Efficiency of EDTA,SDS, and NaOH Solutions to Clean RO Membranes Processing Swine Wastewater

The increasing use of membranes to treat a broad range of wastewaters requires the development of efficient cleaning strategies. The objective of this study was to optimize the efficiency of EDTA-SDS-NaOH solutions to recover flux and remove proteins and bacteria from RO membranes filtering swine wastewater. At 60-min cleaning time, flux recovery (FR) increased with SDS concentrations up to 18 mM, but decreased at 36 mM. Adding up to 20 mM EDTA to the SDS solutions did not improve FR. The SDS-NaOH solutions yielded higher FRs at pH 11/40°C and pH 12/33°C than pH 10/45°C, indicating that increasing pH had a greater impact on cleaning efficiency than increasing temperature. At pH 11/40°C and pH 10/45°C, increasing cleaning time from 60 to 120 min decreased FR at all SDS concentrations, probably because of surfactant adsorption on membrane surface, as opposed to inadequate foulant removal, since residual protein concentration was lower on membranes cleaned for 120 than 60 or 30 min. At pH 12/33°C, however, increasing cleaning time to 120 min improved FR at all SDS levels. The lower temperature or higher pH may have prevented surfactant attachment to the membrane. At pH 12/33°C and 120 min, a solution containing NaOH only yielded similar FRs than an 18-mM SDS solution after up to four consecutive fouling-cleaning cycles. Increasing cleaning time and pH would thus eliminate the need to add a surfactant to the cleaning solution.     

One-step cleaning method for flux recovery of an ultrafiltration membrane fouled by banknote printing works wastewater

A method was developed to clean ultrafiltration (UF) membranes fouled by banknote printing works wastewater.The cleaning agent was comprised of 0.7 wt.% NaOH, 0.8 wt.% Na₂EDTA, 0.3 wt.% Turkey red oil and 98.2 wt.% de-ionized water. Membrane flux recovered adequately when the cleaning agent was circulated for 20–30 min at 1.5 m/s and 50–60°C. The membrane surfaces before and after cleaning were characterized by SEM/EDX. The spent cleaning agent was analyzed by TOC and ICP. The results showed foulants were removed from the fouled membrane by the cleaning. Pilot-scale experiments were also conducted to validate the efficiency of the cleaning method. This one-step cleaning method replaced an existing four-step cleaning method and was employed to clean OF units in banknote printing works wastewater plants.     

Performance evaluation of polyvinylchloride/polyacrylonitrile ultrafiltration blend membrane

Polyvinylchloride (PVC) membranes were modified by blending with polyacrylonitrile (PAN) as a second polymer. The miscibility of PVC/PAN blend was examined using an incompressible regular solution (CRS) model in no need to make a membrane. The results showed that the PVC/PAN blend was immiscible for all compositions at a temperature range of ?25 to 225 °C. Furthermore, the prediction of the phase behavior of a PVC/PAN/DMF ternary system showed that the blend of two polymers was highly incompatible even in their common DMF solvent. However, this incompatibility led to a remarkable increase in the porosity of the blend membrane and pure water flux compared to those for pure PVC membrane. The pure water flux of the PVC membrane (37.9 ± 1.5 L/m² h) increased about 41 and 76% by adding 10 and 20 wt% PAN, respectively. The blend membranes also showed an enhanced flux recovery ratio (FRR) compared to a pure PVC membrane, although the PVC membrane rejection for Bovine serum albumin (BSA) was decreased after blending with PAN. The PVC/PAN (90/10) blend membrane was subjected to hydrolysis with NaOH alkaline solution at three different concentrations and contact times to further enhance its performance. The membrane, which was hydrolyzed with a 0.5 mol/L NaOH solution for 0.5 h, showed a highest pure water flux of 75.6 ± 7.2 L/m² h due to its increased hydrophilicity. This membrane also revealed an improved FRR and better thermal and mechanical properties compared to an unmodified membrane.     

