Comparative study on the degradation of cephalexin by four electrochemical advanced oxidation processes: Evolution of oxidation intermediates and antimicrobial activity

Autor(es)

Antonin, Vanessa S. ^[1] ; Aquino, Jose M. ^[1] ; Silva, Bianca F. ^[2] ; Silva, Adilson J. ^[3] ; Rocha-Filho, Romeu C. ^[1]

Afiliação do(s) autor(es)

^[1] Univ Fed Sao Carlos, Dept Quim, CP 676, BR-13560970 Sao Carlos, SP - Brazil

^[2] Univ Estadual Paulista, Dept Quim Analit, Inst Quim Araraquara, BR-14800900 Araraquara, SP - Brazil

^[3] Univ Fed Sao Carlos, Dept Engn Quim, CP 676, BR-13560970 Sao Carlos, SP - Brazil

• Tipo de documento: Artigo Científico
• Fonte: CHEMICAL ENGINEERING JOURNAL; v. 372, p. 1104-1112, SEP 15 2019.
• Citações Web of Science: 0

Resumo

The degradation of the beta-lactam antibiotic cephalexin (CEX) was carried out by the following electrochemical advanced oxidation processes (EAOPs): anodic oxidation (AO), Fered-Fenton (EF-Fered), photoassisted anodic oxidation (PAO), and photoassisted Fered-Fenton (PEF-Fered). All experiments were done in a flow reactor incorporating a boron-doped diamond anode, at a low current density; for the PAO and PEF-Fered processes, the solution was irradiated with UVA light. The initial removal of CEX was attained by all EAOPs, but it was much faster by the Fenton-based processes, which thus presented higher initial rates of TOC removal. However, the coupling of the electrolytic and UVA photolytic processes enhanced the mineralization process; as a consequence, significantly greater TOC removals were attained by the PEF-Fered and PAO processes. From the initial oxidation intermediates detected by LC-MS/MS for the PEF-Fered and AO processes, it could be concluded that addition reactions involving the electrophilic HO center dot radicals occurred preferentially in the beta-lactam ring; however, due to the higher availability of HO center dot radicals, the Fenton-based process led to a faster rupture of that ring. Thus, the antibacterial activity of the treated CEX solution against Escherichia coli was completely terminated within less than 1 h of treatment by the PEF-Fered process, compared to 8 h by the AO process. The PEF-Fered and PAO processes yielded enhanced degradation performances despite mere use of UVA light. (AU)

• Processo FAPESP: 04/08572-4 - Utilização de eletrodos tridimensionais recobertos com SnO2-Sb para eletroxidação de poluentes orgânicos
• Beneficiário: Romeu Cardozo Rocha Filho
• Modalidade de apoio: Auxílio à Pesquisa - Regular
• Processo FAPESP: 18/10805-0 - 69th Annual Meeting of the International Society of Electrochemistry
• Beneficiário: Romeu Cardozo Rocha Filho
• Modalidade de apoio: Auxílio à Pesquisa - Reunião - Exterior