Pervaporation Performance Research Articles

Poly(Vinyl Alcohol)/Carbon Nanotube (Cnt) Membranes for Pervaporation Dehydration: The Effect of Functionalization Agents for Cnt on Pervaporation Performance

Poly(Vinyl Alcohol)/Carbon Nanotube (Cnt) Membranes for Pervaporation Dehydration: The Effect of Functionalization Agents for Cnt on Pervaporation Performance

Brine desalination via pervaporation using kaolin-intercalated hydrolyzed polyacrylonitrile membranes

Polyacrylonitrile (PAN) has been mostly used as a base polymer for asymmetric membrane synthesis with the aim of pervaporation (PV) applications, since it has a superior hydrophilicity and the ability to become hydrolyzed with an alkaline solution. Nonetheless, PAN and hydrolyzed PAN membranes have shown moderate permeate fluxes along with a mechanical softness. In this study, we aimed to improve the PV performance by exploring the possible effect of the hydrolysis of a novel mixed matrix membrane based on PAN and kaolin. Specifically, 15% PAN was used as a dope solution along with varying concentrations (2, 5, 7, and 10%) of kaolin to synthesize mixed matrix membranes using a non-solvent-induced phase separation technique. The 2% kaolin addition maximized the hydrophilicity and water sorption capacity of the membrane by developing well-organized, deep channel structures with increased porosity, membrane thickness, and surface roughness. The tensile strength was also the highest with the 2% kaolin addition. Further hydrolysis of the 2% kaolin-embedded PAN caused an extra enhancement of its hydrophilicity with a decrease of pore size due to the amplified carboxylic group density. PV performance tests under different salt concentrations confirmed that the hydrolyzed PAN membrane with a 2% kaolin intercalation had an outstanding permeation flux of 82 kg m-2h−1 and 59 kg m-2h−1 as well as a salt rejection of 99.93% and 99.91% with a 3.5% and 10% NaCl solution, respectively, at a 65 °C feed temperature.

Preparation of modified MFI-type/PDMS composite membranes for the separation of dichlorobenzene isomers via pervaporation.

Zeolite–polymer composite membranes have become promising and effective materials for the pervaporative separation of liquids, especially for isomeric mixtures. In this paper, silicalite-1/PDMS composite membranes have been used to investigate the separation of dichlorobenzene (DCB) isomers via pervaporation for the first time. Silicalite-1 zeolites modified by the silane coupling agent, NH3–C3H6–Si(OC2H5)3, have been incorporated into polydimethylsiloxane (PDMS). Then, the silicalite-1/PDMS composite membranes have been successfully prepared on porous polyvinylidene fluoride (PVDF) supports. The morphology and structure of the silicalite-1 zeolites and silicalite-1/PDMS composite membranes have been characterized by XRD, FTIR, SEM and BET techniques. The results show that the modified silicalite-1 zeolite particles have smaller pore sizes dispersed more uniformly in the active layers of the silicalite-1/PDMS composite membranes and present fewer aggregation and pinholes formed by the accumulation of zeolite particles. The silicalite-1/PDMS composite membranes are all dense and continuous with good homogeneity. To evaluate the pervaporative separation performance of the DCB isomers, the unmodified and modified silicalite-1/PDMS composite membranes have been further tested in single-isomer and binary-isomer systems at 60 °C. The modified silicalite-1/PDMS composite membranes present higher DCB isomer separation factors. The separation factors of the modified silicalite-1/PDMS composite membranes in the binary-isomer systems for p-/o-DCB and p-/m-DCB are 3.53 and 5.63, respectively. The permeate flux of p-DCB through the modified silicalite-1/PDMS composite membranes in the p-/o-DCB binary-isomer system is 116.7 g m−2 h−1 and in the p-/m-DCB binary-isomer system, it is 93.5 g m−2 h−1. The result provides a new approach towards the pervaporative separation of DCB isomers from their mixture for future industrialization applications.

