Activated Charcoal is made by first burning a carbonaceous substance (e.g. wood, coconut shells, bamboo etc) without oxygen which makes a carbon “char”. Next, the “char” is treated chemically or physically to develop an interconnected series of “holes” or pores inside the carbon.
The Char is placed in a tank without oxygen and subjecting it to extremely high temperatures, 600-900 degrees Celsius. Afterwards, the carbon is exposed to different chemicals, commonly argon and nitrogen, and again placed in a tank and superheated from 600-1200 degrees Celsius. The second time the carbon is placed in the heat tank, it is exposed to steam and oxygen. Through this process, a pore structure is created and the usable surface area of the carbon greatly increases.