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Betaine-based natural deep eutectic solvents (NADESs), a new class of green solvents, were immobilized into a porous polyvinylidene fluoride (PVDF) support and evaluated for the separation of CO2 from CO2/N2 and CO2/CH4 mixtures. Two types of NADESs were synthesized by mixing betaine (hydrogen bond acceptor-HBA) with malic acid and tartaric acid (hydrogen bond donors-HBD) respectively. FTIR and Raman spectroscopy were studied to confirm the synthesis and purity of the NADESs. The thermal strength of the NADESs was investigated using thermogravimetric analysis. The gas permeation results of the fabricated NADES-based-supported liquid membranes (NADES-SLMs) showed that the permeability of CO2 increased from 25.55 to 29.33 Barrer on substitution of hydrogen bond donor from tartaric acid to malic acid. Similarly, the ideal CO2/CH4 selectivity varied from 51.1 to 56.4 as tartaric acid was replaced by malic acid as the HBD. The performance of NADES-SLMs was compared with the competing imidazolium-based-supported ionic liquid membranes, and proved NADES-SLMs as a promising alternative considering their green potential and comparable gas separation performance. The current effort for the exploitation of NADESs into PVDF membranes in this study is expected to open new routes for the efficient separation of CO2 from the industrial gas mixture.

Mixed matrix membranes (MMMs) were fabricated by the hydrothermal synthesis of ordered mesoporous KIT-6 type silica and incorporating in polyimide (P84). KIT-6 and MMMs were characterized to evaluate morphology, thermal stability, surface area, pore volume, and other characteristics. SEM images of synthesized MMMs and permeation data of CO2 suggested homogenous dispersion of mesoporous fillers and their adherence to the polymer matrix. The addition of KIT-6 to polymer matrix improved the permeability of CO2 due to the increase in diffusivity through porous particles. The permeability was 3.2 times higher at 30% loading of filler. However, selectivity showed a slight decrease with the increase in filler loadings. The comparison of gas permeation results of KIT-6 with the well-known MCM-41 revealed that KIT-6 based MMMs showed 14% higher permeability than that of MMMs composed of mesoporous MCM-41. The practical commercial viability of synthesized membranes was examined under different operating temperatures and mixed gas feeds. Mesoporous KIT-6 silica is an attractive additive for gas permeability enhancement without compromising the selectivity of MMMs. Graphical abstract.

Novel mixed matrix membranes (MMMs) were fabricated by incorporating bimetallic Zn/Co-ZIF nanoparticles into the prototypical polymer of intrinsic microporosity (PIM-1). The morphological and structural characteristics of Zn/Co-ZIF and ZIF-8 were analyzed with XRD, FTIR, BET and SEM. The characterization results showed that the Zn/Co-ZIF is isostructural to ZIF-8 occupying the same crystallographic sites, however, Zn/Co-ZIF has smaller BET surface area and lower pore volume than ZIF-8. The SEM images of fabricated MMMs demonstrated good dispersion and interaction of the filler in the polymer matrix, even at high loadings. The addition of hydrophobic nanoparticles enhanced the hydrophobicity of the MMMs, and relatively more for the Zn/Co-ZIF/PIM. The MMMs were analyzed for their separation performance of two binary mixtures made of ethanol/water and butanol/water comprising 5 wt% alcohol, via pervaporation. Flux and separation factor of both alcohols increased with filler loadings in both ZIF-8/PIM-1 and Zn/Co-ZIF/PIM-1 membranes, showing an anti-tradeoff effect which is more significant in Zn/Co-ZIF/PIM-1 membranes. Zn/Co-ZIF/PIM-20 wt% membranes showed 129% higher separation in comparison with pristine PIM-1 membranes. Moreover, not only did the Zn/Co-ZIF/PIM-1 membranes show a higher separation factor, but they also had a higher rate of increase with increased loadings, which was quasi-constant for ZIF-8/PIM-1 membranes. ZIF-8/PIM-1 at filler loading of 20 wt% showed the highest normalized flux of 139 kg.µm.m-2.h-1.Keywords: PIM-1; ZIF-8; Zn/Co-ZIF; Mixed Matrix Membranes; Pervaporation.

Microalgae-based products have gained growing interest leading to an increase in large-scale cultivation. However, the high energy associated with microalgae harvesting becomes one of the bottlenecks. This study evaluated an energy-efficient microalga harvesting via ultra-low-pressure membrane (ULPM) filtration (, Membrane fouling; Low pressure membrane system; Microalgae filtration; Aeration; Energy consumption.

A rotating biological contactor (RBC) offers a low energy footprint but suffers from performance instability, making it less popular for domestic wastewater treatment. This paper presents a study on an RBC integrated with membrane technology in which membrane filtration was used as a post-treatment step (RBC–ME) to achieve enhanced biological performance. The RBC and RBC–ME systems were operated under different hydraulic retention times (HRTs) of 12, 18, 24, and 48 h, and the effects of HRT on biological performance and effluent filterability were assessed. The results show that RBC–ME demonstrates superior biological performance than the standalone RBC. The RBC–ME bioreactor achieved 87.9 ± 3.2% of chemical oxygen demand (COD), 98.9 ± 1.1% ammonium, 45.2 ± 0.7% total nitrogen (TN), and 97.9 ± 0.1% turbidity removals. A comparison of the HRTs showed that COD and TN removal efficiency was the highest at 48 h, with 92.4 ± 2.4% and 48.6 ± 1.3% removal efficiencies, respectively. The longer HRTs also lead to better RBC effluent filterability. The steady-state permeability increased respectively by 2.4%, 9.5%, and 19.1% at HRTs of 18, 24, and 48 h, compared to 12 h. Our analysis of membrane fouling shows that fouling resistance decreased at higher HRTs. Overall, RBC–ME offered a promising alternative for traditional suspended growth processes with higher microbial activity and enhanced biological performance, which is in line with the requirements of sustainable development and environment-friendly treatment.

Mixed matrix membranes (MMMs) provide a unique pathway to treat hazardous industrial effluents. MMMs containing zeolitic imidazolate framework-8 (ZIF-8) as filler in polydimethoxysilane (PDMS) matrix were synthesized. ZIF-8 was prepared using a modified recipe and characterized by different techniques to evaluate its morphology, thermal stability, surface area, pore volume, and other characteristics. The performance of membranes was evaluated for their application in industrial dye-stuff wastewater treatment and solvent-resistant nanofiltration. The results demonstrated that increase in the percentage of ZIF-8 loading in PDMS led to simultaneous increase in the solvent permeability as well as solute rejection from wastewater. The permeability of MMMs increased up to 32% as compared with neat PDMS membrane. The organic dye rejection was achieved more than 87% with MMMs incorporated with 20% loading of nanofillers. Rejection of MMMs was 22% higher than that of unfilled PDMS membrane due to the effect of reduced polymer swelling and size exclusion of the nanofillers. Membrane swelling tests with toluene and isopropanol demonstrated that nanofiller amount has inverse relation with membrane swelling, which implied that nanofillers were in good interaction with polymer and allowed defect free membranes with higher solute rejections and reduced membrane swelling.

