Ethanol Flux Research Articles

The performance of integrally skinned polyetherimide asymmetric nanofiltration membranes with organic solvents

Nanofiltration (NF) has become an emerging technology in organic solvent systems and the preparation of organic solvent resistant nanofiltration (SRNF) membranes is the most important aspect of the technology. In this study, integrally skinned polyetherimide (PEI) asymmetric nanofiltration (NF) membranes were prepared by phase inversion in which dimethylacetamide (DMAc) and polyvinyl pyrrolidone (PVP-K30) were employed as solvents and additives in casting solutions. The prepared PEI membranes were characterized by scanning electronic microscopy (SEM) and evaluated in terms of solvent compatibility, solute rejection and solvent flux. The solvents employed were ethanol, isopropyl alcohol, n-hexane and carbon tetrachloride and the solute molecules were rose bengal (molecular weight 1017Da) and methylene blue (molecular weight 374Da). The prepared PEI NF membrane was compared with four commercial SRNF composite membranes (MPF-34, MPF-44, STARMEM 122 and Solsep 010706). The results demonstrated that the PEI membranes were stable in all of the four solvents studied and showed better performance than the four commercial SRNF membranes with regard to solvent compatibility and rejection from ethanol solutions. The PEI membrane had ethanol fluxes of 4–8Lm−2h−1 at 100psi and 95% rejection for methylene blue in ethanol.

A 1D+1D Model of Direct Ethanol Fuel Cells Based on an Optimized Kinetic Mechanism for Ethanol Electro-Oxidation Involving Free and Adsorbed Intermediate Species

A 1D+1D model for liquid-feed direct ethanol fuel cells with detailed ethanol electro-oxidation kinetics is presented. One-dimensional convective transport along the flow channels is coupled to a one-dimensional description for species transport across the MEA accounting for the effect of the electrochemical reactions and the mixed potential due to ethanol and acetaldehyde crossover. The model, validated against previous experimental data, provides the variation of the concentrations of the free species and the output and parasitic current densities along the flow channels. The downstream evolution of ethanol and acetaldehyde affects the anode reaction rates and the ethanol and acetaldehyde crossover fluxes, which in turn impacts on the cathode reaction rates. Polarization curves obtained at different positions along the flow channels show the effect of ethanol consumption and acetaldehyde upstream production and downstream consumption. Power density, parasitic current, fuel utilization and product selectivity curves are presented and discussed for different ethanol feed concentrations and flow rates.

Experimental study on forced convective and subcooled flow boiling heat transfer coefficient of water-ethanol mixtures: an application in cooling of heat dissipative devices

The experimental study is carried out to determine forced convective and subcooled flow boiling heat transfer coefficient in conventional rectangular channels. The fluid is passed through rectangular channels of 0.01 m depth, 0.01 m width, and 0.15 m length. The parameters varied are heat flux, mass flux, inlet temperature and volume fraction of ethanol. Forced convective heat transfer coefficient increases with increase in heat flux and mass flux, but effect of mass flux is less significant. Subcooled flow boiling heat transfer increases with increase in heat flux and mass flux, but the effect of heat flux is dominant. During the subcooled flow boiling region, the effect of mass flux will not influence the heat transfer. The strong Marangoni effect will increase the heat transfer coeffient for mixture with 25% ethanol volume fraction. The results obtained for subcooled flow boiling heat transfer coefficient of water are compared with available literature correlations. It is found that Liu-Winterton equation predicts the experimental results better when compared with that of other literature correlations. An empirical correlation for subcooled flow boiling heat transfer coefficient as a function of mixture wall super heat, mass flux, volume fractions and inlet temperature is developed from the experimental results.

Impact of osmotic agent on the transport of components using forward osmosis to separate ethanol from aqueous solutions

The separation of low molecular weight organic compounds such as the ethanol from aqueous solutions represents an important area to be investigated and increment the range of applications of forward osmosis. This investigation assesses the effects of using different draw solutes for ethanol separation from dilute aqueous solutions. The influence of glucose, sucrose, sodium chloride, and magnesium chloride was evaluated in terms of total permeate, reverse solute and ethanol fluxes. Inorganic solutes promoted higher total permeate and ethanol fluxes than the organic solutes (2.5 and 1.5 times higher in average, respectively) for the same molar concentration, while presenting only 1.1 times higher reverse solute fluxes. Despite the lower ethanol flux promoted by the organic draw solutes, these osmotic agents promoted higher concentration of ethanol in the total permeate flux, suggesting that they can also be alternatives for specific processes. © 2017 American Institute of Chemical Engineers AIChE J, 63: 4499–4507, 2017