POSS-graphene oxide nanocomposite membranes for ethanol permselective pervaporation

Pervaporation has shown great promise in recovering alcohol from fermentation broth. However, the separation performance determined by membrane material and structure should be further improved. In this study, polyhedral oligomeric silsesquioxane (POSS) nanocage was used as nanofillers to provide preferential pathways for ethanol molecules in polydimethylsiloxane (PDMS) membrane. To improve dispersion of POSS nanocages in PDMS matrix, the POSS were anchored on the graphene oxide (GO) nanosheets. At the meantime, the aggregation of GO nanosheets could also be prevented as the GO surface turned to be hydrophobic by the modification of POSS, and the nanoporous POSS cage could reduce interface defects between GO nanosheets and PDMS matrix. The obtained POSS-GO/PDMS nanocomposite membranes exhibited excellent separation performance for ethanol permselectivity. The flux could reach 1346.9 g m −2 h −1 with a separation factor of 11.2 when recovery of ethanol from 5 wt% ethanol/water mixture. In addition, the separation performance of the POSS-GO/PDMS membrane could maintain stability in 120 h. Therefore, the POSS modified GO nanosheets shown great potential in the fabrication of ethanol permselective pervaporation membranes. • POSS-GO nanocomposites were fabricated and incorporated into the PDMS matrix for preparation of pervaporation membranes. • The nanoplates can be well dispersed in PDMS as the hydrophobic POSS has been uniformed anchored to the GO nanosheets. • The obtained POSS-GO/PDMS membranes exhibited excellent pervaporation performance for ethanol permselectivity.

Polymeric membranes through self-initiation and self-polymerization for high-performance bioethanol pervaporation

Prepolymer 1173IPS-MAPDMS shows a stable and homogeneous distribution of PI with an ultrahigh loading. This self-initiated/self-polymerized membrane has an excellent ethanol pervaporation performance and a high scale-up feasibility.

Synthesis a low template B-ZSM-5 membrane with suitable morphology and high performance for the separation of acetone/water mixtures

Synthesizing zeolite membrane using a templating method is often expensive and consumes a lot of energy. Therefore, the synthesis of a high quality B-ZSM-5 zeolite membrane using a low organic template would be required. Here, the synthesis of the low-template B-ZSM-5 zeolite membrane was performed on the surface of α-alumina support modified by TiO2-Bohemite via secondary growth technique under the optimized seeding conditions. A multi-objective optimization method was utilized to identify the optimal support seeding parameters to enhance the performance of the synthesized membrane. Optimization of seeding conditions leads to achieving well intergrowth zeolite membrane with the low template by applying fewer layers. The prepared membrane with a thickness of less than 10 μm showed a high pervaporation performance with a high acetone/water separation factor of 500 and a total flux of 0.13 kg m−2 h−1 for the 1 wt% acetone/water mixture at 333 K and 260 mmHg. The impacts of feed temperature, permeate pressure, and feed concentration on the pervaporation performance, total fluxes as well as membrane separation factor, were investigated. Our results revealed that the separation factor could be significantly increased by increasing the permeate pressure.

De novo synthesis of amino-functionalized ZIF-8 nanoparticles: Enhanced interfacial compatibility and pervaporation performance in mixed matrix membranes applying for ethanol dehydration

The incorporation of attainable amine functionality in zeolitic imidazolate framework-8 (ZIF-8) is utilized to enhance the pervaporation performance for ethanol/ water separation applications. Using 2-aminobenzimidazole, a ligand with NH2-functionalized group, displacement of the ZIF-8 original ligand during de novo synthesis while preserving the ZIF-8 initial structure, which produces a novel mixed- linker ZIF material (ZIF-8-NH2) with smaller nanocrystal size, controllable pore size, and enhanced hydrophilicity. A series of different mixed matrix membranes (MMMs) were fabricated by incorporating ZIF-8-NH2 into poly(vinyl alcohol) (PVA) matrix. Various characterization techniques, such as FTIR, 1H NMR, XRD, SEM, TGA, and Contact angle etc. were employed to demonstrate the properties of prepared ZIF nanoparticles and the MMMs. The results indicated that ZIF-8-NH2 and the MMMs were perfectly fabricated, which were attributed to better dispersion and compatibility between them. In particular, 7-ZIF-8-NH2/PVA MMM exhibited a comparable total flux of 142 g/m2·h and water/ethanol separation factor of 925, which were increased by 73 and 524%, on the basis of the pristine PVA membrane. In addition, different nanofillers, APTES crosslinking, ZIF-8-NH2 loading, operating temperature, feed concentration, and membrane stability were evaluated in detail. This study might provide a promising prospect for designing MOF-based MMMs with the introduction of various functional groups.

