FT-IR spectroscopic and thermodynamic study on the adsorption of carbon dioxide and dinitrogen in the alkaline zeolite K-L

► Variable temperature IR spectroscopy is used to study adsorption of CO2 and N2 in the alkaline zeolite K-L. ► By simultaneously recording IR absorbance, temperature and equilibrium pressure, standard adsorption enthalpy and entropy for each gas was determined. ► The results are discussed in the broader context of gas separation using zeolites; focusing on carbon dioxide capture. The thermodynamics of carbon dioxide and dinitrogen adsorption on the zeolite K-L was investigated by means of variable temperature IR spectroscopy, a technique that affords determination of standard adsorption enthalpy (ΔH°) and entropy (ΔS°) from analysis of IR spectra recorded over a temperature range while simultaneously measuring equilibrium pressure inside a closed IR cell. ΔH° resulted to be −42.5 and −20.6kJmol−1 for CO2 and N2, respectively. Corresponding values of ΔS° were found to be −182 and −151Jmol−1K−1. The obtained adsorption enthalpy values are discussed in the context of carbon dioxide capture and sequestration.