GAS-PHASE ADSORPTION CHARACTERISTICS OF HIGH-SURFACE AREA CARBONS ACTIVATED FROM MESO-CARBON MICRO-BEADS

Gas-phase adsorption characteristics of three active carbons, differing in BET surface area, was investigated by measuring the adsorption isotherms of methane, carbon dioxide, and ethane at 273.15, 298.15, and 323.15 K up to 1200 kPa. Among active carbons M-20, M-30, and M-38, having approximately 2000, 3000 and 3800 m2/g BET surface areas respectively, carbon M-30 adsorbs the largest amount of methane and carbon dioxide, while carbon M-38 adsorbs the most ethane at elevated pressure, in a slightly stepwise manner. These adsorption characteristics were explained by the pore-size distribution data (0.4-0.5 nm for M-20 and M-30; 0.5-0.7 nm for M-38) and analysis by use of an isotherm equation. Mixed-gas adsorption data are obtained for two binary gases, methane + ethane and carbon dioxide+ethane, on M-38 at 298.15K and 500 kPa, which are correlated by the ideal adsorbed solution theory.