A porous and thermally stable metal organic framework (MOF) of yttrium and 1,3,5-benzenetricarboxylate was synthesized, which belongs to the family of lanthanide-based MOF-76. Mixed-matrix membranes were developed by incorporating MOF-76 yttrium nanocrystals into Matrimid® 5218. The structure, composition, and morphology of synthesized lanthanide-based MOF-76 yttrium nanocrystals and mixed-matrix membranes were characterized by X-ray diffraction, Fourier-transform infrared spectroscopy, scanning electron microscopy, and thermogravimetric analysis. The characterizations and gas permeation results of the prepared mixed-matrix membranes confirmed better adhesion and distribution of filler particles in the polymer. The results demonstrated that the addition of MOF-76 yttrium nanocrystals to the polymer matrix improved both the gas selectivity and permeability of mixed-matrix membranes compared to pure Matrimid membranes. Permeability of CO2 increased from 7.24 to 27.29 Barrer by increasing the particle content from 0 to 30% in pure gas experiments. Whereas with 30 wt% concentration of MOF-76(Y) at 50:50 feed compositions, the selectivity increased for CO2/CH4 and CO2/N2 was 67% and 68%, respectively. The rise in temperature from 298 to 338 K decreased the ideal selectivity up to 25% for both gas pairs due to polymer chain relaxations at elevated temperatures. The commercial importance of membranes was evaluated at different feed compositions and operating temperatures.

Functionalized mixed matrix membranes (MMMs) have the potential to upgrade the separation performance of conventional polymeric membranes while as yet keeping their processing benefits and lower costs. This study investigated the highly stable zirconium based metal-organic framework UiO-66 functionalized with sulfonic group, which was grafted by silane coupling agent mercaptopropyl trimethoxysilane. Sulfonic group imparted high separation properties to UiO-66. Polysulfone (PSf) was used as a polymer matrix and MMMs were synthesized for non-functionalized and functionalized UiO-66; and their results were compared. The characterization and permeation results ascribed that functionalized UiO-66 adhered well with the PSf matrix. The results demonstrated that increasing sulfonic group concentration resulted in higher selectivities owing to their high affinity towards CO2 gas molecules. The MMMs exhibited high CO2 permeabilities and selectivities under pure and mixed gas conditions; and proved this material promising for CO2 separation. In order to evaluate the practical commercial viability of these MMMs, investigation was conducted under different temperatures and compared with existing literature.

In the current study, polysulfone (PSF) membranes incorporated with nano alumina (Al2O3) were synthesized by a phase inversion method to improve the efficiency of the PSF membrane for wastewater treatment. Dimethylformamide was used as solvent while polyvinylpyrrolidone was used as a pore former. Different concentrations of nanoparticles of Al2O3 were used in the casting solution to get an optimum condition for the highest water flux. Cross section morphology of the membranes was investigated through scanning electron microscope. Membranes were characterized by pure water flux, permeability, hydrophilicity, porosity, and retention of Cu(II). All the mixed matrix nanocomposite membranes showed higher water flux than the nascent PSF membrane due to their increased porosity and hydrophilicity with the addition of nano alumina. Cu(II) rejection was also enriched by composite membranes due to a high number of adsorption sites on membranes surface as a result of better hydrophilicity and dispersion of nano alumina. The membrane with 0.1 wt% nano Al2O3showed the best performance in terms of water flux (32.60 L·m-2·h-1) and significant Cu(II) removal (61.95%) compared to other membranes after continuous treatment of 150 min. The reusability test of the PAl0.1 membrane confirmed the durability of the composite membranes after several cycles using ethylenediaminetetraacetic acid as a regenerator.

Chitosan was functionalized to synthesize Quaternized N-trimethyl chitosan (TMC) and incorporated in polyethersulfone (PES) polymer to fabricate membranes for enhanced antifungal activity and water treatment. The TMC was synthesized from chitosan via reductive alkylation and methylation. The effect of concentration of chitosan and TMC on the properties of functionalized PES membranes was investigated. The membrane with the lowest concentration of TMC 5% (w/w) resulted in the largest average pore size than the PES membrane without chitosan or TMC. The surface wettability was enhanced as contact angle was reduced from 90° to 57° by increasing concentration of TMC to 15% (w/w). The resultant membranes exhibited improved water hydrophilicity, permeability and inhibition against fungal species. The functionalized membranes had shown noticeable antifungal activity against Aspergillus niger in the case of 15% TMC with 72% antifungal activity and 15% chitosan with 63% antifungal activity against Fusarium solani.

This paper reports the development of high performance mixed matrix membranes (MMMs) comprising of bio metal-organic framework (Bio-MOF-1) and polysulfone (PSf) polymer matrix. For the very first time, a Bio-MOF was used as filler in MMMs. Bio-MOF-1 crystals showed well defined rectangular-like shapes (nano-bars) with lengths of ∼0.5–4.0 µm and widths of ∼0.05–0.20 µm and smooth surfaces. SEM images of membranes demonstrate good dispersion and interaction of the filler in the polymer matrix, even at high loadings. The gas transport properties of MMMs with Bio-MOF-1 loading up to 30 wt% were investigated, and the results showed such MMMs had a CO2 permeability of 16.57 Barrer and ideal selectivity of 42.6 and 45.6 for CO2/CH4 and CO2/N2 respectively. This corresponds to an increase in 168% and 58% for CO2 permeability and ideal selectivity respectively in comparison to pristine polymer membranes. Analysis of solubility-diffusivity in the MMMs revealed that the presence of adeninate amino and pyrimidine Lewis basic sites that decorate the pores and have relatively narrow pore dimensions in Bio-MOF-1 can greatly enhance the adsorption of the CO2 molecules. All synthesized MMMs were tested at different condition of CO2 feed concentration, various operating temperatures and their activation energies were also calculated. Finally, the comparison with relevant literature showed that even without any functionalization of Bio-MOF-1, it showed higher selectivity than amine functionalized MOFs and quite comparable permeability.

