Pervaporation Performance Of Membranes Research Articles

Membrane pervaporation performance applied for brackish water prepared by vacuum impregnation method

Coating method and number of membrane layer are crucial factors on membrane performance. Through a vacuum impregnation method allows a sol solution uniformly fill into membrane support and it is required only less solution. The aim of this study is to apply vacuum impregnation method through vacuum calcination and air calcination during fabrication of silica membranes and to investigate the effect of layer variations on silica membranes performance to apply for brackish water. The sol solution was made from TEOS as silane precursor, ethanol and dual catalysts (citric acid + ammonia). Alumina membrane support was coated by vacuum impregnation method and calcined the membrane under air and vacuum condition. From the FTIR result, it indicates that silica membranes calcined in air and vacuum calcination have Si-O-Si and Si-OH. The vacuum impregnation obtained smoother surface membranes. The silica membrane calcined via vacuum calcination performs excellent water fluxes and salt rejection of 22.01 kg.m− 2.h−1 and 98.98 %. If compare to silica membranes calcined in air, the water flux (19.11 kg.m− 2.h−1) and salt rejection (98.75 %). It also found the two layers silica membrane is better than three layers for the membrane performance result.

Microstructural characterization and evaluation of pervaporation performance of thin-film composite membranes fabricated through interfacial polymerization on hydrolyzed polyacrylonitrile substrate

A series of thin-film composite (TFC) polyamide membranes was fabricated through interfacial polymerization on a modified polyacrylonitrile (mPAN) substrate, where an aqueous solution of diamine was reacted with an organic solution of diacyl chloride. Various monomers were used: two different diamines [1,3-diamino-2-propanol (DAPL) and hydrazine] and two different diacyl chlorides [succinyl chloride (SCC) and trans-5-norbornene-2,3-dicarbonyl chloride]. Combining these monomers resulted in a new polyamide layer. We investigated the effect of the monomer chemical structure and interfacial polymerization conditions on the membrane pervaporation performance in dehydrating an aqueous solution of ethanol. According to field emission scanning electron microscopy, DAPL-SCC provided the thinnest polyamide layer, which was also confirmed through positron annihilation lifetime spectroscopy. The results were used to correlate the variation in the membrane microstructure with the pervaporation performance of the fabricated TFC polyamide membranes. Both microstructural characteristics and surface properties affected the pervaporation performance. DAPL-SCC/mPAN membranes with lower free-volume sizes and suitable hydrophilicity were evaluated to deliver the highest water concentration in permeate and the lowest permeation flux (on the basis of the pervaporative dehydration of an aqueous solution of 90 wt% ethanol at 25 °C).

Fabrication of Crosslinkable Hollow Fiber Membranes for Pervaporation Dehydration

Integrally-skinned asymmetric Polyetherimide/Poly (vinyl alcohol) (PEI/PVA) hollow fber membranes for pervaporation dehydration were fabricated by non-solvent induced phase inversion. PVA inside the PEI matrix could be crosslinked to provide membrane performance stability during long term operation. The effects of different PEI/PVA blend ratio, external coagulant type and flow rate, and crosslinking conditions on the membrane structure and the separation performance were investigated. Generally, hollow fbers using PEI/PVA blend are less selective than those of neat PEI, probably due to the defects evolved between PEI and PVA. The influence of coagulant type on membrane pervaporation performance was specifc to dope formulation; when using n-butanol as external coagulant, the higher the coagulant flow rate, the better the membrane separation performance. PVA crosslinking by maleic acid (MA) enhanced the membrane performance, obviously. PEI/PVA Hollow fbers formed using n-butanol as external coagulant obtained a separation factor of 28 after crosslinking, much better than 4.4 with the original one. The crosslinked membrane exhibited higher stability than the neat PEI membrane. The separation factor of the latter degraded by more than half after around 200 h operation. Finally, this work has provided a new approach for fabricating crosslinkable asymmetric membrane suitable for pervaporation dehydratio.