INFLUENCE OF K+ AND NA+ IONS ON DIRECT ELECTROSYNTHESIS OF SOLID K2FEO4 AND COMPARISON OF THE PHYSICOCHEMICAL PROPERTIES OF K2FEO4 SAMPLES

The influence of K⁺ and Na⁺ ions on the direct electrosynthesis of solid K₂FeO₄ was investigated in 14 M OH^? solutions. At 50 or 60°C, the maximum current efficiency of electrosynthesis is obtained in 9 M KOH +5 M NaOH solution. The maximum current efficiency of 64.9% is obtained at 60°C in 9 M KOH +5 M NaOH solution, similar to the maximum value of 63.9% at 70°C in 14 M KOH solution in the temperature ranges studied. The result shows that the temperature at which the maximum current efficiency is obtained in 9 M KOH +5 M NaOH is much lower than that in 14 M KOH. Solid K₂FeO₄ powders directly electrosynthesized in 9 M KOH +5 M NaOH and 14 M KOH solutions were characterized by Fourier transform-infrared spectrometry (FT-IR), scanning electron microscopy (SEM), and X-ray diffraction (XRD), and their electrochemical performance was investigated by means of galvanostatic discharge. The result shows that the two samples have similar physical properties and discharge performance.     

Fractionation of Pre‐Hydrolysis Products from Lignocellulosic Biomass by an Ultrafiltration Ceramic Tubular Membrane

Abstract

Development of the lignocellulosic‐biomass‐based biorefinery for making transportation fuels requires the production of valuable byproducts, minimizing the chemical consumables, and efficient water recovery and reuse. Our focus is on a liquid stream containing a variety of soluble lignin species and alkalinity that is produced by a novel extrusion reactor that was used to break down corn stover to cellulose, sugar acids, and lignin. We report on the ambient temperature fractionation of this byproduct stream with a γ‐alumina ceramic tubular membrane. There are four primary figures‐of‐merit investigated in this study: permeance decline, total organic carbon recovery (TOC) and sodium recovery, and the average molecular mass of organic compounds rejected and permeated. These fractionation results are compared relative to differing feed compositions, recovery, and flux. There was definite fractionation between organic (mostly soluble lignin) compounds. The average molar mass of the organic compounds in the permeate remained around 1000 g/mol; however, they ranged from 1500–4000 g/mol in the retentate. In contrast to the TOC, there was no rejection of sodium ions by the membrane (a desirable objective.) With respect to flux decline, the primary form of resistance (>99%), causing significant permeance decline, was a gel/deposition layer formed on the membrane surface. However, this could be flushed away with periodic rinses using water and/or 0.1 M NaOH. After operation at a cumulative filtration load of ～4.9 Mg/m² with various soluble lignin containing streams, 70% of the membrane's virgin pure water permeance could be recovered by a more vigorous cleaning with 0.1 M NaOH including soaking and permeation. Our results seem very consistent with those previously observed for membrane applications within the pulp and paper industry.     

High-Pressure Jet Cleaning of Polymeric Microfiltration Membranes

The cleaning effect of a high-pressure jet of water on a polymeric microfiltration membrane was investigated at different pressures, durations, and angles. The angle of 70° at a pressure of 130 bar and a cleaning duration of 10 s were found to be promising parameters. Throughput measurements show that this cleaning method can restore about 80 % of the initial throughput of the membrane. Analyses by capillary flow porometer and UV-vis spectrophotometer imply that an impact on the membrane was detectable after 1800 cleaning cycles at a pressure of 130 bar. Therefore, high-pressure jet cleaning is a promising method for mechanical cleaning of track-etched microfiltration membranes.     

Influence of Water Compositions and Conditioning on Flux Enhancement in an Immersed Membrane System

Abstract

The objective was to quantify the importance of operational conditions, aeration, and physico‐chemical conditioning on membrane fouling intensity. The suspension filterability was also analysed by using frontal filtration and a cake filtration model. Results pointed out the moderated role of aeration to reduce compound accumulation on the membrane surface. It did not appear as a determining criterion to prevent membrane fouling. In contrast, the physico‐chemical conditioning appeared as a determining criterion to increase critical flux. According to the experimental conditions 200 l/m²/h/bar membrane permeability could be maintained transmembrane pressure (TMP) when filtering stored rainwater. This permeability value was 2–3 times higher than the values obtained without conditioning. Moreover, according to the low turbidity of such stored rainwater and because of the high selectivity of the membrane, the coagulation step, a very low amount of 10 mg/l FeCl₃, was sufficient to intensify the filtration step. This conditioning interest appeared less significant when filtering salted water in immersed membrane systems, but a 20 mg/l FeCl₃ addition appeared sufficient to double the value of critical flux. Nevertheless filtration in frontal mode pointed out the significant impact of physico‐chemical conditioning in reducing the cake deposit hydraulic resistance.     

