Enhanced electron transfer for activation of peroxymonosulfate via MoS₂ modified iron-based perovskite

The increasing use of fluoroquinolone antibiotics, which are found in various environmental media, is a constant threat to ecological safety and human health. In this paper, SrFeO₃@MoS₂ heterogeneous catalyst was prepared to activate peroxymonosulfate (PMS) for the degradation of levofloxacin (LVO). The characteristics of SrFeO₃@MoS₂ samples were studied and the optimum conditions for the removal of LVO by SrFeO₃@MoS₂/PMS system were investigated. The removal of LVO by the SrFeO₃@MoS₂-0.3/PMS system could reach 96.06% within 20 min of reaction. The effect of inorganic anions (SO₄^2-, Cl^-, NO₃^- and H₂PO₄^-) commonly found in actual water bodies on catalytic reaction was explored. The reusability investigation revealed that the catalyst could still remove 88.06% of LVO within 20 min after four cycles. Moreover, SO₄^•-, ^•OH and ¹O₂ were identified by Electron Paramagnetic Resonance (EPR) tests and scavenger experiments, where the SO₄^•- and ^•OH were dominant reactive species. Combining with the XPS characterisation, the activation mechanism of SrFeO₃@MoS₂-0.3/PMS was proposed, and the oxygen vacancies and transition metals on the sample surface were active sites of PMS activation. Furthermore, the possible degradation pathways of LVO were well-established based on the detected intermediates.