Hydrogen separation and purification using crosslinkable PDMS/zeolite A nanoparticles mixed matrix membranes

The transport properties of gases in polydimethylsiloxane (PDMS)/zeolite A mixed matrix membranes (MMMs) were determined based on pure gas permeation experiments. MMMs were prepared by incorporating zeolite 4A nanoparticles into a PDMS matrix using a new procedure. The permeation rates of C₃H₈, CH₄, CO₂, and H₂ were evaluated through a dense homogeneous pure PDMS membrane and PDMS/4A MMMs to assess the viability of these membranes for natural gas sweetening and hydrogen purification. SEM investigations showed good adhesion of the polymer to the zeolite in MMMs. Permeation performance of the membranes was also investigated using a laboratory-scale gas separation apparatus and effects of feed pressure, zeolite loading and pore size of zeolite on the gas separation performance of the MMMs were evaluated. The MMMs exhibited both higher selectivity of H₂/CH₄ and H₂ permeability as compared with the neat PDMS membrane, suggesting that these membranes are very promising for gas separations such as H₂/CH₄ separation.     

Molecular-level mixed matrix membranes comprising Pebax and POSS for hydrogen purification via preferential CO2 removal

The molecular-level mixed matrix membranes (MMMs) comprising Pebax^® and POSS have been developed by tuning the membrane preparation process in this work. They exhibit a simultaneous enhancement in CO₂ permeability and CO₂/H₂ selectivity by optimizing the POSS content at extremely low loadings. This is mainly attributed to the large cavity of POSS itself and its effect on the segmental-level polymeric chain packing. More interestingly, the Pebax^®/POSS MMMs reveal a much higher separation performance in the mixed gas test than that in the pure gas test. The highest CO₂/H₂ selectivity reaches 52.3 accompanied by CO₂ permeability of 136 Barrer at 8 atm and 35 °C. This is due to the CO₂-induced plasticization that improves the free volume and polymer chain mobility, hence benefiting the interaction between the polymer matrix and penetrant CO₂. These features may ensure the superiority of Pebax^®/POSS molecular-level MMMs as CO₂-selective membranes in the industrial application of hydrogen purification.     

GNs/MOF-based mixed matrix membranes for gas separations

NU-1000 and graphene nanosheet (GNs) with different loadings have been used as fillers to prepare mixed matrix membranes (MMMs) with polyethersulfone (PES). The high performance of the MMMs has been successfully fabricated for the evaluation of gas separation at 1 bar and various temperatures (20, 40, 60 °C). The successful fabrication of the MMMs were confirmed by using SEM, FTIR, AFM, and XRD. The crystalline nature of GNs and NU-1000 in the MMMs are evidenced by XRD, which confirms the successful fabrication of the MMMs. In addition, the thermal stability of the MMMs was enhanced with the increase of the GNs. Separation performance of H₂ was superior to CO₂, N₂ and CH₄ separation on the MMMs which is a critical for producing energy. The best gas separation results in terms of both permeability and selectivity were obtained with 0.03% GNs and 10% NU-1000. PG3N membrane presented maximum H₂/CO₂, H₂/N₂ and H₂/CH₄ selectivity of 5, 4.2, 3.3 at 20 C, respectively. With an increase in temperature, the permeability increased, while the selectivity of all the MMMs decreased. The MMMs exhibited excellent gas separation capability, which offers unique opportunities for potential large-scale practical applications.     

Preparation of PPO-silica mixed matrix membranes by in-situ sol–gel method for H2/CO2 separation

Poly(2,6-dimethyl-1,4-phenylene oxide)(PPO)-silica mixed matrix membranes (MMMs) were synthesized through the in-situ sol–gel method. The effects of the acid–base catalysis conditions and silica loading weight on the gas separation performance of the membranes were investigated. The functional groups, crystalline structure, thermal stability, and morphology of the MMMs were examined using Fourier transform-infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), atomic force microscopy (AFM), and thermogravimetric analysis (TGA), respectively. The results indicate that using the in-situ sol–gel method to synthesize PPO-silica MMMs is beneficial for improving the adhesion between the silica and polymer and for the dispersion of the silica. The additives significantly enhanced the thermal stability of the membranes. Compared with pure PPO membranes, the PPO-silica MMMs prepared with 10 wt.% acid-silica loading exhibited the best H₂/CO₂ separation properties: H₂ permeability was enhanced from 82.1 to 548.7 Barrer, and an H₂/CO₂ separation ratio of approximately 3.56 was observed.     

