Photocatalytic degradation of Rh B in Bi2WO6 nanocomposites modified by lignin carbon quantum dots

With the rapid development of economy and society and the rapid advancement of industrialization and urbanization, the sewage discharged in the daily life of urban residents and the wastewater produced by industrial enterprises contain a large number of organic pollutants. Such organic pollutants are easy to flow into urban rivers through surface water, causing serious pollution of water environment, and thus adversely affecting the sustainable green development of cities. In recent years, the degradation of rhodamine B (Rh B) wastewater has become the focus of research on the treatment of refractory organic wastewater. In this paper, alkaline lignin was used as the precursor, and CQDs with fluorescence effect were prepared from bottom to top by hydrothermal method; Bi2WO6 was combined with Bi2WO6, and Bi2WO6/CQDs composite material was prepared to degrade organic pollutants into low-toxicity or non-toxic small molecules, as an effective way to solve the pollution of solar energy resources and environment. Carbon quantum dots (CQDs) have the advantages of excellent electron conduction and optical properties, non-toxicity and good biocompatibility, which will be more conducive to improving the light utilization rate of Bi2WO6 and inhibiting the recombination of electrons and holes, so as to improve its photocatalytic performance. The composite materials were characterized by XRD, FT-IR, TEM, and UV–Vis, and the results confirmed the successful preparation of Bi2WO6/CQDs using a simple hydrothermal method. The introduction of CQDs can reduce the bandgap width of Bi2WO6, thereby improving the absorption of light and promoting photogenerated electron transfer. Under visible light irradiation (300-W xenon lamp, λ > 420 nm), the amount of CQDs was 30 ml, and the degradation rate of Rh B was 86.96% within 120 min. Due to the excellent upconversion photoluminescence, as well as the photoinduced electron transfer and reservoir properties of CQDs, the Bi2WO6/CQDs composite exhibited superior photocatalytic performance in the degradation of Rh B under the irradiation of simulated solar light. This study provides a strategy for the development of high-performance catalysts based on CQDs.