Inorganic silica gel is a highly active adsorption material, usually prepared by reacting sodium silicate and sulfuric acid, and undergoing a series of post-treatment processes such as aging and acid foaming. Silica gel is an amorphous substance, and its chemical formula is mSiO2.nH2O. It is insoluble in water and any solvent, non-toxic and tasteless, chemically stable, and does not react with any substances except strong alkali and hydrofluoric acid. Various types of silica gel form different microporous structures due to different manufacturing methods. The chemical composition and physical structure of silica gel determine that it has many characteristics that are difficult to replace by other similar materials: high adsorption performance, good thermal stability, stable chemical properties, and high mechanical strength.