Degradation and Ecotoxicity Mitigation of Perfluorooctane Sulfonate by Aeration-Assisted Cold Plasma

Various advanced oxidation processes have been used to degrade perfluorooctane sulfonate (PFOS), one of the persistent organic pollutants that dissolves in aquatic ecosystems, but these processes suffer from inherent limitations. This study proposes aeration-assisted cold plasma (CP) technology as an alternative. PFOS removal via CP treatment reached 62.5% after 1 h of exposure, with a degradation rate constant of 3.1 h⁻¹. The detection of sulfate (SO₄²⁻) in the solution provides evidence of effective PFOS degradation. The close agreement between the measured and estimated fluoride concentrations further confirms mass balance after degradation. Acute toxicity tests indicate that PFOS degradation may initially increase the acute toxicity, possibly due to the formation of degradation by-products. However, this increased toxicity can be mitigated through additional exposure to the reactive species generated by CP. Furthermore, investigations into the energy per order of CP and the quantification of hydroxyl radicals support its operational effectiveness. This study confirms that aeration-assisted CP has the potential to serve as a viable treatment option for mitigating the environmental threats posed by PFOS.