• Proceedings of the Membrane Society of Korea Conference
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• 1992.10a
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• pp.10-11
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• 1992

막분리 공정의 응용범위 및 시장규모가 증가함에 따라 최근 기능성 분리막의 개발에 대한 많은 연구가 시도되고 있으나 아직까지도 매우 한정된 범위의 유기질 분리막만이 실용화되고 있을 뿐이다. 막분리 공정의 응용성은 분리막의 특성에 의하여 좌우될수 있는데 현재 주로 사용되고 있는 유기질막은 열적, 기계적, 화학 및 생화학적 안정성이 낮고 세척에 의한 재생성이 용이하지 않기 때문에 차후이들을 대체하여 모든 조업조건하에서 효율적으로 장기간 사용될 수 있는 세라믹막의 개발이 요구되고 있는 실정이다. 특히 2000년도 초반부터는 종래의 유기질막으로서는 기대할 수 없는 고기능성을 부여할 수 있는 세라믹막의 공업적 수요가 급증하여 분리막 공정에서 상당한 비중을 점유하게 될 것으로 예상되고 있으나 현재 전 세계적으로 세라믹막의 제조 및 응용에 대한 기초 및 기술이 확립되어 있지 않아서 공업적인 실용화가 이루어지지 못하고 있다.

• Proceedings of the Membrane Society of Korea Conference
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• 1996.03a
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• pp.25-43
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• 1996

In general, membrane technology in Japan has remarkably developed in these 20 years. Especially, ones treating water is now in high level and seems to be matured. Water shortage of last summer was a new stimulus for promoting membrane research works. The researches are now extending to more precise separation of, for example, isomer and proteins. In such cases, not only polymeric materials but also ceramic or carbon ones are attempted. Concerning pervaporation (PV), water permselective membranes (GFT) are in practical use, PV research works are now concentrating on separation of new targeting substances. Here, I'd like to introduce, first of all, the outline of membrane technology in Japan (not limited to PV), and then of PV research works.

• Journal of Korean Society of Environmental Engineers
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• v.30 no.12
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• pp.1273-1280
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• 2008

This study sought to establish the optimum operating condition for the recovery of caustic (NaOH) solution from mercerization in textile process. As main factors, the silt density index (SDI) evaluation of ceramic membrane for the application of nanofiltration/reverse osmosis (NF/RO) membrane, the recovery yield measurement of caustic solution for the application of polymeric membrane, the optimum condition of chemical cleaning for the membrane regeneration, the optimum removal condition of total organic carbon (TOC), turbidity, color, and the permeate flux of ceramic membrane/polymeric membrane combined process were investigated. As results, ceramic ultrafiltration (UF) in the first step and nanofiltration (NF) in the second step were found to be suitable for the removal of total suspended solid (TSS), residual organics, turbidity including color, and the recovery of caustic solution from caustic wastewater stream in mercerization process. When only the ceramic UF membrane was used, the rejection efficiency of both of TSS and turbidity was more than 99.0%, and the color and TOC were rejected about 74.7% and 49.2%, respectively. Meanwhile, the combined membrane precess of UF and NF membranes showed even more efficient removal abilities and thus more than 99.9% of TSS and turbidity, 87.7% of color, and 78.2% of TOC were removed. In particular, 91.3% of NaOH was successfully recovered with 83.7% of total volume in the combined membrane process. With this regard, a clean caustic solution was obtained in a high purity, which can be reused for mercerization process, expecting to offer economical benefits.

