2019 Fiscal Year Research-status Report
MOF-based polycrystalline nanomembranes directly grown on microporous polymeric supports for advanced post-combustion CO2 separation
| Project/Area Number |
19K15342
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| Research Institution | Kyushu University |
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Principal Investigator |
Selyanchyn Roman 九州大学, カーボンニュートラル・エネルギー国際研究所, 助教 (90729790)
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| Project Period (FY) |
2019-04-01 – 2021-03-31
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| Keywords | thin-film composite / metal-organic network / CO2/N2 separation / selective interface / CO2 philicity / Transport phenomena / Ultramicroporous MOF / Mixed matrix membranes |
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| Outline of Annual Research Achievements |
Metal-organic frameworks (MOFs) represent unique materials that promise breakthrough in many useful applications, in particular for large-scale CO2 capture. Recently discovered class of fluorinated MOFs - SIFSIX, TIFSIX, NbOFFIVE and AlFFIVE materials, consist of two-dimensional networks linked via metal nodes (M) and pillared in the third dimension via an inorganic molecular building block. These MOFs demonstrated excellent adsorptive separation of CO2 from other gases, olefins, and dehydration. Therefore, superior gas separation performance is also expected in membranes that include these fluorinated MOFs.
Selective CO2 adsorption ability of ultramicroporous MOFs (e.g. SIFSIX-n-M, TIFSIX-n-M etc.) is utilized in this work to develop membrane-based CO2 capture solutions. Distinctive feature of the developed membranes (focus of this research) is the inclusion of MOFs in form of thin layer (in contrast to conventional mixed-matrix approach). The aim of such approch is to clearly demostrate the potential of transport selecticity towards CO2.
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| Current Status of Research Progress |
Current Status of Research Progress
2: Research has progressed on the whole more than it was originally planned.
Reason
In this work, NbOFFIVE-1-Ni layer in Pebax-1657 (metal organic framework in organic polymer) membranes were investigated for their performance in respect to CO2, N2, O2 and H2 gases transport as well as separation of mixed CO2/N2. It was found that when reduced in size, ultramicroporous fillers in Pebax-1657 are forming thin layer which is making significant impact on gas transport. With small-sized fillers and their uniform dispersion in the polymer pure gases CO2/N2 selectivity was improved from ~64 in pure Pebax-1657 to ~ 75 in membrane with a layer of NbOFFIVE-Ni. Even better separation selectivity (up to 85) was observed when mixed gases are used suggesting the competitive transport in MOF particles, and demonstrating the transport selectivity (the main focus of this research).
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| Strategy for Future Research Activity |
Screening of the different types of MOFs was conducted during the first year of the research and reveled that many of the compounds are not structurally stable in ambient conditions (most of SIFSIX MOFs). Frameworks based on different inorganic building block ([TiF6]2- or [NbOF5]2-), demonstrated the superior performance, both from the synthetic and stability point of view.
During the second year of research membranes two specific forms of MOFs will be investigated for the gas separation in form of membrane.
The membranes will be designed in a way that incorporate the thin layer of MOF in order to decrease the transport resistance that is often observed in thick mixed matrix membranes.
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