Recycling of phenol from aqueous solutions by pervaporation with ZSM-5/PDMS/PVDF hollow fiber composite membrane

Zeolite (ZSM-5)/polydimethylsiloxane (PDMS)/polyvinylidene fluoride (PVDF) hollow fiber composite membrane was prepared by dynamic negative pressure. The influence of ZSM-5 silanization, coating time and concentration of ZSM-5 on the resulting pervaporation (PV) performance of composite membranes was investigated. The contact angle (CA) was used to measure surface hydrophobic property and it was found that the water contact angle of the membrane was increased significantly from 99° to 132° when the concentration of ZSM-5 increased from 0% to 50%. The morphology of the membrane was characterized by scanning electron microscope (SEM) and those SEM images illustrated that the thickness of the separating layer has obvious differences at varying coating times. Furthermore, the membranes were investigated in PV process to recycle phenol from aqueous solutions as feed mixtures. The impact of phenol concentration in feed, temperature and pressure of penetration side on the PV performance of membrane was studied systematically. When the ZSM-5 concentration was 40% and the coating time was 60min, separation factor and phenol permeability were 4.56 and 5.78g/(m2h), respectively. ZSM-5/PDMS/PVDF membrane significantly improved the recovery efficiency of phenols.

Investigation of pervaporation performance of POMS membrane during separation of butanol from water and the effect of added acetone and ethanol

Abstract In this work the pervaporation performance of a POMS [polyoctylmethyl siloxane] membrane to separate acetone-butanol-ethanol from aqueous solutions was studied. Butanol – water solutions with the addition of acetone and ethanol were analyzed to investigate the effect of multicomponent feed systems on the pervaporation performance of the membrane. Additionally membrane performance in contact with real fermentation broth was investigated. For the binary mixture transmembrane butanol flux increases with increasing feed temperature and feed concentration. Over the whole investigation range the membrane is selective for butanol. It was observed that positive flux coupling for butanol as well as water flux occurs when acetone is present in the feed solution. This results in higher permeance for butanol and water in the investigated range, but similar selectivities. For the quaternary mixture total permeation flux increased, while butanol flux stayed the same. Pervaporation of the real fermentation broth showed, that component permeances increased drastically resulting in high selectivities of 9.8, 3.8 and 0.9, for butanol, acetone and ethanol respectively. This change in membrane performance makes pervaporation with POMS optimal for the product recovery during ABE-fermentation.

ZIF-8 incorporated polyether block amide membrane for phenol permselective pervaporation with high efficiency

Abstract In recent years, zeolitic imidazolate framework-8 (ZIF-8) has received tremendous attention due to its hydrophobic inner channels and good compatibility with the polymer as an inorganic filler for preparation of the mixed matrix membrane (MMM). In this study, ZIF-8 particles were synthesized and incorporated into Ploy (ether block amide) matrix (PEBA-2533) to fabricate a MMM for the enhancement of phenol permselective pervaporation. The structure and morphology of ZIF-8 particle and the obtained MMMs were characterized by XRD, SEM, FTIR, contact angle and BET. It is found that the hydrophobicity of the membrane was enhanced by the incorporation of hydrophobic ZIF-8, and the obtained MMM withstand the extreme operation conditions of pervaporation. The effects of particle loading amount, feed concentration and temperature on the separation performance of ZIF-8 incorporated MMMs were investigated in details. Compared with the pure PEBA-2533 membrane, the permeate flux of ZIF-8 incorporated PEBA-2533 MMM with a 10 wt% loading amount was significantly increased from 846 g m−2 h−1 to 1310 g m−2 h−1, while the separation factor increased from 39 to 53 at 70 °C with 8000 ppm feed phenol concentration. The enhancement of the pervaporation performance could be mainly attributed to the preferential highly permeable regions of the bimodal membrane structure for phenol molecules, which was consisted of ZIF-8 particles. Finally, both of the excellent overall membrane pervaporation performance and the long-term revealed that such a ZIF-8 incorporated MMM has a great potential in separation and recovery of phenol from its aqueous solution for a practical process.

Mechanics and Pervaporation Performance of Ionic Liquid Modified CNT Based SBR Membranes - A Case Study for the Separation of Toluene/Heptane Mixtures

SBR/ionic liquid modified CNT Nanocomposites were prepared using different concentration of CNT. Nano scale dispersion of CNT affected the properties of SBR. The results have been compared with the unfilled SBR films. Cure characteristics and mechanical properties such as tensile strength, modulus, abrasion resistance and hardness were measured for different composites. Morphological behaviour and structural characteristics of the composites were investigated by AFM, TEM, FTIR and Raman spectroscopy. Microstructural development in presence of filler and interfacial interaction between modified CNT and polymer matrix led to enhanced properties. The pervaporation performances of membranes were analysed using a toluene/heptane mixture. Membranes displayed high selectivity towards heptane. The influence of feed composition on pervaporation was also analysed. The 5 phr CNT loaded membrane showed enhanced membrane permeance and selectivity value, an improvement of 18% over the neat polymer. A drop in selectivity and an increase in permeation rate were observed at higher CNT loadings.