Performance of octadecylamine-functionalized graphene oxide nanosheets in polydimethylsiloxane mixed matrix membranes for removal of toluene from water by pervaporation

Functionalized and reduced graphene oxide nanosheets with octadecylamine (rGOODA) were incorporated in polydimethylsiloxane (PDMS) membranes to be used in pervaporation for removal of toluene from water. The properties of the functionalized nanosheets were characterized by FTIR, XRD, Raman, SEM, and TGA analyses. The prepared mixed matrix membranes (MMMs) were characterized using contact angle, AFM, SEM-EDX, TGA, solvent uptake tests. The membranes contained reduced graphene oxide (rGO) represented 111% increment in the enrichment factor compared to that of the bare-PDMS owing to Π-Π interaction of graphene nanosheets and the toluene's aromatic ring as well as high aspect ratio of rGO that causes more tortuous pathways for water permeation. By incorporating rGOODA in the MMMs, the separation factor was increased about 164% rather than that of rGO-contained membrane, which could be mainly attributed to closer Hansen solubility parameter of the functionalized nanosheets to that of toluene, water repelling of the membrane due to more hydrophobicity and steric hindrance of the functionalized nanosheets, their well dispersion which causes more compatibility with the polymeric matrix. The pervaporative performance of membranes with different filler contents were investigated as a function of operational temperatures and feed concentrations. The prepared MMM with 0.4 wt% rGOODA presented the best performance at 30 °C and 150 ppm toluene concentration.

Pervaporation performance of poly(vinyl alcohol)‐graft‐poly(N‐hydroxymethyl acrylamide) membranes for dehydration of isopropyl alcohol‐water mixture

AbstractIn the present work, poly(N‐hydroxymethyl acrylamide) grafted poly(vinyl alcohol) (PVA‐g‐PNHMA) membranes were developed for the dehydration of isopropyl alcohol (IPA) by the use of pervaporation method. The PVA‐g‐PNHMA membranes have been synthesized and their chemical composition and morphology have been characterized by Fourier transform infrared spectroscopy, 13C‐nuclear magnetic resonance spectroscopy, X‐ray diffractometry, differential scanning calorimetry, thermogravimetric analysis, and field emission scanning electron microscopy. The impacts of numerous factors such as temperature, feed concentration as well as membrane thickness on their pervaporation performance were investigated and the optimal conditions were found. With the increase in the grafting percentage of the PVA‐g‐PNHMA membrane, both flux and separation factor also increase. The PVA‐g‐PNHMA membrane with a grafting percentage of 34% revealed the best separation factor of 362 with a flux of 0.0085 kg/m2.h for 12.6% mass of water in the feed solution. It has also been found that swelling behaviors of the membranes are consistent with all pervaporation results. Besides, permeation and diffusion activation energies were determined as 23.69 and 29.21 kJ/mol from the change of permeation flux with temperature. Based on the obtained outcomes, it is obvious that PVA‐g‐PNHMA membranes are quite efficient in the separation of IPA/water mixture via pervaporation.

Improved performance of three-component structure mixed membrane for pervaporation modified by lignosulfonates@2D-MXene

Hydrophilic calcium lignosulfonate combined with 2D-MXene, jointly modified the polysaccharide sodium alginate to prepare a mixed matrix membrane, which has excellent alcohol-water separation performance. • Pervaporation membrane made of sodium alginate, MXene@calcium lignosulfonate. • The hydrophilicity of the membrane increases and the obvious layered structure appears. • The selectivity and permeability of ethanol dehydration are improved simultaneously. Lignosulfonates are a by-product of the agricultural and forestry waste and paper industries. Strengthening the sustainable use of lignosulfonates is a problem to be solved. In this study, hydrophilic agricultural and forestry waste calcium lignosulfonate (CaLS) was combined with single/double-layered MXene, and added to the natural polysaccharide sodium alginate (SA) to prepare a pervaporation me, membrane with a three-component hybrid structure. Characterization experiments such as scanning electron microscopy and contact angle demonstrated that CaLS increased the hydrophilicity and reduced swelling of the membrane, and MXene formed a layered cross-sectional morphology that further reduced swelling. A 90% ethanol aqueous solution was used to evaluate the dehydration performance of the membrane. The results showed that the permeation flux and separation factor of the membrane increased by 74% and 160%, respectively. Compared to the pure SA membrane after CaLS was incorporated. MXene further improved the pervaporation performance of the MXene@CaLS/SA membrane, with the permeation flux of about 938 g·m −2 ·h −1 , and the separation factor of 4612 (two and four times higher than the pure SA membrane, respectively). This study provides a theoretical and technical basis for the development of new separation materials, and will help expand the high-value utilization of lignosulfonates.

