A Study on Permeabilities and Selectivities of Small-Molecule Gases for Composite Ionic Liquid and Polymer Membranes

2013 ◽  
Vol 448-453 ◽  
pp. 765-770 ◽  
Author(s):  
Li Zhe Liang ◽  
Quan Gan ◽  
Paul Nancarrow
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
Gas Separation ◽  
Elevated Temperatures ◽  
Polymer Membranes ◽  
Porous Polymer ◽  
Separation Performance ◽  
Thermal Stabilities ◽  
Wide Range ◽  
Supported Ionic Liquid Membranes

In recent years, the utilisation of ionic liquids supported on porous polymer membranes has been demonstrated to enhance gas separation performance by improving both permeability and selectivity for several industrially-relevant gas mixtures. However, the use of such supported ionic liquid membranes (SILMs) is normally not feasible at elevated process temperatures due to the resulting decrease in ionic liquid viscosity, which can lead to increased loss of ionic liquid from the membrane support during operation. In addition, many of the polymer membranes typically used in SILMs exhibit relatively poor mechanical and thermal stabilities at high temperatures. To overcome these problems associated with SILMs, thermally-stable composite ionic liquid and polymer membranes (CILPMs) have been fabricated in this study, thus exploiting the beneficial properties of ionic liquids for gas separation at elevated temperatures. Poly (pyromellitimide-co-4,4-oxydianiline) (PMDA-ODA PI) in combination with the ionic liquid, [C4mi [NTf2] were used to fabricate the CILPMs. A measurement rig was designed and built to determine permeabilities and selectivities of the CILPMs for H2, N2, CO, CO2 and CH4 over a range of pressures and temperatures. The fabricated CILPMs were shown to maintain excellent mechanical and thermal stability over a wide range of processing conditions. Temperature was shown to greatly affect both permeability and selectivity of the membranes, whilst pressure had less influence. The incorporation of [C4mi [NTf2] into the membranes was found to significantly increase CO2 permeation and, therefore, it is anticipated that these CILPMs hold significant potential for CO2 separation applications.

Investigation of an Ionic Liquid As a High-Temperature Electrolyte for Silicon-Lithium Systems

2020 ◽  
Author(s):  
Christopher Rudolf ◽  
Corey Love ◽  
Marriner Merrill
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
Solid State ◽  
High Temperatures ◽  
Room Temperature ◽  
Elevated Temperatures ◽  
Lithium Ion ◽  
Constant Current ◽  
Wide Range ◽  
Solid State Electrolytes

Abstract Electrolytes for lithium ion batteries which work over a wide range of temperatures are of interest in both research and applications. Unfortunately, most traditional electrolytes are unstable at high temperatures. As an alternative, solid state electrolytes are sometimes used. These are inherently safer because they have no flammable vapors, and solid state electrolytes can operate at high temperatures, but they typically suffer from very low conductivity at room temperatures. Therefore, they have had limited use. Another option which has been previously explored is the use of ionic liquids. Ionic liquids are liquid salts, with nominally zero vapor pressure. Many are liquid over the temperature of interest (20–200°C). And, there is a tremendous range of available chemistries that can be incorporated into ionic liquids. So, ionic liquids with chemistries that are compatible with lithium ion systems have been developed and demonstrated experimentally at room temperature. In this study, we examined a silicon-lithium battery cycling at room temperature and over 150°C. Using half-cell vial and split-cell structures, we examined a standard electrolyte (LiPF6) at room temperature, and an ionic liquid electrolyte (1-ethyl-3-methylimidazolium bis(trifluorosulfonyl)imide) at room temperature and up to ∼150°C. The ionic liquid used was a nominally high purity product purchased from Sigma Aldrich. It was selected based on results reported in the open literature. The anode used was a wafer of silicon, and the cathode used was an alumina-coated lithium chip. The cells were cycled either 1 or 5 times (charge/discharge) in an argon environment at constant current of 50 μA between 1.5 and 0.05 volts. The results for the study showed that at room temperature, we could successfully cycle with both the standard electrolyte and the lithium ion electrolyte. As expected, there was large-scale fracture of the silicon wafer with the extent of cracking having some correlation with first cycle time. We were unable to identify any electrolyte-specific change in the electrochemical behavior between the standard electrolyte and the ionic liquid at room temperature. Although the ionic liquid was successfully used at room temperature, when the temperature was increased, it behaved very differently and no cells were able to successfully cycle. Video observations during cycling (∼1 day) showed that flocs or debris were forming in the ionic liquid and collecting on the electrode surface. The ionic liquid also discolored during the test. Various mechanisms were considered for this behavior, and preliminary tests will be presented. All materials were stable at room temperature, and the degradation appeared to be linked to the electrochemical process. As a conclusion, our working hypothesis is that, particularly at elevated temperatures, ionic liquid cleanliness and purity can be far more important than at room temperature, and small impurities can cause significant hurdles. This creates an important barrier to research efforts, because the “same” ionic liquids could cause failure in one situation and not in another due to impurities.

