Pervaporation Performance Research Articles

Manipulation of homogeneous membranes with nano-sized spherical polyelectrolyte complexes for enhanced pervaporation performances in isopropanol dehydration

Spherical polyelectrolyte complexes (PECs) sized at 10–20 nm were synthesized to fabricate homogeneous polyelectrolyte complex membranes (HPECMs). The PEC dispersions at various concentrations were employed to manipulate the thickness of HPECMs. Zeta potentials were measured to quantify the charge density of PECs. Scanning electron microscopy was utilized to examine membrane morphology and thickness. The surface hydrophilicity of HPECMs was evaluated by using static water contact angles. Being subjected to isopropanol dehydration, the synthesized HPECMs with nano-sized spherical PECs exhibited excellent separation performance, good stability and durability. The HPECM with the thickness of 1.1 μm displayed a significantly high permeation flux (6.12 kg m–2 h−1) with an ideal water concentration in permeate (99.85 wt%). The use of nano-sized spherical PECs ensured the homogeneous nature of synthesized polyelectrolyte complex membranes, leading to the enhancement of pervaporation performances in isopropanol dehydration. The extension of this work would trigger a large-scale application of HPECMs for dehydration of organic solvents.

Fabrication of PDMS based membranes with improved separation efficiency in hydrophobic pervaporation

PDMS based membranes were prepared using various modification approaches. Structural and surface properties of prepared membranes were investigated applying a number of instrumental techniques (AFM, FT-IR, DSC, SEM, CA). Finally, transport and separation properties of the developed membranes were determined during pervaporation (PV) experiments in contact with water and water-ethanol mixture. The results were compared with efficiency of the native and commercial PDMS based membrane.Applied preparation procedures resulted in creation of membranes possessing different morphology and pervaporative performance, e.g. modification of membrane matrix with salt method resulted in smaller crosslinking ratio of poly(dimethyl siloxane) sample comparing with pristine PDMS membrane. Whereas, plasma treatment of PDMS sample caused reduction of hydrophobic properties of PDMS membrane resulting in much lower separation factor (β = 6.0).PV results showed that PDMS_NaCl (β = 10.5) and PDMS_Al2O3_mod._C8 (β = 10.8) possessed the most selective properties towards organics among all PDMS based membranes tested in this study, showing that salt method and filling of poly(dimethylsiloxane) matrix with triethoxy(octyl)silane (C8) modified Al2O3 allowed to obtain improved membranes performance in hydrophobic pervaporation.

Development of metal organic framework filled PDMS/PI composite membranes for biobutanol recovery

Butanol is a second generation biofuel with high potential to replace fossil fuels in the future. The main drawbacks in biobutanol production are the low yields of operation and high cost of separation. In this study, n-butanol recovery from its aqueous solutions was carried out by pervaporation as an alternative separation process using polyimide supported polydimethylsiloxane membranes, which were especially prepared for this purpose. To enhance the separation efficiency of the membrane, metal organic framework fillers of MOF-199 were included in its structure. Several combinations of polyimide supported PDMS active layered membranes were prepared with the fillers in each layer of the membrane, in both layers of membrane and membranes without fillers. Thus, the effect of the fillers on the separation performance was investigated. It was found that the inclusion of MOF-199 enhances the membrane performance; meanwhile, the support layer also contributes to mass transfer of n-butanol. Furthermore, the effect of the process parameters on the pervaporation performance was investigated. Results of pervaporation tests indicate that the developed membranes have a good potential for n-butanol recovery from aqueous mixtures.

Organotemplate-free synthesis of ZSM-5 membrane for pervaporation dehydration of isopropanol

ZSM-5 membrane was prepared on tubular macroporous alpha-alumina support using a different synthesis route. The effects of organic template agent and Si/Al ratio of the synthesis gel on morphology, structure, and separation performance of the ZSM-5 membrane used for dehydration of isopropanol were investigated. High water perm-selectivity ZSM-5 membrane with a thickness of about 3.0 um and a low Si/Al ratio of 10.1 was successfully prepared from organotemplate-free synthesis gel with a molar composition of SiO2 : 0.050Al2O3 : 0.21Na2O : NaF : 51.6H2O at 175 degree Celcius for 24 h. The ZSM-5 membrane exhibited high pervaporation performance with a flux of 3.92 kg/(m2.h) and corresponding separation factor of higher than 10,000 for dehydration of 90 wt.% isopropanol/water mixture at 75 degree Celcius.

