Plasma-assisted multi-layered coating towards improved gas permeation properties for organosilica membranes

Preparation of carbon membranes has rapidly attracted much attention in gas separation processes because of thermal and chemical stabilities and exhibit superior separation performance. Carbon hollow fiber membranes (CHFM)s derived from polymer blend of polyetherimide (PEI) and polyvinylpyrrolidone (PVP) were extensively prepared through stabilization under air atmosphere followed by carbonization under N2 atmosphere. The effects of the stabilization temperature on the morphological structure and gas permeation properties were investigated by means of scanning electron microscopy (SEM) and single gas permeation system. Experimental results indicate that the transport mechanism of small gas molecules of N2, CO2, and CH4 is dominated by the molecular sieving effect. Based on morphological structure and gas permeation properties, an optimum stabilization condition for the preparation of CHFM derived from PEI/PVP was found at 300°C under air atmosphere. The selectivity of about 55 and 41 for CO2/CH4 and CO2/N2, respectively, were obtained.

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Poly(1-trimethylsilyl-1-propyne)-Based Hybrid Membranes: Effects of Various Nanofillers and Feed Gas Humidity on CO2 Permeation

Membranes ◽

10.3390/membranes8030076 ◽

2018 ◽

Vol 8 (3) ◽

pp. 76 ◽

Cited By ~ 13

Author(s):

Zhongde Dai ◽

Vilde Løining ◽

Jing Deng ◽

Luca Ansaloni ◽

Liyuan Deng

Keyword(s):

Gas Permeation ◽

Polymeric Membranes ◽

Inorganic Nanoparticles ◽

Co2 Separation ◽

Separation Performance ◽

Hybrid Membranes ◽

Mixed Gas ◽

Separation Membrane ◽

Separation Performances ◽

Permeation Properties

Poly(1-trimethylsilyl-1-propyne) (PTMSP) is a high free volume polymer with exceptionally high gas permeation rate but the serious aging problem and low selectivity have limited its application as CO2 separation membrane material. Incorporating inorganic nanoparticles in polymeric membranes has been a common approach to improve the separation performance of membranes, which has also been used in PTMSP based membrane but mostly with respect to tackling the aging issues. Aiming at increasing the CO2 selectivity, in this work, hybrid membranes containing four types of selected nanofillers (from 0 to 3D) were fabricated using PTMSP as the polymer matrix. The effects of the various types of nanofillers on the CO2 separation performance of the resultant membranes were systematically investigated in humid conditions. The thermal, chemical and morphologic properties of the hybrid membranes were characterized using TGA, FTIR and SEM. The gas permeation properties of the hybrid membranes were evaluated using mixed gas permeation test with the presence of water vapour to simulate the flue gas conditions. Experiments show that the addition of different fillers results in significantly different separation performances; The addition of ZIF-L porous 2D filler improves the CO2/N2 selectivity at the expenses of CO2 permeability, while the addition of TiO2, ZIF-7 and ZIF-8 increases the CO2 permeability but the CO2/N2 selectivity decreases.

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Gas Permeation Properties of High-Silica CHA-Type Zeolite Membrane

Membranes ◽

10.3390/membranes11040249 ◽

2021 ◽

Vol 11 (4) ◽

pp. 249

Author(s):

Yasuhisa Hasegawa ◽

Chie Abe ◽

Mayumi Natsui ◽

Ayumi Ikeda

Keyword(s):

Molecular Size ◽

Gas Permeation ◽

Zeolite Membrane ◽

Type Zeolite ◽

High Silica ◽

Separation Of Co2 ◽

Α Al2o3 ◽

Separation Performances ◽

Molecular Sieving ◽

Permeation Properties

The polycrystalline CHA-type zeolite layer with Si/Al = 18 was formed on the porous α-Al2O3 tube in this study, and the gas permeation properties were determined using single-component H2, CO2, N2, CH4, n-C4H10, and SF6 at 303–473 K. The membrane showed permeation behavior, wherein the permeance reduced with the molecular size, attributed to the effect of molecular sieving. The separation performances were also determined using the equimolar mixtures of N2–SF6, CO2–N2, and CO2–CH4. As a result, the N2/SF6 and CO2/CH4 selectivities were as high as 710 and 240, respectively. However, the CO2/N2 selectivity was only 25. These results propose that the high-silica CHA-type zeolite membrane is suitable for the separation of CO2 from CH4 by the effect of molecular sieving.