Separation of fermentation products from ABE mixtures by perstraction using hydrophobic ionic liquids as extractants

In this work, the perstraction process was implemented to separate butanol, acetone and ethanol from aqueous solutions using four different commercial hydrophobic ionic liquids (ILs) as receiving phase: [bmin][PF6], [bmim][Tf2N], [omim][Tf2N] and [P6,6,6,14][DCA]. These ILs constituted by different cations and anions were selected in terms of its hydrophobicity, good solubility of butanol and commercial availability.Perstraction assays were carried out using a symmetric membrane made in polydimethylsiloxane (PDMS) in order to quantify the extraction percentage and transmembrane fluxes of butanol, acetone, ethanol and water. The results indicate that the transmembrane fluxes of butanol were particularly high considering that the PDMS membrane used in the experiments was relatively thick (160µm). The highest average flux of butanol was obtained using [P6,6,6,14][DCA] as the extractant reaching a value of 5.5×10−3kgh−1m−2. Nevertheless, the IL with the best separation performance was [omim][Tf2N] with a low flux of butanol (4.3×10−3kgh−1m−2) but with the highest butanol/water selectivity value equal to 64.25.This perstraction technique combined with ILs could allow to design a wide range of separation processes to purify a large variety of molecules. Besides that, the perstraction process could be considered a good alternative for the selective separation of fermentation or reaction products with high commercial value.

Poly(ether sulfone) supported hybrid poly(vinyl alcohol)–maleic acid–silicone dioxide membranes for the pervaporation separation of ethanol–water mixtures

ABSTRACTMicroporous poly(ether sulfone) (PES) supported hybrid polymer–inorganic membranes were prepared by the crosslinking of poly(vinyl alcohol) (PVA), maleic acid (MA), and SiO2 via an aqueous sol–gel route and a solution‐casting method. The membrane performance was tested for the pervaporation separation of ethanol–water mixtures from 20 to 60 °C with a feed ethanol concentration of 96 wt %. The membrane characterization results reveal that different SiO2 loadings affected the crystallinity and roughness of the membranes. The PVA–MA–SiO2 membrane containing 10 wt % SiO2 showed that SiO2 nanoparticles were well dispersed within the polymer matrix; this resulted in significant enhancements in both the flux and selectivity. The membrane achieved a high water permeability of 1202 g·μm·m−2 h−1 kPa−1 and a selectivity of 1027 for the separation of a 96 wt % ethanol‐containing aqueous solution. This enhanced membrane performance might have been due to the dense crosslinking membrane network, increased free volume, and uniform distribution of SiO2 nanoparticles. Both the water and ethanol fluxes increased with the feed water concentration and temperature. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 44839.

Removal of atmospheric ethanol by wet deposition

AbstractThe global wet deposition flux of ethanol is estimated to be 2.4 ± 1.6 Tg/yr with a conservative range of 0.2–4.6 Tg/yr based upon analyses of 219 wet deposition samples collected at 12 locations globally. This estimate calculated by using observed wet deposition ethanol concentrations is in agreement with previous models (1.4–5 Tg/yr) predicting the wet deposition sink using Henry's law coefficients and atmospheric ethanol concentrations. Wet deposition is estimated to remove between 6 and 17% of the total ethanol emitted to the atmosphere on an annual basis. The concentration of ethanol in marine rain (25 ± 6 nM) is an order of magnitude less than in the majority of terrestrial rains (345 ± 280 nM). Terrestrial rain samples collected in locations impacted by high local sources of biofuel usage and locations downwind from ethanol distilleries were an order of magnitude higher in ethanol concentration (3090 ± 448 nM) compared to rain collected in terrestrial locations not impacted by these sources. These results indicate that wet deposition of ethanol is heavily influenced by local sources. Results of this study are important because they suggest that as biofuel production and usage increase, the concentration of ethanol in the atmosphere will increase as well the wet deposition flux. Additional research constraining the sources, sinks, and atmospheric impacts of ethanol is necessary to better assist in the debate as whether or not to increase consumption of the alcohol as a biofuel.

