• Membrane Journal
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• v.34 no.5
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• pp.272-282
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• 2024

Porous two-dimensional (2D) materials offer unprecedented opportunities for the fabrication of ultra-selective separation membranes, owing to their unique morphological characteristics, including high aspect ratios, large lateral dimensions, and thicknesses of a few nanometers. A coating method is a prerequisite for distributing 2D materials uniformly and densely on substrates and obtaining membranes with the desired microstructures and morphologies for use in membrane separation applications. We develop a facile and versatile coating method based on the adsorption of zeolite MFI nanosheets. Zeolite MFI nanosheets, synthesized directly using diammonium cations, exhibit a surface-active property and can be concentrated at water-hydrophobe interfaces. Hydrophobically modifying the surfaces of substrates broadens the applicability of the coating method to various substrates, regardless of their porosities and curvatures. Repetition of the adsorptive coating process easily yields full-coverage nanosheet coatings that can be further intergrown into continuous MFI thin films and membranes. This facile coating method will allow the arrangement of zeolite MFI nanosheets and possibly other 2D materials to be easily manipulated, thereby enhancing the benefits of 2D materials in various applications.

• Membrane Journal
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• v.29 no.3
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• pp.130-139
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• 2019

Various two-dimensional nano materials such as graphene, zeolite, and metal-organic framework have been utilized to develop an ultra-thin high-performance membrane for water purification, gas separation, and so on. Particularly, in the case of graphene oxide, synthesis methods and thin film coating techniques have been accumulated and established since early 2000s, therefore graphene oxide has been rapidly applied to membrane field. The multi-layered graphene oxide thin film can filter molecules separately by the molecular sieving of interlayer spacing between adjacent layers, and it is also possible to separate various materials depending on the surface functional groups or the degree of interaction to intercalated materials. This review mainly focuses on the nanofiltration application of graphene oxide. The major factors affecting the separation performance of graphene oxide membrane in solvent are summarized and other technical elements required for the commercialization of graphene oxide membranes will be discussed including stability issue and fabrication method.