Activated carbon is often used for gas adsorption, separation and purification, solvent recovery, decolorization of sugar solution, oil, glycerin, and medicine, deodorant for drinking water and refrigerators, filter agent in gas masks, air purification, and can also be used as a catalyst or carrier of metal salt catalyst. So, why is activated carbon “alive” with so many functions?
What is special about activated carbon?
First of all, as a kind of charcoal, it is different from common charcoal. From the elemental composition and structure of the material, there is not much difference between activated carbon and charcoal. That is, they are both composed of carbon elements and are loose and porous. The difference between activated carbon and general charcoal is that activated carbon is looser and more “active” (adsorption capacity) than general charcoal. Activated carbon is made from charcoal, but the activated carbon made from general charcoal is not “active”. The “activity” of activated carbon is reflected in its strong adsorption capacity.
Activated carbon has many nanometer-level tiny pores. The surface area of one gram of activated carbon can even exceed 3,000 square meters, while the surface area of one gram of unactivated charcoal is only 2.0-5.0 square meters. Activated carbon has a strong “physical adsorption” and “chemical adsorption” effect, which can adsorb certain organic compounds to achieve the removal effect. Using this principle, we can quickly and effectively remove harmful substances, odors, pigments, etc. in the aquarium water quality, so that the water quality can be directly and rapidly improved. If the adsorption force of everything is the same, the larger the adsorption area, the stronger the adsorption capacity. The huge specific surface area of activated carbon achieves lightweight adsorption.
Generally speaking, good activated carbon products are activated. The activation treatment is to increase the porosity of activated carbon and improve its adsorption effect. The activation treatment of activated carbon generally adopts the gas activation method, which is a method of using oxidizing gases such as water vapor, carbon dioxide, and air as activators to activate and make activated carbon at high temperature. This method is also called physical activation. Using this activation method can decompose the carbon compounds remaining in the activated carbon, remove impurities on the surface, and reopen blocked gaps. In addition, water vapor can corrode the active surface structure and form new gaps, increasing the surface area and improving the adsorption capacity of the activated carbon.