In-situ crosslinked PVA/organosilica hybrid membranes for pervaporation separations

In this work, two novel poly(vinyl alcohol) (PVA)/organosilica hybrid membranes are developed via the sol–gel process, with phenyltriethoxysilane (PTES) and diethoxydiphenylsilane (DEDPS) as crosslinkers and organosilica precursors, and employed for ethanol dehydration via pervaporation. Effects of organosilane type on the membrane morphology, physicochemical properties and pervaporation performance of the as-fabricated membranes are studied. In addition, the effects of the organosilane loading and the thermal treatment temperature on the physicochemical properties and pervaporation performance of the membrane are explored systematically. Various characterization techniques (FT-IR, TGA, SEM, etc) are employed to illuminate physicochemical changes of membranes. The optimal pervaporation performance of PVA–PTES hybrid membrane with 0.4mmol/g PTES loading and thermally treated at 80°C has a flux of 145g/m2h and a separation factor of 1026 for the pervaporation dehydration of 85% ethanol aqueous solution at 40°C.

Microstructural optimization of MFI-type zeolite membranes for ethanol–water separation

High quality pure-silica MFI-type zeolite membranes are successfully prepared by simply controlling the amount of structure directing agent (SDA), i.e., tetrapropylammonium (TPA+) in the synthesis solution for seeded growth. The effects of several synthesis parameters such as alkalinity (OH−/Si), TPA+ concentration (TPA+/Si), and crystallization time on the membrane pervaporation performance are investigated in detail. The synthesized MFI-type zeolite membranes are thoroughly characterized by scanning electron microscopy (SEM), energy dispersive X-ray (EDX) spectroscopy, the water contact angle test, X-ray diffraction (XRD), the pervaporation test and gas permeation. The membrane microstructure is very sensitive to the TPA+/Si ratio of the synthesis solution. At a high TPA+/Si ratio (typically 0.17), parasitic twin crystals are intergrown in the zeolite layer, thus resulting in the formation of membrane defects during SDA removal treatment (calcination at 500 °C). When the membrane is prepared with a low TPA+/Si ratio (≤0.05), the appearance of twin crystals can be significantly suppressed and the synthesized dense MFI-type zeolite membranes exhibit pervaporation separation factors higher than 85 for 5 wt% ethanol–water mixtures at 60 °C. We demonstrate for the first time that controlling the SDA concentration in the precursor solution is beneficial to the elimination of membrane microstructural defects, showing a pathway to high quality MFI-type zeolite membranes.

Study on characterization and pervaporation performance of interfacially polymerized polyamide thin-film composite membranes for dehydrating tetrahydrofuran

Low permeation fluxes with high separation factors were obtained when hydrophilic dense membranes were used for the dehydration of tetrahydrofuran (THF) by pervaporation. To improve the pervaporation performance of a membrane, the polyamide thin-film composite (TFC) membranes were prepared through interfacial polymerization by reacting 1,3-diaminopropane (DAPE), 1,3-cyclohexanediamine (CHDA), or m-phenylenediamine (MPDA) with trimesoyl chloride (TMC) on the surface of a polyacrylonitrile (PAN) membrane (DAPE–TMC/PAN, CHDA–TMC/PAN, and MPDA–TMC/PAN). Pervaporation separation of an aqueous THF solution with polyamide TFC membranes was investigated as functions of diamine structure and operating conditions. Attenuated total reflectance-Fourier transform infrared (ATR-FTIR) spectroscopy, X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), atomic force microscopy (AFM), positron annihilation spectroscopy (PAS), and water contact angle measurements were applied to analyze the chemical structure, surface chemical composition, morphology, surface roughness, free volume, and hydrophilicity of the active polyamide layer of TFC membrane. Varying the diamine structure did affect the physicochemical properties and pervaporation performance of the polyamide TFC membranes. Compared with the CHDA–TMC/PAN and MPDA–TMC/PAN membranes, the DAPE–TMC/PAN membrane showed a lower permeation flux and a higher water concentration in permeate. This was in good agreement with the result of characterization. With an increase in the operating temperature of pervaporation, an increase in the permeation flux and a high water concentration in permeate (>99wt%) were obtained for the DAPE–TMC/PAN membrane. It was also found that the DAPE–TMC/PAN membrane exhibited a superior performance compared with the several hydrophilic polymers and commercial inorganic membranes discussed in the literature.

