Degradation kinetics and mechanism of β-lactam antibiotics by the activation of H2O2 and Na2S2O8 under UV-254nm irradiation.
Τίτλος | Degradation kinetics and mechanism of β-lactam antibiotics by the activation of H2O2 and Na2S2O8 under UV-254nm irradiation. |
Publication Type | Journal Article |
Year of Publication | 2014 |
Authors | He, X., Mezyk S. P., Michael I., Fatta-Kassinos D., & Dionysiou D. D. |
Journal | J Hazard Mater |
Volume | 279 |
Pagination | 375-83 |
Date Published | 2014 Aug 30 |
ISSN | 1873-3336 |
Λέξεις κλειδιά | Anti-Bacterial Agents, beta-Lactams, Hydrogen Peroxide, Hydroxyl Radical, Kinetics, Photolysis, Sodium Compounds, Sulfates, Ultraviolet Rays |
Abstract | 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 β-lactam antibiotics (penicillins: ampicillin, penicillin V, and piperacillin; cephalosporin: cephalothin) by UV-254nm activated H2O2 and S2O8(2-) 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/S2O8(2-) system. Mineralization of the β-lactams could be achieved at high UV fluence, with a slow formation of SO4(2-) and a much lower elimination of total organic carbon (TOC). The transformation mechanisms were also investigated showing the main reaction pathways of hydroxylation (+16Da) at the aromatic ring and/or the sulfur atom, hydrolysis (+18Da) at the β-lactam ring and decarboxylation (-44Da) for the three penicillins. Oxidation of amine group was also observed for ampicillin. This study suggests that UV/H2O2 and UV/S2O8(2-) advanced oxidation processes (AOPs) are capable of degrading β-lactam antibiotics decreasing consequently the antibiotic activity of treated waters. |
DOI | 10.1016/j.jhazmat.2014.07.008 |
Alternate Journal | J. Hazard. Mater. |
PubMed ID | 25086235 |