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Miscible blend polyethersulfone/polyimide asymmetric membrane crosslinked with 1,3-diaminopropane for hydrogen separation

Journal of Polymer Engineering ◽

10.1515/polyeng-2020-0316 ◽

2021 ◽

Vol 0 (0) ◽

Author(s):

Nur’ Adilah Abdul Nasir ◽

Ameen Gabr Ahmed Alshaghdari ◽

Mohd Usman Mohd Junaidi ◽

Nur Awanis Hashim ◽

Mohamad Fairus Rabuni ◽

...

Keyword(s):

Separation Efficiency ◽

Chemical Characterization ◽

Gas Permeation ◽

Separation Performance ◽

Membrane Composition ◽

Asymmetric Membrane ◽

Wet Phase Inversion ◽

Pair Performance ◽

Improved Performance ◽

Physical And Chemical

Abstract Efficient purification technology is crucial to fully utilize hydrogen (H2) as the next generation fuel source. Polyimide (PI) membranes have been intensively applied for H2 purification but its current separation performance of neat PI membranes is insufficient to fulfill industrial demand. This study employs blending and crosslinking modification simultaneously to enhance the separation efficiency of a membrane. Polyethersulfone (PES) and Co-PI (P84) blend asymmetric membranes have been prepared via dry–wet phase inversion with three different ratios. Pure H2 and carbon dioxide (CO2) gas permeation are conducted on the polymer blends to find the best formulation for membrane composition for effective H2 purification. Next, the membrane with the best blending ratio is chemically modified using 1,3-diaminopropane (PDA) with variable reaction time. Physical and chemical characterization of all membranes was evaluated using field emission scanning electron microscope (FESEM), X-ray diffraction (XRD), and Fourier transform infrared (FTIR). Upon 15 min modification, the polymer membrane achieved an improvement on H2/CO2 selectivity by 88.9%. Moreover, similar membrane has demonstrated the best performance as it has surpassed Robeson’s upper bound curve for H2/CO2 gas pair performance. Therefore, this finding is significant towards the development of H2-selective membranes with improved performance.

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

Nanomaterials ◽

10.3390/nano11030582 ◽

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.

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Design and Gas Separation Performance of Imidazolium Poly(ILs) Containing Multivalent Imidazolium Fillers and Crosslinking Agents

Polymers ◽

10.3390/polym13091388 ◽

2021 ◽

Vol 13 (9) ◽

pp. 1388

Author(s):

Kathryn E. O’Harra ◽

Emily M. DeVriese ◽

Erika M. Turflinger ◽

Danielle M. Noll ◽

Jason E. Bara

Keyword(s):

Small Molecules ◽

Crosslinking Agent ◽

Gas Permeation ◽

Polymeric Matrix ◽

Separation Performance ◽

Ionic Polymers ◽

Co2 Solubility ◽

Imidazolium Cations ◽

Crosslinking Agents ◽

Gas Separation Performance

This work introduces a series of vinyl-imidazolium-based polyelectrolyte composites, which were structurally modified via impregnation with multivalent imidazolium-benzene ionic liquids (ILs) or crosslinked with novel cationic crosslinkers which possess internal imidazolium cations and vinylimidazolium cations at the periphery. A set of eight [C4vim][Tf2N]-based membranes were prepared via UV-initiated free radical polymerization, including four composites containing di-, tri-, tetra-, and hexa-imidazolium benzene ILs and four crosslinked derivatives which utilized tri- and tetra- vinylimidazolium benzene crosslinking agents. Structural and functional characterizations were performed, and pure gas permeation data were collected to better understand the effects of “free” ILs dispersed in the polymeric matrix versus integrated ionic crosslinks on the transport behaviors of these thin films. These imidazolium PIL:IL composites exhibited moderately high CO2 permeabilities (~20–40 Barrer), a 4–7× increase relative to corresponding neat PIL, with excellent selectivities against N2 or CH4. The addition of imidazolium-benzene fillers with increased imidazolium content were shown to correspondingly enhance CO2 solubility (di- < tri- < tetra- < hexa-), with the [C4vim][Tf2N]: [Hexa(Im+)Benz ][Tf2N] composite showing the highest CO2 permeability (PCO2 = 38.4 Barrer), while maintaining modest selectivities (αCO2/CH4 = 20.2, αCO2/N2 = 23.6). Additionally, these metrics were similarly improved with the integration of more ionic content bonded to the polymeric matrix; increased PCO2 with increased wt% of the tri- and tetra-vinylimidazolium benzene crosslinking agent was observed. This study demonstrates the intriguing interactions and effects of ionic additives or crosslinkers within a PIL matrix, revealing the potential for the tuning of the properties and transport behaviors of ionic polymers using ionic liquid-inspired small molecules.

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