• Membrane and Water Treatment
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• 제8권4호
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• pp.369-380
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• 2017

Performance evaluation of four commercially available tubular membranes (AFC 80, AFC 30, PU 608, ES 404) was accomplished in self-assembled membrane testing unit. Effects of varying transmembrane pressure, feed concentration and anion type were investigated. Aqueous solutions of salts such as calcium chloride, calcium sulfate, tin chloride and tin sulfate were prepared for this study. It was noted that the investigated parameters e.g., pressure and concentration had significant effects on membrane's performance. Nevertheless, anion type effectively played its role in the rejection of salts since salt having SO4-2 anions had a better rejection than the salts containing Cl-1. It is observed that rejection was dominated by Donnon exclusion for strongly charged nanofiltration membranes whereas for weakly charged ultrafiltration membranes, size exclusion was the key mechanism to reject the ions.

• 멤브레인
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• 제9권1호
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• pp.17-24
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• 1999

본 연구에서는 관형 상용막(ultrafiltration (UF), nanofiltration(NF)을 이용하여 우유를 농축하고 농축 성분의 변화를 알아보았다. 친수성막(sulfonated polysulfone (SPSf), polyacrylonitrile(PAN), cellulose acetate(CA)) 의 경우에는 투과유의 투과속도 감소가 완만하고 소수성막의 경우에는 투과속도 감소가 심하였다. UF 농축이 경우 전고형분, 단백질,지방 미네랄은 농축에 따라 증가하고 탄수화물은 감소하였다. NF 농축의 경우 UF와 같은 경향을 보였지만 탄수화물의 감소경향이 훨씬 적었다.

• 상하수도학회지
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• 제13권1호
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• pp.113-124
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• 1999

We elucidated factors such as membrane pore size, activity of the activated sludge and MLSS. affecting filtering characteristics or filtering resistance in an activated sludge bio-process using tubular type membranes. We used a commercial membrane module with $0.5m^2$ of effective membrane area and a bundle of 7 tubes(13mm of ID and 2m long) in the experiments. As a result, the flux was maintained in the range of $35{\sim}105l/m^2$ hr at 5,000~20,000mg/l of MLSS concentration, and there seemed to be a correlation between the flux and the MLSS. Also the greater the pores were, the higher the flux was in some comparison experiments using UF and MF membranes, but the water permeated through both of the membranes showed almost the same quality. However, the MF membrane showed a great reduction in filtering resistance initially, but went back to a stable stage afterwards. The activity of the activated sludge in the aeration tank was also found to be considered as a factor showing permeation characteristics of the membrane.

• Korean Chemical Engineering Research
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• 제49권6호
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• pp.804-809
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• 2011

$Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}O_{3-{\delta}}$ 조성의 관형 분리막을 압출 성형 방법으로 제조하였다. 압출성형 직후 분리막의 TGA 분석결과 3단계의 무게감소로 첨가제와 탄산염이 분해되었고, 건조 수축율은 68 h 경과 후 변화가 없었으며 외경이 큰 분리막에서 높게 나타났다. 소결 후 분리막의 XRD 및 SEM 분석결과, 분리막은 단일상의 페롭스카이트 구조를 갖는 치밀한 막을 보였고, EDS 분석을 통해 $Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}O_{3-{\delta}}$와 유사한 성분함량을 가짐을 확인하였다. 두께 0.95 mm $Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}O_{3-{\delta}}$ 관형 분리막의 압환강도(radial crushing strength)는 5.7 kgf/$mm^2$이였으며, $950^{\circ}C$에서 산소투과량은 146.85 mL/min($Jo_2$=2.33 mL/$min{\cdot}cm^2$)를 나타냈었다. 투과 측의 진공펌프 사용이 쓸개 가스를 활용한 것보다 산소 투과량 증진에 효과가 있음을 알 수 있었다.

• Korean Chemical Engineering Research
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• 제52권2호
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• pp.214-218
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• 2014

본 연구에서는 용매열합성법(solvothermal method)을 이용하여 매크로 기공의 알루미나 튜브 지지체 위에 나노기공 $Cu_3(BTC)_2$ 분리막을 제조하였다. In-situ 용매열합성법을 이용하는 경우, 매크로 기공의 알루미나 지지체 위에 균일한 핵생성과 성장을 통해 연속적이고 균열이 없는 $Cu_3(BTC)_2$ 층을 형성하기 어렵다. 본 연구에서는 용매열합성 전에 알루미나 지지체 표면을 $200^{\circ}C$로 가열한 상태에서 Cu 전구체 용액을 분무하여 지지체 표면을 개질한 후, 용매열합성법을 수행하여 연속적이고 균열이 없는 $Cu_3(BTC)_2$ 튜브형 분리막을 제조할 수 있었다. 합성된 $Cu_3(BTC)_2$ 분리막은 XRD, FE-SEM 및 기체투과 실험 등을 통해 분석하였다. $5{\mu}m$의 두께를 가진 $Cu_3(BTC)_2$ 튜브형 분리막을 통한 단일기체 투과실험 결과, $80^{\circ}C$에서 $H_2$가 가지는 투과도는 $7.8{\times}10^{-7}mol/s{\cdot}m^2{\cdot}Pa$이고, $H_2/N_2$, $H_2/CO_2$의 이상선택도는 각각 11.94, 12.82로 계산되었다.

