Study on the Preparation of TiO2-SiO2 Composites from Rice Husk Ash

Abstract

In this paper, TiO2-SiO2 composites with different SiO2 content s were prepared by coprecipitation method using rice husk ash as raw material. The effects of the concentration of alkaline leaching solution and reaction temperature on the extraction rate of SiO2 from rice husk ash were investigated. The optimum formation conditions of TiO2-SiO2 composites were explored, and the microstructure and properties of the composites were analyzed. The experiment al results showed that the extract ion rat e of SiO2 from rice husk ash reaches the maximum when the concentration of alkaline leaching solution is 1.5 mol/L and the reaction temperature is 90°C. When the pH value is 7, the TiO2-SiO2 composites can achieve the optimum formation condition. TiO2-SiO2 composites are composed of approximately spherical particles with obvious pore structure of the surface and piling up in fluffy state. The Si atoms enter the crystal structure of TiO2 with Ti-O-Si bonds connected to Ti atoms, which inhibits the growth of TiO2 grains and leads to the increase of the transition temperature of TiO2 from anatase to rutile.