Ba-SAPO-34 membrane synthesized from microwave heating and its performance for CO2/CH4 gas separation

H-SAPO-34 membrane was successfully synthesized using microwave heating at 473 K within a period of 2 h. The H-SAPO-34 membrane was ion-exchanged with alkaline earth cations. A comparison study was conducted to obtain the separation performance of different cation-exchanged membranes. The CO2 permeances reduced with cation-exchanged membranes in the order of Ca2+ > Mg2+ > Sr2+ > Ba2+. The highest increase in CO2/CH4 separation selectivity of about 240% was obtained by ion-exchanging the H-SAPO-34 membrane with Ba2+. Separation of equimolar of CO2 and CH4 was conducted at different separation temperatures and pressure differences across the Ba-SAPO-34 membrane. The maximum CO2/CH4 separation selectivity of 103 with CO2 permeance of 37.6 × 10−8 mol/m2 s Pa was obtained for equimolar feed mixture of CO2 and CH4 at 303 K and 100 kPa pressure difference across Ba-SAPO-34 membrane.

► H-SAPO-34 membrane was formed and ion-exchanged with alkaline earth cations.
► Ion-exchanged membranes exhibited enhanced CO2/CH4 separation selectivity.
► Ba-SAPO-34 membrane was studied for equimolar CO2/CH4 gas separation.
► Maximum CO2/CH4 separation selectivity of 103 was obtained for Ba-SAPO-34 membrane.