Mixed matrix membranes of Pebax1657 loaded with iron benzene‐1,3,5‐tricarboxylate for gas separation

Mixed matrix membranes offer major advantages in gas separation processes due to desirable properties found in both organic and inorganic membranes. In this study, a novel mixed matrix membrane was prepared for such application by incorporating iron benzene‐1,3,5‐tricarboxylate (Fe‐BTC) into the poly(amide‐6‐b‐ethylene oxide) (Pebax1657) polymer. Membranes with various loadings of 5, 10, and 20 wt% Fe‐BTC in the polymer matrix were fabricated to investigate the effect of filler loading on the membrane performance. Membranes, prepared by solution‐casting were characterized by scanning electron microscopy, thermogravimetric analysis, Fourier transform infrared, X‐ray diffraction, and tensile test. Pure gas separation of CO₂, CH₄, and N₂ and ideal gas selectivity of CO₂/CH₄ and CO₂/N₂ were performed and permeation tests were carried out under 4, 8, and 12 bar pressures. Results show that adding Fe‐BTC into the Pebax1657 matrix improved both permeability and selectivity of the filled membranes. For instance, 10 wt% loading of Fe‐BTC into the Pebax1657 matrix led to CO₂ permeability increase of 49% as well as CO₂/CH₄ and CO₂/N₂ selectivities enhancements of about 36% and 16%, respectively. POLYM. COMPOS., 38:1363–1370, 2017. © 2015 Society of Plastics Engineers     

Study the effects of Cloisite15A nanoclay incorporation on the morphology and gas permeation properties of Pebax2533 polymer

In this study, mixed matrix membranes (MMMs) were prepared using commercially available poly(ether‐b‐amide) (Pebax2533) as polymer matrix and organically modified montmorillonite (OMMt) as filler with the aim of investigating their gas permeation properties. The prepared membranes were characterized by Fourier‐transform infrared (FTIR) spectroscopy, X‐ray diffraction (XRD), scanning electron microscope (SEM), thermal gravimetric analysis, and tensile strength analyses. Gas permeation properties of all the prepared membranes were evaluated at different pressures and clay loadings. Results of FTIR and SEM confirmed the appropriate adhesion between polymer and nanoclays so that no void formation was observed in the polymer/clay interface. XRD results showed that in low loading, clay dispersion occurred as exfoliated‐intercalated and at high loading as intercalated‐phase separated. Results of gas permeation test showed that by adding layered and impermeable clay particles to the polymer matrix, the permeation of soluble CO₂ gas reduced by 28% for the highest clay loading. By increasing of pressure from 2 to 6 bar, CO₂/CH₄ permselectivity increased at all nanoclay loadings. The highest CO₂/CH₄ selectivity was obtained for 6 wt % clay MMM at all pressures, while the highest CO₂/H₂ selectivity was achieved for neat polymer at 6 bar. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45302.     

Fabrication and testing of mixed matrix membranes of UiO-66-NH2 in cellulose acetate for CO2 separation from model biogas

Mixed Matrix Membranes (MMMs) of UiO-66-NH₂ nanoparticles dispersed in Cellulose Acetate (CA) were prepared with filler loading of 2–20 wt%. MMMs were tested for the upgradation of model biogas (60%–40%) mixture of CH₄/CO₂ at a feed pressure of 2 bar and 1.5 bar. Detailed characterization of MMMs was performed with Fourier transform infrared spectroscopy (FTIR), Thermo-gravimetric analysis (TGA), Differential scanning calorimetry (DSC), and Field emission scanning electron microscopy (FESEM) to investigate the physical and thermal properties. MMMs formed are defects-free, voids-free, and without polymer rigidification, indicating a better filler polymer interface. MMMs showed improved CO₂ permeability while retaining the CO₂/CH₄ selectivity. The 10 wt.% UiO-66-NH₂/CA MMM showed optimum gas separation performance with CO₂ permeability of 11 Barrer and CO₂/CH₄ selectivity of 10. The UiO-66-NH₂/CA MMMs performed better when compared to the pure CA membrane. The experimental permeability and selectivity data were compared with the predicted data using Maxwell, Lewis–Nielsen, Higuchi, and Bruggeman's model.     

