A Study on Permeabilities and Selectivities of Small-Molecule Gases for Composite Ionic Liquid and Polymer Membranes

Abstract:

In recent years, the utilisation of ionic liquids supported on porous polymer membranes has been demonstrated to enhance gas separation performance by improving both permeability and selectivity for several industrially-relevant gas mixtures. However, the use of such supported ionic liquid membranes (SILMs) is normally not feasible at elevated process temperatures due to the resulting decrease in ionic liquid viscosity, which can lead to increased loss of ionic liquid from the membrane support during operation. In addition, many of the polymer membranes typically used in SILMs exhibit relatively poor mechanical and thermal stabilities at high temperatures. To overcome these problems associated with SILMs, thermally-stable composite ionic liquid and polymer membranes (CILPMs) have been fabricated in this study, thus exploiting the beneficial properties of ionic liquids for gas separation at elevated temperatures. Poly (pyromellitimide-co-4,4-oxydianiline) (PMDA-ODA PI) in combination with the ionic liquid, [C₄mi [NTf₂] were used to fabricate the CILPMs. A measurement rig was designed and built to determine permeabilities and selectivities of the CILPMs for H₂, N₂, CO, CO₂ and CH₄ over a range of pressures and temperatures. The fabricated CILPMs were shown to maintain excellent mechanical and thermal stability over a wide range of processing conditions. Temperature was shown to greatly affect both permeability and selectivity of the membranes, whilst pressure had less influence. The incorporation of [C₄mi [NTf₂] into the membranes was found to significantly increase CO₂ permeation and, therefore, it is anticipated that these CILPMs hold significant potential for CO₂ separation applications.

• Periodical: Applied Mechanics and Materials (Volumes 448-453)
• Pages: 765-770
• DOI: https://doi.org/10.4028/www.scientific.net/AMM.448-453.765
• Online since: October 2013
• Authors: Li Zhe Liang*, Quan Gan, Paul Nancarrow
• Keywords: Composite Ionic Liquid Membrane, Gas Separation, Ionic Liquid (IL), Polybenzimidazole, Polyimide

References

[2] Y. Jiang, Z. Zhou, Z. Jiao, L. Li, Y. Wu, Z. Zhang, J. Phys. Chem. B 111 (2007) 5058-5061.

[3] Y. Park, B. Kim, Y. Byun, S. Lee, E. Lee, J. Lee, Desalination 236 (2009) 342-348.

[4] Q. Gan, Y. Zou, D. Rooney, P. Nancarrow, J. Thompson, L. Liang, M. Lewis, Adv. Colloid Interfac. 164 (2011) 45-55.

[5] R.W. Baker, Ind. Eng. Chem. Res. 41 (2002) 1393-1411.

[6] P. Bernardo, E. Drioli, G. Golemme, Ind. Eng. Chem. Res. 48 (2009) 4638-4663.

DOI: 10.1021/ie8019032

[7] E. Cho, J. Park, S.S. Sekhon, G. Park, T. Yang, W. Lee, C. Kim, S. Park, Journal of the Electrochemical Society 156 (2009) B197-B202.

[8] D. R Pesiri, B. Jorgensen, R. C Dye, J. Membrane Sci. 218 (2003) 11-18.

[9] T. Matsuura, Y. Hasuda, S. Nishi, N. Yamadat, Macromolecules 24 (1991) 5001–5005.

[10] C.A. Scholes, G.W. Stevens, S.E. Kentish, Fuel 96 (2012) 15-28.

[11] C.P. Fredlake, J.M. Crosthwaite, D.G. Hert, S.N.V.K. Aki, J.F. Brennecke, J. Chem. Eng. Data 49 (2004) 954-964.

DOI: 10.1021/je034261a

[12] P. Bonhȏte, A. Dias, N. Papageorgiou, K. Kalyanasundaram, M. Grätzel, Hydrophobic, Inorg. Chem. 35 (1996) 1168-1178.

DOI: 10.1021/ic951325x