Experimental Study of the Photocatalytic Behaviour of Zinc Oxide Nanostructure for Cationic Dye (Malachite Green)

Abstract

In present study, ZnO nanostructures formed by co-precipitation were investigated for their photocatalytic behaviour against cationic dye (Malachite Green). X-ray diffraction (XRD) technique was used to identify the structure, crystallite size and phase of the as synthesized material, Surface morphology and the elemental compositional analysis of the ZnO was carried by using scanning electron microscope (SEM) attached with energy dispersive spectrometer (EDS).  SEM study revealed the formation of round shape pebble like particles having the size between 50 to 150 nm and found to be uniformly distributed. XRD analysis showed the well resolved peaks of ZnO having polycrystalline nature with hexagonal structure. Crystallite size was calculated and found to about 18 nm.  Absorbance spectra was recorded by using UV-Vis spectrometer and optical energy band gap was found to be about 3.29 eV. Band-gap excitonic emission displays emission peaks in the photoluminescence spectrum at 390 nm.

Xenon lamp was used to significantly increase the degradation rate, but the catalyst (40mg) still took 3 hours to degrade 95% of dye (100ml,10mg/L) which showed as synthesized catalyst has poor rate of degradation for cationic dye. The result showed the degradation of Malachite Green dye using ZnO nanoparticles in 3 hours, with 95% efficiency. The decomposition of dye with ZnO nanoparticles can be used in industrial waste water treatment for the existence of mankind as well as the aquatic ecosystem with their habitats.