Sorption properties of hydrogen-selective PDMS/zeolite 4A mixed matrix membrane

The present study explores the fundamental science of estimating sorption of gases in membranes comprised of inorganic porous fillers within a polymer matrix with a novel semi-empirical correlation. The sorption properties of H₂, C₃H₈, CO₂ and CH₄ were determined in polydimethylsiloxane (PDMS)/zeolite 4A mixed matrix membranes (MMMs) to assess the viability of these membranes for hydrogen purification and natural gas sweetening. Zeolite filling in MMMs results an increase in solubility over neat PDMS membrane. In addition, incorporation of zeolite 4A to PDMS membrane improved H₂ permeation and H₂/CH₄ selectivity. The results confirmed that zeolite 4A can significantly improve the separation properties of poorly H₂-selective PDMS membrane from 0.7 up to 11 and this overcomes the Robeson upper-bound limitation. This improvement was explained referring the Flory–Huggins interaction parameter within MMMs.     

Fabrication and characterization of poly(phenylene oxide)/SBA-15/carbon molecule sieve multilayer mixed matrix membrane for gas separation

A novel multilayer mixed matrix membrane (MMM), consisting of poly(phenylene oxide) (PPO), large-pore mesoporous silica molecular sieve zeolite SBA-15, and a carbon molecular sieve (CMS)/Al₂O₃ substrate, was successfully fabricated using the procedure outlined in this paper. The membranes were cast by spin coating and exposed to different gases for the purpose of determining and comparing the permeability and selectivity of PPO/SBA-15 membranes to H₂, CO₂, N₂, and CH₄. PPO/SBA-15/CMS/Al₂O₃ MMMs with different loading weights of zeolite SBA-15 were also studied. This new class of PPO/SBA-15/CMS/Al₂O₃ multilayer MMMs showed higher levels of gas permeability compared to PPO/SBA-15 membranes. The permselectivity of H₂/N₂ and H₂/CH₄ combinations increased remarkably, with values at 38.9 and 50.9, respectively, at 10 wt% zeolite loading. Field emission scanning electron microscopy results showed that the interface between the polymer and the zeolite in MMMs was better at a 10 wt% loading than other loading levels. The increments of the glass transition temperature of MMMs with zeolite confirm that zeolite causes polymer chains to become rigid.     

CO2-selective membranes for hydrogen purification and the effect of carbon monoxide (CO) on its gas separation performance

Industrial hydrogen production may prefer CO₂-selective membranes because high-pressure H₂ can therefore be produced without additional recompression. In this study, high performance CO₂-selective membranes are fabricated by modifying a polymer–silica hybrid matrix (PSHM) with a low molecular weight poly(ethylene glycol) dimethyl ether (PEGDME). The liquid state of PEGDME and its unique end groups eliminate the crystallization tendency of poly(ethylene glycol) (PEG). The methyl end groups in PEGDME hinder hydrogen bonding between the polymer chains and significantly enhance the gas diffusivity. In pure gas tests, the membrane containing 50 wt% additive shows CO₂ gas permeability and CO₂/H₂ selectivity of 1637 Barrers and 13 at 35 °C, respectively. In order to explore the effect of real industrial conditions, the gas separation performance of the newly developed membranes has been studied extensively using binary (CO₂/H₂) and ternary gas mixtures (CO₂/H₂/carbon monoxide (CO)). Compared to pure gas performance, the second component (H₂) in the binary mixed gas test reduces the CO₂ permeability. The presence of CO in the feed gas stream decreases both CO₂ and H₂ permeability as well as CO₂/H₂ selectivity as it reduces the concentration of CO₂ molecules in the polymer matrix. The mixed gas results affirm the promising applications of the newly developed membranes for H₂ purification.     