Preparation and characterization of PVA thin-film composite membrane for pervaporation dehydration of ethanol solution

These days, ethanol fuel has been widely consumed worldwide to replace gasoline due to its possible environmental and long-term economic advantages. In detail, the ethanol fuel (purity ≥ 99.5 wt%) has been produced by traditional separation processes such as azeotropic distillation or molecular sieve adsorption, which excessively employs energy and capital cost. The pervaporation has already been considered as an effective alternative to conventional methods because of its high separation efficiency and low power consumption. Pervaporation separation of ethanol/water solution using hydrophilic membranes has been extensively studied owing to their superior perm-selectivity. In this present work, the polyvinyl alcohol thin-film composite membrane is prepared by casting a thin crosslinked polyvinyl alcohol (PVA) film on the polyacrylonitrile (PAN) porous substrate. The effect of PVA concentration on the pervaporation performance of the fabricated membrane is studied. The physicochemical properties of the prepared membrane are characterized using FTIR, SEM images, and contact angle measurements. The separation performance in terms of permeation flux and selectivity is simultaneously evaluated through a pervaporation dehydration of ethanol/water mixture of 80/20 wt.% at 60°C. The results show that the increase in PVA concentration leads to the decline in the hydrophilicity and the growth of the thickness and swelling degree of the membrane. Therefore, the selectivity of the membrane is found to improve significantly, while the permeation flux decreased with the PVA concentration ranging from 2.5 to 15 wt.%. Based on the results, the PVA membrane prepared from the 10 wt.% concentration is likely to provide high separation performance.

POSS/PDMS composite pervaporation membranes for furfural recovery

In this work, polyhedral oligomeric silsesquioxane (POSS) with two different functional groups, octa(nitrophenyl)silsesquioxane (ONPS) and octa(aminophenyl)silsesquioxane (OAPS), was incorporated with polydimethylsiloxane (PDMS), forming composite membranes for furfural recovery via pervaporation process. The addition of POSS had enhanced the hydrophobicity of the PDMS and improved the affinity of furfural with membranes. At the same filler loading, OAPS/PDMS membrane showed a superior separation factor to the bare PDMS and the ONPS/PDMS composite. The effects of OAPS loading on property and pervaporation performance of the membrane were also investigated. The loading at 15 wt% was found to be the optimum value that could improve water contact angle to 116° and furfural affinity to achieve over 20% improvement in both furfural flux and separation factor. The PDMS membrane with 15 wt% of OAPS could provide 7-fold concentrated furfural solution compared to the feed. The newly developed OAPS/PDMS membrane showed great potential for furfural recovery as the alternative separation method with improved energy-effectiveness and low chemical footprint.

Electrospun carboxyl‐functionalised multi‐walled carbon nanotube/poly(vinyl alcohol) asymmetric pervaporation membrane: Application and modeling

AbstractThis study focuses on the development of an asymmetric membrane comprised of an electrospun carboxyl‐functionalised multi‐walled carbon nanotube (COOH‐MWCNT)/poly (vinyl alcohol) (PVA) composite nanofibre layer on a dense PVA separation layer (MCOOH‐MWCNT). The electrospun nanofibre layer in this study acts as a “pre‐selective layer” instead of its common function as a membrane support. In addition, COOH‐MWCNT, a hydrophilic filler is integrated in the nanofibres to further enhance the membrane pervaporation separation performance. Immense improvement was observed in the pervaporation performance of the resultant asymmetric membranes in the dehydration of aqueous 1,4‐dioxane solutions, owing to the presence of the electrospun composite nanofibres as a hydrophilic layer. The resultant asymmetric membrane showed an increase of nearly 80% in water permeation flux as compared to that of the dense PVA membrane alone, and the separation factor was improved from 392.65 to 605.35. The parameters estimated using Rautenbach model showed that the dehydration of aqueous 1,4‐dioxane solutions via pervaporation is dominantly governed by sorption process. The permeation flux, transport coefficient of water and 1,4‐dioxane of the electrospun asymmetric membrane showed a good agreement in between the experimental data and those predicted using Rautenbach model.