Effect of graphene oxide on the behavior of poly(amide‐6‐b‐ethylene oxide)/graphene oxide mixed‐matrix membranes in the permeation process

Polyether‐block‐amide (Pebax)/graphene oxide (GO) mixed‐matrix membranes (MMMs) were prepared with a solution casting method, and their gas‐separation performance and mechanical properties were investigated. Compared with the pristine Pebax membrane, the crystallinity of the Pebax/GO MMMs showed a little increase. The incorporation of GO induced an increase in the elastic modulus, whereas the strain at break and tensile strength decreased. The apparent activation energies (E_p) of CO₂, N₂, H₂, and CH₄ permeation through the Pebax/GO MMMs increased because of the greater difficulty of polymer chain rotation. The E_p value of CO₂ changed from 16.5 kJ/mol of the pristine Pebax to 23.7 kJ/mol of the Pebax/GO MMMs with 3.85 vol % GO. Because of the impermeable nature of GO, the gas permeabilities of the Pebax/GO MMMs decreased remarkably with increasing GO content, in particular for the larger gases. The CO₂ permeability of the Pebax/GO MMMs with 3.85 vol % GO decreased by about 70% of that of the pristine Pebax membrane. Rather than the Maxwell model, the permeation properties of the Pebax/GO MMMs could be described successfully with the Lape model, which considered the influence of the geometrical shape and arrangement pattern of GO on the gas transport. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015 , 132, 42624.     

Highly permselective MIL‐68(Al)/matrimid mixed matrix membranes for CO2/CH4 separation

With global appeal to green and efficient utilization of energies, metal‐organic frameworks based mixed matrix membranes are standing out in applications such as gas and liquid separation because of the integration of size/shape selectivity of MOFs with processability and mechanical stability of polymers. In the present work, a novel MIL‐68(Al) (MIL = Material of Institute Lavoisier) based mixed matrix membrane (MMM) was developed by adding porous MIL‐68(Al) into Matrimid for the separation of CO₂/CH₄ mixture. The MIL‐68(Al)/Matrimid MMM displays a high CO₂ permselectivity. For the separation of an equimolar CO₂/CH₄ mixture at 373 K and 1 bar, the CO₂ permeability and the CO₂/CH₄ selectivity are 284.3 Barrer and 79.0, respectively, which far exceed the Robeson upper bound limit and those of the previously reported MMMs. Both the operation pressure and temperature have great influence to the separation performance of the MIL‐68(Al)/Matrimid MMM. Further, the MIL‐68(Al)/Matrimid MMM shows a high stability in the long‐term separation of CO₂/CH₄. These properties recommend the MIL‐68(Al)/Matrimid MMM as a promising candidate for the purification of natural gases. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43485.     

In situ carbon deposition in polyetherimide/SAPO‐34 mixed matrix membrane for efficient CO2/CH4 separation

A simple method of pore modification complied with defect removal polymer zeolite mixed matrix membrane was developed by in situ carbon (C) deposition. The C deposition was achieved by the controlled decomposition of polymer matrix by heat treatment. In this study, polyetherimide/silicoaluminophosphate‐34 mixed matrix membrane (MMM) was fabricated on clay‐alumina support tube, followed by carbonization of the polymer matrix for gas separation application. MMM without heat treatment were also synthesized for comparison by conventional method. The membranes were characterized by X‐ray diffraction, field emission scanning electron microscopy, and X‐ray photoelectron spectroscopy. Due to carbonization, in situ C nanoparticles were deposited in to the interfacial pores, and filler particles were oriented in preferable direction. The presence of C?O, C? N, and graphitic carbon in the matrix, may be an indication of partial carbonization and restoration of adherence of polymer with substrate. The separation factor for CO₂/CH₄ achieved 39.15 with a permeance value of 23.01 × 10^?8mol/(m² s Pa) for CO₂ at 30 °C and 200 kPa feed pressure. For the first time, this work shows an improvement toward permeability of MMM by simple carbonization of polymer matrix with commendable values as compare to the reported literature. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 45508.     

