Green synthesis of zinc oxide nanoparticles from Salvadora persica leaf extract: Characterization and studying methyl orange removal by adsorption

The present study conducted a successful green synthesis of zinc oxide nanoparticles (ZnO NPs) from the aqueous solution of Salvadora persica leaf extract as a capping agent. The environmental application of the synthesized ZnO NP was understood from the methyl orange (MO) dye removal investigation. The morphology, chemical composition, crystallinity, optical property, and isothermal behaviour of synthesized NPs were characterized by scanning electron microscopy (SEM), energy-dispersive spectroscopy, Fourier transform infrared (FTIR), X-ray diffraction (XRD), and UV-visible spectroscopy (UV-Vis). The UV-Vis absorption band was found at 365 nm, and the XRD analysis confirmed the crystallinity of the ZnO NP and the particle sizes were in the range of 32–68 nm. The FTIR bands confirm the presence of bioactive compounds. SEM images showed the formation of hexagonal and rod-shaped NPs. The findings suggested that the shape of the synthesized ZnO NPs has a major influence on the removal of MO from water. The results revealed that a maximum MO removal of 68% was obtained with an amount of 0.05 g of ZnO NPs at pH 5. This research demonstrates a green method of preparing various ZnO NPs with a remarkable efficiency towards the removal of MO dye.