Designing nanocomposite hydrogels with oriented nanosheets has emerged as a promising toolkit to achieve preferential performances that go beyond their disordered counterparts. Although current ...fabrication strategies via electric/magnetic force fields have made remarkable achievements, they necessitate special properties of nanosheets and suffer from an inferior orientation degree of nanosheets. Herein, a facile and universal approach is discovered to elaborate MXene‐based nanocomposite hydrogels with highly oriented, heterogeneous architecture by virtue of supergravity to replace conventional force fields. The key to such architecture is to leverage bidirectional, force‐tunable attributes of supergravity containing coupled orthogonal shear and centrifugal force field for steering high‐efficient movement, pre‐orientation, and stacking of MXene nanosheets in the bottom. Such a synergetic effect allows for yielding heterogeneous nanocomposite hydrogels with a high‐orientation MXene‐rich layer (orientation degree, f = 0.83) and a polymer‐rich layer. The authors demonstrate that MXene‐based nanocomposite hydrogels leverage their high‐orientation, heterogeneous architecture to deliver an extraordinary electromagnetic interference shielding effectiveness of 55.2 dB at 12.4 GHz yet using a super‐low MXene of 0.3 wt%, surpassing most hydrogels‐based electromagnetic shielding materials. This versatile supergravity‐steered strategy can be further extended to arbitrary nanosheets including MoS2, GO, and C3N4, offering a paradigm in the development of oriented nanocomposites.
A novel supergravity‐steered approach is designed to manipulate the assembly of arbitrary nanosheets from MXene to MoS2, GO, and C3N4 for fabricating oriented nanocomposite hydrogels with heterogeneous architecture. The resultant MXene‐based nanocomposite hydrogels showcase an extraordinary electromagnetic interference shielding effectiveness (EMI SE) of 55.2 dB yet using a super‐low MXene of 0.3 wt%, surpassing most hydrogels‐based electromagnetic shielding materials.
Thin-film composite (TFC) membranes have been widely used in various separation and purification fields. However, the inherent “trade off” effect limits further improvement in the separation ...performance. Recently, the construction of nanomaterial interlayers between porous substrates and the selective layer has been widely investigated to enhance the permeability and selectivity of TFC membranes simultaneously. Among the interlayer materials, two-dimensional (2D) nanomaterials possess high lateral size and large aspect ratios and can be stacked to cover the pores on the substrate surface, providing a smooth and flat surface for interfacial polymerization. In this review, we first briefly introduced the effects of 2D nanomaterial interlayers in TFC membranes, including the roles of 2D nanomaterial interlayers in the interfacial polymerization process and in the membrane performance. Then, interlayers prepared from some typical 2D nanomaterials are detailedly discussed for the preparation of high-performance TFC membranes. The 2D nanomaterials include graphene oxide (GO), graphitic carbon nitride (g-C3N4), MXene, covalent organic framework (COF), metal organic frameworks (MOFs), and some other nanomaterials. In the fourth part, we summarized the typical applications (e.g., nanofiltration and gas separation) of the TFC membranes with 2D nanomaterial interlayers. Furthermore, we suggested the challenges and prospects of high-performance TFC membranes based on 2D nanomaterial interlayers.
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•Typical 2D nanomaterials as the interlayers of TFC membranes are reviewed.•2D nanomaterial interlayers show great effects on interfacial polymerization and the membrane performance.•Typical applications of TFC membranes with 2D nanomaterial interlayers are summarized.•Challenges and trends of TFC membranes with 2D nanomaterial interlayers are suggested.
