Olefin Recovery by *BEA-Type Zeolite Membrane: Affinity-Based Separation with Olefin-Ag+ Interaction.

Ag+ was introduced into *BEA-type zeolite membrane by an ion-exchange method to enhance olefin selectivity. Ag-*BEA membrane exhibited superior olefin separation performance for both ethylene/ethane and propylene/propane mixtures. Particularly, the separation factor for ethylene at 373 K reached 57 with the ethylene permeance of 1.6×10-7  mol m-2  s-1  Pa-1 . Adsorption properties of olefin and paraffin were evaluated to discuss contribution of Ag+ to separation performance enhancement. A strong interaction between olefin and Ag+ in the membrane caused preferential adsorption of olefin against paraffin, leading to selective permeation of olefin. Ag-*BEA membrane also exhibited high olefin selectivities from olefin/N2 mixtures. The affinity-based separation through Ag-*BEA membrane showed a high potential for olefin recovery and purification from various gas mixtures.