Effect of different organic amino cations on SAPO‐34 for PES/SAPO‐34 mixed matrix membranes toward CO2/CH4 separation

Mixed matrix membranes (MMMs) embedded with functionalized SAPO‐34 were successfully synthesized and characterized. Two different types of organic amino cation, namely ethylenediamine (EDA) and hexylamine (HA), were used to functionalize SAPO‐34 particles prior to MMM synthesis. In this work, the effects of different functionalizing agents on the membrane morphology, pore size, and CO₂/CH₄ gas separation properties were investigated. Surface modification of SAPO‐34 was confirmed via X‐ray photoemission spectroscopy (XPS) where the presence of nitrogen atom was observed for the samples functionalized with amino cations. The dispersion of EDA‐functionalized SAPO‐34 particles was found to have better polymer/filler interface morphology as shown by field emission scanning electron microscopy (FESEM) analysis. The gas separation performance revealed that PES containing EDA‐functionalized SAPO‐34 exhibited better CO₂/CH₄ separation performance as compared to the MMMs containing HA‐functionalized SAPO‐34. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 133, 43387.     

Enhanced CO2 selectivity of polyimide membranes through dispersion of polyethyleneimine decorated UiO-66 particles

Branched polyethyleneimine (PEI) functionalized UiO-66 were synthesized and used as fillers to fabricated mixed-matrix membranes (MMMs) for CO₂/CH₄ separation. The purpose of introducing amino-functional groups in the filler is to improve the interfacial compatibility of the filler with the polymer through the formation of hydrogen bonds with the carbonyl group of 6FDA-ODA. Additionally, the amino group can facilitate CO₂ transport through a reversible reaction, enhancing the CO₂/CH₄ separation properties of MMM. The chemical structure and morphology of fillers and membranes were characterized by employing X-ray photoelectron spectroscopy (XPS), Fourier transform infrared spectrometer (FTIR), X-ray diffraction (XRD), thermogravimetric (TGA), Derivative thermogravimetry (DTG) and scanning electron microscope (SEM). Furthermore, the effects of filler loading and feed pressure on CO₂ permeability and CO₂/CH₄ selectivity have been investigated. MMMs present higher gas separation performance than pure 6FDA-ODA due to the presence of amino groups and the improvement of interface morphology. In particular, the MMM with 15 wt% loading of UiO-66-PEI shows optimum CO₂ permeability of 28.23 Barrer and CO₂/CH₄ selectivity of 56.49. Therefore, post-synthetic modification of UiO-66 particle with PEI is a promising alternative to improved membrane performance.     

Effect of chemically modified clinoptilolite on the thermal,morphological, and gas separation properties of mixed matrix membranes

Mixed matrix membranes (MMM) based on polysulfone and chemically modified clinoptilolite were prepared. Clinoptilolite enriched with Ca²⁺, K⁺, and Na⁺ by ion exchange at two test temperatures was prepared. Chemical composition was monitored by energy dispersive X‐ray spectroscopy. X‐ray diffraction, thermogravimetric analysis, and N₂ adsorption–desorption isotherms were also performed. Thermal and morphological properties of MMM were evaluated. CH₄/CO₂ gas mixture permeability tests at different upstream pressure were carried out. Type of exchanged cation in modified clinoptilolite affected the CO₂ permeability. An improvement on the CO₂/CH₄ selectivity values in the MMM compared to the polymeric membrane was appreciated. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135, 45659.     

Effects of halloysite nanotubes on the morphology and CO2/CH4 separation performance of Pebax/polyetherimide thin-film composite membranes

Enhancing the performance of gas separation membranes is one of the major concerns of membrane researchers. Thus, in this study, poly(ether-block-amide) (Pebax)/polyetherimide (PEI) thin-film composite membranes were prepared and their CO₂/CH₄ gas separation performance was investigated by means of pure and mixed gases permeation tests. To improve the properties of these membranes, halloysite nanotubes (HNT) were added to Pebax layer at different loadings of 0.5, 1, 2, and 5 wt % to form Pebax-HNT/PEI membranes. Scanning electron microscopy, gas sorption, X-ray diffraction, Fourier-transform infrared, and differential scanning calorimetry tests were also performed to investigate the impact of HNT on structure and properties of prepared membranes. Results showed that both CO₂/CH₄ selectivity and CO₂ permeance increased by adding HNT to Pebax layer up to 2 wt %. By increasing HNT loading to 5 wt %, the CO₂/CH₄ selectivity decreased from 32 to 18, while CO₂ permeance increased from 3.25 to 4.2 GPU. Pebax/PEI and Pebax-HNT/PEI membranes containing 2 wt % of HNT were tested using CO₂/CH₄ gas mixtures at different feed CO₂ concentrations and feed pressure of 4 bar. The results showed that with increasing CO₂ concentration from 20 to 80 vol %, CO₂/CH₄ selectivity of Pebax/PEI composite membranes increased by 19%, while, in Pebax-HNT/PEI membrane, CO₂/CH₄ selectivity decreased by 40%. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2020 , 137, 48860.     

