We report on the results of kinetic and equilibrium adsorption measurements for two gases, CF4 and Ar, on RPM1-Co and Cu-BTC metal-organic framework materials. The kinetic experiments were performed at similar relative temperatures (T/T-critical = 0.52 and 0.597) on both adsorbents. The results show that both gases behave differently on Cu-BTC from the way they do on RPM1-Co. In addition, the equilibrium isotherms indicate that there are some sites on Cu-BTC which are accessible to Ar but not to CF4. Taken together, our results for the kinetic and equilibrium experiments suggest that these MOFs have high potential for use in gas separation applications. (c) 2008 American Institute of Chemical Engineers.