Modelling sorption and diffusion of NF3 and CF4 in Teflon AF perfluoropolymer membranes

Branken, D.J.; Krieg, H.M.; Lachmann, G.; Carstens, P. A. B.

doi:10.1016/j.memsci.2014.07.033

Cited by 21 publications

(6 citation statements)

References 62 publications

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“…Our measurements for Teflon AF1600 are comparable to literature reports [19,33], and correspond well with molecular simulations of polymer packing density [34]. The density of Hyflon AD60 is also comparable with that reported by Markhloufi et al [35]; and indicates that Hyflon AD60 achieves a much denser morphology and correspondingly a lower FFV than Teflon AF1600.…”

Section: Density and Fractional Free Volumesupporting

confidence: 90%

Water permeability and competitive permeation with CO 2 and CH 4 in perfluorinated polymeric membranes

Scholes

Kanehashi

Stevens

et al. 2015

Separation and Purification Technology

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The permeability of water through polymeric membranes is of particular interest in gas separation, because of the high water vapor content found in many industrial applications. Polymeric membranes that are resistant to competitive sorption and plasticization by water are especially attractive, since they can reduce the need for gas pretreatment in many membrane applications. The perfluorinated polymers Teflon AF1600 and Hyflon AD60 are studied here for this purpose because of their strong hydrophobicity and unusual solvent properties. It was observed that water permeability through both perfluorinated polymers was of the same magnitude as CO 2 . Indeed, under the conditions studied, Teflon AF1600 was selective for CO 2 over water. Such reverse selectivity for the CO 2 -H 2 O gas pair has not been reported before for glassy polymeric membranes and reflects the very low solubility of water in the polymer. The water permeability through Hyflon AD60 was greater than that for CO 2 with a minimum at 55 o C. The change in both CO 2 and CH 4 permeability through Teflon AF1600 and Hyflon AD60 was investigated as a function of water activity in the feed gas to investigate the effects of competitive permeation. It was observed that CO 2 and CH 4 permeability in both membranes reduced with water activity. For both Teflon AF1600 and Hyflon AD60, the decrease in permeability of both gases with water activity was interpreted as water clusters blocking the diffusion of both CO 2 and CH 4 through the membrane.

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Section: Density and Fractional Free Volumesupporting

confidence: 90%

Water permeability and competitive permeation with CO 2 and CH 4 in perfluorinated polymeric membranes

Scholes

Kanehashi

Stevens

et al. 2015

Separation and Purification Technology

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“…The smaller the probe radius, the larger the accessible volume. Therefore, f was calculated using a spherical probe with a given radius . This behavior of f indicates that the copolymerization of the dimethylsilane in EXL1112 decreases the polymer chain packing efficiency, leading to a larger free volume than OQ2720 and CAIMI110.…”

Section: Results and Dicussionmentioning

confidence: 99%

Thermodynamic Properties and Free Volume Analyses of Polycarbonates by a Combined Experimental and Molecular Simulation Method

Wang

Zhao

et al. 2015

Ind. Eng. Chem. Res.

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A combined experimental and computational approach is applied to amorphous polycarbonates (PCs) to link the macroscopic behavior and molecular features. The Simha−Somcynsky equation of phase (EOS) provides a more accurate description than the Tait EOS for describing the pressure−volume−temperature (PVT) relationship and thermal expansivity. The relationship between the specific volume and the hole free volume was investigated using PVT measurements, positron annihilation lifetime spectra, and molecular dynamics (MD) techniques, to examine the correlations between changes in the behavior of specific volume and molecular packing. We found that the specific volume and hole free volume have linear relationships with temperature. However, the occupied volume displayed remarkable compressibility. The analyses revealed that the PC with side methyl groups and long C−Si bonds contributed to the formation of large free volume. The MD results validate the effectiveness of molecular simulation techniques in designing materials at the molecular level.

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“…To achieve an efficient CF 4 capture, several technologies based on thermal decomposition, plasma treatment, absorption, adsorption, cryogenic recovery, and membrane separation have been developed. Among them, physical adsorption using efficient nanoporous adsorbents ,,− is considered as the most competitive technology for capturing CF 4 due to its low energy consumption, low cost, and easy management. However, only some limited studies in the literature are devoted to CF 4 capture using nanoporous adsorbents.…”

Section: Introductionmentioning

confidence: 99%

CF₄ Capture and Separation of CF₄–SF₆ and CF₄–N₂ Fluid Mixtures Using Selected Carbon Nanoporous Materials and Metal–Organic Frameworks: A Computational Study

2022

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The adsorption of pure fluid carbon tetrafluoride and the separation of CF 4 –SF 6 and CF 4 –N 2 fluid mixtures using representative nanoporous materials have been investigated by employing Monte Carlo and molecular dynamics simulation techniques. The selected materials under study were the three-dimensional carbon nanotube networks, pillared graphene using carbon nanotube pillars, and the SIFSIX-2-Cu metal–organic framework. The selection of these materials was based on their previously reported efficiency to separate fluid SF 6 –N 2 mixtures. The pressure dependence of the thermodynamic and kinetic separation selectivity for the CF 4 –SF 6 and CF 4 –N 2 fluid mixtures has therefore been investigated, to provide deeper insights into the molecular scale phenomena taking place in the investigated nanoporous materials. The results obtained have revealed that under near-ambient pressure conditions, the carbon-based nanoporous materials exhibit a higher gravimetric fluid uptake and thermodynamic separation selectivity. The SIFSIX-2-Cu material exhibits a slightly higher kinetic selectivity at ambient and high pressures.

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Modelling sorption and diffusion of NF3 and CF4 in Teflon AF perfluoropolymer membranes

Cited by 21 publications

References 62 publications

Water permeability and competitive permeation with CO 2 and CH 4 in perfluorinated polymeric membranes

Water permeability and competitive permeation with CO 2 and CH 4 in perfluorinated polymeric membranes

Thermodynamic Properties and Free Volume Analyses of Polycarbonates by a Combined Experimental and Molecular Simulation Method

CF₄ Capture and Separation of CF₄–SF₆ and CF₄–N₂ Fluid Mixtures Using Selected Carbon Nanoporous Materials and Metal–Organic Frameworks: A Computational Study

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Modelling sorption and diffusion of NF3 and CF4 in Teflon AF perfluoropolymer membranes

Cited by 21 publications

References 62 publications

Water permeability and competitive permeation with CO 2 and CH 4 in perfluorinated polymeric membranes

Water permeability and competitive permeation with CO 2 and CH 4 in perfluorinated polymeric membranes

Thermodynamic Properties and Free Volume Analyses of Polycarbonates by a Combined Experimental and Molecular Simulation Method

CF4 Capture and Separation of CF4–SF6 and CF4–N2 Fluid Mixtures Using Selected Carbon Nanoporous Materials and Metal–Organic Frameworks: A Computational Study

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Product

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CF₄ Capture and Separation of CF₄–SF₆ and CF₄–N₂ Fluid Mixtures Using Selected Carbon Nanoporous Materials and Metal–Organic Frameworks: A Computational Study