A study on submerged rotating MBR for wastewater treatment and membrane cleaning

A submerged rotating membrane bioreactor (SRMBR), with a rotatable, rounded, flat-sheet Poly(vinyldiene fluoride) (PVDF) membrane module fixed on hollow axes and moved by an electromotor, was used for wastewater reclamation. It was found that the effluent COD became stable and lower than 20 mg/L after one day running. The equilibrium permeate flux increased from 42.5 to 47.5 L/m²·h with the rotation speed increasing from 15 r/min to 25 r/min. Prolonging relaxation time could alleviate membrane fouling and enhance the flux. Finally, membrane cleaning was studied. The results showed that flushing the membrane surface with water, water/NaOH and water/NaOH/HCl recovered permeate flux to 48.4%, 83.5% and 90.2% of that of the initial operation, respectively.     

Cellulose–poly(acrylamide–acrylic acid) interpenetrating polymer network membranes for the pervaporation of water–ethanol mixtures. II. Effect of ionic group contents and cellulose matrix modification

The separation properties in the dehydration of a water–ethanol mixture and the swelling behavior of interpenetrating polymer network (IPN) pervaporation membranes based on a cellulose or cellulose–hydroxyethyl cellulose (HEC) matrix and poly(acrylamide and/or acrylic acid) were investigated depending on the ionic acrylate groups content (γ) in synthetic polymer chains (0–100 mol %), the HEC content in the matrix (0–50 wt %), and the temperature (25–60°C). The separation factor (α), permeation rate (P), and separation index (αP) significantly improved with increasing γ values only for the separation of concentrated ethanol solutions (～86 wt %). For more dilute solutions of ethanol (～46 wt %), the P and αP values also increased but no considerable increase in α was observed. All types of membranes based on the cellulose matrix were characterized by a drastic decrease in the values of P at [EtOH] ≥90 wt % and, as a result, a decrease in the separation index (kg m^?2 h^?1) from ～2000 (for 86 wt % EtOH, 50°C) to ～240 (for 95 wt % EtOH, 50°C), which correlates with a decrease in the degree of membrane swelling. The modification of the cellulose matrix by introducing HEC into it makes it possible to increase considerably the membrane swelling in concentrated EtOH solutions and, hence, the αP value to ～760 (95 wt % EtOH, 50°C). All types of IPN membranes exhibit a marked increase in both α and P when the temperature increases from 25 to 60°C. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 80: 1452–1460, 2001     

Proton Conductivity of SPEEK Membranes

Novel sulfonated poly(ether ether ketone) (PEEK) copolymers were prepared using a low-viscosity grade PEEK powder. The TGA studies indicated that SPEEK membranes with up to 75% DS have enough thermal stability. The highest conductivity of 2.176 × 10^?2 S cm^?1 has been observed at 100°C for SP96 (DS = 72%). Compared to Nafion-15, SP72 exhibits much higher conductivity at all the temperatures considered. The water sorption experiments indicated that the maximum water uptake was 3.92% for SP24 and it was 60% for SP120. It was observed that the increase in the water content in a membrane caused a decrease in the diffusion coefficient.     

Fabrication of high-performance pervaporation composite membrane for alkaline wastewater reclamation

Pervaporation desalination has a unique advantage to recycle concentrated salt solutions. The merit can be applied to treat alkaline wastewater if the membrane has superior alkali-resistance. In this paper, we used polyethylene microfiltration membrane as the substrate and deposited a glutaraldehyde crosslinked sodium carboxymethylcellulose layer by spray-coating. Pervaporation flux of the composite membrane reached 35 ± 2 kg·m^–2·h^–1 with a sodium chloride rejection of 99.9% ± 0.1% when separating a 3.5 wt-% sodium chloride solution at 70 °C. The desalination performance was stable after soaking the membrane in a 20 wt-% NaOH solution at room temperature for 9 d and in a 10 wt-% NaOH solution at 60 °C for 80 h. Moreover, the membrane was stable in 4 wt-% sulfuric acid and a 500 mg·L⁻¹ sodium hypochlorite solution. In a process of concentrating a NaOH solution from 5 to 10 wt-% at 60 °C, an average water flux of 23 kg·m^–2·h^–1 with a NaOH rejection over 99.98% was obtained.     

