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A membrane-aerated biofilm reactor (MABR) combines membrane technology with biofilm processes and has unique advantages in the treatment of organic wastewater and volatile wastewater. The common membranes for MABR systems usually have relatively uneven pore structures and low bubble point pressure, resulting in unsatisfactory O2 utilization and wastewater treatment efficiency. In this work, polydimethylsiloxane (PDMS) and UiO-66 (a Zr-based metal organic framework) were coated on the surface of a commercial polypropylene (PP) hollow fiber membrane to prepare oxygen-rich MABR membranes and modules, which showed an attractive O2 utilization rate and wastewater treatment efficiency. The bubble points of the PDMS and PDMS-UiO-66 membranes were significantly higher than those of the PP membranes, and the PDMS-UiO-66 membranes had better oxygen enrichment capacity and biological affinity. The optimal PDMS-UiO-66 membrane modules had an O2 permeance of 31.65 GPU (1 GPU = 3.35 × 10−10 mol m−2 s−1 Pa−1), with O2/N2 selectivity of 2.21. The membrane hanging effect and processing capacity for domestic sewage were greatly improved. This study may provide insights and guidelines to fabricate porous mixed matrix membranes and modules in the industry for MABR. The developed products are expected to be applied in the actual separation process. HIGHLIGHTS PDMS and PDMS-UiO-66 were coated on the PP support to prepare O2-rich MABR membranes and modules.; With UiO-66 loading, the module has a higher O2/N2 separation performance, a rougher and more hydrophilic membrane surface.; The PDMS-UiO-66 membrane module exhibits a good biofilm hanging effect and high NH4+-N removal performance.;

An effective strategy to optimize the gas separation performance of hyperbranched polyimide (hyper‐PI) membranes by tuning their average cavity sizes is reported. Triphenylamine (TAPA) and 4,4′‐(Hexafluoroisopropylidene) diphthalic anhydride (6FDA) were used to prepare the hyper‐PI membrane, and the transformation in free fraction volume (FFV) was realized by the addition of an extra B2‐type monomer, 2,4,6‐Trimethylbenzene‐1,3‐diamine (DAM). In hyperbranched networks, DAM, in conjunction with 6FDA, generates longer linear parts and reduces the density of dendritic architectures formed by TAPA. The conformational freedom of hyperbranched TAPA‐6FDA is restricted, and chain packing is hindered. The ratio of DAM:TAPA predominantly influences both the average cavity sizes and the FFVs of the membranes, leading to the variation in gas permeabilities. DAM5:TAPA1‐6FDA shows the best performance in both O2/N2 and CO2/N2 separations. [ABSTRACT FROM AUTHOR]

Mixed matrix membranes (MMMs) containing metal–organic frameworks (MOFs) have been an emerging and promising membrane technology to contribute to different gas separation applications including carbon dioxide (CO2) and oxygen (O2) separation, because of their large surface areas and distinctive gas adsorption features. In this work, the fabrication process of Polydimethylsiloxane (PDMS)-based MMMs was reported, in which 0.5 to 2 wt.% of each type of (Cu, Ni)-based MOF-74 variants were incorporated into a PDMS matrix in order to achieve high CO2/N2, O2/N2, and CO2/O2 separation efficiency. These MMMs and their nanofillers (MOF-74) were extensively characterized using scanning electron microscopy (SEM) along with Energy Dispersive X-Ray (EDX) mapping, X-ray Diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), a single gas permeation testing system, and an ultimate tensile strength testing (UTS) unit in order to gain insight into their properties in relation to their gas separation performance. The 1 wt.% of both (Cu and Ni)-MOF-74@PDMS were selected as the most optimum MMMs due to their uniform morphology and enhanced tensile strength, which exhibited high CO2 permeabilities of 4432 Barrer (37.9% increase) and 4288 Barrer (33.5% increase), respectively. Furthermore, in the case of 1 wt.% Ni-MOF-74@PDMS, the CO2/N2, O2/N2, and CO2/O2 selectivities were also enhanced to 36.2 (141.6% increase), 3.2 (21.9% increase), and 11.25 (98.1% increase), respectively. While, in the case of 1 wt.% Cu-MOF-74@PDMS the CO2/N2 and O2/N2 selectivities showed an increment up-to 94.7 (531.5% increase) and 6.47 (145% increase), respectively, Whereas, at 0.5 wt.%, Cu-MOF-74@PDMS showed the best CO2/O2 selectivity of 25.26 (344.7% increase). [ABSTRACT FROM AUTHOR]