High-performance Mixed-Matrix Membranes (MMMs) comprising of two kinds of porous fillers UiO-66 and Zeolite 4Aand their combination were fabricated with polysulfone (PSf) polymer matrix. For the very first time, UiO-66 and Zeolite 4A were jointly used as nanofillers in MMMs with the objective of complimenting synergistic effects. The individual and complimentary effects of nanofillers were investigated on membrane morphology and performance, pure water flux, humic acid rejection, static humic acid adsorption, and antifouling properties of membranes. Scanning Electron Microscopy (SEM) analysis of membranes confirmed that all MMMs possessed wider macrovoids with higher nanofiller loadings than neat PSf membranes and the MMMs (PSf/UiO-66 and PSf/Zeolite 4A-UiO-66) showed tendency of agglomeration with high nanofiller loadings (1 wt% and 2 wt%). All MMMs exhibited better hydrophilicity and lower static humic acid adsorption than neat PSf membranes. Pure water flux of MMMs was higher than neat PSf membranes but the tradeoff between permeability and selectivity was witnessed in the MMMs with single nanofiller. However, MMMs with combined nanofillers (PSf/Zeolite 4A-UiO-66) showed no such tradeoff, and an increase in both permeability and selectivity was achieved. All MMMs with lower nanofiller loadings (0.5 wt% and 1 wt%) showed improved flux recovery. PSf/Zeolite 4A-UiO-66 (0.5 wt%) membranes showed the superior antifouling properties without sacrificing permeability and selectivity.

Zeolitic imidazole frameworks (ZIFs), a subclass of metal organic frameworks (MOFs), are composed of metal ions linked by organic ligands which offer an exceptionally high surface area and appealing separation potential. In this study, mixed matrix membranes (MMMs) were prepared using polydimethylsiloxane (PDMS) as a hydrophobic polymer and ZIF-67 as inorganic filler particle. ZIF-67 particles and MMMs were characterized by XRD, SEM, FTIR, BET and contact angle measurements. The prepared membranes were tested for the separation of ethanol/water mixtures via pervaporation. Compared to unfilled PDMS membranes, MMMs loaded with 20 wt% ZIF-67 showed an increase in flux and a doubled separation factor. The easy synthesis of ZIF-67 and its enhanced separation performance make ZIF-67 an attractive candidate to prepare MMMs for a variety of membrane applications.

This study focuses on using a (3-aminopropyl)trimethoxysilane and acetate ion based ionic liquid to modify zeolite 4A as a filler in a polysulfone (PSf) membrane for CO2/CH4 and CO2/N2 separation, aiming at improving the polymer-filler interaction and separation performance of the mixed matrix membrane (MMM). The ionic liquid was covalently attached onto the zeolite surface. Zeolite modification was confirmed through FTIR analysis of pristine and modified filler. N2 sorption isotherms were used to characterize the porous structure, which showed decrease in surface area and pore volume after surface modification of zeolite. The crystal structure of zeolite 4A remained unaffected after modification with ionic liquid, as shown by XRD and SEM. Moreover, the synthesized PSf-based MMMs were tested in the separation of CO2 from CH4. Experiments were conducted at different temperatures and feed conditions, and pure and mixed gas permeability/selectivity data was reported. This modification of zeolites with methoxy groups containing cation and acetate anion based ionic liquid, resulted in an improved separation performance, as the modified filler enhanced the MMMs selectivity of CO2/CH4 by 37% and for CO2/N2 by 43% at 30 wt% filler loading as compared to pristine filler MMMs. The 3-(trimethoxysilyl)propan-1-aminium acetate coating acts as a selecting film which notably improves the selectivity at marginal expense of CO2 permeance.

The gas separation performance and miscibility of Matrimid and fluorinated sulfonated aromatic poly (ether ether ketone) (F-SPEEK) blend membranes prepared by solution casting method were studied. F-SPEEK polymer with fixed degree of sulfonation (40%) was used for membrane synthesis. Physical miscibility of both Matrimid and F-SPEEK was observed over the whole composition range, as confirmed by DSC studies and visual observation. The effect of variation in F-SPEEK composition on gas permeability and selectivity of blend membranes was investigated. The gas permeability and selectivity values fall in between those of the individual polymers, varying systematically with variation of F-SPEEK content in the blend. The addition of F-SPEEK in the blend led to simultaneous increase in the gas permeability and selectivity. In order to further study the stability and potential industrial application of these membranes, they were tested at different conditions of feed temperature (298–338 K), feed pressures (10–40 bar) and CO2 concentration in feed. The effect of feed pressure on CO2 permeation was linked to CO2 plasticization of the membranes. The addition of F-SPEEK component in the blend shifted the plasticization pressure thereby imparting anti-plasticization properties to the blend. Improvement in anti-plasticization properties along with enhanced gas separation properties confirms F-SPEEK/Matrimid blend membranes as an excellent candidate for the separation of gaseous mixtures at industrial scale.

A new generation of solvents called ternary deep eutectic solvents have emerged as a promising candidate to replace ionic liquids (IL) in CO2 capturing due to its inherent advantages of both, superbase and deep eutectic solvents (DES). In this work, the binary and ternary DES were synthesized to investigate the effect of superbase on the performance of DES based membrane systems for acid gas capture. The reline DES system was chosen as binary DES and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU) was used as superbase. The ternary DES was prepared by mixing DBU in reline DES system in different molar ratios. The permeability and selectivity of the synthesized membrane for CO2, CH4, and N2 were investigated in pure and mixed gas experiments. Moreover, the effect of the DES molar ratio, operating conditions of feed on the DES based supported liquid membranes (SLMs) performance was studied comprehensively. These novel ternary DES SLMs showed significant permeability and selectivity values up to 38.12 Barrer and 58.65 respectively. These values were found to be significantly higher than the permeability and selectivity value of binary DES-SLM i.e. 31 Barrer and 51.67 respectively. The improved gas performance results of ternary DES can be attributed to the basicity and fast reaction kinetics of the superbase/DBU. The ternary DES can potentially alternate the ILs and commonly used binary DESs in CO2 capturing process due to their high affinity towards CO2 gas.

The ability to tailor ionic liquids can result in very high separation efficiency for CO 2 /CH 4 and CO 2 /N 2 . In this study, a new protic ionic liquid was synthesized with high CO 2 absorption capacity employing (3-aminopropyl) trimethoxysilane and acetic acid, both of these have been reported to exhibit high affinity for CO 2 . The synthesized ionic liquid was characterized by FTIR and the supported ionic liquid membrane was tested to determine the separation of CO 2 from CH 4 . Experiments were conducted at different temperatures and feed conditions, and pure and mixed gas permeability/selectivity data were reported. This combination of silyl ether functionalized cation and acetate ion dramatically improved the membrane separation performance as the SILM displayed CO 2 permeance of 23 GPU combined with CO 2 /CH 4 selectivity of 41. The synthesized SILM was stable upto 10 bar as no leaching of ionic liquid was observed and the permeance increased from 23 to 31 GPU as the temperature was raised from 25 °C to 65 °C, while the selectivity slightly decreased from 41 to 35 over the same temperature range. The exceptionally high selectivity of CO 2 /CH 4 makes [APTMS][Ac] a promising room temperature ionic liquid for CO 2 separation without facilitated transport. A synergistic effect of methoxy groups from [APTMS] part of the ionic liquid caused the enhanced permeability of CO 2 as supported by theoretical calculations.

