Fast photodegradation of antibiotics and dyes by an anionic surfactant-aided CdS/ZnO nanodispersion

Abstract

The photocatalytic technology has broad applications in energy and environmental science. In this study, we synthesized a type II heterojunction CdS/ZnO (CSZ) nanodispersion by means of one-pot precipitation. Different from previous studies, an anionic surfactant was used to improve the photocatalytic activity of CdS/ZnO. The CdS/ZnO nanodispersion showed very good photocatalytic performance in the degradation of tetracycline (TC) under visible light, with the highest degradation rate of 94.4% when pH = 7, both pH > 7 and pH < 7 were not conducive to TC degradation. Fast and high degradation efficiency was observed for three model compounds, and the degradation efficiency of RhB reached 100%. After 5 cycles, the degradation efficiency remains above 85%. In the photocatalysts, CdS nanoparticles act as photosensitizers, extending the light response of ZnO to the region of visible light, meanwhile, effectively reducing the electron-hole binding rate, which greatly improved the photocatalytic activity. In the end, the photocatalytic enhancement mechanism of TC degradation was discussed.