Sorption of CO2/CH4 Mixtures in a Polymer of Intrinsic Microporosity (PIM-1): Effect of Temperature

Prior analysis of permselectivity in high free volume glassy polymers for gas separation shows that solubility selectivity is an important factor. The aim of this work is the study of solubility selectivity with respect to CO2/CH4 mixture of a polymer of intrinsic microporosity (PIM-1). Sorption experiments were carried out at 25°C, 35°C and 50°C up to a pressure of 35 atm at three molar fractions of CO2 (10.9, 31.3, 50.9%). Pressure decay equipped with gas chromatograph was used for the experiments. The results show that solubility coefficient of CO2 is lower for mixed gas experiment than for pure gas experiment, as well as the solubility coefficient of CH4, however the decrease of solubility coefficient of CH4 is higher than that of CO2. This behaviour gives rise to mixed gas solubility selectivity values higher than corresponding pure gas solubility selectivity. Sorption enthalpies were calculated at different gas mixture compositions