A two-dimensional cationic covalent organic framework membrane for selective molecular sieving

Zhang, Wenxiang; Zhang, Liming; Zhao, Haifeng; Li, Bin; Ma, Heping

doi:10.1039/c8ta04178d

Cited by 263 publications

(182 citation statements)

References 61 publications

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“…Furthermore, they retained up to 80 % of the powder surface area as confirmed by nitrogen adsorption measurements (Figure S41), as well as the characteristic FT‐IR imine stretch at approximately 1620 cm −1 (Figure S44). These materials ( S BET =1750 m 2 g −1 ) represent some of the highest quality freestanding COF films reported to date …”

Section: Resultsmentioning

confidence: 96%

“…Covalent organic frameworks (COFs) are an emerging class of porous crystalline polymers constructed from combinations of geometrically compatible monomers that are capable of polymerizing into two‐ or three‐dimensional networks . These materials have attracted significant attention over the past decade due to their high stability, accessible pores, and tunable functionality that demonstrate promise for applications including energy and gas storage, catalysis, and membrane‐based separation . However, most reported syntheses produce COFs as insoluble microcrystalline powders, a morphology that precludes many of these uses .…”

Section: Introductionmentioning

confidence: 99%

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Acid Exfoliation of Imine‐linked Covalent Organic Frameworks Enables Solution Processing into Crystalline Thin Films

et al. 2020

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Covalent organic frameworks (COFs) are highly modular porous crystalline polymers that are of interest for applications such as charge‐storage devices, nanofiltration membranes, and optoelectronic devices. COFs are typically synthesized as microcrystalline powders, which limits their performance in these applications, and their limited solubility precludes large‐scale processing into more useful morphologies and devices. We report a general, scalable method to exfoliate two‐dimensional imine‐linked COF powders by temporarily protonating their linkages. The resulting suspensions were cast into continuous crystalline COF films up to 10 cm in diameter, with thicknesses ranging from 50 nm to 20 μm depending on the suspension composition, concentration, and casting protocol. Furthermore, we demonstrate that the film fabrication process proceeds through a partial depolymerization/repolymerization mechanism, providing mechanically robust films that can be easily separated from their substrates.

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Section: Resultsmentioning

confidence: 96%

Section: Introductionmentioning

confidence: 99%

Acid Exfoliation of Imine‐linked Covalent Organic Frameworks Enables Solution Processing into Crystalline Thin Films

et al. 2020

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“…Besides, Zhang et al. fabricated 2D cationic crystallized COF membrane, namely EB‐COF:Br membrane, with 16.8 Å pore size, by a facile bottom‐up interfacial crystallization approach and layer‐by‐layer restacking process . This resulting membrane showed noticeable molecules sieving performance with relatively high selectivity and permeability .…”

Section: Mechanismmentioning

confidence: 99%

Two dimensional nanomaterial‐based separation membranes

Zhang

Zhan

et al. 2019

Electrophoresis

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Two dimensional nanomaterials including graphene, hexagonal boron‐nitride, molybdenum disulfide, etc., provide immense potentials for separation applications. However, the tradeoff between selectivity and permeability in choosing 2D nanomaterial‐based membrane is inevitable, limiting the progress on separation efficiency for mass industrial applications. To target these issues, versatile strategies such as the rational design of predefined interlayer channels, membrane nanopores, and reasonable functionalization, as well as new mechanisms have been emerged. In this review, we introduce the recent progress on separation mechanisms of 2D nanomaterial‐based membranes with different structures (including the interlayer channels type and the membrane nanopores type) and their inner surface functionalization. Moreover, the interface designs are discussed, in terms of employing dynamic liquid–liquid/liquid–gas interfaces, to advance the selectivity and permeability of the membranes. We further discuss the variety of separation applications based on 2D nanomaterial‐based membranes. The authors hope this review will inspire the active interest of many scientists in the area of the development and application of membrane science.

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“…These materials (S BET = 1750 m 2 g À1 )r epresent some of the highest quality freestanding COF films reported to date. [11,14,24,25,47] NMR spectroscopy measurements of COF solutions in TFA-d/D 2 Or eveal aC OF concentration dependence on the degree of depolymerization. To probe how the roles of the acid and water change as af unction of COF concentration during the film-fabrication process,and establish the generality of the depolymerization/repolymerization mechanism across solvent mixtures,t wo uniform TAPB-PDAC OF solutions (12.5 mg mL À1 and 25 mg mL À1 )w ere prepared in TFA-d (5 % v/v D 2 O) along with a1 ,4-dioxane internal standard and analyzed by 1 HNMR spectroscopy (Figures S51, S52).…”

Section: Angewandte Chemiementioning

confidence: 99%

“…[1][2][3] These materials have attracted significant attention over the past decade due to their high stability, [4] accessible pores,and tunable functionality [5] that demonstrate promise for applications including energy [6,7] and gas storage, [8] catalysis, [9,10] and membrane-based separation. [11][12][13][14] However,m ost reported syntheses produce COFs as insoluble microcrystalline powders,amorphology that precludes many of these uses. [15] Recent efforts have been directed towards fabricating two-dimensional (2D) COF thin films, am orphology ideal for applications requiring rapid mass transport through the pores.…”

Section: Introductionmentioning

confidence: 99%

Acid Exfoliation of Imine-linked Covalent Organic Frameworks Enables Solution Processing into Crystalline Thin Films

Burke¹,

Sun²,

Castano³

et al. 2019

Preprint

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Covalent organic frameworks (COFs) are highly modular porous crystalline polymers that are of interest for applications such as charge-storage devices,n anofiltration membranes,a nd optoelectronic devices.C OFs are typically synthesized as microcrystalline powders,w hichl imits their performance in these applications,a nd their limited solubility precludes large-scale processing into more useful morphologies and devices.W er eport ag eneral, scalable method to exfoliate two-dimensional imine-linked COF powders by temporarily protonating their linkages.T he resulting suspensions were cast into continuous crystalline COF films up to 10 cm in diameter,w ith thicknesses ranging from 50 nm to 20 mmd epending on the suspension composition, concentration, and casting protocol. Furthermore,w ed emonstrate that the film fabrication process proceeds through ap artial depolymerization/repolymerization mechanism, providing mechanically robust films that can be easily separated from their substrates.

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A two-dimensional cationic covalent organic framework membrane for selective molecular sieving

Abstract: A two-dimensional cationic covalent organic framework membrane with extraordinary separation properties and high permeability.

Cited by 263 publications

References 61 publications

Acid Exfoliation of Imine‐linked Covalent Organic Frameworks Enables Solution Processing into Crystalline Thin Films

Acid Exfoliation of Imine‐linked Covalent Organic Frameworks Enables Solution Processing into Crystalline Thin Films

Two dimensional nanomaterial‐based separation membranes

Acid Exfoliation of Imine-linked Covalent Organic Frameworks Enables Solution Processing into Crystalline Thin Films

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