• KSBB Journal
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• v.15 no.4
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• pp.380-387
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• 2000

An extractive fermentation process using pervaporation was studied in a 7 liter fermentor. Pervaporation was performed using a silicone membrane module and a low-acid-producing strain Clostridium acetobutylicu, B18 was used to produce butanol. In batch culture without pervaporation pH 5.5 and initial glucose concentration of 60 g/L resulted in the highest butanol productivity (0.216 g/L$.$h) with butanol yield of 0.261 Butanol flux through the membrane was best at 2.0 L/min-tubing of air flow rate In batch and fed-batch fermentation glucose consumption rate increased by 1.3 times with pervaporation.

• Membrane Journal
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• v.12 no.4
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• pp.193-206
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• 2002

Pervaporation separation is one of promising membrane technology for the energy saving processes and it has been developed to separate complex mixture systems including azeotropic mixture, close-boiling mixture, aqueous organic mixtures etc. Many researchers focused on dehydration pervaporation separation and they commercialized ethanol dehydration and isopropanol recycling processes. Nowadays, petroleum separation and volatile organic compound removal using pervaporation membranes is one of the emerging application of pervaporation separation. We reviewed the development and application of pervaporation membranes.

• KSBB Journal
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• v.13 no.1
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• pp.38-43
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• 1998

Application of pervaporative extraction of ethanol to simultaneous saccharification and fermentation(SSF) of cellulose was investigated. From batch experiments, optimum cellulose substrate and enzyme loadings were found to be 10% and 15 IFPU/g cellulose, respectively. The cellulose conversion was lowered in fed-batch system due to the ethanol accumulation. The activity of the yeast Saccharomyces uvarum used in this study was significantly reduced at ethanol concentrations above around 40 g/L. From pervaporation experiments using PDMS membrane, ethanol was efficiently separated at 38$^\circ C$ and 10 mmHg of a down stream pressure. The pervaporation unit with 240 cm$^2$ of surface area was combined into the SSF reactor. The continuous removal of ethanol by pervaporation during SSF resulted in an improved cellulose conversion. Within the scope of this experiment, ethanol yields in the pervaporative SSF and simple SSF were 68.3% and 56.6%, respectively. The permeate flux for SSF broth pervaporation was about one-half that for the pervaporation of aqueous ethanol solution. Accordingly, the development of a membrane with higher ethanol selectivity and flux will increase the feasibility of this technology.

• Membrane Journal
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• v.1 no.1
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• pp.34-43
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• 1991

The relationships between affinity of membranes and optimum operation conditions were investigated in the pervaporation of water(1)/ethanol(2) mixture through cellulose acetate(CA) membranes having more affinity to water and silicone rubber(SR) membranes having more affinity to ethanol. CA and SR membranes were prepared and amount of sorption, sorption selectivity, pervaporation separation factor and pervaporation rate in both of membranes were determined and compared. The effects of downstream pressure were analyzed using Thompson diagram and the sorption and pervaporation characteristics with composition of feed and operation temperature were examined in terms of affinity, activity coefficient, plasticizing effect and activation energy of individual species. In the separation of water through CA membranes, high performance of both pervaporation separation factor (water to ethanol, $[\alpha^2_1]_{PV}$) and pervaporation rate was obtained in the conditions of low downstream pressure, middle range of feed concentration and high temperature. In the separation of ethanol through SR membranes, pervaporation separation factor(ethanol to water, $[\alpha^2_1]_{PV}$) increased with downstream pressure and decreased with concentration of ethanol in feed and operation temperature, while pervaporation rate showed opposite trends to those of ($[\alpha^2_1]_{PV}$).

• Proceedings of the Membrane Society of Korea Conference
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• 1995.04a
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• pp.34-35
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• 1995

The unique feature of pervaporation is the mass transfer from a liquid phase to a vapor phase through a non-porous polymeric membrane. When a liquid mixture is brought into contact with a membrane at one side, it is sorbed into the membrane. Due to a driving force applied across the membrane, the sotbed liquid molecules permeate through the membrane and evaporate at the downstream side of the membrane. In pervaporation the permeated species are usually removed from the downstream side under a relatively low vapor pressure, for example by evacuation with a vacuum pump. As far as this condition is fulfilled, the evaporation step can be considered to be much faster than sorption or diffusion. Hence evaporation does not contribute to permselectivity. Therefore the separation by pervaporation results from the differences in the preferential sorption of the individual components of a mixture into the membrane together with the diffusion rates through the membrane. This postulation implies that both sorption and diffusion phenomena have to be accounted for to understand the physico-chemical nature of the pervaporation separation process.