• Macromolecular Research
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• 제15권6호
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• pp.565-574
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• 2007

In this study, five representative, commercially available polymers, Ultem 1000 polyetherimide, Kapton polyimide, phenolic resin, polyacrylonitrile and cellulose acetate, were used to prepare pyrolyzed polymer membranes coated on a porous {\alpha}-alumina$ tube via inert pyrolysis for gas separation. Pyrolysis conditions (i.e., final temperature and thermal dwell time) of each polymer were determined using a thermogravimetric method coupled with real-time mass spectroscopy. The surface area and pore size distribution of the pyrolyzed materials derived from the polymers were estimated from the nitrogen adsorption/desorption isotherms. Pyrolyzed membranes from polymer precursors exhibited type I sorption behavior except cellulose acetate (type IV). The gas permeation of the carbon/{\alpha}-alumina$ tubular membranes was characterized using four gases: helium, carbon dioxide, oxygen and nitrogen. The polyetherimide, polyimide, and phenolic resin pyrolyzed polymer membranes showed typical molecular sieving gas permeation behavior, while membranes from polyacrylonitrile and cellulose acetate exhibited intermediate behavior between Knudsen diffusion and molecular sieving. Pyrolyzed membranes with molecular sieving behavior (e.g., polyetherimide, polyimide, and phenolic resin) had a $CO_2/N_2$ selectivity of greater than 15; however, the membranes from polyacrylonitrile and cellulose acetate with intermediate gas transport behavior had a selectivity slightly greater than unity due to their large pore size.

• 한국생물물리학회:학술대회논문집
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• 한국생물물리학회 1999년도 학술발표회 진행표 및 논문초록
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• pp.28-28
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• 1999

The movement of water across cell plasma membranes occurs in all cell types but is particularly rapid in erythrocytes, renal tubular cells. In principle, osmotic/oncotic gradients and hydrostatic pressure difference can drive water across a cell layer by transcellular or paracellular pathways. The aquaporin family of molecular water channels, which now number 10 in mammals and many more in plants and lower organism, are likely to provide a molecular pathway for water transport in some cell membranes.(omitted)

• 멤브레인
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• 제21권2호
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• pp.155-162
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• 2011

$Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}O_{3-{\delta}}$ (BSCF) 조성을 갖는 치밀한 관형 분리막은 압출 성형 방법으로 제조하였다. $Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}O_{3-{\delta}}$ 관형 분리막의 구조적 특성은 x-선 회절분석기 (XRD)와 전자 주사 현미경 (SEM)을 이용하여 분석하였으며, 상대밀도는 94.10%를 보였다. 산소투과량 분석은 700~$950^{\circ}C$ 범위에서 공급 측과 투과 측의 운전조건에 따라 측정되었다. 공급 측과 투과 측에서 대기 중 공기와 진공펌프를 사용할 경우, $Ba_{0.5}Sr_{0.5}Co_{0.8}Fe_{0.2}O_{3-{\delta}}$ 관형 분리막의 산소투과량은 $900^{\circ}C$에서 1.37 mL/$min{\cdot}cm^2$로 높게 나타났다.

• 상하수도학회지
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• 제12권2호
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• pp.42-49
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• 1998

By checking the variations of the raw water quality and MLSS, the effects of the membrane materials on permeable flux and quality of the treated water were investigated in this study. Due to the stability for high variations of MLSS, tubular type membranes were selected. Polysulfone group membranes and polyamide group membranes were tested. The crossflow operation mode was adapted, because membrane fouling problems could be easily controlled by adjusting the linear velocity. Due to the high concentration of the raw water, polyamide group membranes were originally expected to achieve two times higher permeable fluxes. However, difference was only approximately $20l/m^2{\cdot}h$ at $3kgf/cm^2$. It might be resulted from the high concentration of organic materials in the effluent of the RBC process. For the quality of the treated water, polyamide group membranes were slightly less effective. It might be resulted from the fact that polysulfone group membranes had more adsorptive capacities for the organic materials. The effects of temperature on the permeable flux were found to be significant. Despite of the irregular injection of raw water, the quality of the treated water was kept stable.

• Korean Membrane Journal
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• 제3권1호
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• pp.17-23
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• 2001

Polyethersulfone (PES) and cellulose acetate (CA) ultrafiltration (UF) membranes having different molecular weight cut-off values were prepared by immersion precipitation method by changing the compositions of easting solution. Egg white solution was concentrated to volume concentration ratio 4 in tubular UF with membranes made of moderately hydrophobic PES and hydrophilic CA. The process Parameters such as pressure and fluid velocity were controlled in order to apply successfully for egg white solution and to investigate the pressure dependency. The resistance values were measured to investigate the fouling and concentration polarization effect on membrane performance. During concen- tration of egg white solution by UF, the fouling layer appeared to contribute little resistance to flux compared to that of polarized layer.