MICROPORE STRUCTURE OF ACTIVATED CARBONS PREPARED FROM A SPANISH SUBBITUMINOUS COAL STUDIED BY CO2, BENZENE, AND CYCLOHEXANE ADSORPTION

Two series of activated carbons with different degrees of activation were prepared from a Spanish subbituminous coal by pyrolysis and steam activation. The micropore structure of the activated carbons so obtained was characterized by CO2 adsorption at 273 K by applying the Dubinin-Astakhov equation and by benzene and cyclohexane adsorption at 303 K by applying the Dubinin-Stoeckli equation corrected with the Dubinin-Zaverina equation, This last method has allowed discovery of the real micropore volume and its distribution and dispersion, as well as the mesopore surface area of the activated carbons. Results obtained also show that the Dubinin-Astakhov equation applied to CO2 adsorption isotherms on activated carbons with a medium to high degree of activation is affected by the adsorption on the mesopore surface.