Photocatalytic degradation of xanthates under visible light using heterogeneous CuO/TiO2/montmorillonite composites

Abstract

Due to the significant demand for xanthate treatment in mineral effluents, photocatalytic techniques have emerged as one of the most promising solutions. In this study, a high-performance TiO2/CuO/montmorillonite photocatalyst was prepared. In this configuration, TiO2 was the classic photocatalytic material and CuO and montmorillonite were utilized to broaden the adsorption range of solar light and acted as carriers to support the photocatalyst. X-ray diffraction, scanning electron microscopy, transmission electron microscopy, and X-ray photoelectron spectroscopy were employed for the comprehensive characterization of the microstructure of the ternary photocatalyst. The results revealed that fine-sized TiO2 and CuO nanoparticles were uniformly and tightly loaded on the montmorillonite layers. The photocatalytic properties of the photocatalyst were evaluated using sodium butyl xanthate as the target contaminant. For pristine TiO2, ultraviolet (UV) light was required to effectively degrade sodium butyl xanthate. Meanwhile, the degradation reaction could be processed efficiently under visible light using the TiO2/CuO/montmorillonite composite as the photocatalyst. Moreover, UV–visible diffuse reflectance spectroscopy, photoluminescence spectroscopy, and radical quench experiments were performed to elucidate the degradation process, and a possible degradation model and mechanism were proposed.