This study demonstrates a new strategy in which deep eutectic solvents (DES), a new class of sustainable organic solvents, were impregnated into micro porous polymer support for separation of CO2 from CH4. Three different types of DESs were prepared by mixing and subsequent heating of betaine as hydrogen bond acceptor (HBA) in combination with either glycerol (G), ethylene glycol (EG) or urea (U) as hydrogen bond donors (HBD) in 1:3 stoichiometric mole ratio. The Fourier transform infrared (FTIR) spectroscopy was performed to confirm the formation of DESs. The gas permeation results showed that permeability of CO2 increased from 31.23 to 35.67 Barrer on substitution of HBD from glycerol to urea. The selectivity of CO2/CH4 increased from 43.32 to 57.53 for the substitution of HBD from ethylene glycol to urea. These intriguing results are ascribed by the high interaction of CO2 with DES in which solubility of CO2 is directly influenced by the HBDs. The membranes were also tested under conditions relevant to industrial feed gas and the results were compared with the competing state of the art membranes. The impregnation of DESs into the porous polymer supports provides a pathway for future material design for the efficient separation of CO2 from gases mixtures.

Amine based solvents are being used extensively for CO2 capture for the last several decades owing to their relatively high CO2 affinity. They are considered as standard solvents for CO2 separation but still, face limitations of high energy requirement, high volatility, high vapor pressure and toxicity. To overcome these limitations, for the first time in this study, amine based deep eutectic solvents (DES) are incorporated into membranes for CO2 capture. Three different alkanolamines; monoethanolamine, (MEA), diethanolamine (DEA), triethanolamine (TEA) were selected as HBDs and choline chloride as HBA. The synthesis of the DESs was confirmed by FTIR characterization as well as physicochemical properties of the resulting liquid mixture. Subsequently, the synthesized DESs were impregnated into the porous support to prepare supported liquid membranes (SLMs). The SLMs showed excellent selectivity of CO2 up to 70.47 and 78.86 for CO2/CH4 and CO2/N2 respectively. This high selectivity of CO2 over CH4 and N2 can be attributed to the chemisorption of CO2 with DES and high basicity of DES. The effect of operating temperature, the HBA: HBD mole ratio, and CO2 concentration on membrane performance was also investigated. The results of amine DESs were compared with the competing ionic liquids based membranes, and the significant high gas separation was attributed to the low viscosity and the high CO2 solubility in amines that makes them an appropriate alternative to the conventional ILs.

This study focuses on a forward looking approach in which deep eutectic solvents (DESs), a new class of designer solvents, were impregnated into micro porous polyvinylidene fluoride (PVDF) membrane for the separation of CO2 from CH4. Three types of DESs were prepared by mixing and heating of hydrogen bond acceptor (choline chloride) with either malic acid, tartaric acid or oxalic acid as hydrogen bond donor. The Fourier transform infrared spectroscopy confirmed the hydrogen bond interactions in the resulting DES. Thermal gravimetric analysis (TGA) was used to evaluate the thermal stability of the prepared membranes. The DES based supported liquid membranes were investigated systematically to determine the permeability and selectivity for the mixture of gases at both ambient and elevated temperatures. The results showed that Choline Chloride-Malic acid, Choline Chloride-Tartaric acid and Choline Chloride-Oxalic acid DES-SLMs exhibited CO2 permeability of 30.32 Barrer, 34.00 Barrer and 37.30 Barrer, respectively while ideal selectivity of these membranes was found 51.39, 55.74 and 60.16 for CO2/CH4, respectively. The fabricated membranes were compared with some of the imidazolium supported ionic liquid membranes (SILMs) on the Robeson upper bound plot. The current study on DES-SLMs is expected to open new pathways for the exploitation of DESs for CO2 capture.

The synergetic effect of nitrogen-rich and CO2-philic filler and polymer in mixed matrix-based membranes (MMMs) can separate CO2 competently. The introduction of well-defined nanostructured porous fillers of pores close to the kinetic diameter of the gas molecule and polymer matrix compatibility is a challenge in improving the gas transportation characteristics of MMMs. This study deals with the preparation of porphyrin filler and the polysulfone (PSf) polymer MMMs. The fillers demonstrated uniform distribution, uniformity, and successful bond formation. MMMs demonstrated high thermal stability with a glass transition temperature in the range of 480–610 °C. The porphyrin filler exhibited microporous nature with the presence of π-π bonds and Lewis’s basic functionalities between filler-polymer resulted in a highly CO2-philic structure. The pure and mixed gas permeabilities and selectivity were successfully improved and surpass the Robeson’s upper bound curve's tradeoff. Additionally, the temperature influence on CO2 permeability revealed lower activation energies at higher temperatures leading to the gas transport facilitation. This can be granted consistency and long-term durability in polymer chains. These results highlight the unique properties of porphyrin fillers in CO2 separation mixed matrix membranes and offer new knowledge to increase comprehension of PSf performance under various contents or environments.

Antifouling polyethersulfone (PES) membranes for water disinfection were fabricated by incorporating varying concentrations of carbohydrate polymer chitosan and Zinc oxide hybrid nanoparticles (CS-ZnO HNPS). The CS-ZnO HNPS were prepared using chemical precipitation method and were characterized using SEM, XRD and FTIR. The membranes were then fabricated by incorporating nanoparticles of CS-ZnO HNPS with three different concentrations of 5%, 10% and 15% w/w in the casting solution of PES through phase inversion method. The influence of nano-sized CS-ZnO HNPS on the properties of PES was characterized to study morphology, contact angle, water retention, surface roughness and permeability flux. The membranes with the maximum concentrations of 15% HNPS resulted in larger mean pore sizes and lowest contact angle value as compare to the pristine PES membrane. The prepared membranes exhibited significant water permeability, hydrophilicity and prevention against microbial fouling. The prepared membranes were observed to have significant antibacterial as well as antifungal properties due to the synergistic effect of chitosan and ZnO against both bacteria of the type of S. Aureus, B. Cereus, E. coli, and fungi such as S. typhi, A. fumigatus and F. solani.

This paper aims to develop novel hydrophilic ionic liquid membranes using pervaporation for the recovery of biobutanol. Multiple polyvinyl alcohol (PVA) membranes based on three commercial ionic liquids with different loading were prepared for various experimental trials. The ionic liquids selected for the study include tributyl (tetradecyl) phosphonium chloride ([TBTDP][Cl]), tetrabutyl phosphonium bromide ([TBP][Br]) and tributyl methyl phosphonium methylsulphate ([TBMP][MS]). The synthesized membranes were characterized and tested in a custom-built pervaporation set-up. All ionic liquid membranes showed better results with total flux of 1.58 kg/m2h, 1.43 kg/m2h, 1.38 kg/m2h at 30% loading of [TBP][Br], [TBMP][MS] and [TBTDP][Cl] respectively. The comparison of ionic liquid membranes revealed that by incorporating [TBMP]MS to PVA matrix resulted in a maximum separation factor of 147 at 30 wt% loading combined with a relatively higher total flux of 1.43 kg/m2h. Density functional theory (DFT) calculations were also carried out to evaluate the experimental observations along with theoretical studies. The improved permeation properties make these phosphonium based ionic liquid a promising additive in PVA matrix for butanol-water separation under varying temperature conditions.