High performance ZIF-8/PBI nano-composite membranes for high temperature hydrogen separation consisting of carbon monoxide and water vapor

Two types of advanced nano-composite materials have been formed by incorporating as-synthesized wet-state zeolitic imidazolate frameworks-8 (ZIF-8) nano-particles into a polybenzimidazole (PBI) polymer. The loadings of ZIF-8 particles in the two membranes (i.e., 30/70 (w/w) ZIF-8/PBI and 60/40 (w/w) ZIF-8/PBI) are 38.2 vol % and 63.6 vol %, respectively. Due to different ZIF-8 loadings, variations in particle dispersion, membrane morphology and gas separation properties are observed. Gas permeation results suggest that intercalation occurs when the ZIF-8 loading reaches 63.6 vol %. The incorporation of ZIF-8 particles significantly enhances both solubility and diffusion coefficients but the enhancement in diffusion coefficient is much greater. Mixed gas tests for H₂/CO₂ separation were conducted from 35 to 230 °C, and both membranes exhibit remarkably high H₂ permeability and H₂/CO₂ selectivity. The 30/70 (w/w) ZIF-8/PBI membrane has an H₂/CO₂ selectivity of 26.3 with an H₂ permeability of 470.5 Barrer, while the 60/40 (w/w) ZIF-8/PBI membrane has an H₂/CO₂ selectivity of 12.3 with an H₂ permeability of 2014.8 Barrer. Mixed gas data show that the presence of CO or water vapor impurity in the feed gas stream does not significantly influence the membrane performance at 230 °C. Thus, the newly developed H₂-selective membranes may have bright prospects for hydrogen purification and CO₂ capture in realistic industrial applications such as syngas processing, integrated gasification combined cycle (IGCC) power plant and hydrogen recovery.     

Development of high performance amine functionalized zeolitic imidazolate framework (ZIF-8)/cellulose triacetate mixed matrix membranes for CO2/CH4 separation

High cost and complex fabrication process of inorganic membranes and lower position of pristine polymeric membranes in the Robeson upper bound curve urged the researchers to develop mixed matrix membranes (MMMs). Cellulose acetate being most commercially used polymer, dominates the market of CO₂ separation mainly because of low cost and environmental friendly resource. In the present study, MMMs consists of amine functionalized zeolitic imidazolate framework (NH₂-ZIF-8) and cellulose triacetate were fabricated for the first time. NH₂-ZIF-8 was used as a filler because the pore size of ZIF-8 is between the kinetic diameter of separating gases (CO₂ and CH₄). Moreover,  NH₂ group attached on the surface of ZIF-8 has affinity with condensable gases like CO₂. Morphology, crystallinity, tensile strength and functional groups of fabricated membranes were investigated using different analytical techniques. Results revealed that the increase of feed pressure has increased CO₂ permeability and decreased permselectivity. However, improvements in gas separation performance were observed with the addition of nanofiller. Best position in Robeson's upper bound curve at 4 bar was obtained with 10 wt% loading with CO₂ permeability and CO₂/CH₄ permselectivity of 218 barrer and 13.84, respectively. The improvement in the gas separation performance with loading is attributed to the increased diffusion coefficients as well as solubility coefficients, which was increased to 33% and 3.8%, respectively.     

In situ fabrication of cross-linked PEO/silica reverse-selective membranes for hydrogen purification

Targeting at hydrogen purification, cross-linked organic–inorganic reverse-selective membranes containing poly(ethylene oxide) (PEO) are fabricated in situ by using functional oligomers (O,O′-bis(2-aminopropyl) polypropylene glycol-block-polyethylene glycol-block-polypropylene glycol: Jeffamine^® ED-2003) with a high content of PEO and epoxy-functional silanes (3-glycidyloxypropyltrimethoxysilane: GOTMS). Changes in physicochemical properties due to varying silica content have been characterized; including a great decline in melting temperature; an improvement in glassy and degradation temperature, and the suppression of PEO crystallinity. The strong affinity between quadrupolar CO₂ and polar ethylene oxide (EO) groups enhances the CO₂/H₂ separation performance of hybrid membranes, which can be further tuned by controlling the organic/inorganic ratio. The organic–inorganic hybrid membrane with 90 wt% of ED-2003 demonstrates an appealing CO₂ permeability of 367 Barrer with an attractive CO₂/H₂ selectivity of 8.95 at 3.5 atm and 35 °C. The transport performance trend with composition variations is explained by analyzing the calculated solubility and diffusivity based on the solution-diffusion mechanism. Moreover, CO₂ permeability increases with applied pressure in pure gas tests because of CO₂ plasticization phenomena, which is beneficial for CO₂/H₂ separation. Attributing to CO₂ plasticization and CO₂ dominant sorption, the mixed gas test results of the membrane containing only 25 wt% ED-2003 show greatly improved CO₂/H₂ selectivity of 13.2 with CO₂ permeability of 148 Barrer at 35 °C compared to pure gas results. Interestingly, at a stipulated CO₂ pressure, the inherent tension in cross-linked networks maintains the CO₂ permeability stable with the time. The cross-linked organic–inorganic membranes with enhancements in mechanical and thermal properties are promising for industrial-scale hydrogen purification.     