A graphene oxide membrane with self‐regulated nanochannels for the exceptionally stable bio‐oil dehydration

AbstractThe transport behaviors and nanochannel structures of a graphene oxide (GO) membrane were studied for pervaporation dehydration of bio‐oil with a high acidity and a complex composition. The GO membrane showed an unprecedentedly stable water flux of approximately 0.43 kg m−2 hr−1, with a water content of 97 wt% in the permeate throughout 70 hr of pervaporation testing at 30°C. Both the calculated activation energy for water permeation and X‐ray diffraction characterization results confirmed that the nanochannel structures of the GO membrane were temperature‐ and liquid media‐responsive. The molecular intercalation‐induced self‐regulation of the size of laminar nanochannels in the GO membrane was suggested to be primarily responsible for the significantly reduced membrane fouling and the exceptionally stable pervaporation performance for the GO membrane. The mechanistic insights into the nanochannel structures and antifouling properties would provide important inspiration for the design of novel highly fouling‐resistant membrane materials for practical applications.

Nanocomposite membranes based on sodium alginate/poly(ε-caprolactone)/graphene oxide for methanol, ethanol and isopropanol dehydration via pervaporation

Novel biodegradable nanocomposite membranes were prepared by incorporating different concentrations (2, 4 and 6 wt%) of graphene oxide (GO) as a nanoadditive into a blend of sodium alginate/poly(e-caprolactone) at ratio of 3:1 (SA:PCL) on the basis of solution-casting method and were then used for dehydration of a series of alcohols (methanol, ethanol and isopropanol) through pervaporation. The effects of feed composition, GO content and various alcohols on pervaporation performance were investigated. In addition, the swelling behaviors of SA/PCL/GO nanocomposite membranes were measured. All membranes were water selective, and the permeation rate increased with raising the GO content. The presence of GO having the functional groups increased the hydrophilicity of the SA/PCL blend polymer matrix, which resulted in the formation of a higher flux to water molecules. The best separation performance was achieved for the SA/PCL/GO-6 nanocomposite membrane containing 6 wt% GO with isopropanol–water feed at 30 °C. An enhancement in water concentration from 20 to 80 wt% increased the flux values from 506 to 779 g/m2 h. Likewise, an increase in feed water composition in the case of ethanol–water and methanol–water mixtures increased the flux values from 461 to 757 g/m2 h and from 298 to 569 g/m2 h, respectively. However, the separation factor of water for all membranes decreased with the increase in feed concentration. Pervaporation dehydration of aqueous isopropanol mixtures also proceeded easier than that of aqueous ethanol and methanol mixtures due to the larger molecular size of isopropanol. High dehydration performance of alcohol–water mixtures demonstrated the utility of these membranes for use in solvent dehydration application with higher efficiency.

Preparation and characterization of chitosan-boehmite nanocomposite membranes for pervaporative ethanol dehydration

Pervaporative ethanol dehydration was studied using some chitosan-boehmite nanocomposite membranes. Nanocomposite membranes were prepared by incorporation of 1 and 2 Wt. % loading of the boehmite nanoparticles synthesized by the low temperature sol-gel process. The prepared samples were characterized by FTIR, FESEM and XRD analysis. The results showed the filler particles uniform distribution within the chitosan matrix. Pervaporation performance of the prepared pristine and the nanocomposite membranes were evaluated for ethanol dehydration. The 2 Wt. % loaded boehmite nanocomposite membrane exhibited highest ethanol dehydration performance for 20 Wt. % water content feed at 50 °C as 0.513 kg/m2 h and 676 as permeation flux and separation factor revealed ∼50% and 2 times increments, respectively.

Hydrophobic *BEA-Type Zeolite Membranes on Tubular Silica Supports for Alcohol/Water Separation by Pervaporation.

