Characterization of zinc oxide nanostructures prepared by hydrothermal method with antibacterial property


In this research, zinc oxide nanostructures were prepared via hydrothermal method utilized two compounds, zinc nitrate hexahydrate and sodium hydroxide consider as a precursor. Three annealing temperatures were used to study their effect on ZnO nanostructures properties. The synthesized nanostructure was described utilizing x-ray diffraction (XRD), Field Emission Scanning Electron Microscopy (FESEM), Atomic Force Microscope (AFM), and Fourier Transform Infrared Spectroscopy (FTIR). Optical characterization was studied utilized UV -visible spectroscopy. XRD analysis confirms that all ZnO nanostructures have the hexagonal wurtzite structure with average crystallite size within the range of (30.59-34.52) nm. The crystallite size increases due to the incensement of annealing temperature. FESEM analysis indicates that ZnO has hexagonal shape of cylindrical pores, plate-like nanocrystals and Nanorods. AFM analysis shows that the average surface roughness of ZnO nanostructures increases from 3.96 to 19.1 nm with the increase of annealing temperature. The FTIR peaks indicate successful preparation of ZnO nanostructures. The FTIR method was used to analyses the chemical bonds which conformed the present of the Zn-O group in the region between (400-500) cm-1. UV-visible analysis appears red shift in absorption spectra due to shifting in energy gap with increment of particle size. The band gap energy has been calculated from the optical absorption spectra. The annealing process has been found more effective on the value of energy gap. As the annealing temperature increases, the value of energy gap, increases as well; from (3.12 to 3.22) eV. The prepared nanostructure is used for antibacterial property shows strong activity against S. aureus bacteria, P.aeuruginosa bacteria by disc diffusion test (agar method test). White precipitate of ZnO nanostructures has superior antibacterial activity towards gram-positive (S. aureus) bacteria than gram-negative (P.aeuruginosa) bacteria.