How does activated carbon work?

The adsorption of activated carbon can be divided into physical adsorption and chemical adsorption.

Physical adsorption mainly occurs in the process of removing impurities in liquid and gas phase by activated carbon. The porous structure of activated carbon provides a large number of surface areas, which makes it very easy to absorb and collect impurities. Just like magnetic force, all molecules have mutual attraction. Because of this, a large number of molecules on the pore wall of activated carbon can produce strong attraction, so as to attract impurities in the medium into the pore diameter. It must be pointed out that the molecular diameter of these adsorbed impurities must be smaller than the pore diameter of the activated carbon, so that the impurities can be absorbed into the pore diameter. This is why we constantly change the raw materials and activation conditions to create activated carbon with different pore structure, which is suitable for the application of various impurities absorption.

In addition to physical adsorption, chemical reactions often occur on the surface of activated carbon. Activated carbon not only contains carbon, but also contains a small amount of chemical binding, functional groups of oxygen and hydrogen on its surface, such as carboxyl, hydroxyl, phenols, internal lipids, quinones, ethers, etc. These surfaces contain earth oxides or complexes which can react with the adsorbed substances, and then combine with the adsorbed substances and accumulate on the surface of activated carbon. Take a typical example: in the process of water treatment, the activated carbon can react with the chlorite in the water to change the chlorite into the form of chloride ion, so as to remove the chlorite in the water and make the water no longer have the unpleasant taste and smell.