Fig. 5 Gas separation performance of MMCMs. Effect of MOF loading on CO2 permeance and CO2/CH4 selectivity (feed gas: CO2/CH4 = 3/7 vol% mixed gas, 1 bar) of (a) MMCM-A, (b)MMCM-B. Effect of CO2 partial pressure on separation performance of pristine polyimide, MMCM-A and MMCM-B (equimolar mixed gas, 30°C): (c) CO2 permeance, (d) CO2/CH4 selectivity. Long-term stability of pristine polyimide, MMCM-A and MMCM-B (feed gas: CO2/CH4 = 3/7 vol% mixed gas, 1 bar, 30°C): (e) CO2 permeance, (f) CO2/CH4 selectivity.