H2-selective mixed matrix membranes modeling using ANFIS,PSO-ANFIS,GA-ANFIS

The novel contribution of the current study is to employ adaptive neuro-fuzzy inference system (ANFIS) for evaluation of H₂-selective mixed matrix membranes (MMMs) performance in various operational conditions. Initially, MMMs were prepared by incorporating zeolite 4A nanoparticles into polydimethylsiloxane (PDMS) and applied in gas permeation measurement. The gas permeability of CH₄, CO₂, C₃H₈ and H₂ was used for ANFIS modeling. In this manner, the H₂/gas selectivity as the output of the model was modeled to the variations of feed pressure, nanofiller contents and the kind of gas, which were defined as input (design) variables. The proposed method is based on the improvement of ANFIS with genetic algorithm (GA) and particle swarm optimization (PSO). The PSO and GA were applied to improve the ANFIS performance. To determine the efficiency of PSO-ANFIS, GA-ANFIS and ANFIS models, a statistical analysis was performed. The results revealed that the PSO-ANFIS model yields better prediction in comparison to two other methods so that root mean square error (RMSE) and coefficient of determination (R²) were obtained as 0.0135 and 0.9938, respectively. The RMSE and R² values for GA-ANFIS were 0.0320 and 0.9653, respectively, and for ANFIS model were 0.0256 and 0.9787, respectively.     

Active block copolymer layer on carboxyl-functionalized PET film for hydrogen separation

To rationalize the energy requirements and environmental complications of the world, supply of pure hydrogen is the most promising as well best possible approach of such issues. Purified hydrogen gas is the necessity factor for the hydrogen-based economy. Hydrogen perm-selective membrane plays a crucial role for producing a large amount of hydrogen. Palladium is one of the best materials because of its excellent affinity to absorb hydrogen. In present work, our aim to improve selectivity as well permeability of the H₂ gas compare to N₂ and CO₂ gases of the block copolymer coated functionalized porous PET membrane. Porous polyethylene terephthalate (PET) membranes having pore size 0.2 μm, functionalized with a carboxyl group. The supramolecular assembly was prepared from PS (35500)-b- P4VP (4400) and 2-(4- Hydroxyphenylazo) benzoic acid (HABA) in 1, 4-dioxane. Chemically synthesized palladium nanoparticles were deposited on carboxylated block copolymer (BC) coated porous PET membrane. It is an appropriate way to use H₂ sensitive materials with block copolymer coated functionalized membranes to enhance the selectivity of H₂. It has been found that such membranes gain better permeability and selectivity towards H₂ as compared with N₂ and CO₂. Increment with the dipping time of these membranes in the palladium nanoparticle solution, permeability as well selectivity of H₂ over N₂, CO₂ increases as the more attachment of Palladium nanoparticles. A fine active layer of block copolymer on the carboxyl functionalized PET membrane play a crucial role for hydrogen based gas separation. The magnitude of the permeability of such membranes for different gases shows dependency on the pore size of the upper layer (BC coated) of the membrane in addition to the molecule size of the permeating gas. Block copolymer coating of the membranes established an effective responsibility for the selectivity of H₂ over CO₂ gas as well over N₂ gas.     

Enhancing hydrogen gas separation performance of thin film composite membrane through facilely blended polyvinyl alcohol and PEBAX

Polymeric membranes offer economic separation processes but are less explored for H₂ separation application. This work aims to unveil the H₂ separation potential of polymeric membrane by developing PVA-based reverse selective composite membrane. CO₂-selective PEBAX was blended at different PVA:PEBAX ratio. The effect of PEBAX blending on membrane morphology, crystallinity and gas separation behavior was studied. Incorporation of PEBAX at <50 wt% resulted in composite with improved CO₂ permeability but selectivity loss. Blending of >60 wt% PEBAX enhanced both permeance and selectivity of the resulted composite as the host matrix was dominated by this PEO containing material thus greatly enhancing polymer chain mobility and promoting CO₂-solubility. The best composite which contains 60 wt% PEBAX exhibited CO₂ permeability of 20.0 Barrer and CO₂/H₂ selectivity of 7.6. This performance surpasses the Robeson's boundary and unleashes the potential of tailoring the properties of polymeric nanocomposite membrane for H₂ separation application through facile PVA/PEBAX blending.     