Mixed matrix membranes were prepared by incorporating pyrazole functionalized SBA-16 type mesoporous silica as filler in polysulfone (PSf) matrix. The structure, morphology, and porosity of functionalized filler were confirmed by Fourier transform infrared (FTIR) spectra, scanning electron microscope (SEM) images, 13C NMR spectra and N2 adsorption-desorption analysis. A good uniform interaction of filler with polymer matrix was observed for all membranes. The porosity of filler enhanced the CO2 gas diffusivity through the membrane leading to increased CO2 permeability of up to 14.43 Barrer (116% increase) at the highest filler loading of 30%. The presence of CO2-philic functional groups resulted in a simultaneous increase in both ideal and mixed gas CO2/N2 selectivity of 42.44 and 46.13 respectively (68.34% and 87.06% increase respectively), compared to non-functionalized filler).

The minimisation of the continuously enhancing level of the CO2 released to the atmosphere is one of the most significant issues faced by the scientific community. Rigorous research efforts have been carried out for the development of sustainable and cost-effective nitrogen-rich porous adsorbent materials for energy-efficient and enhanced polar gas separation, i.e. pre-combustion and post-combustion CO2 capture. Among different porous adsorbent materials, the covalent triazine frameworks (CTFs) are found to be remarkable candidates for CO2 capturing because of their facile and scalable synthesis, high surface area, permanent porosity, structural tunability, synthetic diversity, low density, high hydrothermal and physicochemical stability. A contextual overview is described on the key challenges in CO2 sequestration, parameters consideration for the design of CO2 selective porous adsorbents, evaluation criteria for the adsorption processes, assessment criteria for the selection of suitable adsorption configuration, and the factors influencing the CO2 adsorption capacity. This review comprises deep critical scrutiny of the current investigation and development on Triazine-, benzimidazole-, and triazole-based COPs with improved CO2 storage capacities. The conversion of CO2 into useful products including the carbon monoxide (CO), methane (CH4), methanol (CH3OH), and other products including the hydrocarbons has been critically reviewed by using the heterogeneous catalysis. Finally, a concise conclusion and recommendation section are presented indicating that the area of Triazine-, benzimidazole-, and triazole-based COPs for CO2 capture needs more attention to synthesise the next-generation materials for real-time applications.

A surprisingly simple, yet effective blending method for ionic liquids (ILs) and polysulfone (PSf) is presented in this paper. Not only is the IL properly immobilised in the polymer matrix, which is crucial in high-pressure gas separation applications, but this method also produces tunable porous surfaced membranes that can be useful in several other applications. The size and distribution of the pores are dependent on the type and amount of IL incorporated into the PSf. A membrane formation mechanism is proposed to explain the presence of such a regular surface pore structure. Several commercially available ILs were tested to examine their compatibility with the polymer, and the CO 2 /N 2 gas separation performance of the resulting membrane was screened. ATR-FTIR spectroscopy, FTIR microscopy, and SEM imaging were also employed to shed light on the observed membrane structures.

Mesoporous silica particles after extraction from rice husk ash were used as fillers in polysulfone based mixed-matrix membranes (MMMs). The fillers were functionalized with 4-aminophenazone (4-AMP) to enhance the CO2-philic properties. The attractive feature of this research was the utility of extracted silica from a biological waste-the rice husk ash. A good dispersion and adhesion of the filler within the polymer matrix were confirmed by the gas permeation results, SEM images and FTIR analysis. The results revealed that all MMMs showed high permeabilities in comparison to pristine polysulfone membrane. The higher gas permeabilities were attributed to the presence of large mesopores in the filler that led to faster diffusion of the penetrant gas. The functionalized silica showed significantly higher CO2/CH4 and CO2/N2 selectivities. The highest ideal selectivities obtained for CO2/N2 and CO2/CH4 at a maximum of 40% filler loading, were 32.79 and 33.31 respectively. All synthesized membranes were tested at various operating temperatures and their activation energies were also calculated. The highly ordered structures with short and straight pore channels and improved gas permeation properties warrant the silica extracted from rice husk as promising filler for industrial gas separation under varying conditions of temperature.

Polymeric membranes containing sulfonated and fluorinated poly (ether ether ketone) were prepared by solution casting method. The monomers were pre-sulfonated before the polymerization to avoid the side-effects of polymer post-sulfonation, like low degree of sulfonation and poor mechanical and thermal properties. The degree of sulfonation was varied from 20% to 40% to study its influence on the membrane performance. Pure and mixed gas permeation experiments were performed to evaluate the potential of this novel polymer in separation of CO2 from mixtures containing CH4 and N2. Increasing degree of sulfonation improved the CO2 permeability and selectivity for both gas pairs. The incorporation of fluorinated groups further enhanced the performance of membranes by simultaneous increase in gas permeability and selectivity. Diffusion and solubility measurements were also performed in order to get further insight into the role of sulfonic and fluorinated groups in membrane performance. The comparison of results with literature revealed the promising characteristics of the polymer in industrially relevant gas separations.

Mixed matrix membranes (MMMs) have a potential to improve the separation performance of polymeric membranes while maintaining their advantages of easy processing and lower costs. In this work, series of MMMs were developed via solution casting by adding porous carbon-silica nanocomposite (CSM) fillers to a readily available Matrimid (R) membrane. CSMs were prepared by a hard template synthesis technique to get a tuneable porosity and surface chemistry which is controlled by the optimization of the filler porosity using carbon deposition, the pyrolysis conditions, and the maximization of polarity via oxygen functional groups. SEM images of the synthesized MMMs confirmed the good adhesion and dispersion of the fillers within the polymer matrix. The separation results demonstrate that the overall separation efficiency is increased by the addition of a carbon phase, providing an increased affinity for the CO2 gas molecules next to the creation of extra porosity and free volume. It was showed that significantly improved CO2 mixed gas selectivity and permeability for CO2:N-2 and CO2:CH4 gas mixtures at 9 bar and 308 K was achieved. For gas mixtures with a 50:50 (CO2:N-2) feed composition, a 2-fold and 6-fold increase of the mixed gas selectivity (up to 42.5) and permeability (up to 27 Barrer) compared to unfilled PI was achieved, respectively. The performance of the membranes was compared to the existing literature data. (C) 2015 Elsevier B.V. All rights reserved.

