Microwave-assisted synthesis of TiO2 and ZnO nanostructures for photocatalytie wastewater Treatment

Abstract

The aim of this study was to synthesize metal oxide nanoparticles of TiO2 and ZnO using the microwave synthesis method, and to evaluate their application on organic pollutants such us methyl orange dye in aqueous solutions. After a detailed theoretical study about the methods of synthesis and characterization of nanoparticles, an experimental application for the elaboration of nanoparticles of TiO2 and ZnO was carried out, using micro-wave assisted synthesis method. The results of the characterization techniques are summarized as follows: ? X-ray fluorescence (XRF) showed that the obtained powders of TiO2 and ZnO were 98.21%, 99.10% pure respectively. ? There corded XRD patterns confirmed the phase formation of both anatase and rutile phase for TiO2 and hexagonal Wurtzite for ZnO. XRD analysis also revealed a crystallite size of TiO2 and ZnO were 25 nm and 18 nm respectively. ? The as-synthesized nanocatalysts were made of a mesoporous network of aggregated TiO2 and ZnO nanoparticles according to N2 sorption and scanning electron microscopy analysis. ? FTIR and UV-vis results confirmed the results obtained by XRD shows that both of TiO2 and ZnO are in anatase and hexagonal wurtzite respectively. Based upon the above results it is concluded that the microwave method is powerful for the preparation of nanoparticles with varying composition, shape, structure and properties. The photocatalytic activity of our synthesized materials was then investigated for the degradation of methyl orange dye in water solution under various conditions. The effect of initial methyl orange concentration on the photocatalytic activity was studied and it was found that the degradation of methyl orange is strongly dependent on the initial dye concentration. So this study uncovered a simpler way to synthesize TiO2 and ZnO nanoparticles with controllable size and highly efficient catalytic application.