• Journal of Korean Society of Environmental Engineers
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• v.35 no.2
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• pp.144-150
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• 2013

Hybrid ceramic membrane (HCM) processes that combined ozonation with a ceramic membrane (CM) or a reactive ceramic membrane (RM), an iron oxide nanoparticles (IONs) incorporated-CM were investigated for membrane fouling control. Alumina disc type microfiltration and ultrafiltration membranes doped with IONs by sintering method were tested under varying mass fraction of IONs. Scanning electron microscope (SEM) images showed that IONs were well-doped on the CM surface and doped IONs were approximately 50 nm in size. Change in the pure water permeability of RM was negligible compared to that of CM. These results indicate that IONs incorporation onto CM had little effect on CM performance in terms of the flux. Natural organic matter (NOM) fouling and fouling recovery patterns during HCM processes confirmed that the RM-ozonation process enhanced the destruction of NOM and reduced the extent of fouling more than the CM-ozonation process by hydroxyl radical formation in the presence of IONs on RM. In addition, analyses of NOM in the feed water and the permeate showed that the efficiency of membrane fouling control results from the NOM degradation during HCM processes; leading to removal and transformation of relatively high contents of aromatic, high molecular weight and hydrophobic NOM fractions.

• Membrane Journal
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• v.22 no.4
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• pp.243-250
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• 2012

The effect of water back-flushing period (filtration time, FT) was investigated in hybrid process of alumina microfiltration and photocatalyst for advanced drinking water treatment in this study, and compared with the previous studies with carbon microfiltration or alumina ultrafiltration membranes. The FT was changed in the range of 2~10 min with fixed 10 sec of BT. Then, the FT effects on resistance of membrane fouling ($R_f$), permeate flux (J) and total permeate volume ($V_T$) were observed during total filtration time of 180 min. As decreasing FT, $R_f$ decreased and J increased as decreasing FT, which was same with the previous results with carbon microfiltration or alumina ultrafiltration membranes. The treatment efficiency of turbidity was high beyond 98.1%, and the effect of FT was not shown on treatment efficiency of turbidity, which was same with the previous result of carbon microfiltration. The treatment efficiency of organic matters was the highest value of 89.6 % at FT 8 min, which was a little higher than those of the previous results, and the effect of FT was not shown on treatment efficiency of organic matters.

• Applied Chemistry for Engineering
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• v.9 no.2
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• pp.306-310
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• 1998

The soluble polyimides(PMDA/diamine/dianhydride) were prepared and investigated. After coating the prepared PMDA/diamine/dianhydride solution into the commercial tubular alumina ceramic membranes, gas permeation characteristics was investigated. $T_g{\prime}s$ of the polyimides were in the range of $337{\sim}358^{\circ}C$ and thermal stability was good. The polymer was soluble in NMP, DMAc, DMSO, THF, and m-cresol. The adhesion between the alumina membrane and the soluble polyimide was excellent. The soluble polyimide/alumina membranes containing 6FDA showed the highest permeability among others. The permeability of nitrogen of PMDA/1,3PDA/6FDA-alumina membrane was about $7.6{\times}10^{-7}(mol/m^2{\cdot}Pa{\cdot}s)$ in the gas permeation experiments. The ideal separation factor of $O_2/N_2$ and $H_2/N_2$ in PMDA/1,3PDA/6FDA-alumina membrane were 6.19, and 70.0, respectively.

• Journal of the Korean Ceramic Society
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• v.40 no.6
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• pp.594-600
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• 2003

L $a_{0.7}$S $r_{0.3}$G $a_{0.6}$F $e_{0.4}$ $O_{3-}$$\delta$/ perovskite-type mixed conducting membranes, which could permeate oxygen selectively, have been fabricated and the microstructural features developed by varying the sintering conditions have been analyzed. The effects of surface modification and the membrane thickness on oxygen permeability have been evaluated under He/air environment. With increasing a grain boundary fraction, the overall oxygen permeability decreased. The syngas (CO+ $H_2$) has been produced by partial oxidation reaction of methane with the oxygen permeated through the membrane. Methane conversion and syngas yield have been evaluated as functions of the compositional ratio of feed gas and reaction temperature. In long-term duration test for 600 h, under C $H_4$+He/air environment, L $a_{0.7}$S $r_{0.3}$G $a_{0.6}$F $e_{0.4}$ $O_{3-}$$\delta$/ membrane showed a highly stable performance.