Effects of mixed solvents and PVDF types on performances of PVDF microporous membranes

Polyvinylidene fluoride (PVDF) microporous flat membranes were cast with different kinds of PVDFs and four mixed solvents [trimethyl phosphate (TMP)–N,N‐dimethylacetamide (DMAc), triethyl phosphate (TEP)–DMAc, tricresyl phosphate (TCP)–DMAc, and tri‐n‐butyl phosphate (TBP)–DMAc]. The effects of different commercial PVDFs (Solef® 1015, FR 904, Kynar 761, Kynar 741, Kynar 2801) on membrane morphologies and membrane performances of PVDF/TEP–DMAc/PEG200 system were investigated. The membrane morphologies were examined by scanning electron microscopy (SEM). The membrane performances in terms of pure water flux, rejection, porosity, and mean pore radius were measured. The membrane had the high flux of 143.0 ± 0.9 L m^?2 h^?1 when the content of TMP in the TMP–DMAc mixed solvent reached 60 wt %, which was 2.89 times that of the membrane cast with DMAc as single solvent and was 3.36 times that of the membrane cast with TMP as single solvent. Using mixed solvent with different solvent solubility parameters, different morphologies of PVDF microporous membranes were obtained. TMP–DMAc mixed solvent and TEP–DMAc mixed solvent indicated the stronger solvent power to PVDF due to the lower solubility parameter difference of 1.45 MPa^1/2 and the prepared membranes showed the faster precipitation rate and the higher flux. The less macrovoids of the membrane prepared with TEP (60 wt %)–DMAc (40 wt %) as mixed solvent contributed to the higher elongation ratio of 96.61% ± 0.41%. Therefore, using TEP(60 wt %)–DMAc (40 wt %) as mixed solvent, the casting solution had the better solvent power to PVDF, and the membrane possessed the excellent mechanical property. The microporous membranes prepared from casting solutions with different commercial PVDFs exhibited similar morphology, but the water flux increased with the increment of polymer solution viscosity. © 2009 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

Treatment of effluents from textile-rinsing operations by thermally stable nanofiltration membranes

Thermally stable nanofiltration membranes were used to recover hot water from rinsing effluents from acid and reactive dyeing operations. Two types of flat-sheet membranes, MPF-34 (MWCO 200) and MPF-36 (MWCO 1000), were tested at 60°C and 10 bar. Experiments carried out with the made-up feeds containing acid dye and acetic acid showed that both membranes were able to retain more than 99% of dye. MPF-36 suffered from substantial flux decline due to the dye and acid in the feeds but still provided higher fluxes than MPF-34. Furthermore, reactive dye rejection of MPF-36 was acceptable, ranging from 97 to 99.5%, while the fluxes, 105-140 1/m².h, were exceptionally high. MPF-36 was then further tested with the wastewater from industrial processes. The membrane could recover hot water by removing more than 98% of acid dye and 90% of reactive dyes. Despite severe fouling by acid dye, the membrane was still able to provide 40-50 1/m².h of permeate fluxes. For the reactive dye rinsing effluents, remarkably high fluxes of 120-1501/m2.h were obtained. Chemical cleaning of the used membrane with 0.2% wt. HNO₃ and subsequently 0.5% wt. NaOH recovered 80-100% of the flux.     

Hexamethylene diisocyanate crosslinking 2‐hydroxypropyltrimethyl ammonium chloride chitosan/poly(acrylonitrile) composite nanofiltration membrane

The effects of membrane preparation conditions on membrane properties were studied in detail. The results suggested that composite nanofiltration (NF) membrane from 2.0 wt % 2‐hydroxypropyltrimethyl ammonium chloride chitosan (HACC) vaporized for 2.5 h at 50°C, and then crosslinked for 9 h at 50°C with hexamethylene diisocyanate (HDI)/ethanol (0.45/50 wt/wt) were found to have optimal performance. The resultant membrane was called HACC/PAN [poly(acrylonitrile)] NF membrane. The characteristics of this membrane such as pure water permeability, molecular weight cut‐off, rejection of salts, and swelling were investigated. And its cut‐off molecular weight (MWCO) was ～520 Da. At 25°C and 1.0 MPa, the permeability of water was 17.24 L/h m² MPa. Swelling in water decreased and rejection of salts increased with increasing HDI concentration, indicating pore contraction and increase in hydrophobicity as well as pore tortuosity due to crosslinking. The order of rejection to different salt solutes followed the decreasing of CaCl₂, MgCl₂, NaCl, KCl, and Na₂SO₄, suggesting that this membrane was positively charged. The rejections to MgCl₂ and CaCl₂ were more than 0.90; therefore, this membrane can be used for hardness removal in water treatment process. © 2007 Wiley Periodicals, Inc. J Appl Polym Sci, 2007.     

