Abstract: A novel process was adopted to gain activated carbon with high specific surface area from coconut shell charcoal. The charcoal was crushed to pieces of 0.28-0.90 mm and activated by the mixture of steam and carbon dioxide for 16-17 h to obtain activated carbon with surface area greater than 2 700 m²/g.The adsorption isotherms of CO₂ and CH₄ at 25℃ were measured and the highest adsorption amounts reached 20.4 and 9.6 mmol/g respectively.Most pores of the activated carbon had sizes smaller than 2 nm, which were calculated by a simple method based on simplified local density theory.

Key words: activated carbon, high specific surface area, coconut shell charcoal