• Proceedings of the Korean Magnestics Society Conference
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• 2007.05a
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• pp.322.2-322.2
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• 2007

• Membrane Journal
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• v.14 no.2
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• pp.166-172
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• 2004

As a preliminary study for esterification membrane reactor used to produce 2,2,2-trifluoroethylmetacrylate (TFEMA), Pervaporation behaviors with crosslinked Poly(vinyl alcohol) composite membranes were investigated for aqueous TFEA (2,2,2-trifluoroethanol) feed solutions. In this study, crosslinked PVA composite membranes were prepared by reacting PVA with glutaraldehyde (CA)/acid catalyst onto porous polyethersulfone (PES) supports. SEH images (scanning electron microscopy) showed the thicknesses of selective coating layer was about 2-3 ${\mu}{\textrm}{m}$. The swelling tests showed the dogree of crosslinking decreased as content of the crosslinking agent, GA, increased. Total permeation flux decreased while separation factor increased as the CA content increased. As operating temperature increased, total permeation flux remarkably increased in the range of 85-95 wt% TFEA aqueous solutions. Interestingly, however, separation factor decreased in 85-90 wt% with operating temperature, while that increased in 95 wt%. In case of 90 wt% TFEA concentration and operating temperature 8$0^{\circ}C$, the PVA composite membrane crosslinked with 0.1 mol GA per PVA repeating unit showed high permeation flux of 1.5 kg/$m^2$hr and separation factor of 320. These results confirmed the applicability of the PVA composite membranes for the esterification membrane reactor of TFEMA.

• Membrane Journal
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• v.21 no.4
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• pp.336-344
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• 2011

Organophilic ZSM-5 membrane was synthesized on the inside of a porous stainless steel support by a hydrothermal secondary growth with seed crystals. They are used to separate n-butanol from its aqueous solution. Pervaporation characteristics such as a permeation flux and a separation factor are investigated as a function of the feed concentration and the operating temperature. The concentration of n-butanol was changed from 0.001 mole fraction to 0.015 mole fraction with an interval of 0.005 mole fraction; the operating temperature was controlled to be 25C, $35^{\circ}C$ and $45^{\circ}C$. When the operating temperature was $45^{\circ}C$, the flux of n-butanol significantly increased from 2 to $27g/m^2/hr$ as the mole fraction of n-butanol in the feed side increased from 0.001 to 0.015. Consequently, the concentration of n-butanol in the permeate substantially increased from 0.0016 to 0.052 mole fraction. When the feed concentration was 0.015, the flux of n-butanol significantly increased from 13 to $27g/m^2/hr$ as the operating temperature increased from $25^{\circ}C$ to $45^{\circ}C$. As a result, the concentration of n-butanol in the permeate also increased from 0.045 to 0.052 mole fraction.

• Applied Chemistry for Engineering
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• v.9 no.4
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• pp.469-474
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• 1998

Poly (vinyl alcohol) (PVA) membranes crosslinked with poly (styrene-co-maleic anhydride) (PSMAn) have been prepared by the solution method. To investigate the separation behavior of the crosslinked PVA/PSMAn membranes in the pervaporation process, the selective sorption experiment and swelling measurements of the membranes in ethanol-water mixtures of 30~90 wt % ethanol contents were conducted with equipment that was able to measure the concentration and amount of the liquid absorbed in the membranes. The membranes prepared in this study exhibited good selectivity toward water component in sorption and permeation. Also, in the feed containing ethanol more than 50 wt %, the permeation selectivity of the membrane showed better correlation with the sorption selectivity than that with the swelling ratio changing toward the crosslinking content. This behavior was consistence with a solution-diffusion model correlating permeation and sorption selectivity, and led to the conclusion that the permeation selectivity was determined by sorption step rather than by diffusion step in the membrane.

• Clean Technology
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• v.7 no.3
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• pp.195-202
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• 2001

In this study the trace of chlorinated organic compound in aqueous solution was separated by pervaporation process using crosslinked PDMS (polydimethylsiloxane) membrane. The flux of trichloroethylene(TCE) increased linearly with feed composition but the flux of water was slightly increased. The partial flux of TCE was greater than that of tetrachloroethylene(PCE). The partial flux of TCE was not changed with operating temperature, but increased rapidly with feed flow rates. High crosslinking density causes the reduction of solubility and diffusivity for target component. The reduction of flux and selectivity for TCE is due to the chain immobilization and reduction of diffusivity with crosslinking density.

• Proceedings of the Membrane Society of Korea Conference
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• 2008.05a
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• pp.51-57
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• 2008

Mixed matrix membranes of poly(vinyl alcohol) (PVA), loaded with phosphomolybdic heteropolyacid (HPA) and crosslinked with glutaraldehyde have been prepared by the solution casting technique. Pervaporation (PV) experiments have been performed at $30^{\circ}C$ to separate water-isopropanol feed mixtures containing 10 to 40 wt.% of water. The membranes were characterized by DSC and DMTA to understand their thermal behavior and mechanical strength properties. At high content (i.e. 7 wt.% with respect to weight of PVA) of HPA, the mixed matrix membranes could extract water efficiently on the permeate side with a selectivity of 90,000 and a flux of 0.032 $kg/m^2h$ for 10 wt.% of water containing feed mixture (the lowest feed composition of water studied). Flux of the mixed matrix membranes decreased with increasing concentrations of HPA.

• 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.

• Membrane Journal
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• v.23 no.2
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• pp.170-175
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• 2013

Poly (vinyl alcohol) (PVA) solution containing the glutaraldehyde (GA) as a crosslinking agent was coated onto the polyacrylonitrile (PAN) hollow fiber membrane as the supporter. Pervaporation experiments were carried out to characterize the prepared PVA/PAN composite membrane for water-isopropyl alcohol mixture. The flux and separation factor were measured at 30, 50, $90^{\circ}C$ for the feed mixture of aqueous 85 wt% IPA solution with varying the reaction temperature and composition of coating solutions. Typically the flux showed 1,870 $g/m^2{\cdot}hr$ at $90^{\circ}C$ feed mixture and the coating concentration of 3.5 wt% and the highest separation factor of 804 was obtained at $30^{\circ}C$ feed mixture and the coating concentration of 7 wt% as well.

• Membrane Journal
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• v.6 no.1
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• pp.22-31
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• 1996

Pervaporation experiments of isopropanol-water mixtures through a polydimethytsiloxane(PDMS) membrane were carried out at 35$^{\circ}$C and the effect of isopropanol concentration on the separation characteristics was investigated. The total permeation rate showed the largest deviation from the ideal permeation rate at the isoprpanol volume fraction from 0.5 to 0.7, which resulted from the interaction effect between permeants. The plasticizing effect of isopropanol enhanced the permeation of water, while the existance of water resulted in the depression of isopropanol permeation. Both the permeation rate and the selectivity were predicted using Flory-Huggins thermodynamics and modified Maxwell-Stefan equation. The concentration-dependent diffusion coefficients were expressed by Vignes equation. The Flory-Huggins interaction parameter between isopropanol and water was calculated using excess Gibbs energy correlation and the interaction parameters between liquid and polymer membrane were determined by equilibrium swelling experiments. The predicted permeation rates were in accord with the experimental ones within maximum error range of 35 %. The predicted permeation selectivities were in good agreement with the experimental values.

• 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.