A high-performance MOF-based mixed matrix membrane was constructed via incorporating o-BA modified ZIF-8 nanoparticles into PIM-1 matrices. The synergistic effect of molecular sieving and adsorption inhibition of the obtained membrane offers good chance for efficient mixed O 2 /N 2 separation. [Display omitted] • High-performance MOF-based MMMs were developed for mixed O 2 /N 2 separation. • The synergistic effect of size sieving and adsorption inhibition promotes excellent separation performance. • The modification of o-CB on the outer surface of ZIF-8 contributes to the improved interfacial compatibility. • The optimal membrane exhibits a mixed O 2 /N 2 selectivity of 8.9 with O 2 permeability of 796.5 Barrer. Oxygen/nitrogen (O 2 /N 2) separation is of great importance but faces huge challenges owing to their similar molecular size and close polarity. In this work, we construct a polymer of intrinsic microporosity (PIM-1) based mixed matrix membrane (MMM) for efficient O 2 /N 2 separation by using ZIF-8 as the sieving filler along with surface modification of o-carborane (o-CB) to strengthen selective N 2 adsorption fixation as well as polymer-filler interfaces. Markedly, the o-CB on the outer surface of ZIF-8 not only affords the requisite interfacial compatibility in molecular sieving MMMs, but also increases the diffusion difference between O 2 and N 2 by the preferential adsorption with N 2 molecules. This synergistic effect of molecular sieving and adsorption inhibition achieves efficient O 2 /N 2 diffusion differential separation. As expected, the optimal membrane with o-CB-ZIF-8 loading of 35 wt% exhibits an O 2 permeability of 796.5 Barrer and a mixed O 2 /N 2 selectivity of 8.9 with O 2 /N 2 (20:80, vol.) mixtures, exceeding the latest 2015 upper bound limits. Moreover, the according membrane module with o-CB-ZIF-8 loading of 20 wt% also displays moderate O 2 permeability of 391.7 Barrer and O 2 /N 2 selectivity of 5.5 under pressure of 1 bar. This work may provide a feasible platform for designing high-performance MOF-based membranes in air separations. [ABSTRACT FROM AUTHOR]

The incorporation of functionalized graphene oxide (GO) in mixed matrix membrane (MMM) is expected to greatly increase the permeability and selectivity for O2/N2 separation. In the present study, GO functionalized with 3- (Trimethoxysilyl) propyl methacrylate (TMOPMA) was used as inorganic filler and incorporated in to a PVC/pAMPS based MMM to increase the separation efficiency. Membranes of different compositions were synthesized and the best morphology was achieved with 0.5 g of PVC, 1.0 g of pAMPS and 0.015 g of filler. The synthesized membrane and inorganic filler were characterized using SEM, EDS, FTIR, Raman and XRD spectroscopy. Moreover, the gas permeation studies were performed to check the separation factor of synthesized membrane for O2/N2. The maximum permeability achieved for O2 and N2 was 4097 and 3373 barrers, respectively at 5 bar pressure. For the selectivity, a gradual increasing trend was observed with the increase in permeability. The maximum selectivity achieved was 1.215 at 5 bar pressure. The results revealed an increasing trend in selectivity with the increase in permeability of gases across the membrane with the increase in feed gas pressure.

