Synthesis of silica particles by precipitation method of sodium silicate: Effect of temperature, pH and mixing technique

Abstract

The silica (SiO2) particle was synthesized using the precipitation method of sodium silicate (Na2SiO3) precursor by additional HCl as precipitant. In this paper, the precipitant was mixed directly to the solution of sodium silicate (Na2SiO3) in contrast to the conventional dropwise technique which prevented a high production rate. The dropwise of HCl was carried out to know the effect of pH at two different temperature 25 °C (T20) and 80 °C (T80) on the obtained particles. It was obtained that the optimized process was at temperature 25 C. Subsequently, the mixing technique of HCl (conventional dropwise and direct mixing) were investigated at temperature 25 °C. The result showed that direct mixing technique resulted in high production rate with acceptable size and dispersion of silica nanoparticles. It is also highlighted that the proposed direct mixing technique of HCl received a simple and faster-precipitated process in large scale production. Therefore, it is proposed that for the scale-up production of silica nanoparticle by precipitation of the sodium silicate (Na2SiO3) precursor with additional of HCl may be prepared by direct mixing method at pH 7 in temperature 25°C.