Sono-precipitation dispersion of CuO-doped ZnO nanostructures over SiO2-aerogel for photo-removal of methylene blue, congo red and methyl orange from wastewater

Abstract

In this study, to ameliorate the photocatalytic performance of ZnO, being an n-type semicon-ductor, CuO as a p-type semiconductor was applied to produce p-n type heterojunction. To increase the active surface area of CuO-ZnO composite, Silica Aerogel which is of a high spe-cific surface area were applied as a support. Different powers of ultrasound (0–100-200 W) were investigated during the synthesis. Sonication not only prevents composite agglomera-tion, but also improves the diffusion of particles onto the surface of the Silica Aerogel with a fine particle size. For the sake of specifying the physical and chemical properties of the sam-ples, XRD, FESEM, EDX, BET, TEM, and DRS analyses were used. Applying ultrasound assists the distribution of particles on Silica Aerogel, rising the number of active sites in the oxidation process. Silica Aerogel not only has a high specific surface area, but also it prevents electron-hole recombination, increasing the composites efficiency. The operating parameters such as pH, catalyst loading and reusability were studied. The study of the photocatalytic performance of samples represented that the CuO-ZnO/SA(P = 200) were able to remove 95.4 % of methylene blue with 20 mg/Lit initial concentration.