The true extent of a tumor is difficult to visualize, during radiotherapy, using current modalities. In the present study, the safety and feasibility of a mixture of N-butyl cyanoacrylate and ...lipiodol (NBCA/Lip) was evaluated in order to investigate the optimal combination for application as a fiducial marker for radiotherapy. Four combinations of NBCA/Lip injection (1:1-0.1, 1:1-0.15, 1:3-0.1 and 1:3-0.15 ml) were injected into the subcutaneous tissue of BALB/c mice. The changes in gross histopathology, body weight, skin score, marker volume, neutrophil and macrophage counts were observed to analyze the effects of the different mixing ratios and injection volumes, in order to identify the best combination. Evaluation according to the International Organization for Standardization criteria was further conducted in order to test the biocompatibility of the mixture, including an acute systematic assay with mice, cytotoxicity with L929 fibroblasts and delayed-type hypersensitivity tests with guinea pigs and an intradermal test with rabbits. The results revealed that at the seventh week, 42 markers (42/48; 87.5%) were still visible using computed tomography (CT) imaging. No serious adverse effects were observed throughout the study period; however, the combination of 1:1-0.1 ml had the lowest body weight and worst skin score. A review of the histopathological reaction to NBCA/Lip revealed a combination of acute inflammation, chronic inflammation, granulation tissue, foreign-body reaction and fibrous capsule formation. The 1:1 NBCA combination ratio resulted in the most intense tissue repair reaction and a slower degradation rate of markers. In general, the combination of 1:3-0.15 ml had a better fusion with local tissue, maintained a stable imaging nodule on CT images for 7 weeks and the fnal biocompatibility test demonstrated its safety. Overall, the fndings of the present study demonstrated NBCA/Lip as a safe and feasible fiducial marker, when using the 1:3-0.15 ml combination.
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•Hydrophilized g-C3N4 nanosheets are prepared by tannic acid (TA) assisted exfoliation.•TFNi membranes are fabricated by introducing a TA-C3N4 nanosheet interlayer.•The interlayer ...makes ultra-thin separation layer possible.•The TFNi membrane exhibits water permeance of 34.25 L m−2 h−1 bar−1 and Na2SO4 rejection of 98.53%.
Thin film nanocomposite membrane with a nanomaterial interlayer (TFNi) has attracted extensive attention in recent years. Herein, for the first time, tannic acid (TA) functionalized g-C3N4 nanosheets are used to construct an interlayer for the fabrication of TFNi nanofiltration membranes with enhanced separation performance. The TA-C3N4 nanosheet interlayers possess high hydrophilicity, low resistance for water transport, and strong structural stability, which is conducive to improving water permeance of the TFNi membranes. Meanwhile, the uniformity of interfacial polymerization on the interlayers is improved by virtue of the smooth surface of the interlayer, enabling the formation of an integral and dense polyamide layer with a thickness of only about 10 nm. The TFNi membranes exhibit excellent performance with water permeance of 34.25 L m−2 h−1 bar−1 and Na2SO4 rejection of 98.53%, which are obviously higher than those of the corresponding membrane without TA-C3N4 nanosheets (21.03 L m−2 h−1 bar−1 and 92.04%). The TFNi membranes also show significant selectivity improvement toward divalent/monovalent ions. This work gives inspiration for designing advanced nanofiltration membranes with functionalized nanomaterials acting as interlayers.
High-performance polyamide thin film composite (TFC) nanofiltration membranes have received great attention in recent years. Herein, we report the preparation of TFC nanofiltration membranes by ...interfacial polymerization using MoS2 nanosheets as the nanomaterial interlayer. The aqueous monomer and MoS2 nanosheets are distributed on the surface of microporous membrane substrates by a one-step method. The MoS2 interlayer improves the uniformity and smoothness of the microporous substrates, helping to form polyamide nanofilms at ultralow monomer concentration. Moreover, the hydrophilic and negatively-charged MoS2 nanosheets enhance the water permeability and negative charges of the nanofiltration membranes. The composite membranes show both high water permeance of 33.5 L m−2 h−1 bar−1 and Na2SO4 rejection of 97.5%, as well as significantly improved mono-/divalent anions selectivity and antifouling property. It is proved that the interfacial polymerization strategy assisted by the MoS2 interlayer is effective for preparing high-performance nanofiltration membranes.
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•Nanofiltration membranes with MoS2 nanosheet interlayer are fabricated.•MoS2 interlayer provides an even platform for interfacial polymerization.•The nanofiltration membrane shows a water permeance of 33.5 L m-2 h-1 bar-1 and a rejection of 97.5% for Na2SO4.•The nanofiltration membrane exhibits excellent long-term stability and antifouling ability.
