activated carbonIt is a specially treated charcoal that heats organic raw materials (fruit shells, coal, wood, etc.) under isolated air conditions to reduce non carbon components (this process is called carbonization), and then reacts with gas to corrode the surface, producing a structure with well-developed micropores (this process is called activation). Due to the fact that the activation process is a microscopic process, where a large amount of molecular carbides corrode the surface in a point like manner, numerous small pores are formed on the surface of activated carbon. The diameter of micropores on the surface of activated carbon is mostly between 2-50nm. Even a small amount of activated carbon has a huge surface area, with a surface area of 500-1500m2 per gram of activated carbon. Almost all applications of activated carbon are based on this characteristic of activated carbon.

Activated carbon is a general term for carbon materials with developed pore structure, large specific surface area, rich surface chemical groups, and strong specific adsorption ability, which are prepared by pyrolysis and activation processing of carbon containing raw materials such as wood, coal, and petroleum coke.

Usually, it is a porous amorphous carbon with strong adsorption capacity in powder or granular form. Obtained by carbonizing solid carbonaceous materials (such as coal, wood, hard fruit shells, fruit cores, resins, etc.) at high temperatures of 600-900 ℃ under isolated air conditions, and then oxidizing and activating them with air, carbon dioxide, water vapor, or a mixture of the three gases at 400-900 ℃.

Carbonization causes substances other than carbon to evaporate, and oxidation activation can further remove residual volatile substances, generate new and expand existing pores, improve microporous structure, and increase activity. Low temperature (400 ℃) activated carbon is called L-Carbon, and high temperature (900 ℃) activated carbon is called H-Carbon. H-carbon must be cooled in an inert atmosphere, otherwise it will transform into L-Carbon. The adsorption performance of activated carbon is related to factors such as the chemical properties and concentration of the gas during oxidation activation, activation temperature, activation degree, and the composition and content of inorganic substances in activated carbon. It mainly depends on the properties and activation temperature of the activated gas.

The carbon content, specific surface area, ash content, and pH value of the aqueous suspension of activated carbon all increase with the increase of activation temperature. The higher the activation temperature, the more complete the volatilization of residual volatile substances, the more developed the microporous structure, and the larger the specific surface area and adsorption activity.

The ash composition and content in activated carbon have a significant impact on its adsorption activity. Ash content is mainly composed of K2O, Na2O, CaO, MgO, Fe2O3, Al2O3, P2O5, SO3, Cl -, etc. The ash content is related to the raw materials used to produce activated carbon, and increases with the removal of volatile compounds in the carbon.

By 2007, the annual output of activated carbon had reached 900 kt, of which coal based (quality) activated carbon accounted for more than 2/3 of the total output;