Bio-CQDs surface modification BiOCl for the BPA elimination and evaluation in visible light: The contribution of C-localized level

Abstract

Carbon quantum dots (CQDs) doping semiconductors can boost solar-to-hydrogen conversion and the photodegradation in VIS-NIR light, therefore attract great attention, but the perspective of CQDs role is seldom explored. Here, a biomass-CQDs was assembled with BiOCl (CQDs/BiOCl), then served as the visible-photodegradation model for a mechanistic investigation. Furthermore, CQDs/BiOCl removed 90% bisphenol A (BPA) within 2 h under visible light. It was attributed to the C-localized state (CLS) produced by CQDs, which transfers forceless photo-electrons (e−) to generate holes (h+) in the CQDs/BiOCl valence band (VB) under visible light, the h+ mainly involved in the BPA degradation process. Then, the electrochemical experiments and theoretical calculations further proved that the efficiencies of charge separation (ηCS) and injection (ηCI) were proved by CQDs. Meanwhile, the possible BPA degradation pathways were accordingly proposed, and the ecotoxicity evaluation of the intermediates was also conducted by ECOSAR. The transformation pathways of BPA were divided into five orientations, and the toxicity of intermediates was decreased for Fish (LC50, ChV), Daphnid (LC50, ChV), Algae (EC50, ChV) except for P10 and P12. As the result, this study confirmed the feasibility of bio-CQDs/BiOCl preparation and it could be a photocatalyst to remove and detoxify BPA under visible light.