This study deals with the fabrication of hollow fiber mixed matrix membrane, and evaluation its performance toward O2/N2 gas separation. Asymmetric mixed matrix PES membranes with embedded ZIF-8 nanoparticles as the dispersed phase were prepared by dry–wet-spinning method. The morphological, thermal, and chemical properties of spun fibers were characterized by FESEM, EDS mapping, TGA, and FTIR analysis. Effect of spinning parameters and dope composition including bore fluid/ dope flow rate ratio (0.5, 1, 2), bore fluid composition (Water/NMP: 100:0, 50:50, 75:25), polymer concentration (20%, 25%, 30%), and ZIF-8 concentration (0–40%wt at seven stages) were investigated on the morphology of hollow fiber MMMs. In addition, pure O2 and N2 gas permeation through the fibers was tested in order to figure out the effect of different ZIF-8 content embedded in hollow fiber MMMs on the ideal selectivity of O2/N2 separation. Results revealed that the maximum separation performance (ideal selectivity of 5.25) was attained at the ZIF-8 weight content of 10%. The improved performance of hollow fiber MMMs over O2/N2 gas separation could be related to increment in both sieving and solubility selectivity. [ABSTRACT FROM AUTHOR]

• Review the macromolecular structures of microporous polymers for O 2 /N 2 separation. • Explore the aging behavior of innovative microporous materials. • Review the impacts of thermal treatments to reset microporosity and O 2 /N 2 separation. • Investigate the application of polymers and process design in membrane systems. This review summarizes the performance of recently developed microporous polymers for practical industrial O 2 /N 2 separations. The macromolecular design of innovative polymers of intrinsic porosity and derivatives is evaluated from the perspective of pore structure regulation for their outstanding O 2 /N 2 separation performance. The structural groups that could fine-tune the free volume elements are examined to discern the promising moiety and architectures to improve size-based sieving. The long-term aging behaviors of the state-of-the-art macromolecules are also screened to explore the impacts of improved pore/free volume configuration. The strategies using thermal treatments to reset the structure of microporosity are inspected for their potential to improve the gas permeability or enhance size-specific molecular sieving, including the thermal rearrangement of polymeric membranes and pyrolyzed carbon molecular membranes using pre-crosslinked precursors and PIM-derived precursors. Membrane process design and optimization are summarized to evaluate the prospects of these novel membrane materials for large-scale industrial applications. [ABSTRACT FROM AUTHOR]

Membrane separation technology has broad application prospects in O 2 /N 2 separation, and improving the permselectivity of membranes remains a key problem to be solved. O 2 and N 2 have different magnetic properties and can be separated by magnetism. In addition, coupling magnetic separation with the use of a molecular sieve supported by metal-organic frameworks (MOFs) could further enhance the separation ability. In this work, a magnetic core-shell MOF (Fe 3 O 4 @ZIF-8) was prepared as a filler, and the impacts of the Fe 3 O 4 @ZIF-8 morphology, loading, channel magnetic properties and ordered arrangement on membrane O 2 /N 2 selectivity were evaluated. To establish a magnetic-sieving O 2 permeation channel, the preparation process was carried out in a magnetic field so that the fillers in the membrane were arranged orderly. Due to the synergistic impact of the structurally ordered MOF channel and magnetism, the gas transport performance of the resulting magnetic mixed matrix membranes (MMMs) was substantially improved. Therefore, the O 2 permeability and O 2 /N 2 selectivity of the 15 wt%Fe 3 O 4 @ZIF-8-8/Pebax MMMs reached 194 Barrer and 11.97, respectively. This study not only presents a novel approach for creating high-performance O 2 /N 2 membranes but also plays a leading role in the development of magnetism-controlled multiscale (magnetic core-shell and filler-ordered) membrane structural engineering. [Display omitted] • Offering a new mechanism "magnetic sieving" to construct O 2 preferential transmission channels for O 2 /N 2 separation. • Preparing core-shell MOF with magnetic core and sieving MOF shell. Then, arranging the core-shell MOF by a magnetic field during the membrane preparation process to achieve a structurally ordered arrangement. • Investigating the effects of core-shell structure on the magnetic sieving mechanism and the effects of magnetic field on the filler arrangement to optimize the membrane structure. • The optimal membranes exhibited high O 2 permeability and O 2 /N 2 selectivity, showing great potential in the field of O 2 separation. [ABSTRACT FROM AUTHOR]