Current Status and Future Prospect of Polymer‐Layered Silicate Mixed‐Matrix Membranes for CO2/CH4 Separation

The mixed‐matrix membrane (MMM), a state‐of‐the‐art polymer‐inorganic hybrid, is a relatively recent addition to the membrane family which adopts the synergistic advantages of the polymer and inorganic phase. Although marked improvement has been achieved by MMMs in CO₂/CH₄ separation, the development of a defect‐free structure to transcend the Robeson upper bound limit remains a challenge. In previous years, a number of inorganic materials with diverse nature have been studied for CO₂/CH₄ separation; however, layered silicates have not attracted much attention despite their superior thermal and mechanical properties. Analyses of the potential of using layered silicates as inorganic fillers in MMM fabrication for CO₂/CH₄ separation are reviewed. Additionally, the immediate challenges toward successful formation of layered silicate‐based MMM and future prospects are addressed.     

Synthesis of High‐Performance Pebax®‐1074/DD3R Mixed‐Matrix Membranes for CO2/CH4 Separation

This work deals with the incorporation of deca‐dodecasil 3 rhombohedral (DD3R) zeolite as an inorganic filler into the Pebax®‐1074‐based polymer matrix to enhance the performance of the pure polymeric membrane in CO₂/CH₄ separation. The membranes were fabricated with different concentrations of DD3R. Separation performances of the membranes were investigated at various feed pressures and temperatures. Scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR), and differential scanning calorimetry (DSC) analysis of the prepared membranes were performed. In the best case, selectivity for CO₂/CH₄ separation was improved, while the permeability decreased. Membranes with 1 and 5 wt % DD3R were located in the acceptable region beyond the Robeson plot (1991) for CO₂/CH₄ gas pairs.     

Effect of the particle size and particle agglomeration on composite membrane performance

One of the most used methods for studying the rigidification of polymer matrices in composite membranes is differential scanning calorimetry. Glass‐transition temperatures give information about filler–polymer interaction and the rigidity of the polymer matrix. In this study, optical microscopy, mechanical property testing, and X‐ray diffraction, instead of differential scanning calorimetry, were used to study both poly(ether imide) (PEI) matrix rigidification and activated carbon–PEI interfacial adhesion. Then, the permselective properties of the mixed matrix membranes were interpreted. The change in rigidity in these composite membranes was in agreement with the decrease in the flexibility of the composite materials as the filler content increased. This fact was confirmed by the tension and elongation data and X‐ray diffraction (DRX) measurements. However, the Young's modulus value decreased as the carbon content increased. There was an increase in all of the gas permeability coefficients measured in the composites compared with that of PEI. As the particle size grew, a low particle surface area and a poor interfacial adhesion were observed. The carbon agglomerates acted as sites of stress concentration within the polymeric matrix. This decreased the intercatenary distances and limited the movement of polymer chains, which resulted in a more rigid matrix. The higher selectivity of the H₂/CH₄, H₂/CO₂ and O₂/N₂ systems observed in the composite membranes revealed that there were both a preferential sorption of certain gases in the carbon surface or carbon–polymer interface and a molecular size exclusion, which were responsible for that increment, despite the poor interfacial adhesion. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Matrix effect of mixed‐matrix membrane containing CO2‐selective MOFs

Facilitated mixed‐matrix membranes (MMMs) containing Cu‐metal organic frameworks (Cu‐MOFs) with high CO₂ selectivity on an asymmetric polysulfone support were fabricated and examined the effect of gas separation performance using different matrices. An amorphous poly(2‐ethyl‐2‐oxazoline) (POZ) and semicrystalline poly(amide‐6‐b‐ethylene oxide) (PEBAX^®MH 1657) block copolymer were chosen as the polymeric matrix and the effect of the matrix on CO₂ separation for MMMs containing Cu‐MOFs was investigated. The interaction of CO₂ in different matrix was investigated theoretically using the density functional theory method, and it was found that the amide segment in PEBAX would contribute more to the CO₂ solubility than ether segment. The morphological changes were investigated by differential scanning calorimetry, field emission scanning electron microscope and X‐ray diffractometer. The ideal selectivity of CO₂/N₂ was enhanced significantly with the addition of a Cu‐MOF, and the values are higher in the Cu‐MOF/PEBAX MMM compared with that in a POZ based asymmetric MMM. Improvement in the CO₂/N₂ selectivity of a Cu‐MOF/PEBAX MMM was achieved via facilitated transport by the CO₂‐selective Cu‐MOFs due to both their high adsorption selectivity of CO₂ over N₂ and the decreased crystallinity of PEBAX due to the presence of the Cu‐MOFs, which would provide a synergic effect on the CO₂ separation. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016 , 132, 42853.     

