Study on CuO/g–C3N4 S–Scheme heterojunction for enhanced visible-light-driven photocatalytic degradation of xanthate

Xanthate wastewater is a serious threat to the surrounding environment of mining sites, and it is important to use visible light photocatalytic technology to remove xanthatefrom wastewater. In this paper, a simple hydrothermal calcination synthesis route was used to grow submicron-sized CuO onto the surface of g-C3N4 for the degradation of xanthate in mineral processing wastewater. The results showed that the CuO/g–C3N4–0.4 composite catalyst degraded xanthate with an efficiency of 83.2% in 120 min, which was 6.2 times higher than that of pure g-C3N4. The catalyst materials were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, and transmission electron microscopy. It was found that the excellent photocatalytic performance of the composite was attributed to the construction of S-scheme CuO/g–C3N4–Xheterojunction, which not only broadened the light absorption range but also retained the strong redox ability of holes and electrons to participate in the reaction while efficiently separating the photoinduced carriers. Based on the results of active substance capture, an S-scheme charge transfer model was proposed and the photodegradation mechanism of xanthate was reasonably elucidated.