Preparation, activity, and mechanism of ZnIn2S4-based catalysts for photocatalytic degradation of atrazine in aqueous solution

Abstract

Atrazine in aquatic environment poses a potential threat to human health and ecological system, and photocatalytic technology exhibits a promising prospect for eliminating trace pollutants in water. Four photocatalysts, ZnI2S4 (ZIS) and other three ZIS-based catalysts, g-C3N4/ZIS (CZIS), BiOBr/ZIS (BZIS)and Pd-ZIS (PZIS), were prepared by a facile hydrothermal method and characterized by BET, UV–vis DRS, SEM, TEM, XRD and XPS, respectively. It showed that four catalysts had high photocatalytic activities for atrazine degradation under different light sources irradiation, and their active sequence was PZIS < CZIS < ZIS < BZIS. The stronger light intensity the higher photocatalytic efficiency. Under direct solar irradiation of 1 h, the degradation efficiency for 20 mg/L of atrazine solution reached 90 % by PZIS with a dosage of 0.5 g/L. Pd doping increased the specific surface area and shortened the band gap and particle size of the catalyst that resulting in an effective enhancement of photocatalytic activity in the process of atrazine degradation. It confirmed by laser that Pd2+ ion entered the internal structure of ZIS to affect the crystal phase slightly but prohibit the recombination of photogenerated electron-hole pairs effectively. A feasible photocatalytic mechanism of atrazine by PZIS was proposed in the paper. The research work verified high photocatalytic activity of PZIS for its further application in the purification of aquatic environment that polluted by various herbicides including atrazine.