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Polycarbonate/Metal Salt 막의 산소분리특성에 미치는 비용매와 금속염 농도의 영향
서상훈(Sang-Hun Seo),이우태(Woo-Tai Lee) 한국산업융합학회 2001 한국산업융합학회 논문집 Vol.4 No.1
Polycarbonate(PC) membranes for oxygen enrichment from air were prepared by the wet phase inversion method. In order to improve oxygen separation performances of the PC membrane, the effect of the added ethanol(nonsolvent) and CuCl₂(metal salt) concentration in the casting solution on morphology, oxygen permeability ami O₂/N₂ separation factor of the membrane was studied. In addition, tensile strength and elongation at break of the membrane were investigated. An asymmetric membrane with a dense top layer and a porous sublayer was obtained. The thickness of the dense top layer decreased with increasing amount of nonsolvent additive. Compared with pure PC membrane without additive(metal salt), the oxygen permeability and O₂/N₂ separation factor of the PC/CuCl₂ membrane arc significantly improved. The oxygen permeability and O₂/N₂ separation factor is 5.25×10??㎤(STP)·㎝/㎠·sec·㎝Hg and 4.5, respectively. This improvement might be due to good interaction between metal salt and oxygen.<br/> <br/>
안필성(Pil-Seong Ahn),이우태(Woo-Tai Lee) 한국산업융합학회 1999 한국산업융합학회 논문집 Vol.2 No.2
A cellulose acetate membrane containing silver nitrate was prepared by gelatinizing in water at 2℃ after evaporating solvent from the casting solution on a glass plate. Permeation experiments for oxygen and nitrogen were conducted in the ranges of temperature, 5-40℃ and pressure difference, 1-5㎏/㎠ in order to investigate the effects of temperature and pressure difference on permeation characteristics of the membrane. When the evaporation time was increased, the permeability of oxygen decreased but the separation factor of oxygen against nitrogen increased since a more dense layer was formed on the membrane surface. When the silver nitrate was added, the permeation flux was doubled and the separation factor was improved from 3.0 to 3.3. This implies that silver nitrate acts as an oxygen carrier in the membrane.<br/> <br/>
Poly(4-methyl-1-pentene)막을 통한 이산화탄소와 질소의 투과특성
정형일,김진환,이우태 全南大學校 觸媒硏究所 1997 觸媒硏究 論文集 Vol.19 No.-
The transport behaviors of CO₂and N₂in semicrystalline poly(4-methyl-1-pentene) (PMP) membrane were investigated for the purpose of separating and removing CO₂form flue gases, which is one of the main gases of green house effect on the earth. The permeation experiments were carried out by variable volume method with variable pressure differences between 1 atm and 8 atm at the temperatures of 10, 20, 35 and 50℃. The permeability, diffusion and solubility coefficients of both CO₂and N₂in PMP membrane were independent of pressure differences, which means the sorption of these gases in PMP membrane might be expressed by Henry's law. The permeability. diffusion and solubility coefficients of CO₂were higher than those of N₂. The ideal separation factor of CO₂for N₂was 5.66 at 10℃, and decreased with increasing temperature. Dissolutions of CO₂and N₂by the PMP membrane were exothermic processes. Heat of solution of CO₂was -3.19 kcal/mol, and that of N₂was -2.76kcal/mol.
이재광,김진환,이우태 全南大學校 觸媒硏究所 1998 觸媒硏究 論文集 Vol.20 No.-
The permeabilities, diffusivities of oxygen, nitrogen, helium and carbon dioxide were measured by the volumetric method in each of silicone, cellulose acetate, and their composite membranes. The permeation characteristics of the cellulose acetate membrane was adjusted by changing the evaporation time of the solvent in polymeric solutions casted on a glass plate. The permeabilities and diffusivities did not change with increasing pressure difference but. except for carbon dioxide, increased exponentially with temperature. The diffusivity was higher for the gases with smaller molecular diameter while th solubility was higher for the gases with higher boiling points. The permeabilities in the composite membrane determined from the experiments showed a good match with the theoretical values calculated from the permeabilities in single membranes, while the diffusivities showed discrepancies within 10% range. The order of component membranes in th composite was not obtained as a simple ratio of permeability to diffusivity. The permeation characteristics of the cellulose acetate-silicone composite membrane was dominated by the denser cellulose acetate side.
김형우,이우태,김진환 全南大學校 觸媒硏究所 1997 觸媒硏究 論文集 Vol.19 No.-
The permeability and diffusivity of H₂, He, O₂, N₂, and CO₂in cellulose acetate membrane have been measured at temperatures from 10 to 60℃ and pressures up to 6Kg/cm². The membrane was prepared by casting cellulose acetate solution on a glass plate. In this process, the effect of evaporation time on characteristics of the membrane was discussed. The data for the gas diffusivity were obtained by the time lag method. At a given temperature and pressure, difference, the permeability and diffusivity were constant regardless of the increased of pressure difference, but increased exponentially with the increase of temperature. As the square of the gas molecular diameter increased, the diffusivities decreased exponentially and the activation energy for diffusion increased linearly. Much of the observed scatter in these correlations is attributable to uncertainty in the method of defining molecular diameters. On the other hand, the heat of solution decreased linearly with Lennard Jones force constant. With the exception of H₂and He, it is found that dissolution of the gases into the membrane was exothermic.
김진환,이우태,김종혁 全南大學校 觸媒硏究所 1996 觸媒硏究 論文集 Vol.18 No.-
Composite membranes containing a metal complex as an oxygen carrier were prepared and tested for the capability of oxygen enrichment. The permeability characteristics of the membrane were measured by the volumetric method with the pressure difference ranging from 0.2 to 0.8Kg/cm². Both oxygen and nitrogen showed constant permeabilities, diffusion coefficients, and solubilities which do not depend on the pressure difference across the membrane. The metal complexes were also found to play a role of nitrogen carrier to a degree. For the case of the silicone membrane with Co(NO₃)₂.6H₂O complex, the permeability and the separation factor of oxygen were significantly improved to ??/cm³·cm/cm²·sec·cm-Hg and 2.7 respectively, at the pressure difference of 0.4Kg/cm². This improvement was attributed to the metal complex which acts as an oxygen carrier and thus increases the solubility of oxygen in the membrane.