High-Flux Zeolitic Imidazolate Framework Membranes for Propylene/Propane Separation by Postsynthetic Linker Exchange

Angew Chem Int Ed Engl. 2018 Jan 2;57(1):156-161. doi: 10.1002/anie.201708924. Epub 2017 Dec 5.


While zeolitic imidazolate framework, ZIF-8, membranes show impressive propylene/propane separation, their throughput needs to be greatly improved for practical applications. A method is described that drastically reduces the effective thickness of ZIF-8 membranes, thereby substantially improving their propylene permeance (that is, flux). The new strategy is based on a controlled single-crystal to single-crystal linker exchange of 2-methylimidazole in ZIF-8 membrane grains with 2-imidazolecarboxaldehyde (ZIF-90 linker), thereby enlarging the effective aperture size of ZIF-8. The linker-exchanged ZIF-8 membranes showed a drastic increase in propylene permeance by about four times, with a negligible loss in propylene/propane separation factor when compared to as-prepared membranes. The linker-exchange effect depends on the membrane synthesis method.

Keywords: ZIF-8; gas separation; metal-organic frameworks; postsynthetic linker exchange; thin films.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, Non-P.H.S.