scholarly journals Pebax-based composite membranes with high gas transport properties enhanced by ionic liquids for CO2 separation

RSC Advances ◽  
2017 ◽  
Vol 7 (11) ◽  
pp. 6422-6431 ◽  
Author(s):  
Mengdie Li ◽  
Xiangping Zhang ◽  
Shaojuan Zeng ◽  
Lu bai ◽  
Hongshuai Gao ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
Transport Properties ◽  
Gas Separation ◽  
Gas Transport ◽  
Composite Membranes ◽  
Co2 Separation ◽  
Separation Performance ◽  
Gas Transport Properties ◽  
Gas Separation Performance

A series of composite membranes with high gas transport properties enhanced by IL and ZIF-8 have been developed. The influence of ionic liquid and ZIF-8 addition on gas separation performance were systematically investigated.

scholarly journals Effect of methylation of ionic liquids on the gas separation performance of ionic liquid/metal–organic framework composites

CrystEngComm ◽  
2018 ◽  
Vol 20 (44) ◽  
pp. 7137-7143 ◽  
Author(s):  
Vahid Nozari ◽  
Muhammad Zeeshan ◽  
Seda Keskin ◽  
Alper Uzun
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
Liquid Metal ◽  
Gas Separation ◽  
Metal Organic Framework ◽  
Separation Performance ◽  
Metal Organic ◽  
Gas Separation Performance ◽  
Organic Framework

[BMIM][PF6] and its methylated form, [BMMIM][PF6] were incorporated into CuBTC to examine the effect of methylation of ionic liquids (ILs) on the gas separation performance of the corresponding IL/metal–organic framework (MOF) composites.

scholarly journals Integration of Stable Ionic Liquid-Based Nanofluids into Polymer Membranes. Part II: Gas Separation Properties toward Fluorinated Greenhouse Gases

Nanomaterials ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 582
Author(s):  
Fernando Pardo ◽  
Sergio V. Gutiérrez-Hernández ◽  
Carolina Hermida-Merino ◽  
João M. M. Araújo ◽  
Manuel M. Piñeiro ◽  
...  
Keyword(s):  
Ionic Liquid ◽  
Gas Separation ◽  
Value Added ◽  
Gas Permeation ◽  
Mixed Matrix Membranes ◽  
Separation Performance ◽  
Mixed Gas ◽  
Neat Polymer ◽  
Stable Suspension ◽  
Base Polymer

Membrane technology can play a very influential role in the separation of the constituents of HFC refrigerant gas mixtures, which usually exhibit azeotropic or near-azeotropic behavior, with the goal of promoting the reuse of value-added compounds in the manufacture of new low-global warming potential (GWP) refrigerant mixtures that abide by the current F-gases regulations. In this context, the selective recovery of difluorometane (R32, GWP = 677) from the commercial blend R410A (GWP = 1924), an equimass mixture of R32 and pentafluoroethane (R125, GWP = 3170), is sought. To that end, this work explores for the first time the separation performance of novel mixed-matrix membranes (MMMs) functionalized with ioNanofluids (IoNFs) consisting in a stable suspension of exfoliated graphene nanoplatelets (xGnP) into a fluorinated ionic liquid (FIL), 1-ethyl-3-methylpyridinium perfluorobutanesulfonate ([C2C1py][C4F9SO3]). The results show that the presence of IoNF in the MMMs significantly enhances gas permeation, yet at the expense of slightly decreasing the selectivity of the base polymer. The best results were obtained with the MMM containing 40 wt% IoNF, which led to an improved permeability of the gas of interest (PR32 = 496 barrer) with respect to that of the neat polymer (PR32 = 279 barrer) with a mixed-gas separation factor of 3.0 at the highest feed R410A pressure tested. Overall, the newly fabricated IoNF-MMMs allowed the separation of the near-azeotropic R410A mixture to recover the low-GWP R32 gas, which is of great interest for the circular economy of the refrigeration sector.

scholarly journals Investigating the Proton and Ion Transfer Properties of Supported Ionic Liquid Membranes Prepared for Bioelectrochemical Applications Using Hydrophobic Imidazolium-Type Ionic Liquids

Membranes ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 359
Author(s):  
László Koók ◽  
Piroska Lajtai-Szabó ◽  
Péter Bakonyi ◽  
Katalin Bélafi-Bakó ◽  
Nándor Nemestóthy
Keyword(s):  
Mass Transfer ◽  
Ionic Liquid ◽  
Ionic Liquids ◽  
Microbial Fuel Cells ◽  
Transport Numbers ◽  
Liquid Membranes ◽  
Ion Transfer ◽  
Supported Ionic Liquid ◽  
Supported Ionic Liquid Membranes ◽  
Transfer Properties

