The purpose of this research is to separate silica gel from rice husk ash by microwave heating. The
experiments were performed by heating rice husk ash in sodium hydroxide solution with various
concentrations in microwave oven for 5 or 10 minutes. The obtained sodium silicate was neutralized to give
silica gel. The best condition for silica gel production was the reaction with 2.0 M sodium hydroxide at
microwave power of 800 W for 10 minutes. The ability of silica gel as desiccant was investigated by
adsorption test. The results showed that silica gel prepared by low concentration of sodium hydroxide
solution had the highest ability of water adsorption. The power of microwave and volume of reactions
seemed to have only little effect.