Eco-friendly highly efficient BN/rGO/TiO₂ nanocomposite visible-light photocatalyst for phenol mineralization

Boron nitride (BN) and reduced graphene oxide (rGO) of different loadings were composited with commercial P25 TiO₂ (Ti) through the hydrothermal method. The as-prepared nanocomposites were characterized using various techniques: X-ray photoelectron spectroscopy, X-ray diffraction, thermal gravimetric analysis, Fourier transform infrared and Raman spectroscopies, and transmission and scanning electron microscopies. It was observed that 10% and 0.1% of BN and rGO, respectively, loaded on TiO₂ (10BNr0.1GOTi) resulted in the best nanocomposite in terms of phenol degradation under simulated sunlight. A 93.4% degradation of phenol was obtained within 30 min in the presence of H₂O₂. Finally, to ensure the safe use of BNrGOTi nanoparticles in the aquatic environment, acute zebrafish toxicity (acutoxicity) assays were studied. The 96-h acute toxicity assays using the zebrafish embryo model revealed that the LC₅₀ for the BNrGOTi nanoparticle was 677.8 mg L^-1 and the no observed effect concentration (NOEC) was 150 mg L^-1. Therefore, based on the LC₅₀ value and according to the Fish and Wildlife Service Acute Toxicity Rating Scale, BNrGOTi is categorized as a "practically not toxic" photocatalyst for water treatment.