Gas Separation Membrane Materials Research Articles

Thermal rearrangement in thermal cascade reaction polymers via ortho-carbonate ester functionalization of polyimides and their gas separation performance

Thermal Rearrangement Polymers have a strong potential regarding to gas separation membrane materials, especially for the purification of methane containing gas streams, due to their inter-connected bottleneck-type pores. However, most TR polymers reveal high permeabilities and high conversions only at high temperatures of 450 °C. Our study demonstrates a method to enhance the permeability at lower annealing temperatures by tailoring the thermally triggered decomposition and reaction cascade via modification and temperature protocol. In this study a set of seven carbonate ester modifications was prepared and thermo-analytically studied by means of DSC and TGA-FTIR on-line analysis combined with structure determination methods and quantum mechanical simulations. Two decarboxylative alkyl-transfer reaction mechanisms were formulated for the decomposition reaction of the carbonate ester group. A correlation of the size and branching of the carbonate ester connected alkyl group and its effect on the film properties and gas separation performance was studied. High polyimide to polybenzoxazole conversions were determined for the modified polymers and a 2008 upper bound performance was obtained for all materials, after annealing at 400 °C. Furthermore, the ethyl carbonate ester (ECO3PI-1) polymer entered the target zone above an ideal selectivity of CO2/CH4 of 30 after aging, making it an attractive membrane material.

High-flux corrugated PDMS composite membrane fabricated by using nanofiber substrate

Polydimethylsiloxane (PDMS) is a benchmarked membrane material for pervaporation, gas separation, and nanofiltration, remaining challenges in achieving high-flux membrane. Herein, we proposed a high-flux PDMS membrane with corrugated morphology realized by simply coating PDMS solution on nanofiber substrate. It was demonstrated that the electrospun nanofiber substrate with highly interconnected and porous structures could generate a corrugated PDMS membrane layer with highly increased surface area and meanwhile remarkably reduce transport resistance of the membrane. By optimizing the pore structure of nanofiber substrate and reducing the membrane thickness to sub-micrometer, the corrugated PDMS membrane exhibited up to one order of magnitude higher permeation flux compared with state-of-the-arts PDMS membranes for pervaporation separation of ethanol/water mixtures. Specifically, using a 5 wt% ethanol/water mixture as feed at 60 °C, a total flux of 8.7 kg m −2 h −1 and a separation factor of 7.2 were obtained. This work provides a facile approach to develop nanostructured membranes with highly enhanced transport properties. ➢ Corrugated membrane surface is created by coating PDMS on nanofiber substrate ➢ Highly porous and interconnected nanofiber substrate reduce transport resistance ➢ Corrugated PDMS/nanofiber membrane show significantly enhanced pervaporation flux

Tröger’s Base Polyimide Hybrid Membranes by Incorporating UiO-66-NH2 Nanoparticles for Gas Separation

Hybrid membranes based on the Tröger’s base polyimide (PI-TB) as a rigid microporous polymer matrix containing a kinked N-heterocycle and a kind of CO2-philic porous UiO-66-NH2 nano-filler were successfully fabricated for gas separation. This new hybrid membrane exhibits good interfacial compatibility through hydrogen bonds and charge transfer interactions between the PI-TB matrix and the UiO-66-NH2 nano-filler, thus enabling a relatively high loading and well dispersion of nano-filler. Meanwhile, the as-synthesized UiO-66-NH2 nanoparticles increase the average inter-chain spacing distance of PI-TB by interfering with the packing of polymer chains and thus providing additional transport pathways in the membranes. The pure gas permeabilities and ideal selectivities for CO2/CH4, CO2/N2, and O2/N2 systems were investigated at 35 °C and a feed pressure of 1 bar. Among them, the hybrid membrane containing 30 wt % UiO-66-NH2 exhibits the optimal gas separation performance with enhanced permeabilities of CO2 and O2 increased by ∼166% (415 and 92.3 Barrer, respectively) while maintaining comparable CO2/CH4, CO2/N2, and O2/N2 gas pair selectivities (25.0, 18.9, and 4.2, respectively) with the pristine PI-TB membrane. This work enriched the studies on the post-modification of PI-TB as a potential candidate membrane material for gas separation.

