CO2 adsorption and dehydration behavior of LiNaX, KNaX, CaNaX and CeNaX zeolites

In this study, NaX synthetic zeolite was modified by following the conventional cation exchange method at 70A degrees C. 82, 81, 79 and 48% of sodium were exchanged with Li+, K+, Ca2(+) and Ce3(+), respectively. Thermal analysis data obtained by TG/DSC was used to evaluate the dehydration behavior of the zeolites. The strongest interaction with water and the highest dehydration enthalpy (Delta H) value were found for Li-exchanged form and compared with the other forms. The temperature required for complete dehydration increased with decreasing cation size (cation size: K+> Ce3+> Ca2(+)> Na+> Li+). CO2 adsorption at 5 and 25A degrees C was also studied and the virial model equation was used to analyze the experimental data to calculate the Henry's law constant, K (o) and isosteric heat of adsorption at zero loading Q (st). K (o) values decreased with increasing temperature and the highest Qst was obtained for K rich zeolite. It was observed that both dehydration and CO2 adsorption properties are related to cation introduced into zeolite structure.