Gas Permeation Properties of Modified SAPO-34 Zeolite Membranes

Abstract

The global concern to reduce carbon dioxide (CO2) gas emission urges the need to explore for the effective membrane separation technology. Gas permeation properties of the membranes are good indicator in reflecting the gas mixture's separation performance of the membranes. Nowadays, silicoaluminophosphate-34 (SAPO-34) zeolite membrane is gaining increasing popularity among researchers in gas permeations studies due to their small pore structure. In current study, the synthesized SAPO-34 zeolite membrane was modified with Ba2+ cation to form Ba-SAPO-34 membrane. CO2 and CH4 gas permeation studies for the Ba-SAPO-34 zeolite membrane were carried out at temperature of 30 – 180 oC and pressure difference of 100 – 500 kPa. The effect of temperature and pressure difference on the gas permeation properties of the Ba-SAPO-34 zeolite membranes was investigated. When the pressure difference was increased from 100 to 500 kPa at 30 oC, the CO2 flux and CH4 flux increased from 19.5 to 78.7×10-3 mol/m2·s and from 0.35 to 1.75×10-3 mol/m2·s respectively. When the temperature was increased from 30 to 180 oC at pressure difference of 100 kPa, the CO2 flux decreased from 19.5 to 9.8×10-3 mol/m2·s but the CH4 flux remained nearly constant at 0.35×10-3 mol/m2·s. CO2/CH4 ideal selectivity as high as ∼56 was obtained for Ba-SAPO-34 membrane's gas permeation at 30 oC and 100 kPa pressure difference.