• 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.

• Journal of Industrial Technology
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• v.22 no.A
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• pp.249-254
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• 2002

The surface of tube-type alumina substrate was modified with a silane coupling agent in order to modify the membrane surface with hydrophobicity. Contact angle of water drops on modified membrane was greater than $90^{\circ}$. The modified membrane was tested in pervaporation and vapor permeation for the recovery of menthol from dilute menthol/water mixture. With increasing menthol concentration in the feed at $45^{\circ}C$, permeation rate of menthol in pervaporation and vapor permeation increased from $0.039(g/m^2hr)$ to $0144(g/m^2hr)$ and from. $0.077(g/m^2hr)$ to $0.297(g/m^2hr)$ respectively. When feed concentration is 0.005(g/L) at $45^{\circ}C$, separation factor for menthol in pervaporation and vapor permeation is 20,7 and 40.5 respectively.

• Membrane and Water Treatment
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• v.10 no.5
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• pp.381-385
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• 2019

Surface modification is very efficient and scalable approach to achieve improved membrane performance. We treated Reverse Osmosis Thin Film Composite (TFC RO) membrane with various concentrations of Polyethylene Glycol (PEG), a hydrophilic polymer after activation with sodium hypochlorite. This treatment resulted in an increment of the water flux by 43% and the salt rejection by 2.36% for the 3000 mg/l PEG-treated membrane. Further, these PEG-treated membranes were exposed to a mixture of 3000 mg/l PEG and 1000 mg/l sodium hypochlorite for 1 hour. Further modification of this membrane by PEG and sodium hypochlorite mixture increased the water permeance up to 133% when compared with the virgin TFC RO membrane. We characterized the treated membranes to understand the changes in wettability by contact angle analysis, changes in surface morphology and roughness by scanning electron microscope (SEM) and atomic force microscope (AFM) analysis.

• Korean Chemical Engineering Research
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• v.43 no.3
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• pp.366-370
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• 2005

Pervaporation process using a NaY zeolite membrane was applied for separation of water generated in an esterification process as a byproduct. From the binary mixture of water and either ethyl acetate or acetic acid and the ternary mixture of water, ethanol and ethyl acetate which might be present in an esterification reaction for manufacturing ethyl acetate, water was separated by the membrane pervaporation. It was investigated how the operating parameters such as an organic concentration and a temperature affected the permeate flux and the separation factor of water. For the feed mixture of water/ethyl acetate, the total flux and the separation factor of water were observed to be $930-5,000g/m^2/hr$ and 3,700-8,000, respectively. Also it was found for ternary mixtures of water/ethanol/ethyl acetate that the total flux was $1,300-3,900g/m^2/hr$ and the separation factor was 530-1,600. A pervaporation process might be applied in an esterification process since both the total flux and the separation factor of water through the NaY zeolite membrane were shown to be very high.

• Proceedings of the Membrane Society of Korea Conference
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• 2002.11a
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• pp.139-141
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• 2002

• Proceedings of the Membrane Society of Korea Conference
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• 2000.04a
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• pp.77-78
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• 2000

• Proceedings of the Korea Society for Energy Engineering kosee Conference
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• 2003.11a
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• pp.45-49
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• 2003

• Elastomers and Composites
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• v.36 no.4
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• pp.246-254
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• 2001

In this work, the stabilization of chlorosulfonated polyethylene (CSM) rubber emulsion with surfactants, i.e., nonionic (Span 60) or anionic (Sodium laurylsulfate, SLS) surfactants, was investigated. The phase inversion emulsification by interfacial chemical characteristics was used to emulsify the CSM rubber. As a result, the emulsion phase separation was observed in the case of any single surfactant. However, there was no phase separation in the mixture of Span 60 and SLS in the context of emulsion droplet size tests and rheological behaviors. The droplet size decreases by increasing the surfactant mixture, resulting in increasing the viscosity. The viscosity and shear stress determined from shear rate show a shear thinning and yield behaviors. It was then found that the emulsion stabilization can be improved using the phase inversion emulsification method and surfactant mixture.

• Membrane Journal
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• v.17 no.2
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• pp.134-139
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• 2007

Experimental and numerical analysis were performed for separation of carbon dioxide from carbon dioxide and nitrogen gas mixture using a polyethersulfone hollow fiber membrane. The experimental results were compared with those obtained at the same operating condition by the numerical analysis. It was observed that there was a big difference between the experimental results and those by a numerical analysis where the permeance of carbon dioxide and its ideal selectivity over nitrogen were obtained from the pure gas permeation. Therefore, the permeance of carbon dioxide and its selectivity were obtained from the separation experimental results using the numerical analysis as a function of the mole fraction of carbon dioxide, the feed pressure and the permeate pressure in the gas mixture. The results of the numerical analysis using the selectivity obtained from the gas mixture were in good agreement with those of the experimental.

• Journal of the Korean Society of Safety
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• v.13 no.2
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• pp.109-115
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• 1998

Tri-cresyl phosphate(TCP) was synthesized by reaction of phosphorus chloride with mixed cresol(mixture of m-cresol, p-cresol, and others) in the presence of $AlCl_3$. Some of unwanted products and unreactants colored TCP. In order to separate TCP from these, vaccume distillation was carried twice, but colorless TCP could not be producted. Separation of unwanted materials by 2% NaOH solution was introduced before first and second distillation and optimal separation conditions such as NaOH concentration, mixing volume ratio, mixing time, and rpm were investigated for new batch separation and production of colorless TCP Optimal conditions were 2% NaOH solution, 35% mixing volume ratio of 2% NaOH solution, 1.5 hours of mixing time, and 20 rpm.