• Membrane Journal
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• v.14 no.3
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• pp.258-262
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• 2004

Trifluoroethyl methacrylate (TFEMA) is used in the preparation of water-repellant paints and optical fiber clading materials, and is manufactured by esterification reaction of trifluoroethanol (TFEA) and methacrylic acid (MA). To estimate the applicability of a pervaporation membrane for the esterification TFEMA esterification, the basic pervaporation properties for TFEA/water mixture were determined using a commercial poly(vinyl alcohol) membrane (GFT Membrane $Pervap^{\circledR}1005$). The effect of TFEA concentration in feed solution and operating temperature on the pervaporation properties was determined. The total permeation flux decreased with increasing TFEA concentration from 90 to 99 wt%, but the separation factor of TFEA/water showed maximum values at 95 wt% TFEA concentration. With increasing feed temperatures from 50 to 8$0^{\circ}C$, the permeation flux and separation factor increased. Higher separation factors and permeation fluxes were observed at 8$0^{\circ}C$ of feed temperature. This pervaporation performance confirmed that the commercial pervaporation membrane could be successfully applied to esterification of TFEMA.

• Membrane Journal
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• v.17 no.1
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• pp.1-13
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• 2007

Pervaporation process using membrane is newly emerging energy saying and cost effect process instead of distillation process. Especially, in pertrochemical industry, pervaporation process is a strong candidate to substitute the conventional energy consuming processes because that petrochemical industry has much energy consuming separation processes, many azeotrope mixtures to separate and needs to compact space to install new process units. Aromatic/aliphatic separation including benzene/cyclohexane mixture, olefin/paraffin separation, xylene isomer separation, reactive monomer recovery and sulfur compound removal from gasoline have been inversitigated for the application of pervaporation membrane process by many researchers and are under commercializing.

• Textile Coloration and Finishing
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• v.17 no.4 s.83
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• pp.21-26
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• 2005

A combination separation system is composed of three parts, simple microfiltration unit for the pretreatment of real waste IPA, pervaporation unit with plate and frame type module(the effective membrane area 9,040$cm^2$), and simple ultrafiltration unit as a refiner. Utrafiltration module with hollow fiber membrane(MWCO 10,000) used to purify waste aqueous IPA solution. In addition, the flux of $CMPA-K^+$ composite membrane for waste aqueous IPA solution was very steady-state with long experiment time(30 days). And the standard deviation($\sigma$) was 0.152 and then the coefficient of variation($CV\%$)was 10.82 The IPA concentration on the membrane performance using pervaporation module system could be increased from $89.85wt(\%)$ to more than $99.90wt\%$ in about 8hr at operation temperature of $70^{\circ}C$ using the pervaporation module system. Therefore, a combination separation process system of simple filtration and pervaporation was very effective for the purpose of the IPA purification and reuse front industrial electronic components cleaning process.

• Applied Chemistry for Engineering
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• v.3 no.2
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• pp.327-334
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• 1992

As a promising method for the volume reduction of the low-level liquid waste, the pervaporation process was studied using a cellulose acetate membrane. Experimental results showed that the pervaporation method, usually applied to separation of organic materials, has a good decontamination effect for the volume reduction of liquid waste and the evaporation rate of water in this process was markedly faster than that of natural evaporation method, a wide-used process for the volume reduction of liquid waste. Depending on the feed solution conditions, the pervaporation characteristics were evaluated by the experimental results and the optimum conditions for preparation of the cellulose acetate membrane were established to increase the pervaporation flux through the membrane.

• Korean Membrane Journal
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• v.6 no.1
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• pp.55-60
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• 2004

In recent years, an increasing interest in membrane technology has been observed in chemical and environmental industry. Membrane technology has advantages of low cost, energy saving and environmental clean technology comparing to conventional separation processes. Pervaporation is one of new advanced membrane technology applied for separation of azeotropic mixtures, aqueous organic mixtures, organic solvent and petrochemical mixtures. Sodium alginate composite membranes were prepared for the enhancement of long-term stability of pervaporation performance of water-ethanol mixture using pervaporation. Sodium alginate membranes were crosslinked with CaCl$_2$ and coated with polyelectrolyte chitosan to protect washing out of calcium ions from the polymer. The surface structures of PAN and hydrolysed PAN membrane were confirmed by ATR Fourier transform infrared (FT-IR). A field emission scanning electron microscopy (FE-SEM; Jeol 6340F) operated at 15 kV. Concentration profiles for Ca in the membrane surface and membrane cross-section were taken by an energy dispersive X-ray (EDX) analyser (Jeol) attached to the field emission scanning electron microscopy (Jeol 6340F). Pervaporation experiments were done with several operation run times to investigate long-term stability of the membranes.