The Chemical Configuration of Silica Gel

The chemical formula is xSiO2·yH2O. Transparent or milky white granular solid. It has an open porous structure, strong adsorption, and can adsorb a variety of substances. Add dilute sulfuric acid (or hydrochloric acid) to the aqueous solution of water glass and let it stand to form a hydrous silicic acid gel and solidify. Wash with water to remove electrolyte Na+ and SO4 2-(Cl-) ions dissolved in it. After drying, silica gel can be obtained. If it absorbs moisture, some silica gel absorbs moisture up to 40% or even 300%. It is used for gas drying, gas absorption, liquid dehydration, chromatography, etc. It is also used as a catalyst. If cobalt chloride is added, it will be blue when dry, and red after absorbing water. It also can be regenerated and used repeatedly.