Dual acceleration of Co(III)/Co(II) redox cycle boosts peroxymonosulfate activation for superfast chloramphenicol degradation

Co-based nanomaterials have been proven as excellent catalysts in activating peroxymonosulfate (PMS), owing to the high adsorption ability and efficient electron transfer toward PMS molecules. However, the slow Co sites regeneration induced by HSO 5 − /SO 5 – redox cycle alone not only deteriorates the utilization efficiency of PMS, but also restricts the overall catalytic reaction rate. Herein, we report a novel S-FeCoO nano-catalyst to active PMS for chloramphenicol (CAP) degradation. As a result, up to 97.73 % of removal efficiency was achieved within 30 min even with an initial CAP concentration of 50 mg/L, which is substantially superior to other Co or Fe-based PMS activation systems. More importantly, synergistic effects arising from the coexisting Fe and S species were identified by the control experiments and characterization results. Co served as the primary active site, while Fe(II) and S 2− /S 2 2− greatly accelerated Co(III)/Co(II) redox cycle by donating electrons. The proposed strategy of dual acceleration of Co(III)/Co(II) redox cycle, as well as its mechanism insights, is expected to provide important implications on the rational design of advanced catalysts for PMS activation.