ZIF-67-derived monolithic bimetallic sulfides as efficient persulfate activators for the degradation of ofloxacin

In this study, we successfully synthesized ZIF-67 material on three-dimensional (3D) nickel foam (NF) substrate by co-precipitation method, and then fixed CoSx on NF by hydrothermal vulcanization method to form CoSx/NF. The optimized CoSx/NF can effectively activate peroxymonosulfate (PMS) and improve the degradation efficiency of ofloxacin (OFL). The effects of PMS dosage, reaction temperature, initial pH and co-existing ions on the degradation effect of OFL were investigated in detail. CoSx/NF (1 piece 2 × 2 cm) and PMS (1 mM) in an aqueous solution (pH = 7) degraded 85 % of OFL (20.0 mg/L) within 45 min. This favorable degradation performance is mainly attributed to the enhanced electron transfer capability introduced by the bimetallic material. In addition, CoSx/NF still maintained high degradation effect and stable structure after 5 cycles. Quenching experiments further revealed that radicals •OH and 1O2 play a major role in degrading OFL. In addition, the degradation pathway, ecotoxicity evaluation and degradation mechanism of OFL were comprehensively investigated. In summary, the CoSx/NF catalyst proved to be a highly efficient, stable and recyclable heterogeneous composite, and opened up the possibility of using Metal-organic framework (MOF) derivatives in fields such as wastewater treatment.