What is activated carbon?
What is activated carbon? Activated carbon (sometimes called activated charcoal) is a widespread adsorption media used in almost every industrial field. It is used in different applications such as purification (such as gas and water purification), recovery, decolourisation, deodorisation, separation, catalysis, catalytic support, and gas storage.
Activated carbon was described as early as 1550 B.C. in an ancient Egyptian papyrus and has been used since to purify water and air.
Activated carbon purification and adsorption
Activated carbon purification is primarily based on a phenomenon called adsorption, in which molecules of a liquid or gas are trapped by either an external or internal surface of a solid. The phenomenon is somewhat similar to iron filings being held by a magnet. Activated carbon has a very high internal surface area and is thus an ideal material for adsorption.
Activated carbon pores
Activated carbon can be defined as a crude form of graphite with a random or amorphous structure, which is highly porous over a broad range of pore sizes, from visible cracks and crevices to cracks and crevices of molecular dimensions.
Activated carbon has a wide variety of pore sizes. Pores are normally classified by size as
- micropores <2 nm
- mesopores 2 - 50 nm
- macropores >50 nm (typically 50-200 nm )
to distinguish their importance in an application. Sometimes pores are classified by their function. Two types of functional pores can be distinguished within activated carbon:
- adsorption pores that adsorb, and
- transport pores that transport.
If we would compare adsorbate molecules with cars, then transport pores are carbon highways and adsorption pores are carbon parking places. The cars are only stored in the parking places, and the highways are used to move the cars to the parking lots.
At DESOTEC’s facilities, all used carbon is analysed so the right measures can be taken for handling and removing the saturated carbon out of the mobile filters. All molecules that were adsorbed on the activated carbon at the customers’ site, are desorbed inside DESOTEC’s reactivation furnaces. These contaminants are then fully destroyed, in accordance with National and European legislation, by an incineration and neutralisation setup. The entire installation and it's emissions are under continuous on-line monitoring, which guarantees that only harmless water vapour is seen exiting the chimney.