Speaker
Description
The separation of propane and propylene remains a challenging seperation process, due to the similar boiling points and size of both molecules. LTA zeolites have been shown to be promising adsorbents, but a systematic study of the effect of the extra-framework cations on propylene and propane adsorption is lacking.
In this work, we prepared LTA zeolites exchanged with different cations (Na+, Li+, Ca2+, Mg2+, Cu2+, Mn2+, Zn2+). All exchanged samples were synthesized with Na+ as counterion and then partially exchanged with the other cation (30% and 50%). Results were compared with a pure Si-LTA zeolite. Adsorption isotherms were measured using a manometric system, coupled to an isothermal microcalorimeter (Tian-Calvet type), allowing the simultaneous measurement of the released heats of adsorption. While Si-LTA shows no preferential adsorption of propane or propylene and is essentially heterogeneous for both probe molecules, propylene shows a strong interaction with divalent cations. On the other hand, LTA zeolites with monovalent cations (Na+ / Li+) show slow diffusion of propane, opening perspectives for a kinetic separation.