PVDF/ionic liquid polymer blends with superior separation performance for removing CO2 from hydrogen and flue gas

We have demonstrated, for the first time, a polymer blend comprising poly(vinylidene fluoride) (PVDF) and a room-temperature ionic liquid (RTIL) that shows a high CO₂ permeability of 1778 Barrer with CO₂/H₂ and CO₂/N₂ selectivity of 12.9 and 41.1, respectively. The low viscosity RTIL, 1-ethyl-3-methylimidazolium tetracyanoborate ([emim][B(CN)₄]) possesses a high CO₂ solubility, and plays a significant role in CO₂ separation, whereas PVDF provides the mechanical strength to the blend membranes. A series of PVDF/[emim][B(CN)₄] polymer blends with different compositions were tested for their gas separation performance involving H₂, N₂ and CO₂ in both pure gas and mixed gas conditions. Both optical observation and Maxwell predictions confirm the heterogeneous nature of the PVDF/[emim][B(CN)₄] system. However, compared to miscible ionic liquid based blends, where molecular level interactions may restrain chain flexibility and reduce gas permeability, heterogeneous PVDF/RTIL blend systems show far superior gas transport properties. Most of these blend membranes outperform most reported materials and their gas transport and separation capabilities fall within the attractive region bound by the “2008 Robeson Upper Limit” for CO₂/H₂ and CO₂/N₂ gas pairs, and are also very stable at trans-membrane pressure up to 5 atm. Therefore, they are potential materials for H₂ purification and CO₂ capture from hydrogen production and flue gas.     

New PEEK-WC and PLA membranes for H2 separation

The potentialities of PEEK-WC (thermally treated at 120 °C) and PLA polymers have been studied in the field of membrane technology applied to H₂ separation/purification. In particular, for low/medium temperature operation (80 °C), PEEK-WC membranes (66 μm thick) showed good results in terms of H₂/CH₄ separation, showing an ideal selectivity value higher than 40. Meanwhile, we observed interesting selectivity also for H₂/N₂ and H₂/CO₂ separation, reaching values of 24 and 20, respectively. As expected, for PEEK-WC thermally treated membranes, the H₂ permeating flux increased from 25 to 80 °C and by increasing the transmembrane pressure. Furthermore, H₂ permeability at 80 °C was around 20 barrer. Concerning PLA membranes (26 μm thick), it is worth of noting that this polymer was pioneeristically used in this work as membrane application, showing great results in terms of H₂/CO₂ separation. Indeed, we overcame the Robeson's upper-bound (2008), achieving an ideal selectivity H₂/CO₂ around 25 with an H₂ permeability of 25 barrer. Further advantage due to the utilization of PLA membranes was related to the temperature operations set at ambient conditions, constituting a valuable and cost-effective solution for H₂/CO₂ separation processes via polymeric membrane technology.     

Effect of mesoporous silica modification on the structure of hybrid carbon membrane for hydrogen separation

An SBA-15/carbon molecular sieve (CMS) composite membrane, using polyetherimide as a precursor and mesoporous silica as filler, was fabricated for hydrogen separation. The effect of mesoporous SBA-15 on the gas transport properties of the composite membrane was evaluated. The permeability and selectivity coefficients of H₂, CO₂, O₂, N₂, and CH₄ were estimated for the pure CMS and SBA-15/CMS composite membranes at a feed pressure of 2-7 atm for 30 °C. The SBA-15/CMS composite membrane had a gas permeability higher than that of the pure CMS membrane, whereas its selectivity was the same. The permeability was found to be independent of pressure; this indicates that the gases are transported through the membrane by a molecular sieve mechanism. The membranes appeared to have a more microporous structure when the mesoporous silica SBA-15 was incorporated. These results concur with the hypothesis that SBA-15 improves gas diffusivity by increasing pore volume.     

