Persulfate-enhanced degradation of ciprofloxacin with SiC/g-C3N4 photocatalyst under visible light irradiation

Hongqing Zhu; Bing Yang; Jingjing Yang; Ying Yuan; Jinzhong Zhang

doi:10.1016/j.chemosphere.2021.130217

Persulfate-enhanced degradation of ciprofloxacin with SiC/g-C₃N₄ photocatalyst under visible light irradiation

Chemosphere. 2021 Aug:276:130217. doi: 10.1016/j.chemosphere.2021.130217. Epub 2021 Mar 15.

Authors

Hongqing Zhu¹, Bing Yang², Jingjing Yang³, Ying Yuan², Jinzhong Zhang⁴

Affiliations

¹ College of Resources and Environment, Southwest University, Chongqing Key Laboratory of Agricultural Resources and Environment, Chongqing, 400715, PR China; School of Environment and Quality Test, Chongqing Chemical Industry Vocational College, Chongqing, 401228, China.
² School of Environment and Quality Test, Chongqing Chemical Industry Vocational College, Chongqing, 401228, China.
³ School of Environment and Quality Test, Chongqing Chemical Industry Vocational College, Chongqing, 401228, China. Electronic address: hahajing1229@163.com.
⁴ College of Resources and Environment, Southwest University, Chongqing Key Laboratory of Agricultural Resources and Environment, Chongqing, 400715, PR China. Electronic address: jzhzhang@swu.edu.cn.

PMID: 34088097
DOI: 10.1016/j.chemosphere.2021.130217

Abstract

SiC/g-C₃N₄ composite (SCN) showed the potential for photocatalytic degradation of synthetic dyes, it is deserved to study whether it is effective for the photocatalytic degradation of ciprofloxacin (CIP). In this work, persulfate-enhanced CIP degradation was investigated with SCN under visible light irradiation. The results showed that the degradation efficiency of 10 mg L^-1 CIP could reach 95% for 30 min under the conditions of 0.4 g L^-1 SCN, 2 mM persulfate (PS) and solution initial pH 6. The degradation process abided by pseudo ﬁrst-order kinetic equation, and the observed rate constant (k_obs) with SCN/PS (0.132 min^-1) was 13 times of that with SCN (0.0102 min^-1), and twice of that with g-C₃N₄/PS (0.0649 min^-1). The quenching experiments and electron paramagnetic resonance analysis indicated that O₂^-· and ¹O₂ played the main role and other active species (e.g., h⁺, SO₄^-· and ·OH) also participated in CIP degradation. The possible degradation pathways were proposed through identifying the intermediate products, and the main reactions may include the ring opening of piperazine, decarbonylation, decarboxylation and defluorination. Bacterial toxicity test showed that the toxicity of the reaction solution decreased dramatically after 30 min degradation. Overall, this work could provide an efficient and environmentally friendly technology for eliminating CIP.

Keywords: Antibiotic; Biotoxicity change; Degradation pathways; Metal-free photocatalyst; Potassium persulfate.

MeSH terms

Ciprofloxacin*
Kinetics
Light*

Substances

Ciprofloxacin