Hydrophobic pure-silica *BEA-type zeolite membranes with large pores were prepared on tubular silica supports by hydrothermal synthesis using a secondary growth method and were applied to the separation of alcohol/water mixtures by pervaporation (PV), an alternative energy-efficient process for production of biofuels. Amorphous pure-silica tubular silica supports, free of Al atoms, were used for preparing the membranes. In this study, the effects of the synthesis conditions, such as the H2O/SiO2 and NH4F/SiO2 ratios in the synthetic gel, on the membrane formation process and separation performance were systematically investigated. The successfully prepared dense and continuous membranes exhibited alcohol selectivity and high flux for the separation of ethanol/water and butanol/water mixtures. The pure-silica *BEA membranes obtained under optimal conditions (0.08SiO2:0.5TEAOH:0.7NH4F:8H2O) showed high PV performance with a separation factor of 229 and a flux of 0.62 kg·m−2·h−1 for a 1 wt % n-butanol/water mixture at 318 K. This result was attributed to the hydrophobicity and large pore size of the pure-silica *BEA membrane. This was the first successful synthesis of hydrophobic large-pore zeolite membranes on tubular supports with alcohol selectivity, and the obtained results could provide new insights into the research on hydrophobic membranes with high permeability.

Fast, facile and scalable fabrication of novel microporous silicalite-1/PDMS mixed matrix membranes for efficient ethanol separation by pervaporation

Ethanol pervaporation during its fermentative production alleviates product inhibition and hence enhances bioethanol production as a source of renewable energy. In this work, a novel microporous silicalite-1/PDMS mixed matrix membrane was fabricated by spraying as a facile, fast and low-cost method on a flat ceramic membrane. The effect of PDMS (0.05–0.15 g/ml), silica (0–0.06 g/ml) and curing temperature (80–150 °C) on the separation factor and permeation flux of the membranes was investigated using Box-Behnken design for separation 5 wt% ethanol/water solution at 30 °C which circulated at 400 (ml/min). Membranes were characterized by field emission scanning electron microscopy (FESEM), atomic force microscopy (AFM) and contact angle (CA). PDMS concentration acted as an influential factor. Higher curing temperatures led to separation factors less than one due to the higher density of the PDMS matrix. While lower temperatures caused low density, which decreased separation factors. Consequently, pervaporation performance improvement according to the hydrophobicity is possible as far as negative effects on the density of the polymer matrix can be controlled. Additionally, effects of temperature (30–70 °C), concentration (5–10 wt%), and flow rate (400–1000 ml/min) of the feed stream on the optimal membrane performances were examined. The best performances of permeation flux of 3.64 (kg/m2·h) and separation factor of 17.24 corresponded to the membrane (0.08 (g/ml) of PDMS, 0.06 (g/ml) of silica and curing temperature of 109.5 °C) with CA of 142° for separating 5 wt% solution at 60 °C and 400 ml/min. Eventually, this novel membrane can enhance bioethanol production and make it more affordable.

Hydrophobic mesoporous organosilica membranes: Preparation and application in the separation of volatile organic compounds from water

Abstract Mesoporous organosilica membranes were synthesized by sol-gel and dip-coating method using 1,2-bis (triethoxysilyl) ethane (BTESE) as precursor, triblock copolymer poly (ethylene oxide)-block-poly (propylene oxide)-block-poly (ethylene oxide) (P123) as surfactant template. After silylated with 1H,1H,2H,2H-perfluorooctyltriethoxysilane (PFOTES,C8) by post-grafting approach, the membranes were used for the separation of hazardous volatile organic compounds (VOCs) from water via pervaporation process. The results show that ethanol-extraction is considerably effective to remove the surfactant template. The membranes show a smooth surface and a sharp pore size distribution centered at 3.5 nm. The hydrophobic property has been enhanced after silylated with PFOTES, leading to a water contact angle of (105 ± 0.1)°. Hydrophobic mesoporous organosilica membranes are selective toward VOCs and show the highest total flux of 0.36 kgm−2h−1 for methyl tert-butyl ether (MTBE) aqueous solution and the highest MTBE/water separation factor of 27.9. The pervaporation performance depends on the affinity between VOCs and grafted C8 groups. Repeated separation experiments reveal that the membranes are durable in aqueous solution due to the presence of water-resistant Si–C bonds within the framework.