Hydrophobic ionic liquids (IL) may offer a special electrolyte in the form of supported ionic liquid membranes (SILM) for microbial fuel cells (MFC) due to their advantageous mass transfer characteristics. In this work, the proton and ion transfer properties of SILMs made with IL containing imidazolium cation and [PF6]− and [NTf2]− anions were studied and compared to Nafion. It resulted that both ILs show better proton mass transfer and diffusion coefficient than Nafion. The data implied the presence of water microclusters permeating through [hmim][PF6]-SILM to assist the proton transfer. This mechanism could not be assumed in the case of [NTf2]− containing IL. Ion transport numbers of K+, Na+, and H+ showed that the IL with [PF6]− anion could be beneficial in terms of reducing ion transfer losses in MFCs. Moreover, the conductivity of [bmim][PF6]-SILM at low electrolyte concentration (such as in MFCs) was comparable to Nafion.

scholarly journals The spirobichroman-based polyimides with different side groups: from structure–property relationships to chain packing and gas transport performance

RSC Advances ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 5086-5095
Author(s):  
Shuli Wang ◽  
Xiaohua Tong ◽  
Chunbo Wang ◽  
Xiaocui Han ◽  
Sizhuo Jin ◽  
...  
Keyword(s):  
Dihedral Angle ◽  
Gas Separation ◽  
Gas Transport ◽  
Critical Role ◽  
Polymer Membranes ◽  
Separation Performance ◽  
Structure Property ◽  
Chain Packing ◽  
Structure Property Relationships ◽  
Gas Separation Performance

Effect of substituents on the dihedral angle and chain packing plays a critical role in the enhancement in the gas separation performance of polymer membranes.

scholarly journals Tunning CO2 Separation Performance of Ionic Liquids through Asymmetric Anions

Molecules ◽  
2022 ◽  
Vol 27 (2) ◽  
pp. 413
Author(s):  
Bruna F. Soares ◽  
Daniil R. Nosov ◽  
José M. Pires ◽  
Andrey A. Tyutyunov ◽  
Elena I. Lozinskaya ◽  
...  
Keyword(s):  
Ionic Liquids ◽  
Atmospheric Pressure ◽  
Time Lag ◽  
Gas Permeation ◽  
Separation Performance ◽  
Experimental Conditions ◽  
Feed Pressure ◽  
Similar Chemical ◽  
Supported Ionic Liquid Membranes ◽  
Gas Separation Performance

This work aims to explore the gas permeation performance of two newly-designed ionic liquids, [C2mim][CF3BF3] and [C2mim][CF3SO2C(CN)2], in supported ionic liquid membranes (SILM) configuration, as another effort to provide an overall insight on the gas permeation performance of functionalized-ionic liquids with the [C2mim]+ cation. [C2mim][CF3BF3] and [C2mim][CF3SO2C(CN)2] single gas separation performance towards CO2, N2, and CH4 at T = 293 K and T = 308 K were measured using the time-lag method. Assessing the CO2 permeation results, [C2mim][CF3BF3] showed an undermined value of 710 Barrer at 293.15 K and 1 bar of feed pressure when compared to [C2mim][BF4], whereas for the [C2mim][CF3SO2C(CN)2] IL an unexpected CO2 permeability of 1095 Barrer was attained at the same experimental conditions, overcoming the results for the remaining ILs used for comparison. The prepared membranes exhibited diverse permselectivities, varying from 16.9 to 22.2 for CO2/CH4 and 37.0 to 44.4 for CO2/N2 gas pairs. The thermophysical properties of the [C2mim][CF3BF3] and [C2mim][CF3SO2C(CN)2] ILs were also determined in the range of T = 293.15 K up to T = 353.15 K at atmospheric pressure and compared with those for other ILs with the same cation and anion’s with similar chemical moieties.

Industrial uses and applications of ionic liquids

2018 ◽  
Vol 3 (5) ◽  
Author(s):  
Keith E. Gutowski
Keyword(s):  
Ionic Liquid ◽  
Ionic Liquids ◽  
Low Temperatures ◽  
Industrial Applications ◽  
Chemical Processing ◽  
Vapor Pressures ◽  
Thermal Stabilities ◽  
Packaged Goods ◽  
Consumer Packaged Goods

Abstract Ionic liquids are salts that melt at low temperatures (usually defined as less than 100 °C) and have a number of interesting properties that make them useful for industrial applications. Typical ionic liquid properties include high thermal stabilities, negligible vapor pressures, wide liquidus ranges, broad electrochemical windows, and unique solvation properties. Furthermore, the potential combinations of cations and anions provide nearly unlimited chemical tunability. This article will describe the diverse industrial uses of ionic liquids and how their unique properties are leveraged, with examples ranging from chemical processing to consumer packaged goods.

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