Carbon molecular sieve membranes derived from Matrimid® polyimide for nitrogen/methane separation

Xue Ning, William J. Koros

Research output: Contribution to journalArticlepeer-review

180 Scopus citations


A commercial polyimide, Matrimid® 5218, was pyrolyzed under an inert argon atmosphere to produce carbon molecular sieve (CMS) dense film membranes for nitrogen/methane separation. The resulting CMS dense film separation performance was evaluated using both pure and mixed N2/CH4 permeation tests. The effects of final pyrolysis temperature on N 2/CH4 separation are reported. The separation performance of all CMS dense films significantly exceeds the polymer precursor dense film. The CMS dense film pyrolyzed at 800 C shows very attractive separation performance that surpasses the polymer membrane upper bound line, with N 2 permeability of 6.8 Barrers and N2/CH4 permselectivity of 7.7 from pure gas permeation, and N2 permeability of 5.2 Barrers and N2/CH4 permselectivity of 6.0 from mixed gas permeation. The temperature dependences of permeabilities, sorption coefficients, and diffusion coefficients of the membrane were studied, and the activation energy for permeation and diffusion, as well as the apparent heats of sorption are reported. The high permselectivity of this dense film is shown to arise from a significant entropic contribution in the diffusion selectivity. The study shows that the rigid 'slit-shaped' CMS pore structure can enable a strong molecular sieving effect to effectively distinguish the size and shape difference between N2 and CH4. © 2013 Elsevier Ltd. All rights reserved.
Original languageEnglish (US)
Pages (from-to)511-522
Number of pages12
StatePublished - Jan 2014
Externally publishedYes

Bibliographical note

KAUST Repository Item: Exported on 2020-10-01
Acknowledgements: The authors acknowledge the support from King Abdullah University of Science and Technology (KAUST) for funding this research project.
This publication acknowledges KAUST support, but has no KAUST affiliated authors.


Dive into the research topics of 'Carbon molecular sieve membranes derived from Matrimid® polyimide for nitrogen/methane separation'. Together they form a unique fingerprint.

Cite this