Ion-Exchanged Silicoaluminophosphate-34 Membrane for Efficient CO2/N2 Separation with Low CO2 Concentration in the Gas Mixture

The Ba form of a silicoaluminophosphate-34 (SAPO-34) zeolite membrane was synthesized and investigated for carbon dioxide (CO2)/nitrogen (N2) separation with low CO2 concentration (as low as 5) in the feed. The effects of the separation temperature, CO2 concentration in the feed, and pressure difference on the separation performance of the Ba form of a SAPO-34 zeolite membrane were investigated. A CO2 gas permeance of 17.5 � 10-7 mol/m2·s·Pa and a CO2/N2 separation selectivity of 78 were attained for the Ba form of a SAPO-34 zeolite membrane at 100 kPa pressure difference, 303 K, and 5 CO2 concentration in the feed. With low CO2 concentration (5) in the CO2/N2 mixture, the Ba form of a SAPO-34 zeolite membrane was efficient in CO2/N2 separation and displayed good stability for the separation performance of CO2/N2 gas mixtures, in a gas separation durability test up to a total durability test time of 58 h. © 2018 American Chemical Society.