• Proceedings of the Membrane Society of Korea Conference
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• 2004.05a
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• pp.51-54
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• 2004

Utilization of membranes offers the promise of extraordinary energy savings if successfully applied to hydrocarbon-hydrocarbon and other organic separations. Membranes are bound to enter into refining and petrochemical operations involving liquid separations once appropriate materials and modules are developed. Hybrid processes such as utilizing membrane modules to break azeotropes formed during distillation are particularly attractive because they offer less process complexity and reduced capital investment[1,2].(omitted)

• Proceedings of the Membrane Society of Korea Conference
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• 2003.07a
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• pp.115-117
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• 2003

No Abstract, See Full Text

• Membrane Journal
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• v.26 no.3
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• pp.197-204
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• 2016

The objective of this work was to investigate the performance of pervaporation process for recovery of ester compounds from model aqueous solutions and how the fluxes of esters and water were affected by changes in feed concentration and temperature. The flux of ethyl acetate (EA), propyl acetate (PA), ethyl propionate (EP), butyl acetate (BA), and ethyl butyrate (EB) increased with an increase in feed concentration from 0.15 wt% to 0.60 wt%, and increased with temperature change from $30^{\circ}C$ to $50^{\circ}C$. The flux of esters (EA, PA, EP, BA, and EB) was in order of (EA) < (PA, EP) < (BA, EB). This result meant that the flux strongly depended on affinity between esters and membrane surface; EA is the least hydrophobic because it has one hydrophobic function group ($-CH_2-$), (PA, EP) have two ($-CH_2-$), and (BA, EB) are the most hydrophobic because these have three ($-CH_2-$). As well as such an influence of hydrophobicity of ester molecules on ester flux, the influence of hydrophobicity of membrane surface on ester flux needs further investigation. With increase in temperature, water flux of aqueous EA, PA, EP, BA, and EB solution increased. However, water flux of aqueous ester solutions did not change appreciably with increase in concentration. This experimental results may be used as fundamental data for pervaporation (PV) to improve the aroma recovery process as an alternative to thermal evaporation and distillation processes.

• Proceedings of the Membrane Society of Korea Conference
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• 1993.10a
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• pp.7-12
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• 1993

Preparation of asymmetric polyimide membranes by the phase inversion process was investigated to develop ultrafiltration, reverse osmosis and pervaporation membranes for organic solutions, using a commercially available solvent-soluble polymaide. The influences of the various factors such as the composition of a cast solution, casting conditions, gelating solutions and others on membrane structure and performance were studied in detail, and it was made clear that a wide variety of asymmetric polyimide membranes ranging from UF to RO for organic solutions could be prepared from the aromatic polyimide used. It was also found that the chemical stability and separation performance of the asymmetric polyimide membranes could be improved by annealing in a liquid or a vacuum at above 200$\circ$. The membrane annealed at 300$\circ$ in a vacuum exhibited the separation factor $\alpha(H_2O/EtOH)$ of 900 with the flux of 1.0 kg/$m^2\cdot h$ at 60$\circ$C for an aqueous ethanol solution of 95 vol%.

• Membrane Journal
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• v.16 no.1
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• pp.25-30
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• 2006

The NaA zeolite membrane was synthesized on the surface of a porous ${\alpha}$-alumina support from the reaction solution composed of 1Si : 1Na : 4Na $6H_{2}O$. The pervaporation performance of the synthesized NaA zeolite membrane was investigated for the iso-propyl alcohol (IPA) aqueous solution according to the different feed concentration and the different operating temperature. The total flux decreases by increasing the feed IPA concentration and increases by increasing the temperature. The total flux was about $4.0{\times}10^3g/m^2\;hr\;at\;60^{\circ}C$ and 0.6 mole fraction of IPA and the separation factor was $1.8{\times}10^7\;at\;60^{\circ}C$ and 0.8 mole fraction of IPA. The separation performance of water through the NaA membrane was found to be superior to that obtainable with a distillation process just by comparison of the vapor-liquid equilibrium data.

