potentially including superoxide (O2·−) or hydrated electrons (eaq−), in the discharge-treated system. High-resolution mass spectrometry results are consistent with a stepwise chain-shortening pathway dominated by successive –CF2– scission, while fluoride-release measurements provided supporting evidence for partial defluorination. These findings advance the understanding of plasma-assisted PFAS degradation at the gas–liquid interface and provide a basis for the further development of plasma-assisted PFAS treatment strategies.
Chen et al. (2026) studied this question.