High performance ceramic hollow fiber supported PDMS composite pervaporation membrane for bio-butanol recovery

In this work, ceramic hollow fiber supported polydimethylsiloxane (PDMS) composite membranes were developed by dip-coating PDMS layer on the surface of macroporous ceramic hollow fiber support. By controlling the properties of polymer solution and ceramic hollow fiber, high-quality ceramic hollow fiber supported PDMS composite membranes were fabricated for pervaporation (PV) recovery of bio-butanol. It was found both the viscosity of PDMS dip-coating solution and pore size and structure of ceramic support played critical roles in determining the microstructures, the mass transport and the PV performance of PDMS composite membrane. The optimized composite membrane with defect-free PDMS layer and low transport resistance of support showed a total flux of 1282g/m2h and separation factor of 42.9 for 1wt% n-butanol–water mixtures at temperature of 40°C during 200h continuous operation. In addition, the membrane PV performance and stability in acetone–butanol–ethanol (ABE) fermentation broth were investigated. The results showed the PDMS composite membrane exhibited high and stable performance for butanol recovery from ABE systems. Compared with literatures, our work demonstrated that the ceramic hollow fiber supported PDMS composite membrane could be a competitive PV membrane for recovering organic compounds from fermentation broth to produce renewable biofuels.

CuO‐filled aminomethylated polysulfone hybrid membranes for deep desulfurization

ABSTRACTCuO‐filled aminomethylated polysulfone hybrid membranes were prepared for sulfur removal from gasoline. The as‐prepared membranes were characterized using Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), and X‐ray diffraction (XRD). The separation performance of the hybrid membranes was evaluated by pervaporation (PV) separation of n‐heptane/thiophene binary mixture. CuO‐filling leads to a decrease in permeation flux. The sulfur‐enrichment factor increased first and then decreased with increasing CuO loading, and it is worth noting that there is a rebound in enrichment factor above 8 wt % CuO loading. Influencing factors such as nitrogen content, feed temperature, sulfur content, and various hydrocarbons on membrane PV performance were also evaluated. Permeation flux of 23.9 kg·μm·m−2·h−1 and sulfur‐enrichment factor of 3.9 can be achieved at 4 wt % CuO loading in PV of n‐heptane/thiophene binary mixture with 1500 μg·g−1 sulfur content. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3718–3725, 2013

Correlating the microstructure of novel polyamide thin-film composite membranes with ethanol dehydration performances

Polyamide thin-film composite (TFC) membranes were prepared by interfacial polymerization. The purpose is to improve the pervaporation performance of polyamide membranes in separating an aqueous ethanol solution. A novel amine monomer 2,2′-dimethylbenzidine hydrochloride (m-tolidine-H) was reacted with an acyl chloride monomer trimesoyl chloride (TMC) on the surface of a modified polyacrylonitrile (mPAN) membrane. The effects of the following interfacial polymerization conditions on the TFC membrane pervaporation performance were investigated: monomer concentration, immersion time of mPAN in aqueous m-tolidine-H solution, and interfacial polymerization (IP) time for reacting m-tolidine-H with TMC. Attenuated total reflectance Fourier transform infrared spectroscopy and scanning electron microscopy were used to characterize the chemical structure and the morphology of the membranes, respectively. To probe the variation in the fine-structure of the polyamide active layer and the free volume depth profile in the TFC membranes, positron annihilation lifetime spectroscopy (PALS) experiments coupled to a variable monoenergy slow positron beam were conducted. The densest portion of the polyamide layer was at the interface of the two immiscible monomer solutions, as detected based on the smallest o-Ps annihilation lifetime at positron incident energies of 1 and 2 keV with 0.05 and 0.5 wt% TMC, respectively. A high pervaporation performance of 2191 g/m2h permeation flux and 99 wt% water content of permeate was delivered by the polyamide TFC membrane that was prepared by immersing the mPAN membrane in a 1.5 wt% aqueous m-tolidine-H solution for 10 s, followed by contacting it with a 0.05 wt% organic TMC solution for 10 s.

