Antimicrobial studies of visible light-responsive nanoflower spheres Bi2WO6/ZnO

Abstract

The contamination of water resources in recent years has resulted in the dissemination of harmful bacteria via water sources, posing a significant threat to the safety and well-being of humans, animals, and plants. Consequently, there is a growing concern over the health and sanitation of water resources. Photocatalysis, a novel and very effective antibacterial method, has gained significant attention in the area of antibacterial research. Bismuth nitrate pentahydrate and sodium tungstate dihydrate were used in a straightforward hydrothermal process to create nanoflower spheres Bi₂WO₆/ZnO photocatalytic composites in molar ratios of 1:1, 1:2, 1:3, and 1:4. The first-ever demonstration of the photocatalytic broad-spectrum antibacterial activity of porous nanoflower spheres Bi₂WO₆/ZnO composites was shown. The samples were analyzed using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), Fourier-transform infrared spectroscopy (FT-IR), and ultraviolet–visible spectroscopy (UV–vis). The antibacterial activity was evaluated using the dilution coated plate technique, with LED light irradiation. The findings indicate that the Bi₂WO₆/ZnO composite has a much superior antibacterial activity against both bacteria and fungus compared to individual Bi₂WO₆ and ZnO. When exposed to LED lighting with an intensity of 35 W, the Bi₂WO₆/ZnO nanoparticles in a 1:2 ratio at a concentration of 1000 mg/L demonstrated complete antibacterial effectiveness against Escherichia coli, Staphylococcus aureus, Pseudomonas aeruginosa, and Bacillus subtilis within 30 min. Similarly, the nanoparticles achieved 100 % antibacterial efficiency against Candida albicans within 90 min. The antibacterial efficacy of 1000 mg/L 1:2 Bi₂WO₆/ZnO nanoparticles against Escherichia coli and Staphylococcus aureus was found to be 100 % within 5 min under natural lighting conditions. The findings indicate that Bi₂WO₆/ZnO nanoparticles have excellent photocatalytic broad-spectrum antibacterial efficacy.