(376n) A Scalable Method to Prepare Zeolitic-Imidazolate Framework ZIF-8 Membranes on Polymer Hollow Fibers for Propylene/Propane Separation
A sub-class of metal-organic frameworks (MOFs), zeolitic-imidazolate frameworks (ZIFs) with zeolite topologies are crystalline nanoporous materials with well-defined aperture sizes (< 5 Å). ZIFs, which are composed of divalent metal ions (typically Zn2+ and Co2+) and imidazole-based ligands4, have been extensively studied especially for gas separation applications. ZIF-8 in particular is a promising membrane material for high resolution propylene/propane separation because the effective pore size of ZIF-8 (~ 4 Å) 5 lies in between the size of propylene and propane molecules. Although ZIF-8 membranes (mostly planar configurations) synthesized either by in-situ or seeded growth method showed excellent propylene/propane separation performances, scaling-up and commercialization of the membranes requires them to be fabricated on a cheap and scalable support (i.e., hollow fiber or tubular support). Polymeric hollow fibers have been utilized as substrates, but only a few of the resulting ZIF-8 membranes showed promising propylene/propane separation performances.6-9
Herein, we would like to present a simple and scalable method to synthesize well intergrown ZIF-8 membranes on polymeric hollow fibers. The method is based on substrates modification followed by solvothermal reaction in linker solution. High-quality ZIF-8 seed layers prepared from the solvothermal reaction are secondarily grown to form high quality ZIF-8 membranes. The resulting ZIF-8 membranes are tested for propylene/propane separation. In this work, the effects of different synthesis parameters on the microstructures of ZIF-8 membranes will be discussed. Finally, the gas separation performances of ZIF-8 membranes especially propylene/propane separation will be presented.
References and Notes
1 Koros, William J. and Fleming, G.K. (1993) âMembrane-based gas separationâ, Journal of Membrane Science, 83, pp l-39
2 Baker RW., (2002) âFuture Directions of Membrane Gas Separation Technologyâ Industrial & Engineering Chemistry Research., 41 (6), pp 1393-1411
3 Tanaka, K., Taguchi, A., Hao, JQ, Kita, H., and Okamoto, K., (1996) âPermeation and separation properties of polyimide membranes to olefins and paraffinsâ, Journal of Membrane Science, 121, pp 197-207
4 Park KS, Ni Z, CÃ´tÃ© AP, et al., (2006) âExceptional chemical and thermal stability of zeolitic imidazolate frameworksâ, Proceedings of the National Academy of Sciences, 103 (27), pp 10186-10191
5 Zhang C, Lively RP, Zhang K, Johnson JR, Karvan O, Koros WJ., (2012) âUnexpected Molecular Sieving Properties of Zeolitic Imidazolate Framework-8â, The Journal of Physical Chemistry Letters., 3 (16), pp 2130-2134.
6 Andrew J. Brown, Nicholas A. Brunelli, Kiwon Eum, Fereshteh Rashidi, J. R. Johnson, William J. Koros, Christopher W. Jones, Sankar Nair, (2014) âInterfacial microfluidic processing of metal-organic framework hollow fiber membranesâ, Science, 345, 6192, pp 72-75
7 FernandoCacho-Bailo, SilviaCatalÃ¡n-Aguirre, MirenEtxeberrÃa-Benavides, OÄuz Karvan, VictorSebastian, CarlosTÃ©llez, JoaquÃnCoronas (2015) âMetal-organic framework membranes on the inner-side of a polymeric hollow fiber by microfluidic synthesisâ, Journal of membrane science, 476, pp 277-285
8 Kiwon Eum, Chen Ma, Ali Rownaghi, Christopher W. Jones, and Sankar Nair (2016) âZIFâ8 Membranes via Interfacial Microfluidic Processing in Polymeric Hollow Fibers: Efficient Propylene Separation at Elevated Pressuresâ, ACS Applied materials and interfaces, 8, pp 25337 â 25342
9 Anne M. Marti, Wasala Wickramanayake, Ganpat Dahe, Ali Sekizkardes, Tracy L. Bank, David P. Hopkinson, and Surendar R. Venna (2017) âContinuous Flow Processing of ZIFâ8 Membranes on Polymeric Porous Hollow Fiber Supports for CO2 Captureâ, ACS Applied materials and interfaces, 9, pp 5678-5682