Photocatalytic wastewater treatment and disinfection using green ZnO-NP synthesized via cera alba extract

Abstract

This is the first report to describe the green fabrication of zinc oxide nanoparticles starting with cera alba (beeswax) extract as an eco-friendly reducing and capping agent. The reaction of zinc nitrate with an aqueous extract of Cera Alba resulted in the formation of zinc oxide nanoparticles (ZnO-W). Treatment of ZnO-W at 550 °C gave pure zinc oxide nanoparticles (ZnO-G). Various techniques, including FT-IR, XRD, TGA, SEM, and HR-TEM, were used to analyze the structures of synthesized nanoparticles. A methylene blue dye solution was used to evaluate the photocatalytic activity. The impact of catalyst dose, reaction time, and pH on photocatalytic degradation under sunlight was studied. At optimal conditions, complete photodegradation of 10 ppm methylene blue occurs in 40 min. The antimicrobial activity of ZnO-G was evaluated against three microbial strains: Bacillus cereus, Escherichia coli, and Candida albicans. The impact of exposing the ZnO-G to various light wavelengths (265 nm, 346 nm, visible light, and sunlight) to inhibit microbial growth was investigated. The best result was obtained when ZnO-G was exposed to 265 nm light. This study's findings support using ZnO-G prepared via cera alba as a powerful photocatalytic and antimicrobial agent.