Effect of the ZIF‐8 Distribution in Mixed‐Matrix Membranes Based on Matrimid® 5218‐PEG on CO2 Separation

In theory, the combination of inorganic materials and polymers may provide a synergistic performance for mixed‐matrix membranes (MMMs); however, the filler dispersion into the MMMs is a crucial technical parameter for obtaining compelling MMMs. The effect of the filler distribution on the gas separation performance of the MMMs based on Matrimid®‐PEG 200 and ZIF‐8 nanoparticles is demonstrated. The MMMs were prepared by two different membrane preparation procedures, namely, the traditional method and non‐dried metal‐organic framework (MOF) method. In CO₂/CH₄ binary mixtures, the MMMs were tested under fixed conditions and characterized by various methods. Finally, regardless of the MMM preparation procedure, the incorporation of 30 wt % ZIF‐8 nanoparticles allowed to increase the CO₂ permeability in MMMs. The ZIF‐8 dispersion influenced significantly the separation factor.     

High speed spin coating in fabrication of Pebax 1657 based mixed matrix membrane filled with ultra-porous ZIF-8 particles for CO<Subscript>2</Subscript>/CH<Subscript>4</Subscript> separation

Modified ultra-porous ZIF-8 particles were used to prepare novel ZIF-8/Pebax 1657 mixed matrix membranes (MMMs) on PES support for separation of CO₂ from CH₄ using spin coating method. TEM and SEM were used to characterize modified ZIF-8 particles. SEM was also used to investigate the morphology of synthesized MMMs. The MMMs with thinner selective layer showed higher CO₂ permeability and lower CO₂/CH₄ selectivity in permeation tests compared to MMMs with thicker selective layer. The plasticization was recognized as the main reason for rise in CO₂ permeability and drop in CO₂/CH₄ selectivity of thinner MMMs. The gas sorption results showed that the high permeability of CO₂ in MMMs is mainly due to the high solubility of this gas in MMMs, leading to high CO₂/CH₄ solubility selectivity for MMMs. The fractional free volume and void volume fraction of MMMs increased as the thickness of membrane decreased. Applying higher mixed feed pressures and permeation tests temperatures resulted in increase in CO₂ permeability and decrease in CO₂/CH₄ selectivity. At highest testing temperature (60 °C), the CO₂ permeability of synthesized MMMs with thinner selective layer remarkably increased.     

Prestructured MXene fillers with uniform channels to enhance CO2 selective permeation in mixed matrix membranes

The packing pattern of two-dimensional (2D) sheet-like fillers in membranes is relatively random, leading to the unfavorable permeability from tortuous diffusion pathway. A new strategy that using prestructured materials with uniform channels as fillers was proposed. In this work, Ti₃AlC₂ is etched to prepare multilayered MXene (m-MXene), the channels aggregate as a whole unit, ensure the impossibility of ineffective packing compared with traditional individual sheets, largely facilitating the selective permeation. Then, the m-MXene/Poly (amide-6-b-ethylene oxide) (Pebax) MMMs are synthesized. SEM images demonstrate the accordion shaped structure of filler, which is the multi-channels laminates. Furthermore, the results of gas permeation test exhibit enhanced performance of m-MXene/Pebax MMMs. MMM with 0.5 wt.% m-MXene behaved best, CO₂ permeability of 86.22 Barrer as well as CO₂/N₂ selectivity of 104.85, transcending the Robeson upper bound (2008). Having distinct enhancement for CO₂ separation, the m-MXene/Pebax MMMs in this work offer prospective practical applications.     

