Synthesis of ZnO/FA composite for methylene blue decolorization

Abstract

In this research, a ZnO/FA composite was successfully synthesized for the photocatalytic treatment of methylene blue. ZnO was obtained from Zn-C battery waste by precipitation method. Zinc metal from battery waste was separated, cleaned, and dissolve in hydrochloric acid to get the ZnCl2 solution. After adding some base until pH = 10, white precipitation was formed. This precipitate was filtered out and calcinated at 400 °C for 4 hours to obtained ZnO. Fly Ash (FA) was obtained from coal combustion waste. Fly ash was cleaned and drying at 105 °C for 3 hours. Synthesis of ZnO/FA composite was synthesized by a solid dispersion method using acetone as a medium with a various composition of ZnO: FA = 20:80; 40:60; 60:40; 80,20 in percentage. The XRD data show that the ZnO/FA composite was successfully synthesized. The SEM photo’s show that different morphology where more ZnO in the composite, the FA particles will be increasingly encased with ZnO particles. Photocatalytic performance studies of ZnO/FA composites for decolorization of methylene blue were carried out in various compositions, exposure times, substrate concentrations, and mass composites. The optimum decolorization was found in 40:60 composition, 3 hours irradiation time, 5 ppm concentration of methylene blue, and 150 mg of photocatalyst mass.