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Extra-high-performance low-level filler-loaded mixed-matrix membranes (MMMs) were fabricated by embedding a flexible cyclooligomer, calix[4]arene (CA), as a macrocyclic porous filler in two blends of a commercial polyether block amide polymer, Pebax MH 1657. Two kinds of liquid phases, PEG550 (PEG) and [OMIM][PF₆] (IL), were separately introduced into the Pebax MH 1657 matrix to prepare blended membranes for enhancing the CO₂ permeability and comparing their performance. Afterward, CA as the third generation of supramolecular hosts with high inherent affinity to CO₂ was synthesized and incorporated in the polymer blends to fabricate high-performance MMMs. The organic nature, the high compatibility of other applied additives with Pebax MH 1657 polymer, and the tiny size of CA particles were responsible for the desirable particle distribution in ternary MMMs. In the case of the Pebax/PEG550 (30 wt%)/CA (0.5 wt%) MMM, the results revealed the CO₂ permeability to be about 632.60 Barrer, with CO₂/CH₄ and CO₂/N₂ selectivities about 59.83 and 139.88, respectively. For Pebax/IL (6.5 wt%)/CA (0.5 wt%), the CO₂ permeability was about 263.82 Barrer, with CO₂/CH₄ and CO₂/N₂ selectivities about 64.39 and 152.45, respectively. Therefore, the fabricated ternary MMMs present a promising outlook for CO₂ separation, which surpasses the Robeson upper limits.

Highlighting mixed matrix membrane (MMM) susceptibility in improving the membrane performance along with established p-tert-butylcalix[4]arene (CA) ability in CO2 sorption, Pebax-1657-based MMMs ha...

In this paper, a novel comprehensive permeation model for mixed matrix membranes (MMMs) is introduced. This model shows the importance of understanding and developing a more reliable model for the permeation behavior of MMMs containing porous filler nanoparticles. A new method is established to provide a more precise/large‐scale three‐dimensional MMMs geometry. The required number of spherical porous fillers in random/nonuniform positions in the polymer matrix is calculated. Interfacial equilibrium constant (K) at the polymer/filler interfaces was adjusted as the concentration ratio of the diffusing penetrants (C2 and C1) at the interface, respectively. In this case, the K values are changed by varying the intended gaseous concentration due to their permeation through the MMM. Hence, its effect on penetrants effective diffusion coefficient was examined. Then, the obtained results were evaluated with similar experimental data, which showed much consistency. Therefore, the accurate calculation method for MMMs permeability was governed for the entire range of the operating pressures in MMMs. The results showed that the permeability of MMMs increases with increasing filler particle size. On the other hand, variations that occur in the MMM permeability at various particle size were much more distinct at higher loadings. Moreover, some well‐known analytical permeation models were used to compare and validate the model's permeability results. It can be concluded that this model provides a method for more precise and realistic design of MMMs as well as to better construe the large number of related experimental data. © 2019 Society of Chemical Industry and John Wiley & Sons, Ltd.

Mixed matrix membranes were made of polysulfone and Matrimid® polymers, and SiO2 and TiO2 nanoparticles in order to improve the efficiency of polymeric membrane in gas separation and review the efficiency of membrane separation process, laboratory. The modeling results of selectivity and permeability of gases O2, N2, CO2 and CH4 were discussed for different membranes. Another objective of this study was to submit a report on the importance of the statistical analysis and modeling in design and optimizing mixed matrix membranes to separate gas. The D-optimal method was applied to model and optimize the selectivity and permeability due to the main parameters. The obtained results indicated that the permeability of all gases demonstrated an ascending trend when the nanoparticles were increased. Under optimized conditions, the permeability of the gases O2, N2, CO2, CH4 in the membrane of PSF (12)/SiO2 (13.82) was 2.49, 1.113, 12.82 and 0.885 Barrer, respectively. A statistical method was practiced in the current research to design, optimize and separate gas membranes through effective efficiency for different applications.

