A multifaceted investigation on photocatalytic performance of Bi2WO6/TiO2/ZIF-8: Adsorption, artificial neural networks, density functional theory, and antibacterial assessment studies

Bi₂WO₆/TiO₂/ZIF-8 photocatalytic degradation and antibacterial toxicity of degraded methylene blue were studied in this paper. The optimum mass ratio of ZIF-8 to Bi₂WO₆/TiO₂ was determined via comprehensive investigation through photocatalytic experiments, and morphological, structural, and photoelectrochemical characterizations. Operating conditions like initial pH, photocatalyst dosage, initial pollutant concentration, and light intensity were examined. The results were modeled by artificial neural networks, and optimization of operating conditions was performed by a genetic algorithm (GA). The GA optimized a cost function expressed as the ratio of the catalyst consumed to the pollutant degraded (mg/g). This optimization computed optimum conditions as pH of 8.41, photocatalyst dosage of 0.05 g/L, dye concentration of 50 ppm, and light intensity of ∼ 580 W/m² for 99.9 % removal efficiency at 360 min. Experimentally, 935 mg/g removal with ¬93.5 % removal efficiency was obtained. To study the toxicity of degraded solution, LC-MS analysis coupled with density functional theory and quantitative-structure activity relationship indicated that by-products became more toxic than the initial contaminant, representing the necessity of complete removal of the organic dye before releasing to the environment. Gram-positive (Staphylococcus aureus) and gram-negative (Klebsiella pneumoniae) bacteria were determined, and the minimum inhibitory concentration was not achieved for the degraded solution.