Activated carbon is a specially treated carbon that heats organic raw materials (nut shells, coal, wood, etc.) in the absence of air to reduce non-carbon components (this process is called carbonization), and then reacts with the gas, and the surface is covered with air. Erosion, resulting in a microporous structure (this process is called activation). Since the activation process is a microscopic process, that is, the surface erosion of a large number of molecular carbides is point erosion, so the activated carbon surface has numerous tiny pores. Most of the micropore diameters on the surface of activated carbon are between 2 and 50 nm. Even a small amount of activated carbon has a huge surface area. The surface area of each gram of activated carbon is 500 to 1500 m2. Almost all applications of activated carbon are based on this feature of activated carbon.