Adsorption of CO2 and N2 onto Charcoal Treated at Different Temperatures

Adsorption properties of wood charcoal prepared by a traditional method are investigated by using CO2 adsorption at 195 K and N2 adsorption at 77 K, focusing on the effects of the treatment temperature. The amount of CO2 adsorbed at 195 K and N2 adsorbed at 77 K increases with treatment temperature. The shape of the N2 adsorption isotherm indicates that the charcoal is predominantly characterized by micropores with the presences of mesopores, when high treatment temperature is applied. At a low treatment temperature, the ratio of nCO2 to nN2 is high, whereas, it approaches to unity at the higher treatment temperature than 773 K. The adsorption of CO2 at 195 K can be used for surface area measurement, in place of N2 adsorption at 77 K, for the charcoal treated higher temperature.