journal of environmental sciences 100 (2021) 203–215 Available online at www.sciencedirect.com w w w . e l s e v i e r . c o m / l o c a t e / j e s Green and effcient degradation of cefoperazone sodium by Bi 4 O 5 Br 2 leading to the production of non-toxic products: Performance and degradation pathway Yingying Chen 1, 3 , Ruiping Li 2, 3 , Yan Gu 2, 3 , Hailin Tian 2, 3 , Yingping Huang 2, 3,* , Junsong Chen 3 , Yanfen Fang 1, 3 , Changying Yang 1, 3, * 1 College of Biology and Pharmacy, China Three Gorges University, Yichang, 443002, China 2 College of Hydraulic and Environmental Engineering, China Three Gorges University, Yichang, 443002, China 3 Engineering Research Center of Eco-environment in Three Gorges Reservoir Region, Ministry of Education, China Three Gorges University, Yichang, 443002, China a r t i c l e i n f o Article history: Received 18 March 2020 Revised 25 July 2020 Accepted 27 July 2020 Keywords: Bi 4 O 5 Br 2 Cefoperazone sodium Photocatalytic activity Degradation products a b s t r a c t Photocatalytic process represents a promising approach to overcome the pollution chal- lenge associated with the antibiotics-containing wastewater. This study provides a green, effcient and novel approach to remove cephalosporins, particularly cefoperazone sodium (CFP). Bi 4 O 5 Br 2 was chosen for the frst time to systematically study its degradation for CFP, including the analysis of material structure, degradation performance, the struc- ture and toxicity of the transformation products, etc. The degradation rate results indi- cated that Bi 4 O 5 Br 2 had an excellent catalytic activity leading to 78% CFP removal com- pared with the pure BiOBr (38%) within 120 min of visible light irradiation. In addi- tion, the Bi 4 O 5 Br 2 presents high stability and good organic carbon removal effciency. The effects of the solution pH (3.12 - 8.75) on catalytic activity revealed that CFP was mainly photocatalyzed under acidic conditions and hydrolyzed under alkaline condi- tions. Combined with active species and degradation product identifcation, the photo- catalytic degradation pathways of CFP by Bi 4 O 5 Br 2 was proposed, including hydrolysis, oxidation, reduction and decarboxylation. Most importantly, the identifed products were all hydrolysis rather than oxidation byproducts transformed from the intermediate of β-lactam bond cleavage in CFP molecule, quite different from the mostly previous stud- ies. Furthermore, the fnal products were demonstrated to be less toxic through the toxi- city analysis. Overall, this study illustrates the detailed mechanism of CFP degradation by Bi 4 O 5 Br 2 and confrms Bi 4 O 5 Br 2 to be a promising material for the photodegradation of CFP. © 2020 Published by Elsevier B.V. on behalf of The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences. ∗ Corresponding authors. E-mails: chem_ctgu@126.com (Y. Huang), changying.yang@ctgu.edu.cn (C. Yang). https://doi.org/10.1016/j.jes.2020.07.023 1001-0742/© 2020 Published by Elsevier B.V. on behalf of The Research Center for Eco-Environmental Sciences, Chinese Academy of Sciences.