Due to their large surface areas and unique gas adsorption properties, mixed‐matrix membranes (MMMs) with metal–organic frameworks (MOFs) have been extensively studied in relation to various gas separations. In the present paper, we report the quick synthesis of MOF‐74 (M = Mg, Mn, Co, Ni) nanocrystals by microwave reactions and the fabrication of MMMs for use in CO2/N2 and O2/N2 separation. The scanning electron microscopy and energy dispersive X‐ray spectroscopy analysis revealed the homogenous distribution of the MOF‐74 nanocrystals within the polydimethylsiloxane (PDMS). The single gas permeation experiments showed the enhanced CO2/N2 and O2/N2 selectivity by adding the MOF‐74 nanocrystals to the PDMS. This enhanced CO2/N2 and O2/N2 selectivity may be due to the affinity of CO2 and O2 toward the Lewis acidic sites of the MOF‐74. [ABSTRACT FROM AUTHOR]

This study revealed, a thorough investigation of coagulation residence time effects on the morphology, crystallinity, mechanical properties and oxygen (O2), nitrogen (N2) gas transport behaviour of asymmetric membranes prepared through PVA/water/THF ternary system using non-solvent induced phase separation method. For this purpose PVA asymmetric membranes were fabricated at different coagulation residence of 3–24 h and then evaluated using various analytical techniques. The scanning electron microscopy was utilised to observe membrane morphologies to determine the membrane matrix structure, pore size distribution and bi-layer thickness ratio. X-ray diffraction was employed to examine the crystallinity of membranes. The variation in overall porosity and mechanical characteristics were investigated through gravimetric based analysis and universal testing machine respectively. Whereas, O2 and N2 gas transport behaviour of asymmetric membranes was recorded using gas permeation testing unit. The results showed that different sponge type, interconnected porous membranes, having thin durable dense layer morphology were obtained by varying residence time of coagulation process at constant temperature and concentration. A shorter residence time favoured the formation of single chain porous network having small pores size (1–2 μm) with porosity of 56.31% and thicker dense layer, having low O2 gas permeation rate and high mechanical characteristics such as tensile strength and elongation at break. However, a long residence time in coagulation bath facilitated the formation of double chain more porous network having pores size distribution between 2 and 3 μm with porosity of 75.52% and thinner dense layer, having high O2 gas permeation rate. The tensile strength of membranes is high in-spite of higher porosity and lower thickness of dense layer. [ABSTRACT FROM AUTHOR]

Zeolite 5A with particle sizes of 100 nm and 1 μm were synthesized and leveraged as filler materials in carbon molecular sieve membranes (CMSMs) using Matrimid® 5218 as the polymeric precursor. Our results show that nanosized zeolite 5A fillers are capable of creating substantially improved CO2 and O2 permeability as compared to the large-sized zeolite 5A at 1 μm, owing to an increase in interfacial surface areas between the filler and carbon matrix. Accordingly, the mixed-matrix CMSMs with 20 wt% loading of nanosized zeolite 5A at 100 nm demonstrated up to 2 orders of magnitude higher permeability than the unfilled CMSM, which not only compensated for the marginal drop in membrane selectivity (between 34 to 41%), but also resulted in performances that transcend the 2008 Robeson upper bound for CO2/CH4 separation. From a different perspective, the effectiveness of the fillers at different loadings was also confirmed using a filler enhancement index, Findex, which is a new composite rating that accounts for both permeability and selectivity enhancements. Our evaluations showed that nanosized zeolite 5A fillers at 100 nm are indeed more competent than the large-sized zeolite 5A crystals in improving the separation performances of the mixed-matrix CMSMs. Essentially, nanosizing filler materials for mixed-matrix CMSMs is a straightforward and effective strategy to elevate separation performances of CMSMs, making this approach highly relevant for biogas (CO2/CH4) and air (O2/N2) separations.