Separation performance of novel vinyltriethoxysilane (VTES)-g-silicalite-1/PDMS/PAN thin-film composite membrane in the recovery of bioethanol from fermentation broths by pervaporation

Organophilic pervaporation (OPV) has been considered as one of the most promising separation processes for the recovery of biofuels from fermentation broths, however, in addition to preferred target product – liquid biofuels, the yeast cells and fermentation nutrients could affect the recovery efficiency of biofuels from broths by pervaporation. In this paper, the influence of the yeast cells and the fermentation nutrient components such as the sources of carbon, nitrogen and salts on the separation performance of the vinyltriethoxysilane (VTES)-grafted- (VTES-g-) silicalite-1/PDMS/PAN thin-film composite membrane was conducted systematically. The results revealed that glucose, xylose, protein, and salts cannot permeate through the membrane. Glucose concentration in the fermentation broth should be kept at a lower level (less than 20g/L) to eliminate its deleterious influence on ethanol flux and membrane selectivity. Xylose and corn steep liquor (CSL) have little effect on the pervaporation performance of the composite membrane. The addition of NaCl improved the membrane selectivity and ethanol flux but slightly lowered down total permeation flux. Adding dry yeast cells to the ethanol solution can enhance the turbulence in the feed mixtures, resulting an increase of the membrane flux and selectivity. The pervaporation performance of fermentation broths was also studied. The results showed that the nutrients and the deposition of yeast cells on the membrane surface didn’t deteriorate the pervaporation performance, indicating excellent fouling resistance of the novel VTES-g-silicalite-1/PDMS/PAN composite membrane in operation with fermentation broths. The continuous ethanol fermentation can be directly connected to the in-situ pervaporative recovery system without requiring prior removal of yeast cells.

Characterization of Clostridium ljungdahlii OTA1: a non-autotrophic hyper ethanol-producing strain.

A Clostridium ljungdahlii lab-isolated spontaneous-mutant strain, OTA1, has been shown to produce twice as much ethanol as the C. ljungdahlii ATCC 55383 strain when cultured in a mixotrophic medium containing fructose and syngas. Whole-genome sequencing identified four unique single nucleotide polymorphisms (SNPs) in the C. ljungdahlii OTA1 genome. Among these, two SNPs were found in the gene coding for AcsA and HemL, enzymes involved in acetyl-CoA formation from CO/CO2. Homology models of the respective mutated enzymes revealed alterations in the size and hydrogen bonding of the amino acids in their active sites. Failed attempts to grow OTA1 autotrophically suggested that one or both of these mutated genes prevented acetyl-CoA synthesis from CO/CO2, demonstrating that its activity was required for autotrophic growth by C. ljungdahlii. An inoperable Wood-Ljungdahl pathway resulted in higher CO2 and ethanol yields and lower biomass and acetate yields compared to WT for multiple growth conditions including heterotrophic and mixotrophic conditions. The two other SNPs identified in the C. ljungdahlii OTA1 genome were in genes coding for transcriptional regulators (CLJU_c09320 and CLJU_c18110) and were found to be responsible for deregulated expression of co-localized arginine catabolism and 2-deoxy-D-ribose catabolism genes. Growth medium supplementation experiments suggested that increased arginine metabolism and 2-deoxy-D-ribose were likely to have minor effects on biomass and fermentation product yields. In addition, in silico flux balance analysis simulating mixotrophic and heterotrophic conditions showed no change in flux to ethanol when flux through HemL was changed whereas limited flux through AcsA increased the ethanol flux for both simulations. In characterizing the effects of the SNPs identified in the C. ljungdahlii OTA1 genome, a non-autotrophic hyper ethanol-producing strain of C. ljungdahlii was identified that has utility for further physiology and strain performance studies and as a biocatalyst for industrial applications.

Electrochemical kinetic and mass transfer model for direct ethanol alkaline fuel cell (DEAFC)

A mathematical model is developed for a liquid-feed DEAFC incorporating an alkaline anion-exchange membrane. The one-dimensional mass transport of chemical species is modelled using isothermal, single-phase and steady-state assumptions. The anode and cathode electrochemical reactions use the Tafel kinetics approach, with two limiting cases, for the reaction order. The model fully accounts for the mixed potential effects of ethanol oxidation at the cathode due to ethanol crossover via an alkaline anion-exchange membrane. In contrast to a polymer electrolyte membrane model, the current model considers the flux of ethanol at the membrane as the difference between diffusive and electroosmotic effects. The model is used to investigate the effects of the ethanol and alkali inlet feed concentrations at the anode. The model predicts that the cell performance is almost identical for different ethanol concentrations at a low current density. Moreover, the model results show that feeding the DEAFC with 5 M NaOH and 3 M ethanol at specific operating conditions yields a better performance at a higher current density. Furthermore, the model indicates that crossover effects on the DEAFC performance are significant. The cell performance decrease from its theoretical value when a parasitic current is enabled in the model.

