silica gel is a high absorbent. Exposing in the air (RH 80%-90%, T 25%) 7 hours, it can absorb 35-39% water. The silica gel is made by people with the Na 2 SiO 2 andchemical relative. The character is a lot of holes in inner, the outside structure is the anomalistic graininess. The inner configuration makes many hiatus net, forming the effect of capillary absorbent and coagulating. So it can absorb the surrounding water, alcohol, hydrocarbon and any other chemical molecules. People use sio 2 physical character and now make it the best absorbent.