Enhancing Dehydration Performance of Isopropanol by Introducing Intermediate Layer into Sodium Alginate Nanofibrous Composite Pervaporation Membrane

A novel three-tier composite membrane based on highly porous nanofibrous substrate was demonstrated for efficient isopropanol dehydration by pervaporation. Here, polyethyleneimine (PEI) modified graphene oxide (GO) sheets were vacuum-assistant assembled onto porous electrospun polyacrylonitrile (PAN) nanofibrous substrate to achieve a smooth, hydrophilic and compact PEI-GO intermediate layer. The introduction of PEI chains endowed GO interlayer with sufficient interaction for bonding adjacent GO nanosheets to enhance stability in water/isopropanol mixture and also with the ascended interlamellar space to improve the water-sorption ability due to the abundant active amino groups. Benefiting from PEI-GO layer, a defect-free sodium alginate (SA) skin layer could be facilely manufactured with elaborately controlled thickness as thin as possible in order to reduce mass transfer resistant and enhance permeability maximally. Meanwhile, the interlayer would also contribute to enhance interfacial adhesion to promote the structure integrity of three-tier thin-film nanofibrous composite (TFNC) membrane in pervaporation dehydration process. After fine-tuning of membrane preparation process, the SA/PEI(75)-GO-60/PAN TFNC membrane exhibited competitive pervaporation performance with the permeate flux of 2009 g/m2 h and the separation factor of 1276 operated at 70 °C for dehydration of 90 wt% isopropanol solution. The unique three-tier composite membrane structure suggested an effective and facile approach to design novel membrane structure for further improvement of pervaporation performance.

Preparation, structure, and pervaporation performance of poly(amide–imide)‐sulfonated polyimide composites

ABSTRACTPoly{[4,4′‐bisdiphenyl‐2,2′‐disulfonic acid]imide‐1,3‐bis(3,4‐dicarboxyphenoxy)benzene} was synthesized via polycondensation and subsequent thermal imidization in m‐cresol:triethylamine. The obtained polymer and its composites with aromatic poly(amide–imide) obtained through polycondensation of 4‐chloroformyl‐(N‐p‐chloroformylphenyl)phthalimide and 4,4′‐diaminodiphenyl ether were investigated by use of nuclear magnetic resonance, thermogravimetric analysis, dynamic mechanical analysis, differential scanning calorimetry, Fourier transform infrared spectroscopy, scanning electron microscopy, and X‐ray diffraction analysis. Transport properties of composite films were studied during pervaporation of water–alcohol mixtures. On the basis of the data obtained, suggestions on the structure of materials and its influence on transport and other physical properties were made. The addition of 30 wt % of sulfonated polyimide to the poly(amide–imide) matrix enhances its separation factor in the process of separation of an azeotrope water/ethanol mixture by four times while permeability remains unchanged. The methanol permeability increases with an increase of the mass fraction of sulfonated polyimide in the composite film. © 2019 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019, 136, 48197.

Surface-modified halloysite nanotube-embedded polyvinyl alcohol/polyvinyl amine blended membranes for pervaporation dehydration of water/isopropanol mixtures

Surface modification of a halloysite nanotube (HNT) was performed by piranha etching of the HNT surface to generate hydrophilic moiety on the surface. The HNT and surface-modified HNT (MHNT) were embedded in polyvinyl alcohol/polyvinyl amine (PVA/PVAm) membranes. Surface modification of the HNT was confirmed using X-ray photoelectron spectroscopy, Fourier transform infrared, and transmission electron microscopy analyses. The 5 wt% MHNT-embedded membrane showed the best pervaporation performance (flux = 0.13–0.031 kg/m2 h and separation factor = 427–93,313) among all membranes at 40 °C with 80–90 wt% of isopropanol (IPA) in the feed solution. Up to 5 wt% loading of HNT and MHNT in the membrane, the flux decreased, while the separation factor increased and subsequently decreased continuously with further HNT and MHNT loading. This was attributed to the hydrophilicity arising from HNT inclusion in the membranes. The membrane performance was evaluated under various pervaporation-operating conditions. Based on the solution diffusion model, with increase in water content, flux increased, while separation factor decreased. The temperature dependence of flux followed the Arrhenius equation. The energy of activation for the permeation of water (25.99 kJ/mol) was less than that of IPA (143.49 kJ/mol for the 5 wt% MHNT-loaded membrane at an 85 wt% of feed IPA composition). Overall, the pervaporation data suggested that the presence of MHNT in the PVA/PVAm membrane benefited pervaporation dehydration.