Effect of Stretching Parameters on Structure and Properties of Polytetrafluoroethylene Hollow‐Fiber Membranes

AbstractPolytetrafluoroethylene (PTFE) porous hollow‐fiber membranes were prepared by a method involving billet preform, paste extrusion, stretching, and sintering. The influence of stretching parameters including stretching ratio, temperature, and speed was systematically investigated. The structure and properties of these membranes were characterized by field emission scanning electron microscopy, filtration performance, and mechanical strength test. The results indicate that the stretching ratio is the most significant influencing factor for the formation of various regions in the stress‐strain curve. With increasing stretching ratio, the porosity, maximum pore size, and ethanol flux increase remarkably while bovine serum albumin rejection is reduced. These findings have the potential to facilitate PTFE membrane fabrication with finely tuned microporous structure for various application processes.

Tuning the microstructure and permeation property of thin film nanocomposite membrane by functionalized inorganic nanospheres for solvent resistant nanofiltration

Abstract Herein, a series of thin film nanocomposite (TFN) membranes are prepared by incorporating functionalized silica nanospheres into polyethyleneimine (PEI) matrix for solvent resistant nanofiltration (SRNF). Three functional groups are grafted onto the nanospheres in form of polymer layer via distillation–precipitation polymerization for manipulating the free volume cavities of PEI matrix by interfacial interactions along PEI-nanosphere domains. The effects of nanospheres on the microstructures, physicochemical and permeation properties of TFN membranes are investigated systematically. The tested data suggest that the nanospheres are uniformly dispersed in PEI matrix without obvious defects, offering the excellent thermal stability and appropriate solvent resistance to the membranes. The microstructures of TFN membranes are elaborately regulated by varying the fractional free volume (FFV) and surface hydrophilic/hydrophobic nature, jointly yielding the tunable permeation properties. In particular, the permeate flux of ethanol is elevated from 21.2 to 30.8 L m−1 h−1 with the increase of FFV from 0.452% to 0.473% by incorporating various hydrophilic nanospheres. Meanwhile, the addition of hydrophobic nanospheres provided much higher fluxes for n-heptane from 0.1 to 21.7 L m−1 h−1, due to the enhanced solution capability. Moreover, the presence of nanospheres donates high rejection ability and promising operation stability to the TFN membranes.

Biogeochemistry of Ethanol and Acetaldehyde in Freshwater Sediments

This study reports the first ethanol and acetaldehyde measurements in sediment porewaters collected at multiple freshwater locations. Ethanol concentrations ranged from 11 to 2535 nM and acetaldehyde concentrations ranged from 6 to 320 nM. A significant positive correlation (p < 0.001) was observed between ethanol concentrations and the percent organic carbon content of sediments (TOC). Porewater depth profiles at two sites within the same lake indicated potential diffusion of ethanol into sediments from the overlying water at a lower TOC site and upwards diffusion from sediment into the water column at a higher TOC site. Diffusion of water column ethanol into sediments was observed at individual sites from October to January, whereas the opposite was true from June to August indicating the seasonal variability of ethanol flux from sediments. Changes in ethanol concentrations during a long-term sediment incubation experiment showed an inverse relation with acetaldehyde concentrations. The lack of a quantitative conversion was likely due to other sources and sinks that control their abundance. Our study provided new information on the biogeochemistry of ethanol in freshwater sediments and shed light on the potential role of ethanol in the global carbon cycle.

Structure and performance characterization of PDMS/PES-based pervaporation membranes for ethanol/water separation

Composite membranes, with a supporting layer of polyethersulfone (PES) and different active layers based on poly(dimethylsiloxane) (PDMS), were prepared to perform pervaporative separation of ethanol from water. Two approaches were adopted to enhance the ethanol selectivity of PDMS by: (1) evaluation of the effects of PDMS viscosity of two different grades and (2) the incorporation of new hydrophobic silica in the active layer. First, the structural morphology of support and active layers of the composite membranes was characterized. AFM images were evidence of the nodular structure of the membrane surfaces. Mean pore size and pore size distribution of PES layer, mean nodular size of PDMS layer, and their surface roughness and water contact angle were determined. The relationship between these structural properties and the pervaporation performance of composite membranes has then investigated. The effects of operating parameters, feed concentration and temperature on the membrane performance indicated that increasing the feed temperature improved PDMS/PES membranes pervaporative efficiency. Based on the results obtained, it was found that PDMS viscosity influenced the pervaporation performance; low-viscosity PDMS had a greater separation factor and greater permeation fluxes than high-viscosity PDMS. Moreover, silica-filled membranes improved the separation factor and enhanced the ethanol flux relatively.

