Surface-crumpled thin-film nanocomposite membranes with elevated nanofiltration performance enabled by facilely synthesized covalent organic frameworks

Gu, Zhengyang; Li, Ping; Gao, Xiang; Qin, Yuan; Pan, Yishuai; Zhu, Youbing; Yu, Shuili; Xia, Qing; Liu, Yanling; Zhao, Dongsheng; Liu, Guicai

doi:10.1016/j.memsci.2021.119144

Cited by 35 publications

(8 citation statements)

References 58 publications

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“…On the other hand, defects were likely present in the highly wrinkled polyamide layer when an excessively large concentration of C 8 ‐CDs (i.e., larger than 0.4 wt%) was involved in the membrane preparation, resulting in the sharp drop in the Na 2 SO 4 rejection rate of the TFN‐C 8 ‐CDs membrane. [ 48 ] Slight decreases in the salt rejection rates are also observed for the TFN‐C 1 ‐CDs and TFN‐C 4 ‐CDs membranes with loading concentrations greater than 0.4 wt%. [ 46 ] By considering both the permeability and rejection performances, the optimum concentration of 0.4 wt% CDs was used in the preparation of the TFN membranes for all the characterization and filtration tests.…”

Section: Resultsmentioning

confidence: 99%

High‐Precision and High‐Flux Separation by Rationally Designing the Nanochannels and Surface Nanostructure of Polyamide Nanofiltration Membranes

et al. 2022

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High‐precision separation with increased water permeability is critical for efficient membrane‐based water treatment processes. To achieve high selectivity toward different targeted species while allowing rapid water transportation, the structure of the membrane polyamide selective layer requires delicate regulation. Herein, an effective approach to systematically expand the pore size of polyamide layers by incorporating ammonium ion‐modified carbon dots (CDs) into the polyamide network is developed. The ammonium ions with different alkyl chain lengths attached to the CDs create nanochannels of different sizes in the network to lower the energy barrier for water transportation while maintaining high selectivity to targeted species. When the alkyl chain length of the ammonium ions reaches eight carbon atoms (i.e., C8 ions), the amphiphilic C8‐CDs induce the formation of the ridged nanostructure on the membrane surface and hence the increased membrane filtration area. The resultant thin‐film nanocomposite (TFN) membrane, denoted as the TFN‐C8‐CDs membrane, demonstrates a higher Na2SO4 rejection of 98.9% and NaCl/Na2SO4 selectivity of 83.1 than the pristine polyamide membrane, together with a tripled pure water permeability of 29.0 L m−2 h−1 bar−1. Herein, a viable approach for ingeniously designing the nanochannels and surface nanostructure of polyamide membranes for more efficient filtration processes is provided.

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Section: Resultsmentioning

confidence: 99%

High‐Precision and High‐Flux Separation by Rationally Designing the Nanochannels and Surface Nanostructure of Polyamide Nanofiltration Membranes

et al. 2022

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“…Recently, incorporating COFs into a PA membrane to synthesize COF mixed matrix membranes attracted much attention. COF nanoparticles are usually dispersed in an aqueous PIP/MPD solution [88,89] and then removed after contacting with the membrane substrate for a certain time. Following the addition of TMC to the organic solution, the PA layer forms, and the COFs successfully embed inside.…”

Section: Blendingmentioning

confidence: 99%

Advanced Covalent Organic Framework‐Based Membranes for Recovery of Ionic Resources