Highly permeable ZIF-8 membranes for propylene permselective pervaporation under high pressure up to 20 bar

ZIF-8 membrane has been deemed as the most promising contender for addressing the chemical industry's energy-intensive C3H6/C3H8 separation process. However, to the best of our knowledge, there are no reports available to access the realistic separation performance of the ZIF-8 membrane under industrial conditions. In this work, we systematically studied the pervaporation performance of ZIF-8 membranes for liquid C3H6/C3H8 mixture. First, we refine the dip-coating and thermal conversion (DCTC) method to achieve highly permeable ZIF-8 membranes. The C3H6 permeances of the resultant ZIF-8 membranes can be controlled in the range from 6.5 × 10−9 to 9.3 × 10−8 mol m−2 s−1 Pa−1 with C3H6/C3H8 separation factor consistently higher than 100. Then, the ZIF-8 membrane was employed for the pervaporation separation of equimolar C3H6/C3H8 mixture at 50 °C and 20 bar, achieving C3H6 flux up to 0.93 kg m−2 h−1 along with a separation factor of 19. Furthermore, we explore the performance of the ZIF-8 membrane for a liquid C3H6/C3H8 mixture (70:30), which is a similar composition to that produced from the upstream depropanizer. Consequently, the resultant ZIF-8 membrane exhibits excellent pervaporation stability with a separation factor of 13 and C3H6 flux of 1.1 kg m−2 h−1, demonstrating the great prospect of ZIF-8 membrane in energy-intensive C3H6/C3H8 separation.

SUZ-4 zeolite membrane fabricated by dynamic hydrothermal crystallization for pervaporation separation of MeOH/MMA mixture

The SUZ-4 zeolite membrane was prepared on the hollow fiber ceramic membrane via the secondary growth method modified by the dynamic hydrothermal process. The surface morphology and pervaporation (PV) performance of zeolite membranes fabricated by dynamic and static hydrothermal processes were studied. The surface of the zeolite membrane prepared by the dynamic hydrothermal process was covered with rod-shaped crystals, while the static one was full of crystal clusters fabricated by small-sized crystals. Besides, the separation factor of the SUZ-4 zeolite membrane made via dynamic hydrothermal method for separating 10 wt% methanol (MeOH)/methyl methacrylate (MMA) mixture at 50 °C exceed 10000 with a flux of 3.83 kg·m−2·h−1, which was better than the static one and showed excellent long-term stability. This work provided the important assistance for the preparation of SUZ-4 zeolite membranes in the separation of MeOH/MMA and MeOH/dimethyl carbonate (DMC) organic mixtures and demonstrated the great potential of dynamic process in promoting the membrane properties.

Synthesis of LTA zeolite membranes from metal alkoxides and examination of the pervaporation performance

In the dehydration of ethanol, membrane separation using LTA zeolites is commonly employed in place of distillation due to its lower energy consumption. In the membrane separation process, a thin zeolite membrane is preferred to reduce the permeation resistance of water in the membrane. From the aspect of reducing the resistance, the authors successfully prepared LTA zeolite membranes from metal alkoxides. The influence of the crystal growth conditions on the separation performance was investigated by the pervaporation of an ethanol-water mixture. As a result, the thickness of the LTA zeolite membrane could be decreased to less than 3 μm by optimizing the aging time of the secondary growth solution and secondary growth time. For 90 wt% ethanol solution at 343 K, the permeation flux and separation factor of the membrane were 6.3 kg m −2 h −1 and >10,000, respectively. In this paper, the SEM observation and XRD analysis were examined to understand the structure of zeolite membrane. As a result, the change in crystallographic orientation caused by the aging was proposed as key factor of permeability of the membrane. • LTA zeolite membrane was prepared by hydrothermal treatment of seed crystals with hydrolyzed metal alkoxide. • Influence of aging of secondary growth solution of the membrane on its pervaporation performance was examined. • Water permeability of the membrane decreased as the aging proceeded. • X-ray diffraction analysis of the membrane surface revealed that orientation of the crystallites in the LTA layer changed to less (200) plane being parallel to the surface of the membrane. • Decrease of (200) oriented plane by the aging may be responsible for the reduction of water permeability of the membrane.

