The synthesis of ZnO/HAp Composites for the Photocatalytic Degradation of Methylene Blue

Abstract

The amount of battery waste and goat bone waste in Indonesia is very abundant; therefore, it needs further processing not to waste and pollute the environment. Battery waste has the potential as a source of ZnO and goat bone waste has the potential as a source of hydroxyapatite (HAp). Both materials are synthesized into ZnO/HAp composites which have the potential as photocatalysts to reduce the intensity of dyes in wastewater. This study aims to synthesize ZnO/HAp composites to reduce the intensity of methylene blue dyes. ZnO/HAp composites were synthesized by solid dispersion method with acetone solvent in the variation of ZnO/HAp mass ratio by 20:80; 30:70; 40:60; 50:50; 60:40; 70:30; and 80:20. The resulting ZnO particles are wurtzite minerals and hydroxyapatite particles are hydroxyapatite minerals. SEM data shows that the ZnO/HAp composite crystal morphology is in the form of chunks and hexagonal rods of non-uniform size and particle agglomeration. Synthesis of ZnO/HAp composites can reduce the intensity of methylene blue dyes by using visible light. In applying ZnO/HAp composites to the decolorization of methylene blue, several variations were made including variations in the composition of composites, the mass of composites and irradiation time. The best condition for reducing the intensity of methylene blue dyes is using ZnO/HAp composite with a ratio of 40:60 as much as 25 mg in 20 mL of 10 ppm methylene blue solution for 3 hours. The percentage of decolorization is 95.70%.