Synthesis And Characterizations Of Zinc Oxide Nanoparticles For Antimicrobial Applications

Abstract

In this study, the ZnO nanoparticles were synthesised from precursors Zn(NO3)2.6H2O and Zn(CH3COO)2.2H2O by using Sol- gel, thermal decomposition and Precipitation method respectively. The synthesized ZnO NPs characterized using X-Ray Diffraction (XRD), Fourier Transform Infrared (FTIR), UV-Vis spectroscopy, Scanning Electron Microscopy (SEM) and Fluorescence Spectroscopy. From XRD results the synthesized ZnO NPs have wurtzite hexagonal structure and its crystallite sizes increase as the temperature increases, the lattice parameters (a and c) are temperature dependent i.e. an increase in temperature leads to expansion of lattice parameters due to this the volume of cell decreasing and spacing between the lattice planes decreasing when annealing temperature increase. The morphology of ZnO NPs was characterized by SEM. It indicated that S-2 and S-4 ZnO NPs was flower and spherical shape and the particle size of S-4 greater than S-1 ZnO NPs which agree with XRD result. The optical absorption of ZnO NPs measured at different annealing temperatures indicates red shift as the temperature increases. The ZnO NPs were showed two emission bands, an ultraviolet emission band due to the transition from conduction band edge to valence band, and visible emission band due to defects that are related to deep level emissions. The synthesised ZnO NPs were applied for antimicrobial activity on Gramnegative bacteria E. coliand P. aeruginosa, Gram-positive bacteria S. aureus B. subtilis and S. typhi and Fungus candida albicans using well diffusion agar method. All synthesisedZnO NPs were showed admirable antibacterial activity. Among synthesisedZnO NPs, the S-3 ZnO NP which was synthesized using thermal decomposition method was showed excellent antibacterial activity.