Molecular Jamming in Tortuous Nanochannels

Dementyev, Petr; Yang, Yang; Резвова, М. А.

doi:10.1021/acs.jpclett.9b03256

Cited by 14 publications

(39 citation statements)

References 25 publications

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“…The fact that CNMs readily yield graphene is indicative of the favorable orientation of their sp 2 constituents. Interestingly enough, the results of our gas and vapor permeation measurements evidenced a tortuous character for the membrane interior . The only way to correlate these data with the earlier reported AFM images is to assume that the interlaminar spacing in CNMs is the very bottleneck controlling their separation performance.…”

Section: Resultssupporting

confidence: 76%

“…In fact, despite the difference in the molecular sizes, the fluxes measured are comparable to that of helium, and the explanation is the different transport mechanisms. While only direct impact translocation is possible for helium atoms, adsorption‐mediated permeation is likely to take place for solvent molecules . However, surface diffusion was not observed for bulkier hexane molecules which is very much analogous to TPT CNMs .…”

Section: Resultsmentioning

confidence: 99%

“…Thus far, terphenylthiol (TPT) (Figure ) has been mostly employed as a precursor in mass transfer experiments with free‐standing CNMs . In particular, TPT CNMs were found to enable selective permeation of water molecules in mixtures with a range of gases and organic vapors . The topography of the material was probed with atomic force microscopy (AFM), and densely packed arrays of ordered TPT molecules were revealed to be transformed completely to a new sponge‐like morphology.…”

Section: Introductionmentioning

confidence: 99%

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Carbon Nanomembranes from Aromatic Carboxylate Precursors

et al. 2020

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Self-assembled monolayers (SAMs) serve as convenient platform for fabricating carbon nanomembranes (CNMs) of extended lateral dimensions. Highly porous CNMs are emerging as interesting materials for membrane technologies as they exhibit selectivity for water permeation and, owing to their reduced dimensionality, promise increased energy efficiency compared to established systems. In the present study terphenylcarboxylate SAMs, prepared on silver underpotential deposited on Au and irradiated by 100 eV electrons, were successfully converted into free-standing CNMs. Infrared and X-ray photoelectron spectroscopy reveal pronounced chemical changes both of the anchoring carboxylate moiety and the aromatic backbone upon electron irradiation. Permeation studies showed high specificity for water as demonstrated by the separation from tetrahydrofuran. Compared to thiols on gold, the standard CNM precursor system, the carboxylic acid based SAM exhibits equivalent characteristics. This suggests that electron-induced carbonization is insensitive to the particular choice of the anchor moiety and, therefore, the choice of precursor molecules can be extended to the versatile class of aromatic carboxylic acids.[a] Dr.

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Section: Resultssupporting

confidence: 76%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Carbon Nanomembranes from Aromatic Carboxylate Precursors

et al. 2020

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“…The novel ACP methodology has emerged as a versatile tool to probe molecular diffusion at functional interfaces. [ 18,19 ] It consists in measuring permeation rates across planar nanomaterials equipped with angstrom‐scale openings under well‐defined feed environments. Due to the small internal volume, the transmembrane passage is governed by entrance kinetics and depends much on the amount of adsorbed species which imparts high sensitivity to surface processes.…”

Section: Resultsmentioning

confidence: 99%

“…Recently, we presented a convenient model system for studying membrane performance in breaking aqueous azeotropes. [ 19 ] The mixture of 60 mol% D 2 O and 40 mol% 1‐propanol (PA) was proven to be a positive azeotrope at room temperature, as expected from H 2 O‐PA VLE. [ 21 ] Upon exposing to the feed mixture, CNMs were found to pass water molecules as fast as water vapor alone indicating unimpeded single‐file flow.…”