During the production of oil and gas, a large amount of oily wastewater is generated, which would pollute the environment if discharged without proper treatment. As one of the most promising treatment options, membrane material used for oily wastewater treatment should possess desirable properties of high hydraulic performance combined with high membrane fouling resistance. This project employs the vapor induced phase separation (VIPS) technique to develop a hydrophilic polyvinylidene fluoride (PVDF) membrane with polyethylene glycol (PEG) as an additive for produced water treatment. Results show that thanks to its slow nonsolvent intake, the VIPS method hinders additive leaching during the cast film immersion. The results also reveal that the exposure of the film to the open air before immersion greatly influences the structure of the developed membranes. By extending the exposure time from 0 to 30 min, the membrane morphology change from typical asymmetric with large macrovoids to the macrovoid-free porous symmetric membrane with a granular structure, which corresponds to 35% increment of steady-state permeability to 189 L&middot, m&minus, 2h&minus, 1bar&minus, 1, while maintaining &gt, 90% of oil rejection. It was also found that more PEG content resides in the membrane matrix when the exposure time is extended, contributes to the elevation of surface hydrophilicity, which improves the membrane antifouling properties. Overall results demonstrate the potential of VIPS method for the fabrication of hydrophilic PVDF membrane by helping to preserve hydrophilic additive in the membrane matrices.

Precise prediction of the gas permeability behavior through the mixed matrix Composite membranes (MMMs) composed of the tubular fillers using existing theoretical approaches are infrequent. This is normally due to the neglecting the interfacial characteristics of the tubular filler particles i.e. multi-walled structured carbon nanotubes (MWCNTs) and a matrix composed of polymeric material in the existing theoretical models, especially, the Kang-Jones-Nair (KJN) model and Hamilton-Crosser model (HC) which were developed for the prediction of gas permeability behavior through the mixed matrix membranes (MMMs) composed of the tubular fillers. In this work, raw- and functionalized MWCNTs filler based MMMs in polysulfone (PSF) matrix were synthesized successfully, followed by morphological analysis on matrix interfacial layers parameters. KJN model was modified by introducing pseudo-dispersed phase fillers that influenced the interfacial layer and consequently overall gas permeabilities, which was ignored in existing models. The new proposed theoretical model is able to predict the gas permeability behavior with significantly reduced average absolute relative error (%AARE) of 1.26% compared to 52.43% and 42.71% for unmodified KJN and HC models, respectively. Furthermore, the mKJN model revealed that the interfacial layer thickness is a unique characteristic and is autonomous of the penetrant molecules of gas which may be influenced by the heterogeneity in the experimental conditions. The cross-sectional morphology and mKJN model revealed that the filler functionalization may lead to the improvement in filler-polymer interaction which thus reduced interfacial layer thickness.

Alarming concentration of CO2 in atmosphere has risen global concern for its mitigation to avoid global warming. Supported ionic liquid membranes (SILMs) have dual benefits as they combine striping process of liquids with high solubility of CO2 in room temperature ionic liquids (RTIL) in membranes. In this study, we have investigated the performance of a recently synthesized RTIL in SILM, experimentally and theoretically. Benzimidazolium-1-acetate was used to prepare SILM over a polyimide support. The prepared SILM was tested for different gas mixtures (CO2/CH4 and CO2/N2). In order to evaluate the commercial potential of these membranes, there were also tested under different operating conditions. Density functional theory (DFT) calculations were also performed to predict the interactions of CO2 with the RTIL. SILM showed high selectivity of 37.92 and 40.29 for CO2/CH4 and CO2/N2 respectively. These results also strengthen DFT calculation results indicating promising applications for gas separation.

Mixed matrix membranes (MMMs) are a promising alternative to conventional polymeric membranes but suffer from compatibility issues of polymer and filler. This study reports simultaneous improvement in CO2 permeability and selectivity employing novel metal organic frameworks (MOFs), namely NOTT-300 and Pebax®1657 as polymer matrix. MMMs are characterized and investigated for separation of CO2/CH4 and CO2/N2 gas mixtures at ambient and elevated temperatures. Well-dispersed NOTT-300 particles are observed in SEM images of MMMs with no visible defects even at higher loadings. Single and mixed gas permeation results showed their outstanding performance exhibiting a simultaneous upsurge in CO2 permeability and CO2/CH4 and CO2/N2 selectivity. In comparison to neat Pebax®1657 membrane, the incorporation of NOTT-300 at 40% filler loading enhanced the permeability of CO2 by 380%, and selectivity to 68% and 26% for CO2/CH4 and CO2/N2 respectively. The results proved the potential of NOTT-300 as filler material for MMMs aimed at CO2 capture because of their high porosity and CO2 philic properties.

A combination of organic filler exhibiting CO2 philic nature with a polymer to develop mixed matrix membranes (MMMs) can capture CO2 efficiently. This work reports the synthesis of perylene filler and polysulfone (PSf)-based MMMs via solution casting method. The successful incorporation of fillers, uniformity/asymmetric, and amorphous nature of MMMs were investigated by FT-IR, FESEM, and PXRD analysis, respectively. MMMs demonstrated high thermal stability with significant weight retention over 750 °C investigated by TGA analysis. The existence of Lewis's basic functionalities, hydrogen bonding, and π-π bonds between the filler-polymer resulted in the formation of highly CO2 philic structure. Results revealed that the perylene is found to be highly porous (1050 m2/g) and compatible with the PSf to form additional channels, enhancement of free PSf volume and tendency to prevent the agglomeration and non-selective interfacial voids. It demonstrated improved permeabilities of CO2 (138%), CH4 (59%), and N2 (60%) without any significant variation in selectivities CO2/CH4 (3%) and CO2/CH4 (7%). Similarly, mixed gas permeabilities were improved for (CO2–CH4 – 119%) and (CO2–N2 – 116%) along with enhanced selectivities (CO2–CH4 – 50%) and (CO2–N2 – 46%). Furthermore, the influence of temperature on gas permeabilities revealed improved kinetic energy and flexibility in the polymer chains. The mechanical strength analysis revealed high filler-polymer compatibility. These results revealed great potential of MMMs for efficient CO2 separation from pre- and post-combustion sources.