Multi-scale computational screening to accelerate discovery of IL/COF composites for CO2/N2 separation

Covalent organic frameworks (COFs) have emerged as novel adsorbents and membranes for gas separation. Incorporation of ionic liquids (ILs) into COFs is important to exceed the current performance limits of COFs. However, synthesis and testing of a nearly unlimited number of IL/COF combinations are simply impractical. Herein, we used a multi-scale computational screening approach combining COnductor-like Screening MOdel for Realistic Solvents (COSMO-RS) method, Grand Canonical Monte Carlo (GCMC), molecular dynamics (MD) simulations, and density functional theory (DFT) calculations to unlock both the adsorption- and membrane-based CO2/N2 separation performances of IL/COF composites. Several adsorbent and membrane performance assessment metrics including selectivity, working capacity, regenerability, adsorbent performance score, and permeability were computed. Our results revealed that IL incorporation into COFs significantly improves CO2/N2 adsorption selectivities (from 12 to 26) and adsorbent performance scores (from 3.7 to 12 mol/kg). By performing DFT calculations, the nature of the interactions between CO2, N2, COFs, and their IL-incorporated composites was evaluated. The high CO2 selectivity of IL/COF composites was attributed to the cooperative intermolecular effects induced by the COF and the IL. Finally, IL/COF membranes were studied, and results showed that they achieve significantly higher CO2 permeabilities (2.4 × 104–9.4 × 105 Barrer) than polymeric and zeolite membranes with comparable selectivities (up to 15.7). This shows a great promise of IL/COF composites to replace the conventional membrane materials for flue gas separation. Our results will be useful in accelerating the experimental efforts to design new IL/COF composites that can achieve high-performance CO2 separation.

Poly(ethylene glycol) Diacrylate Iongel Membranes Reinforced with Nanoclays for CO2 Separation.

Despite the fact that iongels are very attractive materials for gas separation membranes, they often show mechanical stability issues mainly due to the high ionic liquid (IL) content (≥60 wt%) needed to achieve high gas separation performances. This work investigates a strategy to improve the mechanical properties of iongel membranes, which consists in the incorporation of montmorillonite (MMT) nanoclay, from 0.2 to 7.5 wt%, into a cross-linked poly(ethylene glycol) diacrylate (PEGDA) network containing 60 wt% of the IL 1-ethyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([C2mim][TFSI]). The iongels were prepared by a simple one-pot method using ultraviolet (UV) initiated polymerization of poly(ethylene glycol) diacrylate (PEGDA) and characterized by several techniques to assess their physico-chemical properties. The thermal stability of the iongels was influenced by the addition of higher MMT contents (>5 wt%). It was possible to improve both puncture strength and elongation at break with MMT contents up to 1 wt%. Furthermore, the highest ideal gas selectivities were achieved for iongels containing 0.5 wt% MMT, while the highest CO2 permeability was observed at 7.5 wt% MMT content, due to an increase in diffusivity. Remarkably, this strategy allowed for the preparation and gas permeation of self-standing iongel containing 80 wt% IL, which had not been possible up until now.

Novel Polymers with Ultrapermeability Based on Alternately Planar and Contorted Units for Gas Separation

Polymers of intrinsic microporosity (PIMs) have been the potential candidates as gas separation membrane materials, because of their high permeability and good processing. Here, three PIMs (PIM-ABA...

Fabrication of a flexible hydrogen-bonded organic framework based mixed matrix membrane for hydrogen separation

Hydrogen-bonded Organic Frameworks (HOFs), consisting of H-bonds and strong π-π interaction, are novel materials with ordered and flexible porous frameworks. With permanent porosity, HOFs are considered as a promising material for large-scale preparation of gas separation membranes owing to their superior stability. Herein, we report a novel HOF-based Mixed-Matrix Membrane (MMM) termed HOF-30@PI by blending HOF-30 crystals with PolyImide (PI) for hydrogen separation. The added amount of HOF-30 has a crucial effect on gas separation performance. A HOF-30@PI MMM with 10 wt% HOF-30 exhibits a high hydrogen permeability of 428.1 barrer and H2/CH4 separation factor of 61.7. Owing to good compatibility and the proper pore size of HOF-30 with 4 Å, the HOF-30@PI MMM shows excellent stability and has no obvious separation performance degradation after a 240 h testing. Interestingly, HOF-30@PI MMM has a certain response on pressure because of its flexibility due to hydrogen bonds. Therefore, the usage of HOFs as porous fillers in MMM develops a novel way toward the tailored synthesis of advanced composite membrane materials for gas separation.