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.

Hydrophobic polydimethylsiloxane thin-film composite membranes for the efficient pervaporative desalination of seawater and brines

The pervaporative desalination of synthetic seawater and brines was studied to explore the water flux and salt rejection of a thin-film composite (TFC) membrane made of polydimethylsiloxane (PDMS) dip-coated on porous polysulfone support. Despite the hydrophobic nature of rubbery PDMS, we demonstrate that nonporous TFC membranes exhibit remarkable pervaporative desalination performance as evidenced by very high water permeance and 99.8 ± 0.2% NaCl rejection. For comparison, two commercial hydrophilic polyamide thin-film composite membranes designed for reverse osmosis (RO) were also tested in pervaporation mode. At the highest temperature explored (85 °C) the PDMS thin-film composite membrane produced an outstanding pure water flux of ∼70 kg m−2 h−1, which was 2.6 times higher than that of the best commercial RO membrane tested in this work. Although the presence of salt in the feed water reduced water flux to 36 kg m−2 h−1 (at a brine sodium chloride concentration of 70,000 ppm and 85 °C), the hydrophobic PDMS composite membrane performed among the best compared with previously reported hydrophilic TFC polymer membranes.

Separation of tomato aroma compounds from binary model solutions using PEBA and EPDM membranes in pervaporation: Comparison of membranes performance and investigation of temperature effect

AbstractThe pervaporation separation of four important aroma compounds of tomato juice (1‐hexanol, hexanal, 2‐heptenal, and 6‐methyl‐5‐hepten‐2‐one) was investigated. Ethylene propylene diene monomer (EPDM) and polyether block amide (PEBA) membranes were fabricated and applied to treat binary model solutions containing one of the aroma compounds in water. Results showed that at 25°C, PEBA membrane had higher total flux, organic flux, and pervaporation separation index (PSI) than EPDM membrane, while EPDM performed better in terms of separation factor. For PEBA, the highest total flux (395.93 g/m2hr) was observed in separating 1‐hexanol, and for EPDM, the highest total flux (116.82 g/m2hr) was seen in treating 6‐methyl‐5‐hepten‐2‐one/water at 25°C. Furthermore, the impact of feed temperature on pervaporation performance was investigated. A rise from 25 to 45°C increased the total and organic fluxes for both of the membranes. The separation factors of PEBA and EPDM changed differently with temperature; higher temperatures led to improved separation factor for PEBA and reduced separation factor for EPDM. Moreover, increased feed temperature improved PSI for both membranes, while the change was more significant for PEBA.Practical applicationsIn this study, for the first time, tomato aroma compounds have been separated from their aqueous solutions in a pervaporation process. The findings obtained by the present research can be employed by any plant which processes tomato enabling them the use of aroma compounds in order to reach value added products and therefore increase worth of processing outputs.

Highly selective polybenzoxazinoneimide vs. its nonselective prepolymer in separation of water-ethanol mixture: Role of sorption parameters in pervaporation performance

ABSTRACT Relationship between structure and transport properties of two polyheteroarylenes is studied on the example of polybenzoxazinoneimide (PBOI) and its prepolymer – polyamic acid imide-containing (PAAI). Formation of dense membranes, determination of their physical parameters, and control of membrane morphology by SEM were carried out. Transport properties of the membranes in the separation of the water – ethanol mixture were determined by sorption and pervaporation experiments. The equilibrium sorption degree, diffusivity, as well as sorption selectivity and diffusion selectivity of the PAAI and PBOI membranes were considered. The pervaporation experimental data on the total flux and the separation factor of the membranes were converted into permeability and selectivity to estimate the performance of the membranes. Due to the – COOH groups in the structure, PAAI membrane exhibits significantly higher sorption degree of water (4 times more) and ethanol (10 times more) as compared with those of PBOI. However, the PAAI membrane has water/ethanol sorption selectivity lower than 1, which indicates the absence of separation efficiency in the ethanol dehydration. In contrast, the PBOI membrane is very effective in the ethanol dehydration as the separation factor reaches 9000 in pervaporation of the mixture containing 10 wt% water.