Combined microcalorimetric and IR spectroscopic study on carbon dioxide adsorption in H-MCM-22

The thermodynamics of carbon dioxide adsorption in the protonic zeolite H-MCM-22 (Si:Al = 16:1) was investigated by means of adsorption calorimetry and variable-temperature IR spectroscopy, a technique that affords determination of standard adsorption enthalpy (ΔH0) and entropy (ΔS0) from analysis of a series of IR spectra recorded over a temperature range while simultaneously measuring equilibrium pressure inside a closed IR cell. ΔH0 resulted to be −24.5 (±2) kJ mol−1, while for the entropy change the value of ΔS0 = −115 (±10) J mol−1 K−1 was obtained. The obtained ΔH0 value is compared with those reported in the literature for the adsorption of CO2 on other zeolites, and discussed in the context of carbon dioxide capture and sequestration.