Augmentation of Photocatalytic Degradation of Oxytetracycline by Cu–CdS and Deciphering the Contribution of Reactive Oxygen Species

Abstract

Production of Copper (Cu) modified Cadmium sulfide (CdS) nanomaterial, named as Cu–CdS, was successfully synthesized through hydrothermal and photo deposition method to degrade oxytetracycline (OTC) antibiotics in aqueous solution. Uniform surface loading of copper was observed on CdS using Scanning Electron Microscopy-mapping (SEM-mapping). The Cu induced improvement in the visible light absorption was observed using UV-vis absorption spectrum. Thus, this material can exhibit excellent oxytetracycline (OTC) degradation by photocatalysis. The best OTC degradation efficiency of 90% was be achieved under the optimal concentration of 4% Cu–CdS, with 0.1 g L−1 dosage (pH 5) under UV irradiation. 0.167 mg L−1 min−1 was observed as the reaction kL-H on the peripheral of the catalyst. In addition, OTC can also be degraded under visible light with removal efficiency approximately 90%. Moreover, the contribution of main reactive oxygen species (ROS), including hydroxyl radicals, superoxide radical and holes, is evaluated as 18%, 43% and 29%.