More than 100 types of activated carbon for all your purification applications:
- Granular activated carbons (GAC)
- Extruded or pelletised activated carbons (EAC)
- Powdered activated carbons (PAC)
- Acid washed and high purity activated carbons
- Specialist Impregnated carbons
- Production capacity of more than 75,000 metric tonnes per year
- We can supply activated carbon anywhere in the world!
What is Activated Carbon?
Activated carbon, also known as activated charcoal, is a crude form of graphite, the substance used for pencil leads. It differs from graphite by having a random, imperfect structure which is highly porous over a broad range of pore sizes from visible cracks and crevices to molecular dimensions. The graphite structure gives the carbon its very large surface area which allows the carbon to adsorb a wide range of compounds.
Activated carbon (activated charcoal) has the strongest physical adsorption forces, or the highest volume of adsorbing porosity, of any material known to mankind.Activated carbon (activated charcoal) can have a surface of greater than 1000m²/g. This means 3g of activated carbon can have the surface area of a football field.
What is adsorption?
Adsorption is the process by which liquid or gaseous molecules are concentrated on a solid surface, in this case activated carbon (activated charcoal). This is different from absorption, where molecules are taken up by a liquid or gas.
What is activated carbon made from?
Activated carbon (activated charcoal) can made from many substances containing a high carbon content such as coal, coconut shells and wood. The raw material has a very large influence on the characteristics and performance of the activated carbon (activated charcoal).
Forms of activated carbon
There are three main forms of activated carbon (activated charcoal).
Granular Activated Carbon (GAC) - irregular shaped particles with sizes ranging from 0.2 to 5 mm. This type is used in both liquid and gas phase applications.
Powder Activated Carbon (PAC) - pulverised carbon with a size predominantly less than 0.18mm (US Mesh 80). These are mainly used in liquid phase applications and for flue gas treatment.
Extruded Activated Carbon (EAC) - extruded and cylindrical shaped with diameters from 0.8 to 5 mm. These are mainly used for gas phase applications because of their low pressure drop, high mechanical strength and low dust content.
Activated carbon is also available in special forms such as a cloth and fibres.
What makes molecules adsorb on activated carbon ?
Adsorption is caused by London Dispersion Forces, a type of Van der Waals Force which exists between molecules. The force acts in a similar way to gravitational forces between planets.
London Dispersion Forces are extremely short ranged and therefore sensitive to the distance between the carbon surface and the adsorbate molecule. They are also additive, meaning the adsorption force is the sum of all interactions between all the atoms. The short range and additive nature of these forces results in activated carbon having the strongest physical adsorption forces of any material known to mankind.
Gas Phase Adsorption - This is a condensation process where the adsorption forces condense the molecules from the bulk phase within the pores of the activated carbon. The driving force for adsorption is the ratio of the partial pressure and the vapour pressure of the compound.
Liquid Phase Adsorption - The molecules go from the bulk phase to being adsorbed in the pores in a semi-liquid state. The driving force for adsorption is the ratio of the concentration to the solubility of the compound.
What compounds are adsorbed ?
All compounds are adsorbable to some extent. In practice, activated carbon is used for the adsorption of mainly organic compounds along with some larger molecular weight inorganic compounds such as iodine and mercury.In general, the adsorbability of a compound increases with:
- increasing molecular weight
- a higher number of functional groups such as double bonds or halogen compounds
- increasing polarisability of the molecule. This is related to the electron clouds within the molecule