Xia

et al. 2022

Small

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metal ions have strong chemical toxicity including carcinogenicity, mutagenicity and teratogenicity, which can cause danger threat to the natural ecosystem and public health. [2] These heavy metal ions, unlike organic pollutants, are nonbiodegradable, highly soluble, and mobile, and remain in the environment. [3] This water contamination has further aggravated water scarcity, causing a new and unprecedented challenge for mankind. On the other hand, pure ions such as lithium, heavy metal ions, and radionuclides are important resources for industrial applications. [4] For example, lithium has rising demand for various applications especially the recent burgeoning of lithium-ion batteries for electric equipment and energy storage devices. [5] Consequently, the efficient recovery of these ion resources with high purity is becoming an urgent issue.Many technologies have been implemented for water treatment, among which membrane technology attracted much attention because of its low energy consumption, small carbon footprint, convenient operation, and good scalability. [6] Recently, novel membranes constructed from advanced materials such as porous carbons, [7] layered double hydroxides, [8] graphene, [9] molybdenum disulfide nanosheet, [10] and metal organic frameworks (MOFs) [11] have attracted extensive attention for their high surface area and porous structures. These unique physical structures have an excellent separation performance over conventional polymer membranes. [12] Recently, a new class of crystalline material-covalent organic frameworks (COFs) has been put forward and applied in membrane fabrication. COFs have crystalline porous network structures with regular and periodical assembly covalent bonds synthesized from reversible reactions, and were first reported by Yaghi and co-workers in 2005. [13] After that, various COF materials including bromo-based COFs, imine-based COFs, and amine-based COFs were reported. [14] The geometry of the COF depends on the size, symmetry, and connectivity of the connecting bonds, enabling a precise fine-tuning of the COF-based membrane channels to separate molecules or ions with different sizes. Varieties of synthesis methods have been developed to produce novel COFs, [15] such as the hydrothermal method, [16] the ion thermal method, [17] the mechanochemical method, [18] and the microwave method. [19] The unique structure endows COFs with superior properties like orderly assembled channels, tunable pore size and miscibility with organics, [20] Membrane technology has shown a viable potential in conversion of liquidwaste or high-salt streams to fresh waters and resources. However, the nonadjustability pore size of traditional membranes limits the application of ion capture due to their low selectivity for target ions. Recently, covalent organic frameworks ( COFs) have become a promising candidate for construction of advanced ion separation membranes for ion resource recovery due to their low density, large surface area, tunable channel structure, and tailored functionality...

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“…[90][91][92] Some other 3-dimentional nanomaterials were involved in PA selective layers. Yu et al 93 synthesized a novel nanoporous covalent organic framework (COF) and deposited it onto a substrate to induce crumpled PA layers. The surface of the membrane gradually turned from tent-like to mesh morphology with increasing the amount of incorporated COF.…”

Section: Nanomaterialsmentioning

confidence: 99%

“…Comparison in surface roughness of the original membranes and crumpled membranes based on the literatures 45,48,[60][61][62]66,[69][70][71][72][73]78,79,[81][82][83][84]86,88,90,91,[93][94][95]97,[99][100][101]111,[114][115][116]118,121 [Color figure can be viewed at wileyonlinelibrary.com]…”

Section: Comparison Of the Performance Of Crumpled Tfc Membranes With...mentioning

confidence: 99%

“…The membrane with largest roughness showed best antifouling property for dye solution in long-term experiment for 11 h, because of the chemical bonds between substrate and PA layer improving the stability of the membrane. Layered MoS 2 nanosheets with negative charge exhibited excellent antifouling performance when added F I G U R E 1 5 Comparison in water permeability (a) and salts rejection (b) of the original membranes and crumpled membranes based on the literatures 45,46,[60][61][62]65,66,69,71,[73][74][75][76][79][80][81][82][83][84]86,88,90,91,[93][94][95]97,[99][100][101]107,111,112,114,117,118,121 [Color figure can be viewed at wileyonlinelibrary.com] into PA layer. Though the surface roughness was heightened by the addition of nanosheets, the flux decline was less than the traditional membrane in the presence of BSA and NaCl.…”

Section: Anti-fouling Properties Of Crumpled Tfc Membranesmentioning

confidence: 99%

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Constructing highly rough skin layer of thin film (nano)composite polyamide membranes to enhance separation performance: A review

Ren

et al. 2022

J of Applied Polymer Sci

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The thin-film (nano)composite (TFC or TFN) polyamide membrane prepared by interfacial polymerization method has a wide range of applications in water treatment. The preparation of TFC or TFN membrane with a highly wrinkled morphology in the selective layer can significantly improve the permeability of the membrane and is an effective way to break the "trade-off" effect. However, the formation mechanism of highly rough skin layer and the membrane fouling performance associated with the rough structure have been underexplored.

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Surface-crumpled thin-film nanocomposite membranes with elevated nanofiltration performance enabled by facilely synthesized covalent organic frameworks

Cited by 35 publications

References 58 publications

High‐Precision and High‐Flux Separation by Rationally Designing the Nanochannels and Surface Nanostructure of Polyamide Nanofiltration Membranes

High‐Precision and High‐Flux Separation by Rationally Designing the Nanochannels and Surface Nanostructure of Polyamide Nanofiltration Membranes

Advanced Covalent Organic Framework‐Based Membranes for Recovery of Ionic Resources

Constructing highly rough skin layer of thin film (nano)composite polyamide membranes to enhance separation performance: A review

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