Biosynthesis of Zinc Oxide Nanoparticles Using Punica granatum L. Waste Peel Extract, and Assessment of Antioxidant and Catalytic Activity

Abstract

Green synthesis assisted by plant extracts is a recent research focus in diverse branches of chemistry. Through simple synthesis, different nanoparticles (NPs) can be produced that include oxides of zinc, copper, magnesium, or silver using various types of plant extracts. A remarkable attribute of plant aqueous extracts is their capability to act as reducing and capping agents. This study assessed the antioxidant and catalytic properties of phytosynthesized zinc oxide (ZnO) NPs using the fresh aqueous extract of pomegranate (Punica granatum) peel. Scanning electron microscopy indicated that the produced NPs had an average size of 49.52 nm with a spherical shape. X-ray diffraction confirmed the hexagonal phase of ZnO NPs and that their average crystallite size was 41.23 nm according to the Scherrer equation. Analysis of the ultraviolet-visible spectrum was performed to confirm the formation of ZnO NPs, and Fourier transform-infrared analysis illustrated the presence of diverse phytochemicals in the plant extract and ZnO NPs. The 2,2-diphenyl-1-picrylhydrazyl assay was used to determine the radical scavenging activity of these NPs. The novel ZnO phyto-nanocatalyst mediated by extracts from plant waste material, exhibited a well-defined reduction of methylene blue dye. Within 20 min, the catalytic degradation of methylene blue was completed, demonstrating that ZnO NPs have excellent catalytic properties.