2. Academic Validation
  3. Insights into the degradation mechanisms and pathways of cephalexin during homogeneous and heterogeneous photo-Fenton processes

Insights into the degradation mechanisms and pathways of cephalexin during homogeneous and heterogeneous photo-Fenton processes

  • Chemosphere. 2021 Dec:285:131417. doi: 10.1016/j.chemosphere.2021.131417.
Yejing Gou 1,  Lai Peng 2,  Haixing Xu 3,  Shengjun Li 4,  Chang Liu 4,  Xiaoyong Wu 2,  Shaoxian Song 2,  Chenguang Yang 5,  Kang Song 6,  Yifeng Xu 7
Affiliations

Affiliations

  • 1 School of Chemistry, Chemical Engineering and Life Sciences, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei, 430070, China; Hubei Key Laboratory of Mineral Resources Processing and Environment, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei, 430070, China.
  • 2 Hubei Key Laboratory of Mineral Resources Processing and Environment, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei, 430070, China; School of Resources and Environmental Engineering, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei, 430070, China.
  • 3 School of Chemistry, Chemical Engineering and Life Sciences, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei, 430070, China. Electronic address: [email protected].
  • 4 School of Resources and Environmental Engineering, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei, 430070, China.
  • 5 Institute of Deep Sea Science and Engineering, Chinese Academy of Sciences, Sanya, Hainan, 572000, China.
  • 6 State Key Laboratory of Freshwater Ecology and Biotechnology, Institute of Hydrobiology, Chinese Academy of Sciences, Wuhan, Hubei, 430072, China.
  • 7 Hubei Key Laboratory of Mineral Resources Processing and Environment, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei, 430070, China; School of Resources and Environmental Engineering, Wuhan University of Technology, Luoshi Road 122, Wuhan, Hubei, 430070, China. Electronic address: [email protected].
PMID: 34246101 DOI: 10.1016/j.chemosphere.2021.131417
Abstract

The widespread occurrence of Antibiotics in the environment poses a potential threat to human health. The photo-Fenton process has demonstrated better degradation performance compared with the conventional wastewater treatment processes. In this study, the degradation of cephalexin was evaluated comparatively by homogeneous (Fe2+/H2O2/UV) and heterogeneous (MoS2@Fe/H2O2/UV) photo-Fenton processes. Key influencing factors affecting photo-Fenton performance were assessed, confirming the optimum Fe2+ concentration at 0.2016 mg L-1 and H2O2/Fe2+ molar ratio at 6. Higher degradation efficiency (73.10%) and pseudo-first-order degradation rate constant (0.0078 min-1) were achieved with the assistance of MoS2@Fe as the heterogeneous catalyst. Completely different degradation products were identified in the homogeneous and heterogeneous photo-Fenton processes, with main degradation pathways proposed as β-lactam ring-opening, sulfoxide formation, demethylation, N-dealkylation, decarbonylation, hydroxylation and deamination in the Fe2+/H2O2/UV system and β-lactam ring-opening, hydroxylation, dehydration, amide hydrolysis, and demethylation and ring contraction in the MoS2@Fe/H2O2/UV system, respectively. The formation of newly identified products might root in the attack on cephalexin from active species (i.e., OH, h+, e-, O2-) photoinduced by the MoS2@Fe catalyst. Results also indicated the importance of understanding the underlying mechanisms and pathways to eliminate the antimicrobial activities of Antibiotics in the future.

Keywords

Active species; Antibiotics; Degradation products and pathways; Heterogeneous catalyst; Photo-Fenton processes.

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