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 N-2 adsorption at 77 K, focusing on the effects of the treatment temperature. The amount of CO2 adsorbed at 195 K and N-2, adsorbed at 77 K increases with treatment temperature. The shape of the N-2 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 n(CO2) to n(N2) 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 N-2 adsorption at 77 K, for the charcoal treated higher temperature.