Powdered charcoal. Charcoal is an amorphous form of carbon produced from burning wood in little or no oxygen. Charcoal can also be obtained from other substances, for example bones. Because it is porous, powdered charcoal is used in chemistry for the adsorption of gases and solids. Adsorption is the attachment of atoms or molecules of one substance to the surface of a solid or liquid of another substance. Charcoal is used in purification, for example of water; for drying of gases and as a filter in gas masks.