461218 Consequences of 1-Butyl-3-Methylimidazolium Tetrafluoroborate Incorporation on Gas Separation Performance of ZIF-8
Burak Koyutürk, Seda Keskin,* Alper Uzun*
Chemical and Biological Engineering Department, Koç University, Istanbul 34450, Turkey
Metal organic frameworks (MOFs), which consist of metals and organic linkers, have gained significant attention for gas storage and separation applications specifically thanks to their high surface area and tunable pore sizes. ZIF-8 is one of the MOFs which is used in membrane-based and adsorption-based gas separations.[2,3] The windows of ZIF-8 allow the passage of small gas molecules, such as hydrogen and carbon dioxide (having kinetic diameters of 2.89 Å and 3.3 Å, respectively ) as well as larger molecules, such as methane and nitrogen (having kinetic diameters of 3.80 Å and 3.60 Å, respectively) due to the flexibility of its structure. [4,5]
In this study, we confined 1-butyl-3-methylimidazolium tetrafluoroborate ([BMIM][BF4]) into ZIF-8 at a loading of 30 wt.% by impregnation and characterized the resulting materials in terms of its crystalline structure, thermal stability, surface area and bond interactions. Volumetric adsorption measurements were performed for CO2, CH4, and N2 gases and selectivities of binary gas pairs were calculated using the single-component gas adsorption isotherms. Data illustrate that IL incorporation directly improve the selectivities of CO2/CH4, CO2/N2 selectivity by 50 % and 102% at low pressures as a results of interactions of the ionic liquid with the ZIF-8 framework. Results offer opportunities to tune the adsorption and separation performance of MOFs by the incorporation of ionic liquids with tunable physicochemical properties.
This work is supported by the Scientific and Technological Research Council of Turkey (TUBITAK) under 1001-Scientific and Technological Research Projects Funding Program (project number: 114R093) and by Koç University Seed Fund Program. Financial support provided by the KUTEM (Koç University TUPRAS Energy Center) is gratefully acknowledged. S.K. acknowledges TUBA-GEBIP and A.U. acknowledges the support by the Science Academy of Turkey under the BAGEP Award Program. Authors thank Koç University Surface Science and Technology Center (KUYTAM) for providing help with the sample characterization.
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