Mixed matrix membranes based on 6FDA polyimide with silica and zeolite microsphere dispersed phases

Mixed matrix membranes (MMMs) prepared with 6FDA‐DAM polymer using ordered mesoporous silica MCM‐41 spheres (MSSs), Grignard surface functionalized MSSs (Mg‐MSSs) and hollow zeolite spheres are studied to evaluate the effects of surface modification on performance. Performance near or above the so‐called permeability‐selectivity trade‐off curve was achieved for the H₂/CH₄, CO₂/N₂, CO₂/CH_4, and O₂/N₂ systems. Two loadings (8 wt % and 16 wt %) of MSSs were tested using both constant volume and Wicke–Kallenbach sweep gas permeation systems. Besides single gas H₂, CO₂, O₂, N₂, and CH₄ tests, mixed gas (50/50 vol %) selectivities were obtained for H₂/CH₄, CO₂/N₂, CO₂/CH₄, and O₂/N₂ and found to show enhancements vs. single gases for CO₂ including cases. Mg‐MSS/6FDA‐DAM was the best performing MMM with H₂/CH₄, CO₂/N₂, CO₂/CH₄, and O₂/N₂ separation selectivities of 21.8 (794 Barrer of H₂), 24.4 (1214 Barrer of CO₂), 31.5 (1245 Barrer of CO₂), and 4.3 (178 Barrer of O₂), respectively. © 2015 American Institute of Chemical Engineers AIChE J, 61: 4481–4490, 2015     

Efficient CO2 Separation Using a PIM-PI-Functionalized UiO-66 MOF Incorporated Mixed Matrix Membrane in a PIM-PI-1 Polymer

Metal–organic framework (MOF) incorporated mixed–matrix membranes (MMMs) attract great interest for gas separation applications because they overcome limitations faced by typical polymer membranes, including permeability–selectivity trade-off, aging effect, and plasticization phenomenon. However, optimal MOF–polymer interface compatibility is the key challenge in fabricating defect-free high-performance gas-separation MMMs. Here, a surface modification strategy of the UiO-66-NH₂ MOF using a covalently bound PIM-PI-oligomer is developed to engineer interface compatibility with the polymer that has an identical chemical structure (PIM-PI-1) in the MMMs. A series of MMMs are prepared with different loadings of homogeneously distributed PIM-PI-functionalized MOFs (PPM). Significant improvements in CO₂/N₂ and CO₂/CH₄ selectivity and permeability are achieved with these MMMs, ranging from 5 to 10 wt% of the PPM loadings. The MMM with 10 wt% loading (PPM-10@MMM) shows a CO₂ permeability of 3827.3 Barrer and a CO₂/N₂ and CO₂/CH₄ selectivity of 24 and 13.4, respectively. This surpasses the 2008 Robeson upper bound for CO₂/N₂ and is very close to the 2008 upper bound for CO₂/CH₄. The experimental results are further compared using Maxwell's equation for MMMs. The resulting MMMs show a plasticization resistance against CO₂ up to 25 atm pressure and anti-aging performance for 180 h.     

Synthesis,characterization, and performance evaluation of PES/EDA‐functionalized TiO2 mixed matrix membranes for CO2/CH4 separation

Poor adhesion between hydrophobic polymers and hydrophilic inorganic fillers is a challenge that encumbers a high separation performance of mixed matrix membrane (MMM). In this study, Titanium(IV) oxide (TiO₂) nanoparticles were functionalized using ethylenediamine (EDA) before embedment in poly(ether sulfone) (PES) polymer matrix. MMMs were synthesized through dry phase inversion technique. Membranes morphology and nanoparticles dispersion was drastically enhanced posterior amine modification indicating an improved adhesion between the polymer and filler particles. Membranes thermal stability was likewise improved as higher degradation temperatures were perceived for PES/EDA–TiO₂ MMMs. Gas separation evaluation for pure carbon dioxide (CO₂) and methane (CH₄) gases revealed a remarkably enhanced separation performance upon amine‐grafting of TiO₂ as EDA‐TiO₂ MMMs exhibited a higher separation performance as compared to MMMs with pristine TiO₂. The highest ideal separation factor achieved was 41.52 with CO₂ permeability of 10.11 Barrer at an optimum loading of 5% wt of EDA‐TiO₂ which is threefold higher as compared to neat PES membrane and approximately twofold higher than MMMs with pristine TiO₂, respectively, at the same filler loading. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134, 45346.