|Activated carbon 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 it's very
large surface area which allows the carbon to adsorb a wide range of
Activated carbon has the strongest physical adsorption forces or the highest volume of adsorbing porosity of any material known to mankind.
can have a surface of greater than 1000mē/g. This means 5g 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. This is different from absorption, where molecules are taken up by a liquid or gas.
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|What is activated carbon
Activated carbon can made from many substances containing a high carbon content such as coal, wood and coconut shells. The raw material has a very large influence on the characteristics and performance activated carbon.
What makes it activated ?Activation refers to the development of the adsorption properties of carbon. Raw materials such as coal and charcoal do have some adsorption capacity, but this is greatly enhanced by the activation process.
Forms of activated carbonThere are three main forms of activated carbon.
Granular Activated Carbon
|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
|Powder Activated Carbon (PAC) - pulverized 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.|
Pelleted Activated Carbon
Activated Carbon - 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
|Activated carbon is also available in special forms such as a cloth and fibres.|