Prediction of the effects of preparation conditions on pervaporation performances of polydimethylsiloxane(PDMS)/ceramic composite membranes by backpropagation neural network and genetic algorithm

In this study, the preparation process of polydimethylsiloxane (PDMS)/ceramic composite membrane was successfully modeled by the hybrid models which employed backpropagation neural network (BPNN) to predict the effects of preparation conditions on pervaporation performances of membranes and used genetic algorithm (GA) to choose the initial connection weights and biases of BPNN. The PDMS concentration, crosslinking agent concentration and dip-coating time were taken as inputs, flux of ethanol and selectivity of ethanol/water were outputs, and trial-and-error method was used to determine the architectures of the hybrid models. Using these models, the detailed relationships between the preparation conditions and the membrane performances were established. Connection weight analyses show that each preparation condition almost has the same influence on the membrane flux and selectivity. Excellent agreements between the predictions of the hybrid models and the experiments validate that the hybrid models have sufficient accuracy. Furthermore, the results predicted by the hybrid models were compared with those predicted by the response surface methodology (RSM) models which were widely used in the optimization of nonlinear relationships. It is found that the standard deviations of both the training and the predicting data obtained by the hybrid models are much smaller than those by the RSM models. Hence, the hybrid models can be used to design the preparation conditions to obtain desired membrane performances in the preparation of pervaporation membranes.

Integral PVA-PES Composite Membranes by Surface Segregation Method for Pervaporation Dehydration of Ethanol

A facile surface segregation method was utilized to fabricate poly(vinyl alcohol)-polyethersulfone (PVA-PES) composite membranes. PVA and PES were first dissolved in dimethyl sulfoxide (DMSO), then casted on a glass plate and immersed in a coagulation bath. During the phase inversion process in coagulation bath, PVA spontaneously segregated to the polymer solution/coagulation bath interface. The enriched PVA on the surface was further crosslinked by glutaraldehyde. Scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and energy dispersive spectrometer (EDS) confirmed the integral and asymmetric membrane structure with a dense PVA-enriched surface and a porous PES-enriched support, as well as the surface enrichment of PVA. The coverage fraction of the membrane surface by PVA reached up to 86.8% when the PVA content in the membrane recipe was 16.7% (by mass). The water contact angle decreased with the increase of PVA content. The effect of coagulation bath type on membrane structure was analyzed. The membrane pervaporation performance was evaluated by varying the PVA content, the annealing temperature, feed concentration and operation temperature. The membrane exhibited a fairly good ethanol dehydration capacity and long-term operational stability.

Multilayered Poly(vinylidene fluoride) Composite Membranes with Improved Interfacial Compatibility: Correlating Pervaporation Performance with Free Volume Properties

A spin-coating process integrated with an ozone-induced graft polymerization technique was applied in this study. The purpose was to improve the poor interfacial compatibility between a selective layer of poly(2-hydroxyethyl methacrylate) (PHEMA) and the surface of a poly(vinylidene fluoride) (PVDF) substrate. The composite membranes thus fabricated were tested for their pervaporation performance in dehydrating an ethyl acetate/water mixture. Furthermore, the composite membranes were characterized by field emission scanning electron microscopy (FE-SEM) for morphological change observation and by Fourier transform infrared spectroscopy equipped with attenuated total reflectance (ATR-FTIR) for surface chemical composition analysis. Effects of grafting density and spin-coating speed on pervaporation performance were examined. The composite membrane pervaporation performance was elucidated by means of free volume and depth profile data obtained with the use of a variable monoenergy slow positron beam (VMSPB). Results indicated that a smaller free volume was correlated with a higher pervaporation performance of a composite membrane consisting of a selective layer of spin-coated PHEMA on a PHEMA-grafted PVDF substrate (S-PHEMA/PHEMA-g-PVDF). The composite membrane depth profile illustrated that an S-PHEMA layer spin-coated at a higher revolutions per minute (rpm) was thinner and denser than that at a lower rpm.