Combinatorial Methodology for Screening Selectivity in Polymeric Pervaporation Membranes.

Combinatorial methodology is described for rapid screening of selectivity in polymeric pervaporation membrane materials for alcohol-water separations. The screening technique is demonstrated for ethanol-water separation using a model polyacrylate system. The materials studied are cross-linked random copolymers of a hydrophobic comonomer (n-butyl acrylate, B) and a hydrophilic comonomer (2-hydroxyethyl acrylate, H). A matrix of materials is prepared that has orthogonal variations in two key variables, H:B ratio and cross-linker concentration. For mixtures of ethanol and water, equilibrium selectivities and distribution coefficients are obtained by combining swelling measurements with high-throughput HPLC analysis. Based on the screening results, two copolymers are selected for further study as pervaporation membranes to quantify permeability selectivity and the flux of ethanol. The screening methodology described has good potential to accelerate the search for new membrane materials, as it is adaptable to a broad range of polymer chemistries.

Fabrication of cellulose triacetate/graphene oxide porous membrane

Cellulose triacetate (AC)/graphene oxide (GO) porous membranes were successfully fabricated by combining ultrasonication and phase inversion method. The structures and morphologies of the resultant composite membranes were investigated by X-ray diffraction (XRD), scanning electron microscopy, and transmission electron microscopy, respectively. Microscopic and X-ray diffraction measurements revealed that GO sheets were uniformly dispersed within the AC matrix. The pore size and structure were modulated by changing GO concentration from 0.25 to 1 wt%. Membrane thermal properties were also studied. Among all tested membranes, the most favorable GO amount was 1 wt%, giving Td3% of 274°C, which represents a 22°C enhancement compared with AC. Conversely, the membranes showed improved barrier properties against water and ethanol. The decrease of both ethanol and water fluxes was assigned to the stabilization of composite membrane structure, as a result of GO progressive addition. Bovine serum albumin rejection assay indicated an increasing from 78% in the case of CA membrane to 99% in the case of CA/GO 1 wt% of the rejection degree after 90 min. Copyright © 2015 John Wiley & Sons, Ltd.

Metabolic control analysis of L-lactate synthesis pathway in Rhizopus oryzae As 3.2686.

The relationship between the metabolic flux and the activities of the pyruvate branching enzymes of Rhizopus oryzae As 3.2686 during L-lactate fermentation was investigated using the perturbation method of aeration. The control coefficients for five enzymes, pyruvate dehydrogenase (PDH), pyruvate carboxylase (PC), pyruvate decarboxylase (PDC), lactate dehydrogenase (LDH), and alcohol dehydrogenase (ADH), were calculated. Our results indicated significant correlations between PDH and PC, PDC and LDH, PDC and ADH, LDH and ADH, and PDC and PC. It also appeared that PDH, PC, and LDH strongly controlled the L-lactate flux; PDH and ADH strongly controlled the ethanol flux; while PDH and PC strongly controlled the acetyl coenzyme A flux and the oxaloacetate flux. Further, the flux control coefficient curves indicated that the control of the system gradually transferred from PDC to PC during the steady state. Therefore, PC was the key rate-limiting enzyme that controls the flux distribution.

Steady-state metabolism of ethanol in perfused rat livers treated with cyanamide: quantitative analysis of acetaldehyde effects on the metabolic flux rates.

