Degradation Performance and Toxicity Evaluation of Nanoflower-Like g-C 3 N 4 /CQDs/Bi 4 O 5 I 2 Z-Scheme Heterojunction for Photocatalytic Emerging Pollutants

Bisphenol A (BPA) and other recently identified pollutants in water bodies are posing a hazard to the natural environment. To solve this problem, a straightforward one-pot solvothermal method was used to create the g-C₃N₄/CQDs/Bi₄O₅I₂ Z-scheme heterojunction catalyst, and the rate at which BPA degraded under visible light was examined. Under ideal conditions, the degradation rate of BPA by g-C₃N₄/CQDs/Bi₄O₅I₂ was 96.77% within 120 min. At the same time, g-C₃N₄/CQDs/Bi₄O₅I₂ also showed excellent salt tolerance, versatility, and cycle stability. Terahertz time-domain spectroscopy (THz-TDS) test results show that the density of states of the composite catalyst increases. The construction of the Z-scheme heterojunction, which increases the separation efficiency of photogenerated carriers and expands the visible light response range, is responsible for the enhancement of the photocatalytic activity of g-C₃N₄/CQDs/Bi₄O₅I₂, according to other relevant characterization data. Along with the toxicity of the degradation solution, the likely degradation pathway of BPA and the potential photocatalytic degradation mechanism of g-C₃N₄/CQDs/Bi₄O₅I₂ were also investigated. This work broadens the potential use of bismuth-based catalysts in wastewater treatment.