Photocatalytic degradation of 1:2 metal complex dye Acid blue 193 under solar light condition using ZnO nanoneedles and ZnO/bentonite nanocomposite synthesized via microwave irradiation

This paper describes a novel method for the preparation of ZnO nanoneedles and ZnO/bentonite nanocomposite with the assistance of a household microwave irradiation and their successful application for the photocatalytic degradation of 1:2 metal complex dye Acid blue 193 under solar energy. The products were analyzed by transmission electron microscopy (TEM), scanning electron microscopy (SEM), diffuse reflectance spectra and X-ray diffraction. The results confirm that synthesized ZnO nanoneedles are highly crystalline having a hexagonal wurtzite structure. TEM and SEM images show that wurtzite ZnO nanoneedles are well impregnated and homogeneously supported on the bentonite surface. The optical gap of ZnO nanoneedles was found to be 3.08 eV. The highest degradation efficiency of 1:2 metal complex dye Acid blue 193 was obtained at pH 8 for ZnO nanoneedles and ZnO/bentonite nanocomposite. In the kinetic study, the results for catalysts showed that the experimental data were fitted the pseudo-first-order model.