The present work is focused on preparation, characterization, and antibacterial activity evaluation of graphene oxide/polyethersulfone mixed matrix filtration membranes. Graphene oxide (GO) was synthesized via improved Hummer’s method and characterized by XRD, FTIR, and SEM. FT-IR spectra showed the presence of carboxylic acid and hydroxyl groups on GO nanosheets. Different concentrations of the synthesized GO at 0.25, 0.5, and 1.0 wt. % were incorporated in polyethersulfone (PES) matrix via phase inversion method to fabricate GO-PES membranes. Increasing porosity and formation of wider, finger-like channels were observed with increased GO concentrations relative to pristine membranes as evident from scanning electron microscopy (SEM) micrographs of the fabricated membranes. However, membranes prepared with 1 wt. % GO appear to contain aggregation and narrowing of pore morphology. GO-incorporated membranes demonstrated enhanced flux, water-retaining capacities, and wettability as compared to pristine PES membranes. Shake flask and colony counting methods were employed to carry out antibacterial testing of synthesized GO and fabricated GO-PES membranes against Salmonella typhi (S. typhi)—a gram-negative bacteria present in water that is known as causative agent of typhoid. Synthesized GO showed significant reduction up to 70.8% in S. typhi cell count. In the case of fabricated membranes, variable concentrations of GO are observed to significantly influence the percentage viability of S. typhi, with reduction percentages observed at 41, 60, and 69% for 0.25, 0.5, and 1.0 wt. % GO-incorporated membranes relative to 17% in the case of pristine PES membranes. The results indicate a good potential for applying GO/PES composite membranes for water filtration application.

Membrane distillation (MD) purifies water by transporting its vapor through a hydrophobic membrane. An ideal MD membrane poses high water flux and high fouling, scaling, and wetting resistances. In this study, we develop polyvinylidene fluoride (PVDF) membranes for MD by focusing on reduction of PVDF degree of crystallinity. We explore the roles of dope solution temperature in dictating the phase separation mechanisms as well as the structure and the performance of semicrystalline PVDF membranes. DSC spectra show that higher dope solution temperature depresses crystallinity via formation of imperfect crystal. Such findings were also supported by FTIR and XRD results. The SEM images reveal formation of spherulite-like morphology in the membrane matrices for membranes prepared from high temperature dope solutions. A good balance between solid-liquid and liquid-liquid phase separations that offers low degree of crystallinity was found at a dope solution temperature of 60°C (PVDF-60), which showed the MD flux of 18 l/m2 h (vs. 6 l/m2 h for temperature of 25°C, as a benchmark) and nearly complete salt rejection when run at hot and cold temperatures of 65°C and 25°C, respectively. The PVDF-60 shows a high wetting resistance and stable MD flux of 10.5 l/m2 h over a 50 h test for treating brine solution as the feed (70 g NaCl/l).

Mixed-matrix membranes (MMMs) composed of polyimide (PI) and metal-organic frameworks (MOFs) were synthesized using Matrimid as the polymer and zirconium terephthalate UiO-66 as the filler. The modulation approach, combined with the use of amine-functionalized linkers, was used for synthesis of the MOF fillers in order to enhance the intrinsic separation performance of the MOF and improve the particle-PI compatibility. The presence of amine groups on the MOF outer surface introduced either through the linker, through the modulator, or through both led to covalent linking between the fillers and Matrimid, which resulted in very stable membranes. In addition, the presence of amine groups inside the pores of the MOFs and the presence of linker vacancies inside the MOFs positively influenced CO2 transport. MMMs with 30 wt % loading showed excellent separation performance for CO2/CH4 mixtures. A significant increase in the mixed-gas selectivity (47.7) and permeability (19.4 barrer) compared to the unfilled Matrimid membrane (i.e., 50% more selective and 540% more permeable) was thus achieved for the MMM containing the MOF prepared from 2-aminoterephthalic acid and 4-aminobenzoic acid, respectively used as the linker and as the modulator.

Ordered mesoporous silica spheres (MCM-41) were used as fillers in polyimide (Matrimid) based mixed-matrix membranes (MMMs). The filler particles were functionalized with sulfonic acid (–SO3H) groups to increase the separation performance of the membranes by increasing the CO2 solubility. The fast diffusion of gases through the mesoporous materials, accompanied by this increased interaction with CO2, resulted in the simultaneous increase of gas permeability and selectivity. The functionalized membranes showed up to 31% increase in CO2 permeability and 14% increase in CO2/CH4 selectivity. In order to study the stability of these newly developed MMMs, they were tested at different operating conditions (temperatures, mixed-gas feeds and CO2 feed concentration).

Mixed matrix membranes (MMMs) can potentially improve the separation performance of traditional polymeric membranes while still maintaining their processing advantages and lower costs. In this work, MMMs composed of acrylate derivatized polysulfone and functionalized mesoporous MCM-41 were prepared by solution casting. The voids at the polymer-filler interface were removed by the introduction of covalent linkages between the modified polymer and the functionalized fillers. Gas permeation results and SEM images of the synthesized MMMs confirmed a good adhesion and dispersion of the fillers within the polymer matrix. In comparison to MMMs with unmodified MCM-41, covalently linked MCM-41 fillers rendered the MMMs significantly higher CO 2 /CH 4 and CO 2 /N 2 selectivities due to the presence of a covalent link between the –NH 2 group of the filler and the acrylate of the polymer. The highest ideal selectivities obtained here for CO 2 /N 2 and CO 2 /CH 4 were 32.97 and 31.48 (CO 2 permeability=9.13 Barrer), respectively. Different operating temperatures were also studied and activation energies calculated.

By filling a PDMS top layer with porous carbon–silica microspheres, a defect-free mixed matrix membrane was created with notable CO2 reverse selective separation properties. For the separation of CO2 over H2 at room temperature and 10 bar inlet pressure, these membranes demonstrate high CO2 gas fluxes up to 3 × 10−7 mol cm−2 s−1, in combination with ideal separation factors in the range of 6 to 9. The present separation data signify an important step forward in the removal of CO2 from H2 using a reverse selective separation strategy. Moreover, they elucidate the potential of such mixed matrix membranes in the emerging field of CO2 separation.

© The Royal Society of Chemistry. Mixed matrix membranes (MMMs) aim at combining the processibility of polymers with the molecular sieving of fillers to improve gas separation performance. Metal-organic frameworks (MOFs) are a new family of materials with promising potential as fillers. The first part of this work reports on exploiting the versatility of MOF synthesis routes by forming ZIF-8 particles in polymer solutions to subsequently cast membranes directly from the solution. Although MOFs can be synthesised in a polymer medium, the decline in the synthesis yield does not allow for high loading in the MMMs. The second part describes a method for preparing MMMs with the commercial polyimide (PI) Matrimid® and ZIF-8, ZIF-7 and NH2-MIL-53(Al) as non-dried filler with 30 wt% and 50 wt% loading. A comparison of this method with the conventional approach of drying MOFs prior to incorporation exhibits the flexibility MOFs provide in membrane synthesis, in contrast to e.g. zeolites which intrinsically have to be calcined to become useful. The membranes with non-dried MOFs show some improvement in performance as compared to the unfilled polymer-only membranes, while those with dried MOFs even lose the inherent selectivity of the polymer. crosscheck: This document is CrossCheck deposited related_data: Supplementary Information copyright_licence: The Royal Society of Chemistry has an exclusive publication licence for this journal history: Received 14 September 2016; Accepted 28 November 2016; Accepted Manuscript published 30 November 2016; Version of Record published 8 December 2016 ispartof: RSC Advances vol:6 issue:115 pages:114505-114512 status: published

The miscibility and gas separation performance of Matrimid and sulfonated aromatic poly(ether ether ketone) (S-PEEK) blend membranes prepared by solution casting method were studied. A S-PEEK polymer with fixed degree of sulfonation was used for membrane synthesis. Both Matrimid and S-PEEK were physically miscible over the whole composition range, as confirmed by visual observation and DSC studies. The effect of variation in composition on gas permeability and selectivity of blend membranes was investigated. The gas permeability and selectivity values fall in between those of the individual polymers, varying systematically with variation of S-PEEK content in the blend. The effect of feed pressure on CO2 permeation was linked to CO2 plasticization of the membranes. The Matrimid component of the blend membrane was cross-linked with p-xylenediamine to improve the anti-plasticization properties of the blend. In order to further study the stability and potential industrial application of these membranes, they were tested at different conditions of feed pressure, temperature and CO2 feed concentration.

