Cation-diffusion controlled formation of thin graphene oxide composite membranes for efficient ethanol dehydration

Guan, Kecheng; Liu, Quan; Zhou, Guanyu; Liu, Guozhen; Ji, Yufan; Liu, Gongping; Jin, Wanqin

doi:10.1007/s40843-018-9401-1

Cited by 29 publications

(21 citation statements)

References 62 publications

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“…The divalent metal ions (Mg 2+ , Co 2+ , and Ni 2+ ) have similar values which are significantly lower than those for trivalent ions (Al 3+ , Fe 3+ , and Co 3+ ). The univalent K + ion shows poor hydration energy which may not be suitable to link with the OH groups, and the similar conclusion is confirmed by density functional theory (DFT) calculations for GO . As revealed in Figure S12 (Supporting Information), the monoliths prepared with the divalent ions like Fe 2+ , Co 2+ , and Ni 2+ showed similar porous structure with 3D interconnected MXene NSs.…”

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confidence: 55%

Fast Gelation of Ti₃C₂T_x MXene Initiated by Metal Ions

et al. 2019

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Graphene faces the same problem, but its self-assembly into a 3D structures can effectively solve these problems. [5,6] The gelation of graphene oxide (GO) is the mostly used method to prepare a 3D assembled structure, and this process is triggered by the surface chemistry changes of GO NSs in solution. However, the gelation of the other 2D materials, such as transition metal dichalcogenides (TMDs), transition metal oxides (TMOs), and h-BN, [7][8][9][10] is difficult to achieve because of the fewer functional groups on their surface and their poor dispersion in an aqueous solution.Different from the above 2D materials, MXenes prepared by selective etching contain a number of functional groups on their surfaces and edges (F − , O, and OH) [11] show good dispersion in aqueous solution and have the potential to build 3D MXene-based assemblies by solution-based techniques. With the GO as the linker, 3D graphene/MXene hybrid monoliths have been assembled in solution with a low temperature heating. [12,13] In the assembly processes, the laminated MXene domains interacted with the π-conjugated GO sheets which then guided the formation of the 3D structure. The use of surfactants or polymers as the linkers to realize side-by-side joining of MXene NSs also has the potential to build 3D MXene-based monoliths. [14][15][16] However, all these strategies involve a complex process in which the MXenes are easily oxidized due to their high chemical activity. In addition, the above assembly process is different from the GO assembly that relies on self-gelation and has many advantages for achieving structure control by simply changing the solvent or the drying process. [17,18] Until now, the gelation of MXene in a similar manner to that of GO has been difficult to realize.Here, we report the fast gelation of MXene in an aqueous solution initiated by divalent metal ions. In a typical process, Fe 2+ ions are introduced in the MXene solution to destroy the electrostatic repulsive forces between the NSs and link them together, forming a stable 3D MXene hydrogel, similar to the GO hydrogel and its gelation process. [19] The use of metal ions as the joining sites enhances the interlinking of MXene NSs to form a 3D network due to their strong binding energy with the OH groups on the MXene surface. As a result, the formed hydrogel effectively suppresses the restacking of MXene NSs Gelation is an effective way to realize the self-assembly of nanomaterials into different macrostructures, and in a typical use, the gelation of graphene oxide (GO) produces various graphene-based carbon materials with different applications. However, the gelation of MXenes, another important type of 2D materials that have different surface chemistry from GO, is difficult to achieve. Here, the first gelation of MXenes in an aqueous dispersion that is initiated by divalent metal ions is reported, where the strong interaction between these ions and OH groups on the MXene surface plays a key role. Typically, Fe 2+ ions are introduced in the MXene dispersion whic...

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confidence: 55%

Fast Gelation of Ti₃C₂T_x MXene Initiated by Metal Ions

et al. 2019

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“…Laminar GO membranes have demonstrated attractive gas separation efficiency owing to the sharp size‐exclusion effect from the well‐defined interlayer spacing . However, during the operation in aqueous environment, the hydrophilic GO interlayer channels can adsorb a large amount of water molecules, which subsequently lead to an enlarged interlayer spacing (swelling) or even membrane delamination . The resulting GO membrane usually shows a low separation factor and a poor long‐term stability, especially for subnanometer‐scale separations.…”

