MoS2 nanosheets loaded on collapsed structure zeolite as a hydrophilic and efficient photocatalyst for tetracycline degradation and synergistic mechanism

Abstract

In this study, MoS2@Z photocatalysts were synthesized by combining ultrasonic and hydrothermal methods, and used for the degradation of tetracycline. The structure characteristics and photocatalytic degradation mechanism of photocatalysts were also systematically investigated. The obtained MoS2@Z-5 exhibits the highest photo-degradation efficiency of tetracycline (87.23%), which is 3.58 times more than alkali-modified zeolite (24.34%) and 1.80 times more than pure MoS2 (48.53%). Furthermore, the MoS2@Z-5 showed significant stability in three times photocatalytic recycles and the removal efficiency only decrease by 9.03%. Crystal structure and micromorphology analysis show modified zeolite with collapsed structure can regulate the morphology of nano-MoS2 and make MoS2 appear fault structure, which can expose more active sites. In addition, low Si/Al ratio zeolite increases the hydrophilia of MoS2@Z-5. Reactive-species-trapping experiments show that the hole is the main reactive oxidizing species. The superior photo-degradation efficiency is mainly attributed to outstanding hydrophilia, exposure of the edge active sites, and efficient separation of photogenerated charge and holes. A possible photocatalytic mechanism and degradation pathways of tetracycline were proposed. The results indicate that MoS2@Z-5 may become an efficient, stable, and promising photocatalyst in tetracycline wastewater treatment.