Ionic liquid-modified MCM-41-polymer mixed matrix membrane for butanol pervaporation.

Because of the preferential butanol selectivity of some ionic liquids (ILs), an increasing amount of research has appeared regarding their application in butanol separation. In this research, two ionic liquids, namely, 1-ethyl-3-vinylimidazolium bis[(trifluoromethyl)sulfonyl]imide ([EVIM][Tf2N], IL1) and N-octyl-pyridinium bis[(trifluoromethyl)sulfonyl]imide ([OMPY][Tf2N], IL2), were applied to modify a mesoporous molecular sieve MCM-41. The IL-modified MCM-41 samples were characterized by XPS, BET, XRD, SEM and TEM. The ionic liquid-modified MCM-41 was incorporated into the polymer PEBA to prepare mixed matrix membranes to study the influences of the filling of IL-modified MCM-41 and operating conditions on the performance of the mixed matrix membrane for butanol pervaporation. The results indicated that the pervaporation performance of the PEBA membrane was enhanced by the incorporation of IL-modified MCM-41. When the temperature of the feeding liquid was 35°C and the mass fraction of butanol was 2.5 wt%, the 5% MCM-41-IL2-PEBA membrane showed a permeation flux of 421.7 g m−2 h−1 and a separation factor of 25.4. The permeation flux and the separation factor of the membrane increased as the temperature of the feeding liquid increased. The results of the long-period experiment suggested that the 5% MCM-41-IL2-PEBA membrane exhibited high stability within 100 h of operation.

Graphene oxide functionalized with zwitterionic copolymers as selective layers in hybrid membranes with high pervaporation performance

Zwitterionic copolymers, poly(glycidyl methacrylate-sulfobetaine methacrylate) [poly(GMA-SBMA)], was incorporated into graphene oxide (GO) to form a GO–poly(GMA-SBMA) framework. This compound was then deposited onto a polysulfone support through pressure-assisted filtration to fabricate hybrid membranes. Optimum fabrication conditions were determined by varying the poly(GMA-SBMA) loading. Attenuated total reflectance-Fourier transform infrared and X-ray photoelectron spectroscopy confirmed the covalent bonding between poly(GMA-SBMA) and GO. On account of loading incremental amounts of poly(GMA-SBMA), the membrane thickness was increased (illustrated by field emission scanning electron microscopic images), the interlayer spacing between GO sheets was expanded (shown by X-ray diffraction patterns), and the membrane hydrophilic properties were enhanced (indicated by water contact angle data). Relative to the pristine GO membrane, hybrid membranes fabricated at optimum conditions exhibited superior separation performance (99.60 wt% water concentration in permeate and 1102 g m−2⋅h−1 permeation flux) on dehydrating a 70 wt% aqueous isopropanol solution by pervaporation. This present study explored the potential of poly(GMA-SBMA) for developing hybrid membranes with excellent pervaporation performance.

Improving pervaporation performance of PDMS membranes by interpenetrating polymer network for recovery of bio-butanol

In order to improve PV performance of PDMS membranes, PDMS/fluoropolymer interpenetrating polymer network (IPN) membrane was prepared. The IPN was characterized by FTIR, DMA and swelling experiments. The effects of feed concentration, feed temperature and composition of the IPN were discussed. Both separation factor and total flux increase consistently with feed concentration and feed temperature. By the formation of the IPN structure, butanol diffusion of the PDMS membrane is obviously accelerated and the PV performance is greatly improved. Molecular dynamics simulations indicated that both solvation and diffusion of the butanol/water molecules play important role in the IPN pervaporation. The PV performance obtained the best when the fluoropolymer content of the IPN is 30%, which obtained a separation factor of 64.4 with a total flux of 1519.6 g/m2h at 68 °C for the separation of 2.75% butanol.

Effects of by-products of fermentation of banana pseudostem on ethanol separation by pervaporation.