Influence of Clay Content and Amount of Organic Modifiers on Morphology and Pervaporation Performance of EVA/Clay Nanocomposites

Poly(ethylene-co-vinyl acetate)/organically modified clay nanocomposites were prepared using different clay loadings and by varying the amount of organic modifier. The morphology of the nanocomposites was investigated using small-angle X-ray scattering (SAXS), scanning electron microscopy (SEM), and transmission electron microscopy (TEM). SAXS results displayed intercalation of polymeric chains between the silicate layers in all the cases. The interlayer distance varies slightly between the series. TEM images showed a better dispersion of the clay platelets at lower loading for both series of samples. The pervaporation performances of membranes were analyzed using a chloroform/acetone mixture. Membranes displayed high selectivity. The influence of feed composition on pervaporation was analyzed. The nanoclay content and the influence of free volume on pervaporation performance were also investigated in detail. A drop in selectivity and an increase in permeation rate were observed at higher clay loadings.

Pervaporation Separation of Butanol-Water Mixtures Using Polydimethylsiloxane/Ceramic Composite Membrane

Pervaporation has attracted considerable interest owing to its potential application in recovering biobutanol from biomass acetone-butanol-ethanol (ABE) fermentation broth. In this study, butanol was recovered from its aqueous solution using a polydimethylsiloxane (PDMS)/ceramic composite pervaporation membrane. The effects of operating temperature, feed concentration, feed flow rate and operating time on the membrane pervaporation performance were investigated. It was found that with the increase of temperature or butanol concentration in the feed, the total flux through the membrane increased while the separation factor decreased slightly. As the feed flow rate increased, the total flux increased gradually while the separation factor changed little. At 40°C and 1% (by mass) butanol in the feed, the total flux and separation factor of the membrane reached 457.4 g·m −2·h −1 and 26.1, respectively. The membrane with high flux is suitable for recovering butanol from ABE fermentation broth.

Influence of glycol additives on the structure and performance of cellulose acetate/zinc oxide blend membranes

The effects of different types and concentration of glycol additives in the membrane blend formulations for pervaporation studies were investigated. The glycol additives used were polyethylene glycol 600 (PEG 600), propylene glycol (PG) and ethylene glycol (EG). Glycol additive filled cellulose acetate (CA)/zinc oxide (ZnO) blend membranes were prepared for pervaporation separation of isopropanol (IPA)/water mixtures. The structural morphology and thermal stability of the blended membranes were characterized by SEM, FTIR, DSC, and TGA. The mechanical properties were determined by using UTM. It was found that the presence of PEG 600 in the blend membrane enhanced the membrane pervaporation performance. The effect of the PEG 600 content in the blended membranes on the pervaporation was studied and discussed in terms of permeation flux and separation factor. The separation factor and permeation flux were increased by the addition of the PEG 600 content in the range of 7.5–10 wt.%. Among all the fabricated blended membranes, the membrane containing 10 wt.% PEG 600 showed the highest separation factor of 1448.03 and a permeation flux of 558.63 g/m 2 h for a feed composed of 71 wt.% IPA in the aqueous solution at 40 °C.

Mussel-inspired fabrication of structurally stable chitosan/polyacrylonitrile composite membrane for pervaporation dehydration

The structural stability of chitosan (CS)/polyacrylonitrile (PAN) composite membrane for pervaporation dehydration was improved by the introduction of mussel-adhesive-mimetic molecule, carbopol (CP). The composite membranes were simply fabricated by layer-by-layer technique, in which CP as an intermediate layer bridging the CS active layer and the PAN support layer. The structure and morphology of composite membranes were characterized by Fourier transform infrared spectroscopy (FT-IR) and field emission scanning electron microscope (FESEM). The methylene iodide contact angle measurement, T-peel test and molecular dynamics (MD) simulation were employed to analyze the wetting characteristics, adhesion strength and interaction at the interface. Positron annihilation lifetime spectroscopy (PALS) was employed to probe the fractional free-volume properties of the CS active layer. The membrane pervaporation performance was investigated by varying the molecular weight (CP981, 940, 974) and concentration of CP as well as the cross-linking degree of the CS active layer. When the concentration of CP974 was 0.5 wt.%, GCCS(60)/CP(0.5)/PAN composite membrane displayed the permeation flux of 1247 g/(m 2 h) and separation factor of 256 for ethanol dehydration at 353 K. Furthermore, the enhancement of the long-term operation stability of membrane by incorporating the CP layer was also verified.