Preparation of GO/BiOI composites and their degradation performance in Congo red solution

GO/BiOI photocatalytic nanocomposites were synthesized through a hydrolysis precipitation method, utilizing (Bi(NO₃)₃·5H₂O) as the bismuth precursor and graphene oxide (GO) as the substrate. The removal effect of the material on Congo red (CR) in water was investigated by taking CR as the target pollutant. The composite’s structure and characteristics were examined through various analytical methods, including XRD, BET, FT-IR, FE-SEM, TEM, and UV–Vis techniques. The findings indicate that the integration of GO with BiOI preserves the layered crystalline structure of BiOI and mitigates particle aggregation. The specific surface area of the GO/BiOI composites increased significantly, from 21.98 m²/g for BiOI to 80.2586 m²/g, and the bandgap was decreased from 1.94 eV to 1.82 eV. The GO/BiOI photocatalytic degradation conformed to the first-order kinetic model. When the initial concentration of CR was 20 mg/L, the rate constant was the largest, and the correlation coefficient was 0.9988. At a dosage of 200 mg/L for GO/BiOI, with an initial concentration of 20 mg/L for CR solution, a pH level of 5, and under LED illumination at 12 W, the composite material achieved a CR removal efficiency of 96.09 %. After being reused five times, the removal rate could still reach more than 90 %.