New composite membrane poly(vinyl alcohol)/graphene oxide for direct ethanol–proton exchange membrane fuel cell

This study investigated a simple synthesis of a crosslinked poly(vinyl alcohol)/ graphene oxide composite membrane with lower ethanol permeability membrane for passive direct ethanol–proton exchange membrane fuel cells (DE-PEMFCs). The chemical and physical structure, morphologies, ethanol uptake and permeability, ion exchange capacities, water uptake, and proton conductivities were determined and found that transport properties of the membrane were affected by the GO loading. The composite membrane with optimum GO content (15 wt %) exhibited the highest proton conductivity of 9.5 × 10⁻³ Scm⁻¹ at 30°C, 3.24 × 10⁻² Scm⁻¹ at 60°C, respectively and reduced ethanol permeability until 1.75 × 10⁻⁷ cm² s⁻¹. In the passive DE-PEMFC, the power density at 60°C were obtained as 5.84 mW cm⁻² higher than those by commercial Nafion 117 is 4.52 mW cm⁻². © 2018 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2019 , 136, 46928.     

Carbon dioxide capture under postcombustion conditions using amine-functionalized SBA-15: Kinetics and multicyclic performance

ABSTRACT

In this work, ordered mesoporous SBA-15 was synthesized and functionalized by polyethyleneimine (PEI). The morphological properties were characterized by N₂ adsorption/desorption, field–emission scanning electron microscopy (FE-SEM), high–resolution transmission electron microscopy (HR-TEM) and Fourier transform infrared (FTIR) spectroscopy methods. The carbon dioxide (CO₂) uptake on the sorbents, kinetics of CO₂ adsorption/desorption and long-term multicycle stability of PEI-impregnated sorbent were measured. An optimal amine loading of 50 wt.% showed a CO₂ adsorption capacity ~3.09 mmol g^?1 using 10% pre-humidified CO₂ at 75°C. The presence of moisture in flue gas showed a promoting effect in CO₂ sorption capacity. The temperature swing adsorption/desorption cycles showed excellent multicycle stability over 60 cycles during 65 h of operations under humid CO₂.     

Perfluorosulphonic acid (Nafion) membrane as a separator for an advanced alkaline water electrolyser

Nafion membranes of two different equivalent weights (eq. wt) were evaluated as a separator in an alkaline electrolyser with nickel screen electrodes in both KOH and NaOH electrolytes over the concentration range of 10–30 wt % and at temperatures from 25 to 160° C. For the same current densities, the cell voltage with 30% KOH electrolytes was more than twice that with 30% NaOH. This result correlates with the water content of the membrane which is almost twice as high in NaOH electrolytes. Thinner membranes and membranes of lower equivalent weight give lower cell voltages. Materials and performance considerations indicate that a membrane of 1000 eq. wt is the optimum separator for an alkaline electrolyser. Indications are that LiOH may be an even better electrolyte than NaOH for use with Nafion membranes. Further improvements in performance can be expected by membrane pretreatment such as exposing the membrane to elevated temperature in water. Nafion membranes have excellent physical and mechanical properties in alkaline electrolyte and can be used at temperatures up to 250° C.Work performed under the auspices of the US Department of Energy.     

Could readily silanized silica particles substitute silica coating and silanization in conditioning zirconium dioxide for resin adhesion?