The incorporation of functionalized graphene oxide (GO) in mixed matrix membrane (MMM) is expected to greatly increase the permeability and selectivity for O2/N2 separation. In the present study, GO functionalized with 3- (Trimethoxysilyl) propyl methacrylate (TMOPMA) was used as inorganic filler and incorporated in to a PVC/pAMPS based MMM to increase the separation efficiency. Membranes of different compositions were synthesized and the best morphology was achieved with 0.5 g of PVC, 1.0 g of pAMPS and 0.015 g of filler. The synthesized membrane and inorganic filler were characterized using SEM, EDS, FTIR, Raman and XRD spectroscopy. Moreover, the gas permeation studies were performed to check the separation factor of synthesized membrane for O2/N2. The maximum permeability achieved for O2 and N2 was 4097 and 3373 barrers, respectively at 5 bar pressure. For the selectivity, a gradual increasing trend was observed with the increase in permeability. The maximum selectivity achieved was 1.215 at 5 bar pressure. The results revealed an increasing trend in selectivity with the increase in permeability of gases across the membrane with the increase in feed gas pressure. [ABSTRACT FROM AUTHOR]

• Membranes containing SNW-1 nanoparticles and Co(acac) 3 were successfully fabricated. • Combined use of SNW-1 and Co(acac) 3 enhanced O 2 permeability and O 2 /N 2 selectivity. • Both solubility and diffision selectivity can be enhanced by Co(acac) 3 and SNW-1. Mixed-matrix membranes containing a porous organic framework (SNW-1 nanoparticles) and a cobalt-based complex (Co(acac) 3) were fabricated using the solution-casting technique for potential applications in O 2 /N 2 separation. The mixed-matrix membranes did not show any appreciable defects. In the following mixture gas permeation testing conducted with a binary mixture composed of 21% O 2 and 79% N 2 at 1 bar feed pressure and 35 °C, the mixed-matrix membranes containing SNW-1 nanoparticles showed an enhanced O 2 permeability, whereas Co(acac) 3 improved the O 2 /N 2 selectivity. Hence, with a combination of both nanoparticles and a Cobalt complex in a polymer matrix, a clear synergistic enhancement in O 2 /N 2 separation properties was reported, in which O 2 permeability and O 2 /N 2 selectivity were escalated by 33% and 18%, respectively. Solubility-diffusivity analysis in the mixed-matrix membranes revealed that SNW-1 and Co(acac) 3 can improve O 2 diffusivity and O 2 solubility, respectively, resulting in an enhancement of both O 2 permeability and O 2 /N 2 selectivity for membranes containing both the nanoparticles and the cobalt complex. Future efforts will be focused on developing asymmetric hollow fiber membranes with thin skin layer comprising both SNW-1 and Co(acac) 3. [ABSTRACT FROM AUTHOR]