• Membrane Journal
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• v.32 no.2
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• pp.163-171
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• 2022

Many studies on pervaporation (PV) for the separation of dilute alcohols as an alternative to conventional energy-intensive technique of distillation have been conducted earlier. The pervaporation transition behavior of ethanol-water mixtures through the PDMS/PSF membrane is important, in order to understand the mechanism of diffusion process. Therefore, in the present work, transient PV behavior for 50 wt% EtOH/H₂O mixture at 50℃ was investigated by using 1194 cm² PDMS/PSF hollow fiber membrane modules. The overall total flux and the separation factor of all the membrane modules increased initially and then gradually decreased with respect to PV time. The initial increase can be attributed to fact that membrane fibers were dry and it took time to dissolve into the membrane surface, but the subsequent decrease is due to the depletion of ethanol concentration in the feed. Therefore, it was confirmed that the ethanol permeation through a PDMS membrane is governed by the solution-diffusion mechanism.

• Membrane Journal
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• v.10 no.4
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• pp.198-204
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• 2000

Pervaporation membranes were fabricated by low temperature plasma treatment the concentrate butanol solution from fermentation process. Effects of power, reaction time, and monomer flow rate were examined to optimize the (W!FM)t value as 4.0389 x 109 J . min/kg. Various organic compounds were tested in plasma treatment. Contact angle and relative sorption ratio were examined in terms of membrane performance. With the increase of contact angle and relative sorption ratio separation factor was enhanced from 0.186 to 3.525. and butanol flux increased from 0.042 to 0.567 kglm2. hr. Hydrophobicity of the membrane increased the affinity with butanoL Heat of mixing for monomer with butanol was examined, but failed to find the trend, because plasma polymerization of monomer produced the new compounds much different from monomers.

• Membrane Journal
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• v.6 no.1
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• pp.44-52
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• 1996

For the purpose of the optimal design of a frame and plate type of pervaporation module, model equations which can predict the effects of feed flow condition on the temperature distribution of the feed developed in the module were established and the temperature distribution with feed flow condition was investigated through the model si$$\mu$ation. With increasing the Reynolds number of feed flow in the module, the flow velocity gradient in the channel height-direction as well as the volume rate of feed which acts as energy source for the evaporation of perrneants on the permeate-side surface of a membrane increased to such an extent that both mass and heat flux in the channel height direction could increase and the temperature drop of feed due to the evaporation of the permeant could be reduced correspondingly. A decrease in channel height caused the temperature drop of feed because of decreasing feed flow in the module. It was observed that the si$$\mu$ation result on the effect of Re on the temperature distribution of feed in the module has an agreement with experiment.

• Proceedings of the Membrane Society of Korea Conference
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• 1996.10a
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• pp.86-87
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• 1996

IPN (Interpenetrating Polymer Network) is a mixture of two or more crosslinked polymers with physically interlocked network structures between the component polymers. IPN can be classified as an alloy of thermosets and has the characteristics of thermosets such as the thermal resistance and chemical resistance and also has the characteristics of polymer alloys with enhanced impact resistance and amphoteric properties. The physical interlocking during the synthesis restricts the phase separation of the component polymer with chemical pinning process, thus the control of morphology is possible through variations of the reaction temperature and pressure, catalyst concentration and crosslinking agent concentration. Finely dispersed domain structure can be obtained through IPN synthesis of polymer components with gross immiscibility. In membrane applications, particularly for the separation of liquid mixtures, crosslinked polymer component with specific affinity to the permeate is needed. With the presence of the permeant-inert polymer component, the mechanical strength and the selectivity of the membranes are enhanced by restricting the swelling of the transporting polymer component networks.

• Proceedings of the Membrane Society of Korea Conference
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• 1994.04a
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• pp.61-62
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• 1994

In order to prepare polyion complex membranes useful for the separation of water-alcohol by pervaporation, k-carrageenan containing artionic sulfate groups in the backbone and good hydrophilicity was selected for the polyanion membrane material and poly{1,3-bis[4-butyl pyridinium] propane. bromide}, one of the polycations synthesized in our lab and containing cationic pyridinium groups., was used. The polyion complex membranes were prepared by the ion complex formation between kcarrageenan films and poly{1,3-bis[4-butyl pyridinium] propane. bromide}. On the formation process of polyion complex membranes, the way of potyion complex formation was carefully studied. In order to study the effect of the morphology on the permeation properties of the polyion complex membranes, which is one of the important factors affecting on the permeation properties of membranes but rarely studied, the microstructure behaviors of the polyion complex mem6ranes in methanol-water mixtures with different compositions Were also studied with x-ray diffractometry and polarizing microscopy.