Section: Resultsmentioning

confidence: 99%

Concentration‐Driven Disruption of Single‐File Water

Резвова

Dementyev

2020

Adv Materials Inter

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interesting as this abundant nanostructured material has been widely pursued for diverse practical applications. [6,7] Back in 2012, Nair et al. discovered fast and selective permeation of water in GO membranes which was attributed to the collective flow of hydrogen-bonded molecules through nanochannels between graphene layers. [8] Condensed water was speculated to behave in the 2D capillaries as a single file similar to that in carbon nanotubes and aquaporins. [9] The interlayer spacing in GO laminates was found to shrink upon thermal annealing, and water transport rate was correlated with the number of oxygen-containing functional groups. [10] GO nanochannels were demonstrated to enable filtration of ionic solutes revealing a clear size cutoff at 4.5 Å. [11] In order to allow for controlled ionic sieving, the pore size in GO membranes was later shown to be adjusted by both physical and chemical methods. [12] More recently, waterselective GO membranes were employed in pervaporation to dehydrate ethanol, and the transmembrane flux was measured to depend on the alcohol fraction dropping from 1.36 kg m −2 h −1 for pure water to 0.3 kg m −2 h −1 for feed mixtures of 10 wt% water in content. [13] Even though great values of water/ethanol selectivity were achieved, the reduction of the membrane permeability observed indicates complex interfacial phenomena which are likely to differ from those in salt rejection. While the concentration of solid substances in aqueous solutions is limited by saturation points, the composition of liquid mixtures can be varied continuously.Water is fully miscible with a wide range of polar organic solvents, and membrane separation is considered to be advantageous in their recovery and purification. [14] Unlike ordinary fractional distillation, vapor permeation and pervaporation processes can break azeotropes which is also very important in the biofuel production. [15] Dehydration of organics is the most demanded pervaporation technology in industry, and design of thermally stable membrane materials remains a subject of immense scientific efforts. [16] Porous structures capable of the single-file water transport offer the opportunity to fabricate highthroughput membranes for removing water from liquids. However, the production of anhydrous compounds means selective extraction of water down to ppm levels of the residue, whereas the mass transfer under these circumstances is not necessarily the same as for aqueous solutions, exemplified above by GO membranes. Indeed, bulk properties in the binary water-ethanol mixtures are known to change with the molar composition, Strong hydrogen bonding is known to entail some of the spectacular physical properties of liquid water, including fast diffusion under nanoconfinement. Similar to biological channels, the single-file or collective motion of interconnected water molecules has been observed in nanotubes and laminar structures, exhibiting tremendous potential for energy-efficient separation applications. Desalination, breaking azeotropes, and dehum...

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Elucidating molecular transport behavior in vertically‐aligned 2D nanochannels of graphene‐based lamellar membranes

Wang,

Liu,

Chen

et al. 2023

AIChE Journal

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Two‐dimensional (2D) nanochannels with confined spacing and tunable microenvironment exhibit broad application prospects in molecule‐scale processes. However, mass transport behaviors in nanochannels have yet been clearly elucidated, due to the complex physical and chemical structures of nanochannels. Herein, a series of vertically‐aligned nanochannels with tunable chemistry were fabricated by embedding graphene‐based lamellar membranes into epoxy matrix. In this way, 2 mm‐length robust nanochannels can maintain the molecular transport configuration throughout the membrane without the disturbance from entrance and cross‐layer domains. Based on these platforms, it is demonstrated that molecule–channel and molecule–molecule interactions codetermine molecular transport efficiency by controlling molecular configuration and transfer friction. Significantly, matched interaction energies permit fast transport with methanol permeance of over 26.1 L m−2 h−1 bar−1, which outperforms most reported long‐range nanochannels, while mismatched interaction energies fail to do so. In addition, the vertically‐aligned nanochannels membranes hold exceptional stability because of the mechanical protection of epoxy.

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Molecular Jamming in Tortuous Nanochannels

Cited by 14 publications

References 25 publications

Carbon Nanomembranes from Aromatic Carboxylate Precursors

Carbon Nanomembranes from Aromatic Carboxylate Precursors

Concentration‐Driven Disruption of Single‐File Water

Elucidating molecular transport behavior in vertically‐aligned 2D nanochannels of graphene‐based lamellar membranes

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