Section: Introductionmentioning

confidence: 99%

Ultrafast water‐selective permeation through graphene oxide membrane with water transport promoters

et al. 2019

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Graphene oxide (GO), as a representative two-dimensional material, has shown great prospect in developing high-performance separation membranes via forming ordered and tunable nanochannels. However, for aqueous molecular separations, the implementation of an excellent separation performance remains a critical challenge due to the membrane swelling phenomenon and the trade-off effect between permeation flux and separation factor. Herein, a facile and tunable approach is presented for introducing water transport promoters into GO interlayer channels to construct water transport highways. The combination of covalently cross-linked channel structure, facilitated water-selective sorption, and expedited water-preferential diffusion overcome the trade-off effect, achieving a superior performance from an ultrathin GO membrane with a flux of 5.94 kg/m 2 •h and a water/butanol separation factor of 3,965, which exceeds the performance of state-of-the-art membranes for water/ butanol separation. The strategy proposed here is straightforward, holding great potential to produce high-efficiency GO and other two-dimensional (2D)-material membranes for precise aqueous molecular separations.

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“…To explore the roles of CS and GO in membrane formation, pristine CS membranes and pristine GO membranes were prepared using the optimal concentration of the CS solution (0.1 wt%) and spin‐coating layers 29 for the CS/GO membrane. As shown in Figure 3, the water contents in the permeates (water/ethanol separation factor) of both the pristine GO membrane and the pristine CS membrane were very low, indicating the presence of large defects in the membrane layer.…”

Section: Resultsmentioning

confidence: 99%

“…Then, 2 wt% acetic acid solution was used as a solvent to dissolve CS powder with stirring at 40 C for 24 hr to prepare a CS solution. A hydrolyzed PAN support (prepared by soaking PAN in 1.5 M NaOH at 55 C for 30 min) 28,29 was fixed to a glass plate that was placed on the turntable of a spin coater. After the hydrolysis process, the nitrile groups decreased and the hydroxyl groups increased, 28 which can generate more hydrogen bonds with CS to enhance the interfacial adhesion.…”

Section: Membrane Fabricationmentioning

confidence: 99%

Dehydration of C₂–C₄ alcohol/water mixtures via electrostatically enhanced graphene oxide laminar membranes

et al. 2021

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The dehydration of alcohol/water mixtures using pervaporation membranes requires less energy than is required by conventional separation technologies. In this paper, we report electrostatically enhanced graphene oxide (GO) membranes for the highly efficient pervaporation dehydration of C 2 -C 4 alcohol/water mixtures. Positively charged molecules were introduced as the interlayer of negatively charged GO layers via layer-by-layer assembly, thereby creating an electrostatic attraction that drives the assembly of GO nanosheets into ordered interlayer channels. The effects of the feed temperature, water concentration, and continuous operation on the membrane transport behavior were systematically investigated. In the dehydration of 90 wt% alcohol/water mixtures at 70 C, the membrane exhibited ethanol/water, isopropanol/water, and n-butanol/water fluxes of 2.35, 2.98, and 4.69 kg/(m 2 hr), respectively, as well as separation factors for the same mixtures of 3,390, 5,790, and 4,680, respectively. This excellent alcohol/water dehydration performance outperforms those of state-of-the-art polymeric membranes and GO-based membranes.

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Cation-diffusion controlled formation of thin graphene oxide composite membranes for efficient ethanol dehydration

Cited by 29 publications

References 62 publications

Fast Gelation of Ti₃C₂T_x MXene Initiated by Metal Ions

Fast Gelation of Ti₃C₂T_x MXene Initiated by Metal Ions

Ultrafast water‐selective permeation through graphene oxide membrane with water transport promoters

Dehydration of C₂–C₄ alcohol/water mixtures via electrostatically enhanced graphene oxide laminar membranes

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Cation-diffusion controlled formation of thin graphene oxide composite membranes for efficient ethanol dehydration

Cited by 29 publications

References 62 publications

Fast Gelation of Ti3C2Tx MXene Initiated by Metal Ions

Fast Gelation of Ti3C2Tx MXene Initiated by Metal Ions

Ultrafast water‐selective permeation through graphene oxide membrane with water transport promoters

Dehydration of C2–C4 alcohol/water mixtures via electrostatically enhanced graphene oxide laminar membranes

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Product

Resources

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Fast Gelation of Ti₃C₂T_x MXene Initiated by Metal Ions

Fast Gelation of Ti₃C₂T_x MXene Initiated by Metal Ions

Dehydration of C₂–C₄ alcohol/water mixtures via electrostatically enhanced graphene oxide laminar membranes