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.