Sorption studies of novel PIMs for CO2/CH4 separation

During the last four decades, the membrane-based gas separation processes have become an important separation technique used in chemical industry. Nowadays, polymers represent the most important materials for membrane fabrication. It is due to their excellent processability, low-cost and high-scale production. Recently established class of polymeric materials, so called polymers of intrinsic microporosity (PIMs), are known for extraordinary high permeability and moderate selectivity [1]. Currently, these materials represent the promising candidates for radical improvement in gas and vapour membrane separations. In this work, an extensive study of carbon dioxide and methane sorption in PIM-1 [2] and in its structural analogues PIM-PI-SBI [3], PIM-PI-EA [3], PIM-EA-TB [4], PIM-Triptycene-TB [4] and Amine-PIM-1 [5] is presented. Sorption measurements were performed gravimetrically at 25°C in a pressure range 1 - 7 bar using home-made sorption apparatus equipped with precise McBain's quartz spiral balances and automatic CCD camera detection system [2]. The sorption isotherms and the sorption (S) and diffusion coefficients (D) were evaluated from the measured data. According to the dual sorption mode model, the ideal sorption selectivity (?x/y) - i.e. a ratio between sorbed amounts of CO2/CH4 under same condition was calculated for each polymer. The evaluated data revealed the positive effect of structural modifications of PIMs on their sorption properties. Furthermore, our findings confirmed successful development of new materials with enhanced properties for membrane separations. References [1]N. B. McKeown, P. M. Budd, Exploitation of Intrinsic Microporosity in Polymer-Based Materials, Macromolecules 43 (2010), 5163-5176. [2]O. Vopi?ka, K. Friess, V. Hynek, P. Sysel, M. Zga?ar, M. ?ípek, K. Pilná?ek, M. Lan?, J. C. Jansen, C. R. Mason, P. M. Budd, Equilibrium and transient sorption of vapours and gases in the polymer of intrinsic microporosity PIM-1, Journal of Membrane Science 434 (2013), 148-160. [3]Y. Rogan, R. Malpass-Evans, M. Carta, M. Lee, J. C. Jansen, P. Bernardo, G. Clarizia, E. Tocci, K. Friess, M. Lan?, N. B. McKeown, A highly permeable polyimide with enhanced selectivity for membrane gas separations. Journal of Materials Chemistry A 2 (2014), 4874-4877. [4]M. Carta, M. Croad, R. Malpass-Evans, J. C. Jansen, P. Bernardo, G. Clarizia, K. Friess, M. Lan?, N. B. McKeown, Triptycene induced enhancement of membrane gas selectivity for microporous tröger's base polymers. Advanced Materials (2014). [5]C. R. Mason, L. Maynard-Atem, K. W. J. Heard, B. Satilmis, P. M. Budd, K. Friess, M. Lan?, P. Bernardo, G. Clarizia, J. C. Jansen, Enhancement of CO2 affinity in a polymer of intrinsic microporosity by amine modification. Macromolecules 47 (2014), 1021-1029.