(350f) Cation-Exchanged LTA Zeolites for Propane / Propylene Separations
AIChE Annual Meeting
2023
2023 AIChE Annual Meeting
Separations Division
Adsorbent Materials for Sustainable Energy and Chemicals
Wednesday, November 8, 2023 - 2:00pm to 2:18pm
In this work, we synthesized 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%). A comparison was made with pure Si-LTA. Adsorption isotherms were measured using a manometric system, coupled to a Tian-Calvet calorimeter, allowing the simultaneous measurement of the adsorption pseudo-differential enthalpy. These results were compared with DFT calculations. 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. Such materials open perspectives for the equilibrium-based separation of propane and propylene. On the other hand, LTA zeolites with monovalent cations (Na+ / Li+) show slow diffusion of propane, opening perspectives for a kinetic separation.