Photocatalytic degradation of cephalexin by UV activated persulfate and Fenton in synthetic wastewater: optimization, kinetic study, reaction pathway and intermediate products

Ali Almasi; Rohallah Esmaeilpoor; Hoshyar Hoseini; Vahideh Abtin; Mitra Mohammadi

doi:10.1007/s40201-020-00553-1

Photocatalytic degradation of cephalexin by UV activated persulfate and Fenton in synthetic wastewater: optimization, kinetic study, reaction pathway and intermediate products

J Environ Health Sci Eng. 2020 Oct 12;18(2):1359-1373. doi: 10.1007/s40201-020-00553-1. eCollection 2020 Dec.

Authors

Ali Almasi^{1

2}, Rohallah Esmaeilpoor^{1

2}, Hoshyar Hoseini², Vahideh Abtin^{1

2}, Mitra Mohammadi^{2

3}

Affiliations

¹ Social Development and Health Promotion Research Center, Kermanshah University of Medical Sciences, Kermanshah, Iran.
² Department of Environmental Health Engineering, School of Health, Kermanshah University of Medical Sciences, Kermanshah, Iran.
³ Student Research Committee, Kermanshah University of Medical Sciences, Kermanshah, Iran.

Abstract

We used Low pressure mercury vapor lamp activated of Sodium Persulfate (UV/SPS) and Fenton processes in two separate reactors to comparison of cephalexin (CPX) degradation in aqueous solution. The effect of pH, initial concentration of SPS, concentration of CPX, concentration of H₂O₂ and concentration of Fe²⁺ on the degradation of CPX were investigated. The residue of CPX and metabolites were determined by HPLC and GC/MS. The Total Organic Carbon (TOC) analysis was utilized for surveying the mineralization of CPX. Biodegradability of CPX in both advanced oxidation processes was evaluated by BOD5/COD in optimum condition. The results indicated that the maximum CPX removal was obtained at pH 3, H₂O₂ 3 mM, concentration of initial CPX 10 mg/L and by increasing the doses of SPS from 0.1 to 0.2 mM, the degradation of CPX was enhanced. In this study, the most important factors for AOP efficiency was concentration of initial CPX; and then pH in UV/SPS and H₂O₂ in Fenton processes. The TOC measurements indicate that the UV/SPS and Fenton can efficiently mineralize CPX. CPX removed enough to achieve suitable biodegradability for a further biological process. Too, analysis of generated intermediates during the degradation of CPX was conducted by GC/MS method and a degradation pathway was proposed.

Keywords: Advanced oxidation process; Cephalexin; GC/MS; HPLC; Metabolite.