Mineralisation of the antibiotic amoxicillin in pure and surface waters by artificial UVA‐ and sunlight‐induced Fenton oxidation

Abstract

Abstract BACKGROUND: The degradation and mineralisation of the antibiotic amoxicillin by photo‐Fenton reactions, mediated by artificial UVA or solar irradiation, were investigated. Experiments were conducted with 30 mg L −1 amoxicillin solutions prepared with deionised or surface water at Fe 2+ and H 2 O 2 concentrations in the range 0.0179–0.0895 and 1–10 mmol L −1 , respectively. Black‐light irradiation at 365 nm was provided by a 13 W m −2 lamp, while samples were exposed to sunlight at 20 W m −2 for solar experiments. RESULTS: In all cases, quantitative amoxicillin degradation occurred within 5 min and this was accompanied by lower mineralisation rates. Mineralisation followed first‐order kinetics with respect to organic carbon content and it was not affected by the water matrix with either type of illumination. Solar‐induced reactions were only marginally faster than artificial irradiation. Increasing the H 2 O 2 to Fe 2+ concentration ratio increases the extent of mineralisation up to a point beyond which degradation is impeded due to radical scavenging associated with the high concentrations of the Fenton reagents. CONCLUSION: Amoxicillin is readily degradable by homogeneous photocatalysis, being converted to more stable intermediates as indicated by lower mineralisation rates. The process can be driven by solar irradiation, thus providing a sustainable treatment technology. Copyright © 2009 Society of Chemical Industry