In this study, a comprehensive time-dependent mathematical model for gas separation through the facilitated transport membranes (FTMs) is presented. The model results have been validated with independent CO2/N2 binary gas mixture experiments in DEA-impregnated PVA membranes. In the proposed model, non-equal diffusion coefficients of the carrier/complex and equilibrium constant for the chemical reaction kinetics between the carrier/permeant in the FTM have been considered. In addition, a method to compute the diffusion coefficients, which depend on the concentration of each component in the FTM, is presented. Moreover, effect of carrier concentration, feed partial pressure, kinetics of reversible chemical reactions and membrane performances depending on operating condition have been analyzed. Owing to accurate calculation of physical–chemical parameter involved, this model is much more executive comparing to previous works. In addition, the real condition of the reaction kinetics and influencing of diffusion parameters of the components in FTMs, have been investigated. The predicted selectivity and permeability revealed good conformity with experimental data; with standard deviation (SD) 8.57% and 12.87%, respectively. In conclusion, this model with significant validity would be predictive in cases for the entire range of diffusion-limit to a chemical-limit regime where the experimental data, geometry condition, physical–chemical property of parameters is not available.

In this research, the cross-linking of diethanolamine (DEA) impregnated poly(vinyl alcohol) (PVA) on polytetrafluoroethylene (PTFE) by glutaraldehyde (GA) with different blend compositions (GA/PVA: 0.5, 1, 3, 5, 7 ratio%) was performed in the absence of an acid catalyst and organic solvents in order to avoid any interference in CO2 facilitation reaction with DEA. The fabricated membranes were characterized by differential scanning calorimetry (DSC), Fourier transform infrared (FTIR) and scanning electron microscopy (SEM). Furthermore, the effects of cross-linking agent content, feed pressure and composition as well as stability on CO2/CH4 transport properties were investigated in both pure and mixed gas experiments. The cross-linked membranes showed reasonable CO2/CH4 permselectivities in comparison with uncross-linked membranes. The best-yield CO2-selective membranes (DEA-PVA/GA(1 wt%)/PTFE) represented the best CO2/CH4 selectivity of 91.13 and 665 for pure and mixed gas experiments, respectively.

In this paper, polyvinyl alcohol (PVA) membranes impregnated with amines (monoethanolamine and diethanolamine) were prepared for CO2/N2 separation. The cross-linking of DEA impregnated PVA by glutaraldehyde (GA) with different mass ratios (GA/PVA: 0.5, 1, 3, 5, 7%) were investigated with no use of acid catalyst or organic solvents. The effects of the amine type-concentration, cross-linking agent content, and feed pressure as well as stability were examined in both pure and mixed gases. Generally, CO2/N2 performance through the DEA-PVA membranes was higher than that of MEA-PVA membranes. The fabricated membranes were characterized by differential scanning calorimetry (DSC), Fourier transform infrared (FTIR) and scanning electron microscopy (SEM). The cross-linked membranes showed reasonable CO2/N2 permselectivities in comparison with uncross-linked membranes and these are recommended for high performance membrane for CO2/N2 separation. The best-yielding membranes (DEA-PVA/GA(1 wt%)/PTFE) represented the greatest CO2/N2 selectivity of 122.04 and 907.06 for pure and mixed gas experiments, respectively.

The drive toward greater application of membrane has resulted in its rapid development in natural gas processing industry. In this work, amine-mediated membranes were tailored for CO2 removal from CO2/CH4 stream. The effects of various parameters such as amine concentration, microporous support, feed pressure and composition were examined to study the permeation behavior of pure and mixed gases. Generally, CO2 transport through the DEA-PVA membranes was higher than that of MEA-PVA membranes for approximately 70%. The membrane containing 15 wt% DEA and 35 wt% MEA revealed higher permselectivity. CO2 permeance enhancement of amine-PVA membranes in comparison with neat PVA membrane, confirmed that CO2-amine reaction was the dominant transport mechanism. Additionally, with increasing feed pressure, CO2/CH4 permselectivity decreased due to carrier saturation. However, lower partial pressure of CO2 was in favor of reaction mechanism in pure and mixed gas tests. On the other hand, CH4 is not significantly affected by feed pressure confirming that solutiondiffusion is the governing transport mechanism. Additionally, PTFE support with higher wettability showed better performance (18%) regardless of amine type, concentration and feed pressure. DEA-PVA membrane has exhibited good stability during 2 weeks, unlike MEA-impregnated membrane, which was probably due to carrier degradation over time. POLYM. ENG. SCI., 54:1268–1279, 2014. V C 2013 Society of Plastics Engineers