• Membrane Journal
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• v.30 no.4
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• pp.269-275
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• 2020

In this study, CO₂ separation experiment was performed on a CH₄/CO₂ mixed gas using a ceramic hollow fiber membrane contactor (HFMC). In order to fabricate high-performance HFMC, experiments were conducted to manufacture high-permeability hollow fiber membranes, and the prepared hollow fiber membranes were evaluated through N₂ gas permeation experiments. HFMC for CH₄/CO₂ mixed gas separation was manufactured using the manufactured high-permeability hollow fiber membrane. In the experiment, mixed gas of CH₄/CO₂ (34.5% CO₂, CH₄ balance) and monoetanolamine (MEA) was used, and the effect of CO₂ removal efficiency on the flow rate of the absorbent was evaluated. The CO₂ removal efficiency increased as the liquid flow rate increased, and the CO₂ absorption flux also increased with the liquid flow rate.

• Transactions of the Korean hydrogen and new energy society
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• v.22 no.2
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• pp.161-167
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• 2011

Proton conductors have attracted considerable attention for solid oxide fuel cell (SOFC), hydrogen pump, gas sensor, and membrane separators. Doped $SrCeO_3$ exhibits appreciable proton conductivity in hydrogen-containing atmosphere at high temperature. However commercial realization has been hampered due to the reactivity of $SrCeO_3$ with $CO_2$. The chemical stability and proton conductivity are dependent on dopant type. The purpose of this work is to investigate chemical stability of $SrCe_{0.95}Gd_{0.05}O_{3-\alpha}-Ce_{0.9}Gd_{0.1}O_{2-\beta}$ composites in $CO_2$ and $H_2$ gases. Thermogravimetric analysis (TGA) was performed in gaseous $CO_2$ and electrical conductivity of the composites were also measured between 500 and $900^{\circ}C$ in air and $H_2$ atmosphere. $SrCe_{0.95}Gd_{0.05}O_{3-\alpha}-Ce_{0.9}Gd_{0.1}O_{2-\beta}$ composite membranes showed good chemical stability of in $CO_2$ atmosphere and high conductivity at hydrogen condition. The hydrogen permeation of $SrCe_{0.95}Gd_{0.05}O_{3-\alpha}-Ce_{0.9}Gd_{0.1}O_{2-\beta}$ composite membranes was investigated as a function of volumetric content of $SrCe_{0.95}Gd_{0.05}O_{3-\alpha}$. The $SrCe_{0.95}Gd_{0.05}O_{3-\alpha}-Ce_{0.9}Gd_{0.1}O_{2-\beta}$(6:4) membrane with a thickness of 1.0 mm showed the highest hydrogen permeability with the flux reaching of 0.12 $ml/min{\cdot}cm^2$ at $800^{\circ}C$ in 100%$H_2/N_2$ as feed gas.

• Journal of the Korean Ceramic Society
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• v.44 no.4 s.299
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• pp.194-197
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• 2007

Polyacrylonitrile (PAN)/$Fe_2O_3$ nanocomposite membranes with a thickness of 0.02 mm were electrospun by adding 0 to 5 wt% of $Fe_2O_3$ into PAN. The surface tension, density, kinematic viscosity and dynamic viscosity of the PAN solution were determined to be $33.8{\pm}1mN/m$, 0.9794 g/ml, $1548.6mm^2/sec$ and 1516.7 cP, respectively. The average diameters of PAN fibers containing 0, 1 2, 3, and 4 wt% $Fe_2O_3$ particles were 300, 260, 210, 130, and 90 nm, respectively. Fourier-transform infrared spectroscopy results showed that the addition of $Fe_2O_3$ nanoparticles to the PAN mat reduced the absorption peak intensity at $2242cm^{-1}$ ($C{\equiv}N$ bond) while it caused a sharp increase in the peak intensity at $2356cm^{-1}$(C=O bond). Thus, it appears that an appropriate amount of $Fe_2O_3$ nanoparticles in the PAN backbone leads to an improvement of the performance of the $CO_2$ gas sensor, most likely due to the change of functional groups in the membrane.