• Intercalating Iron ferrite NPs into Pebax matrix to intensify the moderate induced magnetic field. • Fabricate low cast, durable and high performance double layer magnetic MMMs for O 2 /N 2 separation. • Long range magneto static order of the NPs, in favor to form channels inside the matrix of the MMMs. • ab-initio calculation to understand the behavior of O 2 &N 2 near surface of the Fe 3 O 4 NPs. • There is quite differences in dynamic of the oxygen molecules compare to the nitrogen molecules. Magnetic field-induced mixed matrix membranes (MMMs) were used for separation of O 2 and N 2 gas according to their different magnetic properties. The double-layered MMMs were made of polyethersulfone (PES) and Pebax-1657 and super-paramagnetic Fe 3 O 4 nanoparticles (NPs) by simultaneous co-casting method. The PES served as the supporting layer while the Pebax layer (intercalated by the Fe 3 O 4 NPs) acted as the selective parts of the MMMs. An external magnetic field (0–0.5 T) was applied to avoid the demagnetizing effects between the polymeric (because of monomer chains mobility) and the magnetic NPs components of the MMMs. In the presence of an external magnetic field (H = 0.4 T), the ideal selectivity of the fabricated MMMs (∼25 µm in thickness) was tested for O 2 /N 2 separation, considering different concentrations of the NPs. The results indicated a substantial improvement up to 3.59 at room temperature for the sample containing 24 wt% Fe 3 O 4 NPs under the gas feeding of 10 bar, whereas the selectivity for non-magnetic MMMs was ∼ 1.87. The results showed that the external magnetic field could facilitate the formation of magnetic channels by loosen hydrogen bonds of the carbonyl groups in the polymer and also alignment of the super-paramagnetic NPs. As a complimentary study, for better understanding of the rule of the magnetic NPs, Density Functional Theory (DFT) simulation was employed to investigate the general behavior of the O 2 and N 2 molecules near the Fe 3 O 4 (magnetite) surface. Based on the results, the magnetic interactions between the NPs and O 2 molecules could form a layered structure for oxygen accumulation, which in turn affects the gas flow rate within the pores and channels of the MMMs near the magnetic NPs. [ABSTRACT FROM AUTHOR]

Membrane-based air separation (O2/N2) is of great importance owing to its energy efficiency as compared to conventional processes. Currently, dense polymeric membranes serve as the main pillar of industrial processes used for the generation of O2- and N2-enriched gas. However, conventional polymeric membranes often fail to meet the selectivity needs owing to the similarity in the effective diameters of O2 and N2 gases. Meanwhile, mixed-matrix membranes (MMMs) are convenient to produce high-performance membranes while keeping the advantages of polymeric materials. Here, we propose a novel MMM for O2/N2 separation, which is composed of Matrimid® 5218 (Matrimid) as the matrix, cobalt(II) phthalocyanine microparticles (CoPCMPs) as the filler, and Pluronic® F-127 (Pluronic) as the compatibilizer. By the incorporation of CoPCMPs to Matrimid, without Pluronic, interfacial defects were formed. Pluronic-treated CoPCMPs, on the other hand, enhanced O2 permeability and O2/N2 selectivity by 64% and 34%, respectively. We explain the enhancement achieved with the increase of both O2 diffusivity and O2/N2 solubility selectivity.

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[Display omitted] • Mixed-ligand MOFs M−AIP−BPY (M = Co or Ni) were prepared for efficient O 2 /N 2 separation by selective adsorption of O 2. • The MOFs exhibited excellent stability and regenerability at ambient temperature. • The MOFs exhibited good dynamic separation performances. • Theoretical calculations explained the mechanism for the O 2 -selective adsorption and regeneration of these MOFs. For air separation, the separation method relying on adsorbents has attracted wide attention as a low energy consumption process, and the development of O 2 -selective adsorbents is of great significance. Metal-organic frameworks with coordinatively unsaturated transition metal sites have great potential in O 2 -selective adsorption, but most of them cannot be completely regenerated at ambient temperature or can only be effective at very low temperatures. Herein, we report two mixed-ligand metal–organic framework adsorbents [M(AIP)(BPY) 0.5 ·H 2 O] n ·2nH 2 O with coordinatively unsaturated cobalt(II) and nickel(II) sites, which can preferentially adsorb O 2 versus N 2 , and their IAST O 2 /N 2 selectivities are both significantly greater than 1 at 25 °C. These materials exhibited excellent stability and had no loss of adsorption capacities even after immersion in water for 7 days. More importantly, O 2 adsorption–desorption cycle experiments showed that these adsorbents can be completely regenerated at ambient temperature after adsorbing O 2 , and the breakthrough experiments further confirmed their dynamic O 2 /N 2 separation potential and regeneration ability. The results of theoretical calculations suggested that the interactions between adsorbents and O 2 are stronger than those of N 2 , and they have relatively obvious differences in the N 2 and O 2 interaction energies. This work provides inspirations for searching for metal–organic frameworks that can selectively adsorb O 2 at ambient temperature. [ABSTRACT FROM AUTHOR]

