Experiment and theoretical analysis of methane adsorption on activated carbon under supercritical temperature

For the development of adsorbent for adsorption of natural gas(ANG),Setaram PCT Pro EE was employed to measure the isotherms of methane adsorption on the activated carbon SAC-02 with specific surface area of 2074 m2·g-1 over a temperature range of 263.15K-313.15K and a pressures range of 0-8MPa.Dubinin and Astakhov's equation(D-A equation),Clausius-Clapeyron equation and Virial plot were used to fit and analyze the adsorption data.The results showed that when the pressure was higher than 0.08MPa,the modified D-A model could much accurately predict the adsorption data with a mean relative error of less than 5%;the isosteric heat of methane adsorption on the activated carbon was 13.99kJ·mol-1-17.57 kJ·mol-1,which revealed the adsorption of methane on energy heterogeneous surface;the limit isosteric heat of methane adsorption linearly changes with temperature,and the average value was 19.43kJ·mol-1.