Degradation kinetics and mechanism of β-lactam antibiotics by the activation of H2O2 and Na2S2O8 under UV-254 nm irradiation

JOURNAL OF HAZARDOUS MATERIALS

卷:279

Article

He, Xuexiang^1,3,4  Mezyk, Stephen P.²  Michael, Irene^3,4  Fatta-Kassinos, Despo^3,4  Dionysiou, Dionysios D.^1,3,4 

[1] Univ Cincinnati, Environm Engn & Sci Program, Cincinnati, OH 45221 USA

[2] Calif State Univ Long Beach, Dept Chem & Biochem, Long Beach, CA 90840 USA

[3] Univ Cyprus, Sch Engn, Dept Civil & Environm Engn, CY-1678 Nicosia, Cyprus

[4] Univ Cyprus, Sch Engn, Nireas Internat Water Res Ctr, CY-1678 Nicosia, Cyprus

关键词: beta-Lactam antibiotics;    UV-254 nm;    Hydrogen peroxide;    Persulfate;    Radical reaction mechanism;   

DOI  :  10.1016/j.jhazmat.2014.07.008

来源: Elsevier

【 摘 要 】

The extensive production and usage of antibiotics have led to an increasing occurrence of antibiotic residuals in various aquatic compartments, presenting a significant threat to both ecosystem and human health. This study investigated the degradation of selected beta-lactam antibiotics (penicillins: ampicillin, penicillin V, and piperacillin; cephalosporin: cephalothin) by UV-254nm activated H2O2 and S2O82- photochemical processes. The UV irradiation alone resulted in various degrees of direct photolysis of the antibiotics; while the addition of the oxidants improved significantly the removal efficiency. The steady-state radical concentrations were estimated, revealing a non-negligible contribution of hydroxyl radicals in the UV/S2O82- system. Mineralization of the beta-lactams could be achieved at high UV fluence, with a slow formation of SO42- and a much lower elimination of total organic carbon (TOC). The transformation mechanisms were also investigated showing the main reaction pathways of hydroxylation (+16 Da) at the aromatic ring and/or the sulfur atom, hydrolysis (+18 Da) at the beta-lactam ring and decarboxylation (-44 Da) for the three penicillins. Oxidation of amine group was also observed for ampicillin. This study suggests that UV/H2O2 and UV/S2O82- advanced oxidation processes (AOPs) are capable of degrading beta-lactam antibiotics decreasing consequently the antibiotic activity of treated waters. (C) 2014 Elsevier B.V. All rights reserved.

【 授权许可】

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