An efficient photocatalytic activation of persulfate oxidation process by Fe-N-C@ZnO for degradation of enrofloxacin, naphthalene, and crude oil:Performance and mechanism

Water pollution has been worsened by increasing human activities, involving both water-soluble and non-water-soluble contaminants. In this study, a Fe-N-C@ZnO activated PS-AOP (persulfate advanced oxidation process) system was developed through the combination of photocatalysis and PS (persulfate) activation for pollutant degradation in freshwater and seawater. First, the optimal performance was determined by adjusting the Fe-N-C@ZnO to PS ratio, with the best results achieved at 5:3. The degradation efficiency and mechanisms were then examined across different pollutant types. Higher degradation rates were observed in the Fe-N-C@ZnO activated PS-AOP system compared to PS alone, in freshwater, improvements of 70.87%, 61.63%, and 46.26% were recorded for enrofloxacin (ENR), naphthalene, and crude oil, respectively. And in seawater, the increases were 57.53%, 46.87%, and 31.49%. Through radical quenching experiments, h⁺, e⁻, and SO 4 ·⁻ were identified as the dominant reactive species. Additionally, DI-MS analysis was used to propose four degradation pathways for ENR (three Piperazine-Routes and one Quinolone-Route) and two pathways for naphthalene (Benzene ring hydroxylation and Tautomerization). Download: Download high-res image (198KB) Download: Download full-size image