Activated carbon, also called activated charcol or activated coal is a form of carbon that has been processed to make it extremely porous and thus to have a very large surface area available for absorption or chemical reactions.
The word activated in the name is sometimes replaced with active. Due to its high degree of microporosity, just 1gram of activated carbon has a surface area in excess of 500 m2 (about one tenth the size of a football field), as determined typically by nitrogen gas absorption. Sufficient activation for useful applications may come solely from the high surface area, though further chemical treatment often enhances the absorbing properties of the material. Activated carbon is usually derived from charcoal.