Separation performance
The gas transport behaviors of the prepared membranes were analyzed by using a reequipped gas permeation analyzer (MGT-01, Labthink CO.). The prepared membranes with exposed area of 3.14 cm2 were sealed in permeation cell by O-ring. After vacuum treating the permeation system, the feed chamber was filled with the gas to be measured with pressure of 100 kPa. The permeate gas was analyzed by gas chromatography. The gas permeability (P, Barrer, 1 Barrer = 10-10 cm3 (STP) cm cm-2 s-1 cmHg-1) was calculated based on the permeate gas volume, membrane thickness, effective area, permeation time, and transmembrane pressure. The selectivity (αi ) was calculated by the permeability of two gases:
\(\alpha_{i}=\frac{P_{\text{CO}_{2}}}{P_{\text{CH}_{4}}}\) (3)