Silica gel is a highly active adsorbent material, which is an amorphous material containing polysiloxane, silicone oil, white carbon black (silica), coupling agent and filler, etc. The main component is silica, its chemistry The molecular formula is mSiO2·nH2O. It is insoluble in water and any solvent, non-toxic and tasteless, chemically stable, and does not react with any substance except strong alkali and hydrofluoric acid. Various types of silica gels have different microporous structures due to their different manufacturing methods. The chemical composition and physical structure of silica gel determine that it has many other similar materials that are difficult to replace: high adsorption performance, good thermal stability, stable chemical properties, and high mechanical strength.