This paper describes the performance of sulfonated aromatic poly(ether ether ketone) (s-peek) membranes, directly prepared from the sulfonated monomer, for co2 separation from gas mixtures containing n-2 or ch4. dense membranes with different degrees of sulfonation were prepared via solvent evaporation. increasing degree of sulfonation simultaneously improves the permeability and selectivity of both gas pairs. the effect of counterions was investigated by converting s-peek membranes from the na+-form in which they are prepared, to the h+ and multivalent cationic forms. gas permeability and selectivity for polymers with divalent and trivalent counterions were higher than those for polymers in the monovalent and h+-forms. in order to study the stability and potential industrial application of these membranes, they were tested at different conditions of feed pressure, temperature and co2 feed concentration. (c) 2011 elsevier by. all rights reserved.

The design and fabrication of a high throughput (HT) gas permeation system will be described. In order to test large sets of membranes, a HT-gas separation module was developed, allowing gas permeation and selectivity testing of 16 membranes simultaneously at different feed pressure and temperature. A variable temperature controller and adjustable upstream pressure controller permit measurements of low-permeability membranes and evaluation of temperature related phenomena. The potential of the developed equipment and the HT-screening concept in general was validated by demonstrating the reproducibility of experimental flux and selectivity data for a lab-made dense Matrimid and a commercial asymmetric membrane at all 16 positions. Permeate flux was measured with increased permeate pressure as function of time in a constant volume auxiliary cylinder. An on-line compact gas chromatograph was used for fast gas selectivity measurements. The reproducibility of the data was highly encouraging, proving that this HT approach can be a useful tool to rapidly screen a large array of operational parameters in membrane processes and of synthesis parameters in the development of new high-performing membranes.

Mixed matrix membranes were prepared from derivatized polysulfone and zeolite particles. Aminopropyltrimethoxysilane was used as coupling agent to covalently link zeolite particles with the acrylate modified polymer. The mixed gas selectivity for H2/CO2 separation increased from 1.53 for pure polysulfone to 3.57 at 40% zeolite loading. The results suggest that the covalent linkage of polymer and filler results in defect free membranes. The effect of different operating conditions (feed pressure, temperature and CO2 feed concentration) was also studied.

Mixed matrix membranes (MMMs) containing fluorinated-sulfonated poly(ether ether ketone) (F-SPEEK) and zeolite 4A filler, were prepared by solution casting. F-SPEEK with a fixed degree of sulfonation (40%) was used for membrane synthesis. The SEM pictures showed good interfacial adhesion between filler particles and polymer, which was also confirmed by the increase in glass transition temperature of MMMs with increase in filler particles. Pure and mixed gas permeation experiments were carried out to investigate the potential of this membrane material. The results revealed that addition of zeolite 4A fillers enhanced both permeability and selectivity owing to the intrinsic nature of polymer and modified membrane morphology due to filler. The highest permeability obtained for CO2 at 30% filler loading was 49.2 Barrer, while highest selectivities obtained for CO2/CH4 and CO2/N2 were 55 and 58 compared to 47 and 51 for the unfilled polymer, respectively. Intrinsic CO2 solubility of F-SPEEK was observed to be decreased from 10.7 to 1.9 (10−2) cm3 (STP)/cm3 cmHg with the addition of Zeolite 4A. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 135, 45952.

This study is focused on the development of ionic liquids (ILs) based polymeric membranes for the separation of carbon dioxide (CO2) from methane (CH4). The advantage of ILs in selective CO2 absorption is that it enhances the CO2 selective separation for the ionic liquid membranes (ILMs). ILMs are developed and characterized with two different ILs using the solution-casting method. Three different blend compositions of ILs and polysulfone (PSF) are selected for each ILMs 10, 20, and 30 wt %. Effect of the different types of ILs such as triethanolamine formate (TEAF) and triethanolamine acetate (TEAA) are investigated on PSF-based ILMs. Field emission scanning electron microscopy analysis of the membranes showed reasonable homogeneity between the ILs and PSF. Thermogravimetric analysis showed that by increasing the ILs loading thermal stability of the membranes improved. Mechanical analysis on developed membranes showed that ILs phase reduced the amount of plastic flow of the PSF phase and therefore, fracture takes place at gradually lower strains with increasing ILs content. Gas permeation evaluation was carried out on the developed membranes for CO2/CH4 separation between 2 bar to 10 bar feed pressure. Results showed that CO2 permeance increases with the addition of ILs 10–30 wt % in ILMs. With 20–30 wt % TEAF-ILMs and TEAA-ILMs, the highest selectivity of a CO2/CH4 53.96 ± 0.3, 37.64 ± 0.2 and CO2 permeance 69.5 ± 0.6, 55.21 ± 0.3 is observed for treated membrane at 2–10 bar. The selectivity using mixed gas test at various CO2/CH4 compositions shows consistent results with the ideal gas selectivity. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45395.

Supported ionic liquid membranes (SILMs) are promising tools for the separation of carbon dioxide from other gases. In this paper, new imidazolium, pyrrolidinium, piperidinium, and morpholinium ionic liquids with a triethylene glycol side chain and tosylate anions, as well as their symmetrical dicationic analogues, have been synthesized and incorporated into SILMs. The selectivities for CO2/N2 and CO2/CH4 separations have been measured. The selectivities exhibited by the dicationic ionic liquids are up to two times higher than the values of the corresponding monocationic ionic liquids. Quantum chemical calculations have been used to investigate the difference in the interaction of carbon dioxide with monocationic and dicationic ionic liquids. The reason for the increased gas separation selectivity of the dicationic ionic liquids is two-fold: (1) a decrease in permeance of nitrogen and methane through the ionic liquid layer, presumably due to their less favorable interactions with the gases, while the permeance of carbon dioxide is reduced much less; (2) an increase in the number of interaction sites for the interactions with the quadrupolar carbon dioxide molecules in the dicationic ionic liquids, compared to the monocationic analogues.