Green Synthesis Of Zinc Oxide Nanoparticles: Characterization, Organic Dye Degradation And Evaluation Of Their Antibacterial Activity

The aim of this work is the green synthesis of zinc oxide nanoparticles (ZnO NPs) via red onion extract. The ZnO NPs wurtzite hexagonal structure was identified through X-ray diffraction (XRD) analysis, with an average crystallite size of 8.13 nm. The capping and stabilization of ZnO NPs biosynthesis were supported by an analysis of infrared spectra (FT-IR). The absorption peak at 374 nm with an energy bandgap of 3.32 eV was discovered via UV-Vis analysis. A morphological study was done by SEM and TEM techniques, and showed that spherical ZnO NPs with diameters ranging from 2.83 to 15.35 nm had formed. Using EDS, it was possible to identify the high purity, intensity, and crystalline width of zinc and oxygen. The removal rates of methylene blue (MB) by photocatalysis and adsorption were compared utilizing ZnO NPs. Under sunlight, the photodegradation of MB 10 mg/L has been examined. It was found that maximum decolorization efficiency happened after 120 minutes and a dose of 25 mg of ZnO NPs. The adsorption capacity (qm) was calculated by the Langmuir equation to be 10.8 mg/g. The kinetic analysis suggests the pseudo-second order model was followed during MB adsorption via the NPs. The findings showed that the photocatalytic and adsorption approaches removed the dye up to 95.2 % more efficiently than in earlier research. ZnO NPs exhibited better antibacterial action against E. coli than S. aureus bacteria when compared to a common antibiotic like Ciprofloxacin.