Asymmetric Two-Layer Porous Membrane for Gas Separation

Liu, Maochang; Song, Dongxing; Wang, Xin; Sun, Chengzhen; Jing, Dengwei

doi:10.1021/acs.jpclett.0c01797

Cited by 17 publications

(10 citation statements)

References 30 publications

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“…On the theory and simulation sides, the mechanism of gas permeation through nanometer-scale pores in NATMs has been investigated in depth. Novel design ideas of NATM pores that enhance gas separation have been proposed based on simulations, including edge functionalization, [196] asymmetrical pores, [104,107] and continuously tunable pore size by strain or by the overlapping of two pores. [101,119,133] Pore nucleation and pore expansion processes have also been gaining increasing attention.…”

Section: Discussionmentioning

confidence: 99%

“…[88,136] Multilayer membranes with overlapping pores in different layers can also be analyzed using the same framework as that used in the case of singlelayer NATMs. [122] For example, conical pores, [107] asymmetric pores, [104] and pores with tunable sizes [101,103] have all been simulated for gas separations.…”

Section: Simulationsmentioning

confidence: 99%

“…In this regard, atomic‐scale simulations have been carried out to estimate the gas permeances more precisely. Figure summarizes the simulation results of gas permeation through NATM pores using molecular dynamics (MD) simulations, [ 59,61,63,64,66,67,73–75,86–107 ] ab initio calculations, [ 29,70,83,108–121 ] or a combination of both, [ 72,82,122–137 ] as well as experimental results of gas permeation through individual graphene nanopores. [ 60,138 ] The gases considered in Figure 4 include H 2 , He, H 2 O, CO 2 , N 2 , O 2 , CH 4 , H 2 S, Ar, SF 6 , ethane, and ethene.…”

Section: Theoretical and Simulation Advancesmentioning

confidence: 99%

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Gas Separations using Nanoporous Atomically Thin Membranes: Recent Theoretical, Simulation, and Experimental Advances

Yuan

et al. 2022

Advanced Materials

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The separation of gaseous mixtures is essential in the chemical industry, including hydrogen separation in ammonia or petrochemical plants, nitrogen separation from air, CO 2 separation in natural gas processing, [7] olefin/ paraffin separation, [1] and H 2 S separation from sour gas. [8] Similar to separation processes in general, thermal-based gasseparation methods, such as cryogenic distillation, amine adsorption, and vapor condensation, consume a high amount of energy, which can be significantly reduced using gas-separation membrane units. [5,8] A membrane that can separate gases allows certain components in a mixture to permeate at higher rates than others. The economic competitiveness of a gas-separation membrane highly depends on its gas permeance K and its selectivity S. The permeance K i of gas species i (in SI units of mol m −2 s −1 Pa −1 ) is defined as K i = F i /Δp i , where F i (in SI units of mol m −2 s −1 ) is the flux of gas i through the membrane, and Δp i is the partial pressure difference (the driving force) of gas i between the feed side and the permeate side. For relatively thick conventional membranes, whose crossmembrane transport resistance is dominated by the bulk interior, the permeance K i is inversely proportional to the membrane thickness d. Correspondingly, the permeability P i of gas i (in SI units of mol m −1 s −1 Pa −1 ) is defined aswhich is an intrinsic property of a material. The selectivity S ij between gases i and j is defined as S ij = K i /K j = P i /P j .Polymers have been the most widely used materials for gasseparation membranes for decades because of their relatively low cost and low manufacturing difficulty. [8,9] However, membrane separations using state-of-the-art polymeric membranes cannot outcompete the thermal-based separation methods economically. [7] One of the limitations of the polymeric membranes is the trade-off between permeability and selectivity, originally investigated by Robeson. [10,11] The best combination of permeability and selectivity for a binary gas pair is referred to as the polymer upper bound. This trade-off originates from the interplay between the free volume spacing in the polymer matrices and the size of the gas molecules. [12] Smaller polymeric spacing increases the selectivity but sacrifices the permeability due to the lower gas Porous graphene and other atomically thin 2D materials are regarded as highly promising membrane materials for high-performance gas separations due to their atomic thickness, large-scale synthesizability, excellent mechanical strength, and chemical stability. When these atomically thin materials contain a high areal density of gas-sieving nanoscale pores, they can exhibit both high gas permeances and high selectivities, which is beneficial for reducing the cost of gas-separation processes. Here, recent modeling and experimental advances in nanoporous atomically thin membranes for gas separations is discussed. The major challenges involved, including controlling pore size distributions, scaling up the membrane ar...