Highlights: [•] Perfluorotributylamine (PFTBA) supported on porous alumina was used as a liquid membrane. [•] The separation of O2/N2 and H2/N2 at 40°C was higher than those of other liquid membranes. [•] The O2/N2 separation factor was ∼60 with an O2 permeance of 8×10−10 molm−2 s−1 Pa−1. [•] The permeance of the membrane correlated with the gas molecular size as H2 >O2 >N2. [ABSTRACT FROM AUTHOR]

Municipal solid waste (MSW) gasification is an attractive waste-to-energy (WTE) technology with promise for future solid waste management, owing to the production of syngas which can be used as an alternative energy resource. However, quality of produced syngas is not meeting expectation. One promising solution is to use oxygen-enriched gas (OEG) to elevate produced syngas quality but producing OEG is costly. Herein, we demonstrated an asymmetric defect-free hollow fiber membrane made up of Matrimid® 5218 polyimide for scaling-up to 2-inch membrane modules. Our modules have an effective surface area up to 2.6 m2 with a packing density of up to 44% to produce OEG of 45% O 2 purity. The 2-inch membrane module was integrated into a lab-scale gasification process to produce syngas using refuse derived fuel (RDF) generated from MSWs collected from the university campus. Prior to this, the lab-scale gasification was first optimized by tuning the gasification temperature, O 2 purity and equivalence ratio (ER). Then, MSW gasification using membrane-based OEG was carried out, and compared against air gasification and synthetic OEG of the same O 2 purity. Our results showed that, at O 2 purity of 45%, gasification temperature of 900 °C and ER of 0.15, the quality of produced syngas was elevated with a lower heating value (LHV) of 9.15 MJ/m3 and H 2 /CO ratio of 1.43, which was substantially higher than air gasification with LHV and H 2 /CO ratio reported at 5.38 MJ/m3 and 0.81, respectively. Gasification results for membrane-based OEG and synthetic OEG were also comparable, while process simulation evidence suggested that membrane-based separation was at least 2-fold less energy-intensive than cryogenic distillation and pressure swing adsorption. Overall, this proof-of-concept successfully demonstrates the viability and competitiveness of membrane process for producing OEG at medium O 2 purity (i.e. , 40–50%) to support MSW gasification for WTE conversion. [Display omitted] • Hollow fiber membrane modules with up to 2.6 m2 surface area were developed. • OEG with O 2 purity of c.a. 45% can be produced at close to 2 L/min flow rate. • Membrane-based OEG gasification produces syngas with 70% higher LHV as that of air gasification. • Membrane-based OEG produces syngas with comparable LHV as that of synthetic OEG. • Simulation shows that membrane separation is less energy-intensive for producing OEG of medium purity. [ABSTRACT FROM AUTHOR]

