Isosteric heats of adsorption of carbon dioxide on zeolite MCM-22 modified by alkali metal cations

Adsorption isotherms of carbon dioxide were measured on cation-exchanged (Li+, Na+, K+, Cs+) MCM-22 zeolite with the molar ratio of Si/Al=15 and series of Na-MCM-22 of Si/Al molar ratios varying in the range from 15 to 40 at 273, 293, 313 and 333 K. Based on the known temperature dependence of CO2 adsorption, isosteric heats of adsorption were calculated. The obtained dependences of isosteric heats related to the amount of CO2 adsorbed have provided detailed insight into the interaction of carbon dioxide molecule with alkali metal cations.