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Section: Discussionmentioning

confidence: 99%

Section: Simulationsmentioning

confidence: 99%

Section: Theoretical and Simulation Advancesmentioning

confidence: 99%

See 1 more Smart Citation

Gas Separations using Nanoporous Atomically Thin Membranes: Recent Theoretical, Simulation, and Experimental Advances

Yuan

et al. 2022

Advanced Materials

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“…Therefore, we adopt hBN and graphene hybrid sheets to form a two-dimensional membrane with stronger adsorption surface in one side and weaker adsorption surface in another side. In this study, we systematically study the quasi-unidirectional molecular transport characteristics through a graphene-hBN bilayer nanopore, following the asymmetric two-layer porous membranes proposed by Liu et al (Liu et al, 2020). We show that the quasi-unidirectional molecular transport is realized by inhibiting the molecular backflow from permeate-side to feed-side.…”

Section: Introductionmentioning

confidence: 92%

Quasi-Unidirectional Transport Bilayer Two-Dimensional Nanopores for Highly-Efficient Molecular Sieving

et al. 2021

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Two-dimensional nanopores are very promising for high-permeance molecular sieving, but the molecular backflow from permeate-side to feed-side is not beneficial for improving molecular permeance. We study the quasi-unidirectional molecular transport through a graphene-hexagonal boron nitride bilayer nanopore, aiming to realize a high-permeance molecular sieving. Molecular dynamics simulations of CO2/CH4 separations show that the bilayer pore presents 3.7 times higher selectivity comparing to the single-layer graphene nanopore with the same size. The quasi-unidirectional molecular transport is attributed to the distinctive adsorption abilities of gas molecules on the two sides of bilayer nanopores and the inhibited molecular backflow from permeate-side to feed-side. This work provides a promising way to realize the ultra-permeable porous membranes with molecular permeance even higher than the single-layer atomic-thickness membranes.

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“…(1)(2)(3)(4)(5) In addition, the membranes which have numerous pores are extensively used to purify contaminated water, separate cathode and anode in battery and separate gas in distillation process. (6)(7)(8)(9)(10) Porous membrane can absorb or lter only pollutants out of wastewater, and it can leads to tremendous environmental virtue. Futhermore, in industrial elds, membrane process with porous materials is able to simplify complicate processes including cryogenic distillation, water puri cation and etc..…”

Section: Introductionmentioning

confidence: 99%

Highly stable porous cellulose materials to utilize lactic acid

Kim¹,

Kang²

2021

Preprint

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In this study, a porous membrane consisting of lactic acid and cellulose acetate was fabricated using a low-cost and pro-environmental process. The wetting action of the lactic acid induced a plasticization effect in the cellulose acetate chain, forming several small pores during the hydrostatic treatment. The surface and cross-section of the membranes were observed using scanning electron microscopy, and the interaction between cellulose acetate and lactic acid was investigated using Fourier transform infrared spectroscopy. Furthermore, thermogravimetric analysis was performed to determine the thermal stability of the membrane and the removal of lactic acid by the hydrostatic treatment. In addition, the optimum composition and performance of the composite were investigated via water flux measurement. Furthermore, the average pore diameter and porosity of the cellulose acetate/lactic acid membrane measured using a porosimeter was 0.38 μm and 65.3%, respectively.

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Asymmetric Two-Layer Porous Membrane for Gas Separation

Cited by 17 publications

References 30 publications

Gas Separations using Nanoporous Atomically Thin Membranes: Recent Theoretical, Simulation, and Experimental Advances

Gas Separations using Nanoporous Atomically Thin Membranes: Recent Theoretical, Simulation, and Experimental Advances

Quasi-Unidirectional Transport Bilayer Two-Dimensional Nanopores for Highly-Efficient Molecular Sieving

Highly stable porous cellulose materials to utilize lactic acid

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