Enhanced photocatalytic activity of Bi2WO6/ZnO nanocomposite in degradation of methylene blue under sunlight irradiation and for antimicrobial activity

Abstract

Photocatalytic degradation of organic pollutants is crucial although this process effectively disintegrates the toxicants that pollute drinking water, which, in turn, result in environmental pollution. Orthorhombic bismuth tungstate (Bi2WO6) in combination with hexagonal zinc oxide (ZnO) effectively degrades toxic methylene blue (MB) from water, by the photocatalytic technique. Composite of Bi2WO6 nanoplates with ZnO was synthesized by the simple hydrothermal method. Raman analysis shows the presence of vibrational and functional modes present in the prepared catalysts. The obtained Bi2WO6/ZnO composite absorbed 650 nm of light and promoted an efficient photocatalytic process. The photocatalytic process was carried out for the degradation of MB under various light irradiation sources such as visible light, UV light, and sunlight (direct). The photocatalyst (50 mg of Bi2WO6/ZnO and 3.2 mg/L MB solution) provided a maximum percentage for the degradation of MB (74%) under sunlight irradiation compared to that under other light irradiation sources. Furthermore, the Bi2WO6/ZnO composite was used to analyze its antimicrobial activity, and it shows the best antimicrobial activities against both gram-positive bacteria and gram-negative bacteria such as Bacillus subtilis, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, and Vibrio cholera.