Visible light photocatalysis of a textile dye over ZnO nanostructures covered onnatural diatomite

Abstract

In the present study, ZnO nanostructures were ultrasonically synthesized and immobilized on the surfaceof diatomite and used for visible light photocatalysis of Acid Red 88 (AR88) in the aqueous phase. Scanning electronmicroscopy (SEM) and X-ray diffraction (XRD) analyses were employed for characterization of the samples. The processwas optimized via response surface methodology (RSM) on the basis of central composite design (CCD). Based onnumerical optimization, for the maximized color removal of 96% the initial dye concentration, the catalyst dosage, thereaction time, and the initial pH were 13 mg/L, 1.5 g/L, 85 min, and 4, respectively. The initial pH produced the largesteffect, while the adsorbent dosage represented the lowest individual effect on the photocatalysis of AR88. The reusabilitytest showed a 20% reduction in decolorization efficiency (%) within four consecutive experimental runs. Overall, ZnO-diatomite nanocomposite can be applied as an efficient photocatalyst for the visible light photocatalysis of target organicdyes.