Construction of direct Z-scheme SnS2@ZnIn2S4@kaolinite heterostructure photocatalyst for efficient photocatalytic degradation of tetracycline hydrochloride

The accumulation of antibiotics in water system and the consequent detrimental effects have drawn worldwide attention extensively. There is an urgent need to develop rapid and efficient degradation methods of antibiotics. In this work, a highly efficient SnS2@ZnIn2S4@kaolinite (SZK) photocatalysts were successfully synthesized by hydrothermal method. In comparison with bare photocatalysts, the SnS2@ZnIn2S4@kaolinite (SZK) heterostructure demonstrated greatly improved adsorption-photocatalytic degradation capability for removal of tetracycline hydrochloride (TCH). Under visible light illumination, the apparent reaction rate of SZK heterostructure reached 0.0231 min−1, which was around 20.81 times and 2.37 times higher than that of SnS2 and ZnIn2S4, respectively. It has been proved that •O2− and 1O2 are the main active species participating the degradation process. Based on HPLC-MS analysis, the possible photodegradation pathways of TCH have been proposed. The superior removal performance is mainly ascribed to the enhanced adsorption ability, elevated light harvesting and the increased separation efficiency originated from the synergistic effect of the components. Our study provides new insights with the utilization of natural minerals for visible light photocatalytic degradation of antibiotics in wastewater treatment.