This study investigated the effect of particle types with different morphology and surface properties on the wettability and adhesion of resin cement to zirconia. Zirconia specimens (5 × 5 × 1 mm³) were wet polished. Specimens were randomly assigned to one of the following protocols (N = 36, n = 9 per group): Group CON: Control, no surface conditioning; Group AL: Chairside air-abrasion with aluminium trioxide (50 μm Al₂O₃) + silane; Group SIL: Chairside air-abrasion with alumina particles coated with silica (SIL) (30 μm SiO2, SilJet) + air-drying + silane; Group 4: Chairside air-abrasion with readily silanized silica particles (SILP) (30 μm SiO_2, SilJet Plus). Adhesive resin was applied and resin cement (Variolink II, Ivoclar) was bonded using polyethylene moulds and photo-polymerized and aged (thermocycling, 6.000 cycles, 5–55 °C). Shear bond test was performed using Universal Testing Machine (1 mm/min). Pretest failures were considered 0 MPa. Contact angle measurements were performed (n = 2/group, sessile drop with water). Data (MPa) were analyzed (ANOVA, Tukey’s (α = 0.05). Two-parameter Weibull distribution values including the Weibull modulus, scale (m) and shape (0), values were calculated. Contact angle measurements were in descending order as follows: SIL (74°)^c < CON (60°)^c < AL (51°)^b < SILP (40°)^a. Bond strength (MPa) with SIL (17.2 ± 4)^a and SILP (17.3 ± 1.9)^a demonstrated no significant difference (p > 0.05), being higher than AL (8.4 ± 1.5)^b and CON (0)^c (p < 0.05). Failure types were exclusively adhesive in all groups. Weibull distribution presented the highest shape (0) for SILP (10.8). SILP presented better wettability than AL. SILP provided similar bond strength to SIL. Readily silanized silica particles may substitute for conventional silica coating and silanization.     

Fuel cell performance of polymer electrolyte membrane based on hexafluorinated sulfonated poly(ether sulfone)

The potential-current fuel cell characteristics of membrane electrode assemblies (MEAs) using hexafluorinated sulfonated poly(ether sulfone) copolymer are compared to those of Nafion^® based MEAs in the case of proton exchange membrane fuel cell (PEMFC) and direct methanol fuel cell (DMFC). The hexafluorinated copolymer with 60 mol% of monosulfonated comonomer based acid form membrane is chosen for this study due to its high proton conductivity, high thermal stability, low methanol permeability, and its insolubility in boiling water. The catalyst powder is directly coated on the membrane and the catalyst coated membrane is used to fabricate MEAs for both fuel cells. A current density of 530 mA cm^?2 at 0.6 V is obtained at 70 °C with H₂/air as the fuel and oxidant. The peak power density of 110 mW cm^?2 is obtained at 80 °C under specific DMFC operating conditions. Other electrochemical characteristics such as electrochemical impedance spectroscopy, cyclic voltammetry, and linear sweep voltammetry are also studied.     

Preparation and characterization of nanoparticle-filled,mixed-matrix membranes for the pervaporation dehydration of isopropyl alcohol

Novel polymeric mixed-matrix membranes (MMMs) were prepared by the incorporation of different amounts of 13X zeolite into a sodium carboxymethylcellulose (NaCMC)/poly(vinyl alcohol) (PVA) blend matrix. The resulting MMMs were characterized by attenuated total reflectance–Fourier transform infrared spectroscopy to analyze the possible chemical reactions between NaCMC, PVA, zeolites, and glutaraldehyde. Scanning electron microscopy, differential scanning calorimetry, thermogravimetric analysis, and X-ray diffraction were used to analyze the surface morphology, thermal stability, and crystallinity, respectively, of the membranes. Swellings studies were performed at 35°C, and we found that membranes containing 20 wt % zeolite showed higher values (960 kg m⁻² h⁻¹) at 17.5 wt % water in an isopropyl alcohol (IPA)/water mixture. Pervaporation (PV) experiments were also performed to evaluate the membrane performance in different compositions of the IPA/water mixture at 35°C. The mechanical properties were also tested, and we found that the optimum mechanical strength and percentage elongation at break were 42.24 N/mm² and 3.38, respectively, for the membrane containing 15 wt % zeolite. The experimental results show that both the flux and selectivity increased with increasing zeolite content. The membrane containing 20 wt % zeolite showed the highest separation selectivity (5118) with a substantial flux of 0.121 kg m⁻² h⁻¹ at 35°C and with 10 wt % water in the feed; this suggested that the membranes could be used effectively to break the azeotropic point of the water–IPA mixture, so as to remove a small amount of water from IPA. © 2012 Wiley Periodicals, Inc. J Appl Polym Sci, 2012