Degradation of ciprofloxacin with Al2O3/MGO as heterogeneous activator of peroxymonosulphate

Abstract

A nano-sized Al₂O₃/MGO composite was studied for its ability to activate peroxymonosulphate (PMS) and generate active radicals for the degradation of ciprofloxacin (CIP). Degradation tests were performed at pH 7 with a CIP concentration of 20 mg × l⁻¹, the Al₂O₃/MGO dose of 2.0 g·l⁻¹, and the PMS dose of 2.0 g·l⁻¹. In addition, the degradation of CIP and the stability of the Al₂O₃/MGO-activated-PMS system were consistent after three repeated experiments. Furthermore, sulphate radicals (\({\text{SO}}_{4}^{ - \bullet}\)) and hydroxyl radicals (\(^{\bullet}\)OH) were detected during the degradation of CIP, leading to the formation of nine degradation intermediates. Additionally, two possible degradation pathways were proposed. The results of this study suggests a new mechanism for the degradation of CIP in Al₂O₃/MGO-activated-PMS system, which could be applied to sulphate radicals (\({\text{SO}}_{4}^{ - \bullet}\)) advanced oxidation processes (SR-AOPs).