Changes in the Properties of Precipitated Silica Depending on the Modification Process of Silica Hydrogel Originated from Rice Husk

Abstract

In this study, the changes in the properties of the prepared precipitated silica were evaluated depending on the conditions of the modification process of the silica hydrogel originated from rice husks. Rice husk silica hydrogel was prepared through a sol-gelation process after alkali soaking extraction of rice husk. The silica hydrogel was modified by adjusting the solution concentration and temperature conditions in acidic and alkali solutions. As a result, the changes in surface chemical properties and the improvement of quality characteristics such as whiteness and impurity removal were confirmed through the modification process. The modification treatment in an acidic atmosphere minimized the decrease in production yield and showed great effects on the whiteness and the removal of impurities such as alkali metals. In a alkaline condition, the improvement in the whiteness was clearly shown, but the reduction in yield increased. It was shown that the effects of the residual alkali metals and the organic substances on the properties of the precipitated silica could be controlled by the control of the modification process conditions.