Structural engineering on copolyimide membranes for improved gas separation performance

The structural engineering and design of 6FDA/BPDA-based copolyimide membranes at a molecular level are developed to achieve advanced membrane materials with improved CO2 plasticization resistance as well as high gas separation performance. The commercially available diamine monomers with/without various electronegative groups (-CH3, –CF3 and -Cl) have been employed to prepare 6FDA/BPDA-based copolyimides via the one-step method. All of the copolyimides show excellent solubility in the common solvent, film-forming ability and thus mechanical properties. More interestingly, the intermolecular charge transfer complex (CTC) effects is finely tuned as confirmed by the fluorescence emission spectrum. The introducing of polar chloride groups in the copolyimides could significantly strengthen the CTC effects to prevent the intrusion of condensable CO2 and limit polymeric chain movements. Thus, the membrane based on the 2,2′,5,5′-tetrachlorobenzidine (e.g. 6FDA:BPDA-TSN:TCDB (1:1:1:1)) shows the best carbon dioxide (CO2) plasticization resistance and slowest physical aging without sacrificing gas separation performance versus the membrane having weak polar groups. The CO2 plasticization pressure as high as 350 psi has been observed for the 6FDA:BPDA-TSN:TCDB membrane with polar chloride groups. This value is much higher than that of the copolyimide membranes with –CH3 or –CF3 groups ranging from 100 psi to 200 psi. Moreover, this membrane shows a good gas separation performance, e.g. CO2 permeability of 45.7 barrer and CO2/CH4 ideal selectivity of 35.2 surpassing the commercial cellulose acetate and Matrimid. Such structurally defined polymer with good mechanical strength, plasticization resistance and solubility harnesses the full potential of promising gas separation membrane materials for hollow fiber spinning. This work offers structural engineering guidance for the preparation of high-performance polymers with good tolerance to CO2-induced plasticization.

Fabrication of Ultrathin Membranes Using 2D-MOF Nanosheets for Tunable Gas Separation.

Two-dimensional (2D) metal-organic frameworks (MOF) nanosheets have emerged as novel membrane materials for gas separation. However, the development of ultrathin MOF membranes with tunable separation performances is still a challenge. Herein, we developed a facile GO-assisted restacking method to fabricate defect-free membranes with monolayer Zr-BTB nanosheets. Obtained ultrathin membranes ranging from 130 nm to 320 nm show tunable separation performances and exceed the 2008 Robeson upper bound by changing the amount of nanolayers in vertical stacking direction. Furthermore, a heating filtration method was used to change the restacking process of nanosheets in the horizontal direction. As a result, H2 /CO2 selectivity can be enhanced by two times with the same membrane thickness (130 nm) and H2 permeance is almost maintained to be 7.0×10-7 mol m-2 s-1 pa-1 . This method may provide a possible way to efficiently tune the gas separation performances of MOF membranes.

Cobalt-Doped Silica Organic-Inorganic Materials by Sol-Gel Method: Preparation and Thermal Stability Calcined under N2 Atmosphere

Cobalt-doped silica organic-inorganic (Co/SiO2) materials were prepared by sol-gel technique using tetraethylorthosilicate (TEOS) and methyltriethoxysilane (MTES) as silicon precursors and Co(NO3)2·6H2O as cobalt source. The influence of calcination temperature on the microstructure of Co/SiO2 material under N2 atmosphere was discussed by X-ray Diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), energy dispersive spectrum (EDS) and thermogravimetric-differential thermogravimetric (TG-DTG) measurements. The results showed that, when calcined at N2 atmosphere, the Co element in the Co/SiO2 material exists not only as the Si-O-Co bond, but also the crystals containing the cobalt element. In the calcing process of 25 ∼ 800 °C, the crystals containing the cobalt element have successively undergone four phase transitions from Co(NO3)2·6H2O to Co3O4, CoO and elemental Co0. The Si-O-Co bonds were formed in the calcined Co/SiO2 materials. The water contact angle on the Co/SiO2 film surface achieved the maximum value of 95.6° when the calcination temperature is at 400 °C. In order to keep the hydrophobicity of Co/SiO2 membrane materials for gas separation, the optimal calcination temperature should be 350 ∼ 400 °C. The Co/SiO2 membrane material calcined at 400 °C has a larger specific surface area, pore volume and mean pore diameter than the SiO2 sample.