In this work, we performed recovery of ethanol from a fermentation broth of banana pseudostem by pervaporation (PV) as a lower-energy-cost alternative to traditional separation processes such as distillation. As real fermentation systems generally contain by-products, it was investigated the effects of different components from the fermentation broth of banana pseudostem on PV performance for ethanol recovery through commercial flat sheet polydimethylsiloxane (PDMS) membrane. The experiments were compared to a binary solution (ethanol/water) to determine differences in the results due to the presence of fermentation by-products. A real fermented broth of banana pseudostem was also used as feed for the PV experiments. Seven by-products from fermented broth were identified: propanol, isobutanol, methanol, isoamyl alcohol, 1-pentanol, acetic acid, and succinic acid. Moreover, the residual sugar content of 3.02 g/L1 was obtained. The presence of methanol showed the best results for total permeate flux (0.1626 kg·m-2 ·h-1 ) and ethanol permeate flux (0.0391 kg·m-2 ·h-1 ) during PV at 25°C and 3 wt% ethanol, also demonstrated by the selectivity and enrichment factor. The lowest total fluxes of permeate were observed in the experiments containing the acids. Better permeance of 0.1171 from 0.0796 kg·m-2 ·h-1 and membrane selectivity of 9.77 from 9.30 were obtained with real fermentation broth than with synthetic solutions, possibly due to the presence of by-products in the multicomponent mixtures, which contributed to ethanol permeation. The results of this work indicate that by-products influence pervaporation of ethanol with hydrophobic flat sheet membrane produced from the fermented broth of banana pseudostem.

ZIF‐8 membrane synthesized via covalent‐assisted seeding on polyimide substrate for pervaporation dehydration

AbstractIn this study, a novel covalent‐assisted seeding method is developed to fabricate well‐intergrown ZIF‐8 membrane on polyimide (PI) substrate with imidazole‐2‐carboxaldehyde (ICA) as the covalent agent between ZIF‐8 layer and PI substrate. Compared to ethylenediamine‐crosslinked PI membrane and ZIF‐8/PI membrane synthesized without covalent‐assisted seeding method, ZIF‐8/PI membrane synthesized with ICA covalent‐assisted seeding method shows improved pervaporation performance for isopropanol dehydration. Subsequent surface coating with polydimethylsiloxane or polydopamine is applied to mitigate the grain boundary of ZIF‐8/PI membrane, which results in a further performance enhancement. The morphologies and physicochemical properties of the resultant membranes are characterized by scanning electron microscope, attenuated total reflectance‐Fourier transform infrared, X‐ray diffraction, and water contact angle. The effect of operation temperature on the separation performance is also carried out. This work demonstrates the novel covalent‐assisted seeding method for the preparation of ZIF‐8 membrane with high‐performance, which may hold a great potential for various ZIF membranes separation applications.

Effect of chain structure on the solvent resistance in aprotic solvents and pervaporation performance of PMDA and BTDA based polyimide membranes

Pervaporation (PV) performance of polyimide (PI) membranes has been attempted for the recovery of high concentrations of aprotic solvents, such as N, N-dimethyl formamide (DMF) and N, N-dimethylacetamide (DMAc). In this work, we explored the effect of chain structure on the solvent resistance and pervaporation performance of hydrophilic pyromellitic dianhydride (PMDA) and 3,3′,4,4′-benzophenonetetracarboxylic dianhydride (BTDA) based polyimide membranes. According to the Hansen solubility parameters and membrane formation morphologies, we selected five aprotic solvent resistant PI membranes with different chain structures. It was found that the swelling degrees in DMF and DMAc was principally determined by the elasticity modulus of the PI membrane, and was significantly influenced by the polymer chain structure. The flexible linkages (such as –OCH2 and CH2) suppressed the PI chain packing, which resulted in the d-spacing and fractional free volume (FFV) of PMDA based PI membrane was higher than BTDA based PI membrane. BTDA-BZD membrane had the highest elasticity modulus together with the lowest d-spacing value (4.68 Å) due to its symmetric intermolecular interaction and rigid chain structure. PV experiments were conducted with DMF/water and DMAc/water mixtures over a wide range of temperatures (30–60 °C) with 90 wt% solvent concentration. The BTDA based PI (M4) composite membrane showed the highest separating factor around 275 at 30 °C in DMAc solution, which was much higher than in DMF solution (the separating factor is about 70). Furthermore, the chemical and thermal stability test for the PI composite membranes in the presence of the feed solvent under the PV process demonstrated the excellent separation stability in DMAc solution.

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).