Development of a hybrid membrane through coupling of high selectivity zeolite T on ZIF-8 intermediate layer and its performance in carbon dioxide and methane gas separation

• A novel hybrid membrane through coupling of zeolite T on ZIF-8 was fabricated.
• CO2/CH4 selectivity of hybrid membrane was 3 folds higher than zeolite T membrane.
• Effect of feed pressure and temperature on the hybrid membrane was studied.

This work demonstrated a novel hybrid membrane development through coupling of zeolite T membrane on ZIF-8 intermediate layer. ZIF-8 which acted as an intermediate layer was firstly grown on a macroporous α-alumina support via vacuum seeding. Pure phase zeolite T membrane was then synthesized on ZIF-8 which was pre-grown on the α-alumina support. Single gas permeation of standing free zeolite T membrane showed a CO2/CH4 selectivity of 68 with CO2 and CH4 gas permeances of 6.08 × 10−8 and 0.09 × 10−8 mol/m2.s.Pa, respectively. On the other hand, the CO2/CH4 selectivity of the hybrid membrane was 3 folds as compared to standing free zeolite T membrane, giving the highest CO2/CH4 selectivity of 182 and the CO2 and CH4 gas permeances of 5.46 × 10−8 and 0.030 × 10−8 mol/m2.s.Pa, respectively. Both gas permeances of CO2 and CH4 increased with increasing feed pressure from 1 to 4 bar with a slight decrease in the selectivity observed at the feed pressure of 4 bar. While for the effect under increasing temperature, CO2 showed an increasing trend of its gas permeability from 5.46 × 10−8 to 6.12 × 10−8 mol/m2.s.Pa while CH4 gas permeability increased slightly from 0.03 × 10−8 to 0.042 × 10−8 mol/m2.s.Pa due to greater mobility of gas molecules promoted by higher temperature.

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