Metal-Organic Frameworks Corset with a Thermosetting Polymer for Improved Molecular-Sieving Property of Mixed-Matrix Membranes.

Metal-organic frameworks (MOFs) are promising materials for gas separation membranes. However, the framework flexibility affects their molecular-sieving properties. Herein, we restrict the flexibility of zeolitic imidazolate framework-7 (ZIF-7) by controlling its phase transition in mixed-matrix membranes (MMMs), relying on the so-called "space-confinement effect" of a novel thermosetting polymer, poly 2,2'-(p-oxydiphenyl)-5,5'-bibenzimidazole (OPBI) polymer. Compared with the pure OPBI membrane, the optimized membranes containing 30 wt % ZIF-7 with a narrow-pore (np) phase (ZIF-7-II) exhibited a significant improvement in H2/CO2 separation, e.g., the H2/CO2 ideal selectivity increased ∼2.8 times, surpassing the state-of-the-art upper bound of polymeric membranes and exhibited excellent stability at increased pressure and temperature (8 bar, 180 °C).

Interfacial manipulation of MOFs/polymer mixed matrix membranes for gas separations: A review

Membrane-based separation technology holds great promise to effectively address separation needs in chemical industries due to advantages in energy efficiency, scalability, and small footprint. Mixed matrix membranes based on polymer/metal organic frameworks (MOFs), which combine the ease of processability of polymer materials with the excellent adsorption characteristics of MOFs, have been widely investigated for gas separations. The preparation of gas separation membrane materials with both high flux and gas selectivity is the key to achieving efficient gas separation. Recent research results show that the permeability coefficient and gas pair selectivity of mixed matrix membrane materials are hardly improved simultaneously by adding second phase materials such as MOFs. When the loading of MOFs increases, most membranes have common problems such as particle agglomeration and non-selective interfacial defective structures, which lead to a significant decrease in separation performance. To resolve these issues, research scientists are devoted to tailoring the interfacial microstructure of mixed matrix membranes with an aim to exceed the Robeson upper limit. Many novel characterization techniques coupled with simulation studies were carried out to probe the filler dispersion behavior and interfacial structure within membranes in order to provide rules for rationally designing mixed matrix membranes. A variety of approaches have been proposed to finely tune the interfacial interaction by constructing hydrogen bonding and covalent bonding in the membranes. For example, synthesizing functionalized MOFs via mixed-linker or ligand exchange methods provides a good option to enhance interfacial adhesion within membranes. The amino groups, hydroxyl groups and other organic functional groups in MOFs have the capability to create hydrogen bonding. Moreover, these groups can preferentially adsorb specific gas molecules (such as CO2 molecules) to improve gas selectivity. Some researchers post-functionalized MOFs to graft reactive groups on their surface, incorporating them with cross-linkable polymers. Then the light/heat induced crosslinking reaction occurred within the membrane to seal its defective structure, thereby achieving a substantial improvement in membrane separation performance. The past publications on mixed matrix membranes in the decade demonstrated that the researchers have much more in-depth understanding and insights on the fabrication process, membrane morphology, and structure-property relationship of mixed matrix membrane materials. With respect to fundamental research, research scientists are committed to investigating the MOFs properties including crystal morphology, coordinated metal ion, functional groups on membrane performance. To yield high performance mixed matrix membranes, highly permeable polymers were rationally designed as the polymer matrix. However, to complement their widespread industrial application, scale-up of hollow fiber mixed matrix membranes needs to be further investigated. The membrane stability in humid gas feeds is required to be improved. It is also of importance to develop stable, cost-effective and scalable MOFs fillers. With a specific focus on interfacial manipulation of MOFs/polymer mixed matrix membranes for gas separations, this paper mainly reviewed the research progress in the fields of MOFs/polymer-based hybrid matrix membranes for gas separations. It focuses on three aspects: (1) Research progress on optimizing and characterizing the interfacial structure; (2) fundamental understanding of the influences of MOFs and polymers properties on membrane performance; (3) research progress on scale-up of mixed matrix membranes. Finally, the future development direction of mixed matrix membrane materials is proposed in order to provide research ideas for the rational design of high-performance mixed matrix membranes.

