Synthesis and Performance of Polymerizable Room-Temperature Ionic Liquids as Gas Separation Membranes

Abstract:In this work, mixed matrix membranes (MMMs) composed of small-pore zeolites with various topologies (CHA (Si/Al = 5), LTA (Si/Al = 1 and 5), and Rho (Si/Al = 5)) as dispersed phase, and the hugely permeable poly(1-trimethylsilyl-1-propyne) (PTMSP) as continuous phase, have been synthesized via solution casting, in order to obtain membranes that could be attractive for oxygen-enriched air production. The O 2 /N 2 gas separation performance of the MMMs has been analyzed in terms of permeability, diffusivity, and solubility in the temperature range of 298-333 K. The higher the temperature of the oxygen-enriched stream, the lower the energy required for the combustion process. The effect of temperature on the gas permeability, diffusivity, and solubility of these MMMs is described in terms of the Arrhenius and Van't Hoff relationships with acceptable accuracy. Moreover, the O 2 /N 2 permselectivity of the MMMs increases with temperature, the O 2 /N 2 selectivities being considerably higher than those of the pure PTMSP. In consequence, most of the MMMs prepared in this work exceeded the Robeson's upper bound for the O 2 /N 2 gas pair in the temperature range under study, with not much decrease in the O 2 permeabilities, reaching O 2 /N 2 selectivities of up to 8.43 and O 2 permeabilities up to 4,800 Barrer at 333 K.

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“…The diffusion coefficient through the membranes is calculated from the transition regime of mass transfer through a dense material [41]:…”

Section: Characterizationmentioning

confidence: 99%

Selective, Room-Temperature Transformation of Methane to C1 Oxygenates by Deep UV Photolysis over Zeolites

et al. 2011

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“…8,9 These RTILs are more stable but they require particular polymerizable groups and sophisticated membrane preparation techniques.…”

Section: Introductionmentioning

confidence: 99%

High Ionic Liquid Content Polymeric Gel Membranes: Preparation and Performance

et al. 2010

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Ionic liquid polymeric gel membranes containing from 20 wt % to 80 wt % of the ionic liquid 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([EMIM][TFSI]) in poly(vinylidene fluorideco-hexafluoropropylene) (p(VDF-HFP)) were prepared by solvent casting from a solution in acetone. The effect of the ionic liquid on the performance and properties of the membranes was discussed and compared with the neat polymer. In the presence of an excess of ionic liquid, p(VDF-HFP) membranes swell in a significant way, especially above 70°C, becoming completely soluble above 90°C. DSC analysis shows a gradual decrease of the melting point of the gel and a decrease in the overall melting enthalpy with increasing IL content, whereas the melting enthalpy normalized for the polymer fraction shows an initial drop and then a gradual increase. In the presence of the ionic liquid, the elastic modulus and break strength decrease dramatically, while the maximum deformation first increases due to higher flexibility of the plasticized polymer and then rapidly decreases above 40 wt % of IL as a consequence of the progressive decrease of the number of entanglements. X-ray studies demonstrate a reduction in the overall crystal content. The position of the strongest diffraction peak remains unaltered in all samples, suggesting that only the polymer chains crystallize and that no cocrystallization of ionic liquid and polymer takes place. Preliminary gas permeation measurements show a significant increase of the permeability in the presence of [EMIM][TFSI], especially for carbon dioxide. This suggests a potential application in gas separation membranes, for instance for natural gas treatment or for CO 2 sequestration from flue gas.

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“…24 The potential of such ILs in gas separations has been recently reported with polymer gas separation membranes based on polymerizable etherderivatized ILs. 25 No thermodynamic property of cyanoalkyl-substituted ILs was found in the literature. Zhao and co-workers showed that these functionalized ILs should be used as electrolytes for lithium secondary batteries.…”

Section: Introductionmentioning

confidence: 99%

Study of Ether-, Alcohol-, or Cyano-Functionalized Ionic Liquids Using Inverse Gas Chromatography

et al. 2010

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Activity coefficients of 52 organic compounds in four ionic liquids (ILs), 1,3-dimethoxyimidazolium bis((trifluoromethyl)sulfonyl)imide, 1-(methylethylether)-3-methylimidazolium bis((trifluoromethyl)sulfonyl)imide, 1-ethanol-3-methylimidazolium bis((trifluoromethyl)-sulfonyl)imide, and 1-(3-cyanopropyl)-3-methylimidazolium dicyanamide, were measured using inverse gas chromatography from (312 to 353) K. The retention data were also converted in gas-to-IL partition coefficients and water-to-IL partition coefficients using the corresponding gas-to-water partition coefficients. Both sets of partition coefficients were analyzed using the modified Abraham solvation parameter model. The derived equations correlated the experimental gas-to-IL and water-to-IL partition coefficient data to within (0.09 and 0.14) log units, respectively.

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Synthesis and Performance of Polymerizable Room-Temperature Ionic Liquids as Gas Separation Membranes

Cited by 391 publications

References 49 publications

Selective, Room-Temperature Transformation of Methane to C1 Oxygenates by Deep UV Photolysis over Zeolites

Selective, Room-Temperature Transformation of Methane to C1 Oxygenates by Deep UV Photolysis over Zeolites

High Ionic Liquid Content Polymeric Gel Membranes: Preparation and Performance

Study of Ether-, Alcohol-, or Cyano-Functionalized Ionic Liquids Using Inverse Gas Chromatography

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