Homogeneous and biphasic cellulose acetate/room temperature ionic liquid membranes for gas separations: Solvent and phase-inversion casting vs. supported ionic liquid membranes

Khakpay, Amir; Scovazzo, Paul; Nouranian, Sasan

doi:10.1016/j.memsci.2019.117228

Cited by 14 publications

(13 citation statements)

References 38 publications

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“…[EMIM][SCN] (purity > 99.0%, CAS 331717-63-6, molar volume = 1.52 × 10 –4 m 3 /mol, MW = 169.25 g/mol) was purchased from IOLITEC Inc. (Tuscaloosa, AL). [EMIM][SCN] has low CH 4 solubility and, hence, produces IL membranes with high selectivities for gases being separated from CH 4 . , …”

Section: Methodsmentioning

confidence: 99%

“…Next, data were recorded at 1 min intervals for 1 h to ensure the achievement of steady-state conditions. The data analysis to convert the recorded data into gas permeances and mixed-gas selectivities is detailed elsewhere. , …”

Section: Experimental Methodsmentioning

confidence: 99%

“…Recent work by Khakpay et al revealed a threefold increase in CO 2 /CH 4 selectivity for 1-ethyl-3-methylimidazolium thiocyanate ([EMIM][SCN]) confined in a porous cellulose acetate (CA) matrix versus the IL homogenously dispersed in the CA film. Previous molecular dynamics (MD) simulations of the confinement of 1-butyl-3-methylimidazolium thiocyanate ([BMIM][SCN]) in MOFs predicted order-of-magnitude differences in CO 2 /N 2 selectivity depending on the hydrophobicity of the confining surface .…”

Section: Introductionmentioning

confidence: 99%

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Effects of Ionic Liquid Nanoconfinement on the CO₂/CH₄ Separation in Poly(vinylidene fluoride)/1-Ethyl-3-methylimidazolium Thiocyanate Membranes

Rahmani

Scovazzo

Pasquinelli

et al. 2021

ACS Appl. Mater. Interfaces

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A combined experimental and molecular dynamics (MD) simulation approach was used to investigate the effects of the nanoconfinement of a highly CO2/CH4-selective ionic liquid (IL), 1-ethyl-3-methylimidazolium thiocyanate ([EMIM][SCN]), in porous poly(vinylidene fluoride) (PVDF) matrices on the gas separation performance of the resulting membranes. The observed experimental CO2/CH4 permselectivity increased by about 46% when the nominal pore diameter in PVDF, which is a measure of nanoconfinement, decreased from 450 to 100 nm, thus demonstrating nanoconfinement improvements of gas separation. MD simulations corroborated these experimental observations and indicated a suppression in the sorption of CH4 by [EMIM][SCN] when the IL nanoconfinement length decreased within the nonpolar PVDF surfaces. This is consistent with the experimental observation that the CH4 permeance through the IL confined in nonpolar PVDF is significantly less than the CH4 permeance through the IL confined in a water-wetting polar formulation of PVDF. The potential of mean force calculations further indicated that CO2 has more affinity to the nonpolar PVDF surface than CH4. Also, a charge/density distribution analysis of the IL in the PVDF-confined region revealed a layering of the IL into [EMIM]- and [SCN]-rich regions, where CH4 was preferentially distributed in the former and CO2 in the latter. These molecular insights into the nanoconfinement-driven mechanisms in polymer/IL membranes provide a framework for a better molecular design of such membranes for critical gas separation and CO2 capture applications.

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Section: Methodsmentioning

confidence: 99%

Section: Experimental Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Effects of Ionic Liquid Nanoconfinement on the CO₂/CH₄ Separation in Poly(vinylidene fluoride)/1-Ethyl-3-methylimidazolium Thiocyanate Membranes

Rahmani

Scovazzo

Pasquinelli

et al. 2021

ACS Appl. Mater. Interfaces

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“…Material optimization in this area is primarily directed towards the improved compatibility between the IL and support used. This optimization can be achieved through surface treatment (e.g., with plasma) [ 42 ], implementation of mesoporous supports with uniform pore sizes [ 34 , 45 ], and by a specific membrane preparation process [ 54 ]. The successful compatibility enhancement, as determined by Scanning Electron Microscopy with Energy Dispersive X-ray Analysis SEM-EDX and X-ray Photoelectron Spectroscopy (XPS) [ 52 , 55 ] analysis, will usually yield prolonged operation times without performance deterioration [ 37 , 56 ] or SILM weight loss [ 29 , 57 , 58 ].…”

Section: Supported Ionic Liquid Membranesmentioning

confidence: 99%

“…The successful compatibility enhancement, as determined by Scanning Electron Microscopy with Energy Dispersive X-ray Analysis SEM-EDX and X-ray Photoelectron Spectroscopy (XPS) [ 52 , 55 ] analysis, will usually yield prolonged operation times without performance deterioration [ 37 , 56 ] or SILM weight loss [ 29 , 57 , 58 ]. Alternatively, the bubble-point or breakthrough pressure measurement [ 42 , 54 ] allows a direct measurement of the critical gas pressure required to displace a gas from the porous support containing the IL. This method allows for fast product and process optimization steps during the SILM development without the necessity to perform elaborate pilot testing in a gas separation setup.…”