The performance of nanoporous phosphorene as membranes for separating three typical C3F7CN insulating gas decomposition products

The performance of three designed pore size phosphorene membranes for the separation of three typical fluoronitrile (C3F7CN) decomposition products, COF2, CHF3, and CF4, were investigated by using density functional theory (DFT). From the calculations, 5.66 Åwidth membrane (P12) presented 1023 order selectivity of COF2/CF4 for P12 with a 0.22 eV energy barrier. Besides, the P12 membrane kept stable COF2 separation performance within the temperature range of 300–600 K. We also found stretching P12 membrane can effectively decrease the energy barrier for CF4 passing the pores and enhance the permeability to industrial standard. When the P12 membrane was stretched 4%, the energy barrier reduced from 1.63 eV to 0.40 eV and the permeance reached to 10-9 mol m−2s−1 Pa−1. Our work indicated the porous phosphorene could be used as a potential membrane material for C3F7CN decomposition gas separation.

Effects of ionic liquid doping on gas transport properties of thermally rearranged poly(hydroxyimide)s

In this study we present a novel and simple approach to improve the gas separation performance of the thermally rearranged membranes, which involves doping the polyimide precursors (HPI) with ionic liquid (IL), and carrying out its degradation along with the conversion process to polybenzoxazole (PBO) in order to facilitate the formation of larger and /or more numerous free volumes. A series of aromatic (co)poly(hydroxyimide)s based on 6FDA and HAB/4MPD diamines in different molar ratios, as well as BPADA-HAB poly(hydroxyimide) were synthesized as the precursors to be doped with IL and thermally rearranged to PBO. The structural modifications of the precursor backbone were applied to study the impact of IL on the physical properties, thermal conversion process, as well as gas transport properties of the doped polymers with different chain rigidities. The pure and IL doped (co)polyimides and their thermally rearranged counterparts were characterized by WAXD, DSC, TGA, tensile tests, and PALS, and examined in pure gas permeation experiments. TR conversion temperature was considerably reduced by IL doping (e.g. by 126 °C). This effect depended on the precursor chemical structure and the IL content. After thermal rearrangement of the IL doped HPIs, the membrane permeability to gases increased significantly compared to the un-doped analogues (e.g. 2 fold increase for O2 permeability). The permeability increase was larger for the higher IL content and the precursor chain rigidity. This was accompanied by a relatively small loss in selectivity leading to the performance shift towards the 2008 upper bound. The differences in permeability among the samples correlated with the free volume size from PALS. In particular, a very good correlation was obtained (r2 = 0.958), when the data fitted to the Cohen-Turnbull model concerned only PBO samples with low cohesive energy density. Further studies on HPIs doped with IL with lower degradation temperatures are suggested to mitigate polymer degradation and explore this new method for the design of improved gas separation membrane materials.

Control of ZIF-7-III aspect ratio using water-in-oil microemulsion

Zeolitic imidazolate framework-7-III (ZIF-7-III), a well-known metal–organic framework (MOF), has attracted attention as gas separation membrane material. For practical realization, it is necessary to adjust the aspect ratio of ZIF-7-III particles because it can affect the gas separation performance. In this study, we demonstrate the control of the aspect ratio by changing the synthesis condition using microemulsion prepared from n-alkyltrimethylammonium bromide as a surfactant, 1-hexanol as a co-surfactant, heptane as a continuous phase, and water as a dispersed phase. When cetyltrimethylammonium bromide (CTAB) was used as surfactant, ZIF-7-III particles with particle sizes of 10–20 μm were prepared by changing the water and CTAB concentration. In synthesis using four types of surfactants, the particle size of the resultant ZIF-7-III particles increased from 7 μm to 26 μm, and the aspect ratio increased from 4.9 to 11 with an increase in the hydrophobic chain length from C12 to C18. The control of the morphology is attributed to the adsorption of surfactants on hydrophobic (001) facets of ZIF-7-III, which is currently hypothesized to be monolayer or bilayer. The supply of the reactants could be hindered further with the increase of the hydrophobic chain length of the surfactants in either cases. ZIF-7-III particles obtained in this study can be exfoliated into nanosheets, which will accelerate the development of ZIF-7-III-based molecular–sieve gas separation membranes.

