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

• Published in: Chemosphere (Oxford) Vol. 276; p. 130257
• Main Authors: Zhao, Jianhui, Wang, Yuanzhou, Li, Ning, Wang, Shaopo, Yu, Junli, Li, Xinxin
• Format: Journal Article
• Language: English
• Published: Elsevier Ltd 01.08.2021
• Subjects: Ciprofloxacin degradation; Mechanism; Oxygen vacancy; Peroxymonosulfate; Photocatalysis; Peroxymonosulfate; Photocatalysis; Mechanism; Oxygen vacancy; Ciprofloxacin degradation
• ISSN: 0045-6535; 1879-1298
• DOI: 10.1016/j.chemosphere.2021.130257

In this work, the magnetic γ-Fe2O3–MnO2 bifunctional catalyst with oxygen vacancy was synthesized for peroxymonosulfate (PMS) activation under visible light. The activity of γ-Fe2O3–MnO2 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-Fe2O3–MnO2 (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-Fe2O3–MnO2 exhibited stability, recyclability and practicability. High selectivity for cipro degradation was observed with coexisting anions in visible-light/γ-Fe2O3–MnO2/PMS system. Furthermore, the enhanced mechanism of PMS activation under visible light with γ-Fe2O3–MnO2 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+, 1O2, •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. [Display omitted] •The oxygen vacancy on γ-Fe2O3–MnO2 was adjusted by the amorphous MnO2 proportion.•Appropriate amount of oxygen vacancy promoted the charge separation.•Cipro was degraded efficiently in visible-light/γ-Fe2O3–MnO2/PMS system.•Radical and non-radical processes were involved in cipro degradation.•The synergy of photocatalysis and PMS activation enhanced cipro degradation.