Section: Supported Ionic Liquid Membranesmentioning

confidence: 99%

A Review on Ionic Liquid Gas Separation Membranes

et al. 2021

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Ionic liquids have attracted the attention of the industry and research community as versatile solvents with unique properties, such as ionic conductivity, low volatility, high solubility of gases and vapors, thermal stability, and the possibility to combine anions and cations to yield an almost endless list of different structures. These features open perspectives for numerous applications, such as the reaction medium for chemical synthesis, electrolytes for batteries, solvent for gas sorption processes, and also membranes for gas separation. In the search for better-performing membrane materials and membranes for gas and vapor separation, ionic liquids have been investigated extensively in the last decade and a half. This review gives a complete overview of the main developments in the field of ionic liquid membranes since their first introduction. It covers all different materials, membrane types, their preparation, pure and mixed gas transport properties, and examples of potential gas separation applications. Special systems will also be discussed, including facilitated transport membranes and mixed matrix membranes. The main strengths and weaknesses of the different membrane types will be discussed, subdividing them into supported ionic liquid membranes (SILMs), poly(ionic liquids) or polymerized ionic liquids (PILs), polymer/ionic liquid blends (physically or chemically cross-linked ‘ion-gels’), and PIL/IL blends. Since membrane processes are advancing as an energy-efficient alternative to traditional separation processes, having shown promising results for complex new separation challenges like carbon capture as well, they may be the key to developing a more sustainable future society. In this light, this review presents the state-of-the-art of ionic liquid membranes, to analyze their potential in the gas separation processes of the future.

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Self‐Assembled Facilitated Transport Membranes with Tunable Carrier Distribution for Ethylene/Ethane Separation

Dou

Wang

et al. 2021

Adv Funct Materials

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Facilitated transport membranes (FTMs) are a forward-looking technology and have triggered revolutions in many energy-intensive gas separations. However, the precise manipulation of carrier distribution within FTMs, as well as the visualization of membrane structure at the nanoscale, has never been reported. Herein, FTMs are constructed with tunable carrier distribution by a facile ion/molecule self-assembly of protic ionic liquid crystal salts (PILSs), polyol, and ethylene-transport carrier for highly efficient sub-angstrom scale ethylene/ ethane (0.416nm/0.443nm) separation. The elaborate regulation of non-covalent interactions by optimizing the ion/molecule compositions within membrane confers the bi-continuous nanostructure of FTMs, resulting in the formation of successive carrier wires and enormous 3D interconnected ethylene transport pathways, which is verified and visualized by molecular dynamics simulations and synchronous small-and wide-angle X-ray scattering (SWAXS). The as-designed FTMs manifest simultaneously super-high selectivity, excellent ethylene permeance, and robust long-term stability, which exceeds previously reported ethylene/ethane separation membranes. This study clearly draws the first picture of carrier distribution within FTMs, and deep insight into membrane structure will shed light on the design of high-performance separation membranes for energy-intensive gas separations.

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Homogeneous and biphasic cellulose acetate/room temperature ionic liquid membranes for gas separations: Solvent and phase-inversion casting vs. supported ionic liquid membranes

Cited by 14 publications

References 38 publications

Effects of Ionic Liquid Nanoconfinement on the CO₂/CH₄ Separation in Poly(vinylidene fluoride)/1-Ethyl-3-methylimidazolium Thiocyanate Membranes

Effects of Ionic Liquid Nanoconfinement on the CO₂/CH₄ Separation in Poly(vinylidene fluoride)/1-Ethyl-3-methylimidazolium Thiocyanate Membranes

A Review on Ionic Liquid Gas Separation Membranes

Self‐Assembled Facilitated Transport Membranes with Tunable Carrier Distribution for Ethylene/Ethane Separation

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Homogeneous and biphasic cellulose acetate/room temperature ionic liquid membranes for gas separations: Solvent and phase-inversion casting vs. supported ionic liquid membranes

Cited by 14 publications

References 38 publications

Effects of Ionic Liquid Nanoconfinement on the CO2/CH4 Separation in Poly(vinylidene fluoride)/1-Ethyl-3-methylimidazolium Thiocyanate Membranes

Effects of Ionic Liquid Nanoconfinement on the CO2/CH4 Separation in Poly(vinylidene fluoride)/1-Ethyl-3-methylimidazolium Thiocyanate Membranes

A Review on Ionic Liquid Gas Separation Membranes

Self‐Assembled Facilitated Transport Membranes with Tunable Carrier Distribution for Ethylene/Ethane Separation

Contact Info

Product

Resources

About

Effects of Ionic Liquid Nanoconfinement on the CO₂/CH₄ Separation in Poly(vinylidene fluoride)/1-Ethyl-3-methylimidazolium Thiocyanate Membranes

Effects of Ionic Liquid Nanoconfinement on the CO₂/CH₄ Separation in Poly(vinylidene fluoride)/1-Ethyl-3-methylimidazolium Thiocyanate Membranes