• The cobalt ionic liquid (IL) was used as a new O 2 carrier in PIM-1 membrane. • The cobalt IL decreases the d -spacing of PIM-1 due to the inter-attraction. • Membranes with cobalt IL show higher O 2 /N 2 selectivity than that with T(4-Cl)PPCo. • The O 2 /N 2 separation performance exceeded the 2008 Robeson upper bound. Ionic liquids (ILs) are attractive and prospective materials used in membranes due to the nonvolatility, structure tunability, and the ability to tune the interface compatibility. The cobalt IL Bmim 2 Co(NCS) 4 possesses the porphyrin-like N4-coordinated cobalt center which could selectively and reversibly interact with O 2. Herein the Bmim 2 Co(NCS) 4 as liquid-phase oxygen carrier was used to fabricate thin-film composite (TFC) membrane with the polymer of intrinsic microporosity (PIM-1). The microstructures, properties and gas separation performance of the membrane were compared with the TFC membrane which takes cobalt porphyrin (T(4-Cl)PPCo) as a carrier. We found that the addition of a small amount of T(4-Cl)PPCo can enlarge the d -spacing of packed chains of PIM-1 and significantly increase the fractional free volume (FFV) and the gas permeability of the membrane, but the selectivity is unsatisfactory. It is worth noting that adding Bmim 2 Co(NCS) 4 into the polymer can increase greatly the O 2 /N 2 selectivity which is higher than that of the membrane with T(4-Cl)PPCo. Although the addition of Bmim 2 Co(NCS) 4 decreases the d -spacing of packed chains of PIM-1, resulting in the slight decline of FFV and gas permeability of the membrane, the Bmim 2 Co(NCS) 4 /PIM-1 TFC membranes exhibit better O 2 /N 2 separation performance than the T(4-Cl)PPCo/PIM-1 TFC membranes in consideration of the Robeson upper bound. [ABSTRACT FROM AUTHOR]

• Non-magnetic and magnetic double-layer MMMs were fabricated using a co-casting method. • MMMs with/without BaFe 12 O 19 NPs prepared in presence and absence of magnetic field. • Effect of magnetic field was investigated using non-magnetic and magnetic modules. • O 2 permeance enhancement of ~220% obtained for non-magnetic MMM at pressure of 2 × 105 Pa. • High O 2 /N 2 selectivity of 4.01 was achieved for 24 wt% BaFe 12 O 19 filled MMM at 10 × 105 Pa. While the development of mixed matrix membranes (MMMs) has revolutionized gas separation applications, O 2 and N 2 gases are hardly separated from each other due to the small difference between their kinetic diameters. Here, magnetic MMMs consisting of polyethersulfone (PES)/Pebax-1657-BaFe 12 O 19 nanoparticles (NPs) are fabricated by using a co-casting method. The PES and Pebax polymers are used as the substrate and top layer, respectively. The Pebax selective layer (~4 µm in thickness) is filled with BaFe 12 O 19 powder in the presence of an external magnetic field (H = 0.5 T), providing efficient dispersion and accumulation of the magnetic NPs in the polymer matrix with high chemical stability. Field-emission scanning electron microscopic images indicate the absence of gaps, collapse, and crush at the contact layers of the two polymers, resulting in a dense top layer. By fabricating magnetic double-layer MMMs with 18 and 24 wt% BaFe 12 O 19 NPs, the respective ideal selectivity of O 2 /N 2 gases in the presence of H = 0.5 T at 25 °C is found to be 4 and 4.01, indicating significant enhancement in the gas separation compared to the non-magnetic MMM with an ideal selectivity of 1.87 in the absence of H. [ABSTRACT FROM AUTHOR]

Membrane-based air separation (O2/N2) is of great importance owing to its energy efficiency as compared to conventional processes. Currently, dense polymeric membranes serve as the main pillar of industrial processes used for the generation of O2- and N2-enriched gas. However, conventional polymeric membranes often fail to meet the selectivity needs owing to the similarity in the effective diameters of O2 and N2 gases. Meanwhile, mixed-matrix membranes (MMMs) are convenient to produce high-performance membranes while keeping the advantages of polymeric materials. Here, we propose a novel MMM for O2/N2 separation, which is composed of Matrimid® 5218 (Matrimid) as the matrix, cobalt(II) phthalocyanine microparticles (CoPCMPs) as the filler, and Pluronic® F-127 (Pluronic) as the compatibilizer. By the incorporation of CoPCMPs to Matrimid, without Pluronic, interfacial defects were formed. Pluronic-treated CoPCMPs, on the other hand, enhanced O2 permeability and O2/N2 selectivity by 64% and 34%, respectively. We explain the enhancement achieved with the increase of both O2 diffusivity and O2/N2 solubility selectivity. [ABSTRACT FROM AUTHOR]