Ultra-selective high-flux membranes from directly synthesized zeolite nanosheets

Journal Article · 15 March 2017 · Nature (London)

DOI: https://doi.org/10.1038/nature21421 · OSTI ID:1373573

Jeon, Mi Young ^[1]; Kim, Donghun ^[1]; Kumar, Prashant ^[1]; Lee, Pyung Soo ^[1]; Rangnekar, Neel ^[1]; Bai, Peng ^[1]; Shete, Meera ^[1]; Elyassi, Bahman ^[1]; Lee, Han Seung ^[1]; Narasimharao, Katabathini ^[2]; Basahel, Sulaiman Nasir ^[2]; Al-Thabaiti, Shaeel ^[2]; Xu, Wenqian ^[3]; Cho, Hong Je ^[4]; Fetisov, Evgenii O. ^[1]; Thyagarajan, Raghuram ^[1]; DeJaco, Robert F. ^[1]; Fan, Wei ^[4]; Mkhoyan, K. Andre ^[1]; Siepmann, J. Ilja ^[1] ; Tsapatsis, Michael ^[1]

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1. Univ. of Minnesota, Minneapolis, MN (United States)
2. King Abdulaziz Univ., Jeddah (Saudi Arabia)
3. Argonne National Lab. (ANL), Lemont, IL (United States)
4. Univ. of Massachusetts, Amherst, MA (United States)

A zeolite with structure type MFI is an aluminosilicate or silicate material that has a three-dimensionally connected pore network, which enables molecular recognition in the size range 0.5-0.6 nm. These micropore dimensions are relevant for many valuable chemical intermediates, and therefore MFI-type zeolites are widely used in the chemical industry as selective catalysts or adsorbents. As with all zeolites, strategies to tailor them for specific applications include controlling their crystal size and shape. Nanometre-thick MFI crystals (nanosheets) have been introduced in pillared and self-pillared (intergrown) architectures, offering improved mass-transfer characteristics for certain adsorption and catalysis applications. Moreover, single (non-intergrown and nonlayered) nanosheets have been used to prepare thin membranes that could be used to improve the energy efficiency of separation processes. However, until now, single MFI nanosheets have been prepared using a multi-step approach based on the exfoliation of layered MFI9,15, followed by centrifugation to remove non-exfoliated particles. This top-down method is time-consuming, costly and low-yield and it produces fragmented nanosheets with submicrometre lateral dimensions. Alternatively, direct (bottom-up) synthesis could produce high-aspect-ratio zeolite nanosheets, with improved yield and at lower cost. Here we use a nanocrystal-seeded growth method triggered by a single rotational intergrowth to synthesize high-aspect-ratio MFI nanosheets with a thickness of 5 nanometres (2.5 unit cells). These high-aspect-ratio nanosheets allow the fabrication of thin and defect-free coatings that effectively cover porous substrates. Finally, these coatings can be intergrown to produce high-flux and ultra-selective MFI membranes that compare favourably with other MFI membranes prepared from existing MFI materials (such as exfoliated nanosheets or nanocrystals).

• Research Organization: Argonne National Laboratory (ANL), Argonne, IL (United States)
• Sponsoring Organization: USDOE Office of Science (SC), Basic Energy Sciences (BES) (SC-22), Scientific User Facilities Division; USDOE Office of Science (SC), Basic Energy Sciences (BES). Chemical Sciences, Geosciences, and Biosciences Division; King Abdulaziz University; National Science Foundation (NSF); USDOE Advanced Research Projects Agency - Energy (ARPA-E)
• Grant/Contract Number: AC02-06CH11357
• OSTI ID: 1373573
• Journal Information: Nature (London), Vol. 543, Issue 7647; ISSN 0028-0836
• Publisher: Nature Publishing GroupCopyright Statement
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
36 MATERIALS SCIENCE