Molecular deposition provides a flexible and versatile platform for preparing positively charged composite nanofiltration membranes. The widely studied building units for molecular deposition are ...polyphenols such as catechins and tannins, which usually cause the complexity of the ultimate selective layer due to their relatively high antioxidant activity and limited positive potential originated from the large number of hydroxyl groups. In this work, a laccase-triggered one-step process has been proposed to prepare composite nanofiltration membranes. Highly positively charged phenolic acid-amine networks, which are represented by ferulic acid (FA) and polyethyleneimine (PEI), are constructed as the dense selective layer with a thickness of about 49 nm. This process is conducted in aqueous solutions under mild conditions, driven by electrostatic adsorption, catalytic oxidation, and covalent crosslinking processes. The structure of the selective layer can be finely tuned by the molecular weights of PEI, the chemical composition, and the pH values of the solutions. The prepared composite nanofiltration membranes can effectively reject MgCl2 (94.5 %) and organic dyes such as alcian blue (AB) (>98.7 %) and methyl blue (MB) (>97.8 %). This work not only demonstrates a facile and versatile method for preparing positively charged composite nanofiltration membranes with great separation performance towards divalent cations, but also expands the membrane building blocks.
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•Highly positively charged nanofiltration membranes are prepared by eco-friendly surface deposition.•The membrane process is conducted through a one-pot and one-step manner under mild conditions.•Laccase-triggered oxidation and crosslinking processes are confirmed during the preparation process.•The positively charged nanofiltration membranes can effectively reject divalent cations such as Mg2+ and Ca2+.
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•Ultra-fine g-C3N4 nanofibers were prepared by a hot alkali treatment method.•A loose nanofiltration membrane was fabricated by cross-linking g-C3N4 nanofibers as the separation ...layer.•The g-C3N4 nanofibers enable the composite membrane with excellent alkali and temperature resistance.•The composite membrane exhibits water permeance of 162.7 L m−2 h−1 bar−1 and Congo red/NaCl selectivity of 301.8.
Loose nanofiltration (LNF) membranes show applications in various fields such as the separation of dyes and salts. The development of LNF membranes with high permeability and high dye/salt selectivity has received great attention in recent years. In this study, inorganic graphitic carbon nitride (g-C3N4) nanofibers modified with polyethyleneimine (PEI) were cross-linked by glutaraldehyde to fabricate a novel LNF membrane on polyethersulfone (PES) microfiltration membrane. Owing to the great hydrophilicity, electro-positivity, and unique structure, the composite membrane exhibits excellent Congo red (CR)/NaCl selectivity of 301.8 with water permeance as high as 162.7 L m−2 h−1 bar−1. Moreover, the cross-linked inorganic separation layer enables the membranes with excellent alkali and temperature resistance. After being immersed in an acidic solution (pH = 1) or an alkaline solution (pH = 13) for 48 h, the rejection to CR does not significantly decrease. Furthermore, the nanofiltration membrane maintains structural stability without obvious decline in CR rejections over the temperature range of 25 ∼ 95 °C, demonstrating the potential in high temperature separation. The present work will open up an avenue for designing and fabricating high-performance nanofiltration membranes.
Nanofiltration (NF) membranes with superior permeability and selectivity are highly desirable for the applications. The development of non-polyamide loose NF membranes with high permeability and ...dye/salt selectivity has aroused great attention in recent years. In this work, 2-hydroxy-1,4-naphthoquinone, a natural compound commonly existed in plants, was chosen to prepare loose NF membranes via the co-deposition with polyethyleneimine (PEI). By optimizing the deposition conditions, we successfully fabricated amine-quinone network coatings on the surface of polyacrylonitrile (PAN) ultrafiltration membranes, and further cross-linked the coatings with glutaraldehyde to improve the compactness and stability. For this kind of loose NF membrane, the rejections to dyes with a molecular weight larger than 600 Da reach 98 %, and the water permeance keeps above 10 L·m−2·h−1·bar−1. In contrast, the rejections to inorganic salts (NaCl, Na2SO4, MgCl2, and MgSO4) are only about 10 %, and the selectivity of the dye molecule alcian blue against NaCl can reach 430. These results prove that this novel composite membrane can realize effective separation for dyes with different molecular weights and desalination for dye solutions. The present work will open up an avenue for designing loose NF membranes with novel separation layers.
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