Recent progress in microporous polymers from thermally rearranged polymers and polymers of intrinsic microporosity for membrane gas separation: Pushing performance limits and revisiting trade‐off lines

AbstractPolymers are promising materials for gas separation membranes. However, the trade‐off relationship between gas permeability and selectivity remains an obstacle for achieving polymer membranes that exhibit high gas permeation with desirable separation efficiency. Improving polymer microporosity is of interest in gas separation membranes to enhance gas transport behavior. Polymer modifications by (a) incorporating intrinsically microporous units and/or (b) increasing chain rigidity can enhance microporosity in conventional polymer membrane materials such as polyimides. These strategies are adopted for new classes of microporous polymers, thermally rearranged (TR) polymers, and polymers with intrinsic microporosity (PIMs), to maximize gas transport properties. Their outstanding gas separation performances have redefined the traditional trade‐off lines. This review aims to explore the advances in microporous polymers for gas separation applications. The approaches on TR polymers and PIMs to enhance their microporosity are listed, and their developments are evaluated in the context of revisiting performance limits for industrially relevant gas separation applications.

Ultrathin Two-Dimensional Membranes Assembled by Ionic Covalent Organic Nanosheets with Reduced Apertures for Gas Separation

Covalent organic frameworks (COFs) are a promising category of porous materials possessing extensive chemical tunability, high porosity, ordered arrangements at a molecular level, and considerable chemical stability. Despite these advantages, the application of COFs as membrane materials for gas separation is limited by their relatively large pore apertures (typically >0.5 nm), which exceed the sieving requirements for most gases whose kinetic diameters are less than 0.4 nm. Herein, we report the fabrication of ultrathin two-dimensional (2D) membranes through layer-by-layer (LbL) assembly of two kinds of ionic covalent organic nanosheets (iCONs) with different pore sizes and opposite charges. Because of the staggered packing of iCONs with strong electrostatic interactions, the resultant membranes exhibit features of reduced aperture size, optimized stacking pattern, and compact dense structure without sacrificing thickness control, which are suitable for molecular sieving gas separation. One of the hybrid membranes, TpEBr@TpPa-SO3Na with a thickness of 41 nm, shows a H2 permeance of 2566 gas permeation units (GPUs) and a H2/CO2 separation factor of 22.6 at 423 K, surpassing the recent Robeson upper bound along with long-term hydrothermal stability. This strategy provides not only a high-performance H2 separation membrane candidate but also an inspiration for pore engineering of COF or 2D porous polymer membranes.

Bis(phenyl)fluorene-based polymer of intrinsic microporosity/functionalized multi-walled carbon nanotubes mixed matrix membranes for enhanced CO2 separation performance

Polymers of intrinsic microporosity (PIM) as one of potential next generation membrane materials for gas separation has attracted great interests due to its ultra-permeable characteristics. Herein, a novel bis(phenyl)fluorene-based PIMs (Cardo-PIM-1) based on 9,9-bis(3,4-dihydroxyphenyl) fluorene (BDPF), 2,3,5,6-tetrafluoroterephthalonitrile (TFTPN) and spirocyclic 5,5′,6,6′-tetrahydroxy-3,3′,3,3′-tetramethylspirobisindane (TTSBI) were prepared vis dibenzodioxane polymerization reaction, and then the functionalized multi-walled carbon nanotubes (f-MWCNTs) were incorporated into Cardo-PIM-1 to fabricate mixed matrix membranes (MMMs) with solution mixing method for CO2 separation. The structure analysis indicated that the MWCNTs were cut into short ropes and the amino groups were incorporated into the nanotubes surface after treated with acid mixtures followed by ethylenediamine modification. FTIR spectroscopy and nuclear magnetic resonance (NMR) measurement confirmed the formation of Cardo-PIM-1 macromolecule. BET and positron annihilation lifetime spectroscopy (PALS) analysis exhibited that Cardo-PIM-1 contained larger pore-size distribution and fractional free volume (FFV), and preferential CO2 adsorption capacity over N2 compared with that of PIM-1. This work investigated the structure of polymer as well as the effect of nanofillers in the gas separation performance. High CO2 permeability of 2.9 × 104 Barrer with a desirable CO2/N2 separation factor of 24.2 was achieved using the MMMs with 7.5 wt% f-MWCNTs loading, which were among the best performance for CO2 separation. The Cardo-PIM-1/f-MWCNTs MMMs will provide a promising alternative in industrial flue gas separation and CO2 capture process.

Novel Inorganic Two-dimensional Materials for Gas Separation Membranes

Novel Inorganic Two-dimensional Materials for Gas Separation Membranes

Perspective on Gas Separation Membrane Materials from Process Economics Point of View

Gas separation membranes are expected to play a significant role in green house reduction, renewable energy production, and energy savings for separations. However, newly developed membrane materia...