Alcohol dehydrogenase (ADH) and aldehyde dehydrogenase (ALDH) are principal enzymes responsible for metabolism of ethanol in mammals. The steady-state metabolic flux of ethanol has been poorly understood. We investigated flux rates of the individual steps of ethanol metabolism in perfused rat livers treated with ALDH inactivator cyanamide as an attempt to mimic human ALDH2 deficiency commonly seen in East Asians. The net rates of ethanol oxidation, acetaldehyde oxidation, and acetate activation were determined with a set of defined equations, based on the set influx rates of ethanol and the measured efflux rates of ethanol, acetaldehyde, and acetate. After intraperitoneal injections of 0.2 and 1.5mg/kg cyanamide, hepatic activities of mitochondrial ALDH2 and cytoplasmic ALDH1A1 decreased to a similar degree, that is, 51 to 57% and 69 to 74%, compared with the corresponding controls, respectively, whereas cytoplasmic ADH1 activity remained unchanged. At infusing 2mM ethanol, acetaldehyde oxidation rate well matched (99%) the net ethanol oxidation rate in control liver. Both the ethanol and acetaldehyde oxidation rates were significantly decreased after cyanamide treatments. At 10mM ethanol, the efflux acetaldehyde was significantly higher than that infusing 2mM ethanol in both control and cyanamide groups. Seventy-eight percent of the oxidized ethanol released as efflux acetate. At 2mM ethanol, the apparent flux control coefficients of ADH1 were assessed to be 0.78, 0.54, and 0.39, respectively, in control, low, and high cyanamide-treated livers. Kinetic simulations revealed that inhibition by acetaldehyde may largely account for the observed reduction of ADH1 oxidation rates after cyanamide treatment. Our results provide the first flux evidence that ADH and ALDH are steps influencing steady-state metabolism of ethanol in rat livers with inactivated ALDHs.

Effects of PES support layer structure on pervaporation performances of PDMS/PES hollow fiber composite membranes

Polyethersulfone (PES) hollow fiber ultrafiltration (UF) membranes were fabricated by the dry/wet-spinning method; hydrophobic PDMS/PES composite membranes which were supported by self-prepared PES hollow fiber UF membranes were prepared for the pervaporation (PV) separation of ethanol from water. Impacts of PES support layer on the PV performances of PDMS/PES composite membranes were studied. Experimental results showed that, while working as a support to PDMS active layer, PES hollow fiber membrane could affect the PV performance of PDMS/PES membranes greatly. Pervaporation performance of the membrane which its PES support layer had bigger porosity and bigger mean pore size was apparently superior to that of the membrane which its PES support layer had smaller porosity and smaller mean pore size. After being treated with ethanol and hexane, PES membrane was dried in air for 20 min before being immersed in PDMS coating solution; the prepared PDMS/PES membrane had the best PV performance with a permeate flux of 330 g/(m2 h) and a separation factor of 5.8. Effects of process parameters, such as feed temperature, permeate pressure, and feed flow rate, on membrane properties were investigated. For the separation of a 5 wt.% ethanol–water mixture, with an increase in feed temperature from 30 to 60°C, water flux and ethanol flux increased from 51 to 328 g/(m2 h) and from 14 to 88 g/(m2 h), respectively; the variation of permeation flux followed the Arrhenius relationship and the activation energy values for water and ethanol were 54.54 and 53.44 kJ/mol, respectively; separation factor varied from 5.1 to 6.0. When the feed temperature was 50°C and feed concentration was 5 wt.%, with an increase in permeate-side pressure from 1 to 40 mm Hg, water flux dropped sharply from 334 to 14 g/(m2 h) and ethanol flux dropped moderately from 82 to 22 g/(m2 h), and as a result, separation factor increased. With the increase in feed flow rate from 0.1 to 10 L/min, both flux and separation factor increased rapidly at first and then leveled off at 2 L/min for the reason of concentration polarization.

Removal of volatile organic compounds from aqueous solutions applying thermally driven membrane processes. 1. Thermopervaporation

Temperature driven membrane thermopervaporation was studied in this work. Impact of various experimental conditions (feed temperature – Tf, type of membrane, type of organic solvent in binary aqueous mixture, feed composition) on transport and selectivity in TPV was investigated experimentally. Two commercially available dense PDMS based membranes (Pervatech and Pervap 4060) were utilized during TPV experiments in contact with pure water and binary aqueous mixtures of acetone, butanol and ethanol. Intrinsic properties (permeance and selectivity coefficient) of membranes were determined and discussed.Transport in thermopervaporation increases with an increase of feed temperature (at constant temperature of permeate). During TPV experiments performed with Pervatech in contact with acetone–water system, permeance of acetone increased from 0.12molm−2h−1kPa−1 at Tf=30°C to 0.24molm−2h−1kPa−1 at Tf=42°C, whereas permeance of butanol increased from 0.45molm−2h−1kPa−1 at Tf=30°C to 0.64molm−2h−1kPa−1 at Tf=41°C.Pervap 4060 membrane showed better properties in thermopervaporative recovery of butanol and ethanol from water than Pervatech membrane. It was also found that the application of stainless steel porous support reduces ethanol and water fluxes, but it does not affect the selectivity up to 3wt.% of ethanol in feed.