In this article, permeation models for nanocomposite polymeric membranes (NCPMs) filled with nonporous particles are discussed and two new models for prediction of effective permeability of NCPMs are proposed. To derive these models, the presence of interfacial layer at the surface of the nanofiller particles as well as the impact of two important phenomena namely creating void volumes and increasing free volume at the interface layer are taken into account. The capability of the models for prediction of reliable results is checked against available experimental data on permeability of NCPMs and is also compared with other presented models for such membranes. The new proposed models show profound superiority over the well known models such as “Bruggeman model in limit” which offers fairly good prediction for NCPMs.

In this study the gas separation performance of polyimide/polysulfone (PI/PSF) mixed matrix membranes filled with zeolite ZSM-5 particles is investigated. The membranes are prepared by solution-casting method and utilized to determine the permeation rates of N2, O2, CO2 and CH4 through pure polymers as well as composite membranes. The membranes are characterized by SEM, TGA and FTIR. The effects of polymers ratio and weight fraction of zeolite on permeation and selectivity of the gases are discussed. Polymers ratio in the mixed matrix have assumed values of 100% PSF, 70/30 (PSF/PI), 50/50, 30/70 and 100% PI while ZSM-5 loadings are varied between 0 and 20 wt.%. SEM results showed that fabricated membranes have homogeneous structure. With pure polyimide membrane, O2 permeability increased from 0.69 Barrer for membrane without zeolite up to 0.73 and 0.89 Barrer for membranes with 10% and 20% zeolite, respectively. Within blended matrices, the minimum permeability (maximum selectivity) and the most homogeneous matrix structure were related to the matrix with 50/50 weight percent of two polymers.

In this study, the effect of TiO2 nanoparticles addition on mixed matrix membranes (MMMs) based on Matrimd5218 prepared by using solution-casting method has been investigated. The morphology of MMM was evaluated by Scanning Electron Microscopy (SEM). TiO2 nanoparticles distribution in matrimid matrix and top surface of membrane films was observed by Transmission Electron Microscopy (TEM) and Atomic Force Microscopy (AFM), respectively. It was found that at low particle loadings (less than 15%) nanoparticles were mainly dispersed individually forming nanoscale aggregates. However, at high volume fractions (more than 20%) the size of aggregates increases and micro-scale aggregates form. The permeability of N2, CH4, O2, CO2 and He have been measured in order to determine the effect of TiO2 on gas separation performance of Matrimid5218. The results demonstrated that inclusion of TiO2 increases the gas permeability of MMMs possibly due to chain packing disruption, void formation at polymer–nanoparticle interface as well as within nanoparticle aggregates. For example, in MMMs containing 15 vol.% TiO2, the permeability of N2, CH4 and CO2 increased up to 2.76, 3.3 and 1.86 times higher than pure matrimid respectively. Diffusivity coefficients of larger molecules obtained by time-lag method show that permeability enhancement is mainly affected by diffusivity increment. Finally, the results reveal that use of TiO2 nanoparticles improves membrane performance in CO2/CH4 separation and presents a trade-off line with similar slope compare to Robeson upper insertion bound.

In this work, the cross-linked poly (vinyl alcohol)/formaldehyde with different blend compositions (FA/PVA: 1, 3, 5 ratio%) were synthesized. In addition, different diethanolamine concentrations ranging from 15-45 wt % were investigated for membrane fabrication. Moreover, the membranes were characterized by Fourier transform infrared (FTIR) and scanning electron microscopy (SEM) and contact angle measurement. Furthermore, the effects of crosslinking agent content, amine concentration and feed pressure on CO2/CH4 transport properties were investigated in pure gas experiments. The results showed that CO2 and CH4 permeances decreased with increasing FA/PVA mass ratio, in comparison with uncross-linked membranes, although the selevtivities increased considerably. The highest selectivity (about 92.72) was achieved from PVA/FA(5wt%)/PTFE membrane. Moreover, it was found that CO2/CH4 selectivity was significantly decreased with increasing cross-linker/PVA mass ratio from 1 wt% to 5 wt%. On the other hand, the cross-linked membranes revealed favorable CO2/CH4 permselectivities in comparison with uncross-linked ones.