Catalytic degradation of ciprofloxacin by a visible-light-assisted peroxymonosulfate activation system: Performance and mechanism

Fei Chen; Gui-Xiang Huang; Fu-Bing Yao; Qi Yang; Yu-Ming Zheng; Quan-Bao Zhao; Han-Qing Yu

doi:10.1016/j.watres.2020.115559

Catalytic degradation of ciprofloxacin by a visible-light-assisted peroxymonosulfate activation system: Performance and mechanism

Water Res. 2020 Apr 15:173:115559. doi: 10.1016/j.watres.2020.115559. Epub 2020 Jan 28.

Authors

Fei Chen¹, Gui-Xiang Huang¹, Fu-Bing Yao², Qi Yang², Yu-Ming Zheng³, Quan-Bao Zhao³, Han-Qing Yu⁴

Affiliations

¹ CAS Key Laboratory of Urban Pollutant Conversion, Department of Applied Chemistry, University of Science & Technology of China, Hefei, China.
² College of Environmental Science and Engineering, Hunan University, Changsha, 410082, China; Key Laboratory of Environmental Biology and Pollution Control (Hunan University), Ministry of Education, Changsha, 410082, China.
³ CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China.
⁴ CAS Key Laboratory of Urban Pollutant Conversion, Department of Applied Chemistry, University of Science & Technology of China, Hefei, China; CAS Key Laboratory of Urban Pollutant Conversion, Institute of Urban Environment, Chinese Academy of Sciences, Xiamen, 361021, China. Electronic address: hqyu@ustc.edu.cn.

PMID: 32028250
DOI: 10.1016/j.watres.2020.115559

Abstract

Peroxymonosulfate (PMS) is extensively used as an oxidant to develop the sulfate radical-based advanced oxidation processes in the decontamination of organic pollutants and various PMS activation methods have been explored. Visible-light-assisted PMS activation to construct a Fenton-like process has shown a great potential for pollution control. In our work, BiVO₄ nanosheets were prepared using a hydrothermal process and used to activate PMS under visible light. A rapid degradation of ciprofloxacin (CIP) was achieved by dosing PMS (0.96 g/L), BiVO₄ (0.32 g/L) under visible light with a reaction rate constant of 77.72-fold higher than that in the BiVO₄/visible light process. The electron spin resonance and free radical quenching experiments indicate that reactive species of ^•O₂^-, h⁺, •OH and SO₄^•- all worked, where h⁺, •OH and SO₄^•- were found as the dominant contributors to the CIP degradation. The spectroscopic analyses further demonstrate that the photoinduced electrons were directly involved in the PMS activation process. The generated ^•O₂^- was partially utilized to activate PMS and more •OH was produced because of the chain reactions between SO₄^•- and H₂O/OH^-. In this process, PMS acted as an electron acceptor to transfer the photo-induced charges from the conduction band of BiVO₄ and PMS was successfully activated to yield the high-powered oxidative species. From the degradation intermediates of CIP detected by a liquid-chromatography-mass spectrometer, the possible degradation pathways were proposed. The substantially decreased toxicity of CIP after the reaction was also observed. This work might provide new insights into the visible-light-assisted PMS activation mechanisms and is useful to construct environmentally-friendly catalytic processes for the efficient degradation of organic pollutants.

Keywords: BiVO(4); Catalytic degradation; Mechanism; Peroxymonosulfate; Visible light; Water treatment.

MeSH terms

Catalysis
Ciprofloxacin*
Light
Peroxides*

Substances

Peroxides
peroxymonosulfate
Ciprofloxacin