Efficient degradation of ciprofloxacin by magnetic γ-Fe2O3–MnO2 with oxygen vacancy in visible-light/peroxymonosulfate system

In this work, the magnetic γ-Fe 2 O 3 –MnO 2 bifunctional catalyst with oxygen vacancy was synthesized for peroxymonosulfate (PMS) activation under visible light. The activity of γ-Fe 2 O 3 –MnO 2 was investigated by ciprofloxacin (cipro) degradation. Results showed that 98.3% of cipro (50 μM) was removed within 30 min in visible-light/PMS system mediated by γ-Fe 2 O 3 –MnO 2 (2:1) with fine-tuned oxygen vacancy. The cipro degradation data fitted well with pseudo-first-order kinetic model with the highest kinetic constant of 0.114 min −1 . Besides, the γ-Fe 2 O 3 –MnO 2 exhibited stability, recyclability and practicability. High selectivity for cipro degradation was observed with coexisting anions in visible-light/γ-Fe 2 O 3 –MnO 2 /PMS system. Furthermore, the enhanced mechanism of PMS activation under visible light with γ-Fe 2 O 3 –MnO 2 was proposed. The appropriate oxygen vacancy enhanced the separation of photo-induced carriers and Z scheme heterostructure maintained the highest redox potential . Accordingly, the synergistic effect of photocatalysis and PMS activation enhanced cipro degradation. Free radical and non-radical species including , h + , 1 O 2 , • OH and co-existed in the coupled system. Impressively, this study provides a handy approach for oxygen vacancy regulation in metallic oxides composite and an easily recycled catalyst with high-activity in coupled oxidation system towards antibiotic degradation.