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

Abstract

The present study conducted a successful green synthesis of zinc oxide nanoparticles (ZnO NPs) from the aqueous solution of Salvadora persica leaf extract as capping agent and used for methyl orange dye removal. The morphology, chemical composition, crystallinity, optical property and isothermal behavior of synthesized nanoparticles were characterized by scanning electron microscopy (SEM), energy dispersive spectroscopy (EDX), Fourier transform infra-red (FTIR), X-ray diffraction (XRD), and UV-visible spectroscopy (UV-Vis). The influencing factors on MO removal such as preparation method, dose, pH, contact time, and dye concentration were examined. 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 nanoparticles. The results revealed that a maximum methyl orange removal of 68% was obtained with an amount of 0.05 g of ZnO NPs at pH 5. The adsorption process can be well explained by the Langmuir isotherm model. This research demonstrates a green method of preparing various ZnO nanoparticle with a remarkable efficiency towards the removal of methyl orange dye.