Gas permeation through H2-selective mixed matrix membranes: Experimental and neural network modeling

Gas permeability through synthesized polydimethylsiloxane (PDMS)/zeolite 4A mixed matrix membranes (MMMs) were investigated with the aid of artificial neural network (ANN) approach. Kinetic diameter and critical temperature of permeating components (e.g. H₂, CH₄, CO₂ and C₃H₈), zeolite content and upstream pressure as input variables and gas permeability as output were inspected. Collected data of the experimental operation was used to ANN training and optimum numbers of hidden layers and neurons were obtained by trial-error method. The selected ANN architecture (4:10:1) was used to predict gas permeability for different inputs in the domain of training data. Based on the results, the predicted values demonstrate an excellent agreement with the experimental data, with high correlation (R² = 0.9944) and less error (RMSE = 1.33E−4). Furthermore, using sensitivity analysis, kinetic diameter and critical temperature were found as the most significant effective variables on gas permeability. As a result, ANN can be recommended for the modeling of gas transport through MMMs.     

Palladium nanoparticle binding in functionalized track etched PET membrane for hydrogen gas separation

In this work, track-etched poly (ethylene terephthalate) (PET) membranes having different pore sizes were functionalized by the carboxylic groups and the amino groups. Palladium (Pd) nanoparticles of average diameter 5 nm were synthesized chemically and deposited onto pore walls as well as on the surface of these pristine and functionalized membranes. Effect of Pd nanoparticles binding on these membranes were explored and aminated membrane were found to bind more Pd nanoparticles due to its affinity. The morphology of these composite membranes is characterized by Scanning Electron Microscope (SEM) for confirmation of Pd nanoparticle deposition on pore wall as well as on the surface. Gas permeability of functionalized and non-functionalized membranes for hydrogen and carbon dioxide has been examined. From the gas permeability data of hydrogen (H₂) and carbon dioxide (CO₂) gases, it was observed that these membranes have higher permeability for H₂ as compared with CO₂. Due to absorption of hydrogen by Pd nanoparticles selectivity of H₂ over CO₂ was found higher as compared to without Pd embedded membranes. Such type of membranes can be used to develop hydrogen selective nanofilters for purification/separation technology.     

Development of hydrogen selective microporous PVDF membrane

Hydrogen is a sustainable clean and green energy source used to eliminate the problem of greenhouse effect. In the present work, the feasibility of gas permeability in separation of H₂ from CO₂ and N₂ have been examined using polyvinylidene fluoride (PVDF) membranes synthesised in our laboratory by the phase inversion process. Effect of various non-solvent additives, such as lithium chloride (LiCl) and Tetraethoxysilane (TEOS) in the PVDF dope solution, have been studied. The resulted asymmetric flat sheet microporous hydrophobic membrane, shows higher hydrogen permeability and selectivity over other gases (CO₂ & N₂). It has been observed that the MT5 membrane has shown the highest selectivity for hydrogen in comparison to CO₂ and N₂. The highest value of selectivity was obtained as 4.8 and 3.7 in case of H₂/CO₂ and H₂/N₂ respectively. The permeability of membrane has been obtained in the range of 2.3–4.2 mega barrer. SEM analysis is used for the investigation of membrane surface morphology.     

Structure-controlled mesoporous SBA-15-derived mixed matrix membranes for H2 purification and CO2 capture

The composite mixed matrix membranes (MMMs) were prepared by incorporating mesopore SBA-15 as a filler to discuss the effects of its particle shape, particle size, and loadings on the organic–inorganic interfacial morphology. The SBA-15 was synthesized by template method and it's particle shape and size was adjusted by adding electrolyte. The results indicated that the spherical SBA-15 can improve the dispersion and have better adhesion with organic phase, which showed better permselectivity than the rod-like one. The SBA-15 filler also could increase the diffusion selectivity of MMMs by the addition of different particle sizes. The permeabilities of H₂ and CO₂ were 1207.9 and 552.86 Barrer, respectively, with selectivities of H₂/CH₄ and CO₂/CH₄ reached 247.0 and 112.8, respectively, when 1.6 μm spherical SBA-15 was added at 3 wt. %. The dissimilarity occurring in the perm-selectivity values with changes made in the particle shape and size are much more pronounced at the lower SBA-15 loading, which exceeded the 2008 Robeson's upper bound limited.