Thermodynamic study of LiNaKLSX zeolites with different Li exchange rate for N2/O2 separation process

The process design for air separation based on adsorption requires knowledge of the following data: pure adsorption isotherms at different temperatures, multicomponent adsorption equilibrium data and kinetic data. In this paper, we present a complete study of oxygen and nitrogen adsorption at three temperatures on a set of Li exchanged NaKLSX zeolites. Pure gas isotherms were obtained for five different zeolites up to 2500 kPa at 303 K and for three of the five also at 288 and 318 K. Co-adsorption equilibria were analyzed for different compositions at 400 kPa and 303 K on the two zeolites which present the best adsorption capacities. Data were obtained with two volumetric apparatus constructed in lab.Furthermore, predictive binary equilibria obtained by Ideal Adsorbed Solution Theory (IAST) from pure component isotherms were compared with experimental mixture data.Finally, the zeolite which has the best adsorption capacities was formed with two different binders and their thermodynamic adsorption properties were compared to the original zeolite.

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► The effect of Li exchange rate is very important for O2/N2 separation.
► Li100%LSX formed with bentonite provides promising results for industrial application.
► IAST provides good predictions for O2/N2 separation.