Enhanced mitigation of membrane fouling and degradation of perfluorooctanoic acid in the treatment of natural surface water through the application of dielectric barrier discharge/sulfite

Abstract

The present study employed a dielectric barrier discharge (DBD)/sulfite system to mitigate membrane fouling and enhance the degradation of perfluorooctanoic acid (PFOA) in surface water. Results showed that the membrane flux was remarkably enhanced by 93.6%, and the degradation of PFOA showed an impressive increase of 87.9%. The synergistic redox effect of free radicals, including hydroxyl radical (•OH), sulfate radical (SO4∙-), electron (e-/eaq-), su-peroxide anion radicals (∙O2-), and other radical, played a crucial role in mitigating membrane fouling, accounting for 36.26%, 30.10%, 18.69%, 6.75%, and 8.20%, respectively. The correlation analysis revealed that effective removal of UV254 and TOC emerged as the most crucial factors positively contributing to mitigating membrane fouling. Additionally, SO4∙-, •OH, and eaq- were identified as the primary active substances responsible for attacking PFOA, accounting for 41.30%, 25.20%, and 23.70%, respectively. The degradation pathway of PFOA was proposed through analysis using density functional theory and mass spectrometry, reducing the biotoxicity of its degradation products. This study presents a suitable strategy for simultaneous mitigation of membrane fouling and enhancement of PFOA degradation, which holds great potential for advancing the field of water treatment towards practical applications.