• Membrane Journal
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• v.14 no.4
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• pp.329-338
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• 2004

In this study the discharged wastewater from paper manufacturing plant was filtrated by 4 kinds of tubular ceramic microfiltration and ultrafiltration membranes (carbon material) with periodic water-back-flushing, and we tried to find the optimum back-flushing time (BT). As results of water-BT effect for each ceramic membrane, the longer BT was more effective for a membrane having the larger pore size. And we could acquire the most volume of total permeate and the highest recovery efficiency of purified water, Then, the results of permeate flux vs. initial permeate flux during 180 min's operation showed that the longer BT was more effective for longer filtration time (FT) to obtain the higher permeate flux because membrane fouling proceeded deeply at long FT condition. And the optimum BT that founded from the trends of membrane fouling resistances almost accorded with the optimum BT from the trends of permeate flux, too.

• Membrane Journal
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• v.22 no.6
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• pp.415-423
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• 2012

For hybrid water treatment of carbon fiber ultrafiltration and photocatalyst, we used the hybrid module that was composed of photocatalyst packing between tubular membrane outside and module inside. Photocatalyst was PP (polypropylene) bead coated with $TiO_2$ powder by CVD (chemical vapor deposition) process. Water back-flushing of 10 sec was performed per every period of 10 min to minimize membrane fouling for modified solution, which was prepared with humic acid and kaolin. Resistance of membrane fouling ($R_f$) decreased as humic acid concentration changed from 10 mg/L to 2 mg/L, and finally the highest total permeate volume ($V_T$) could be obtained at 2 mg/L, which was the same with the previous results. Then, treatment efficiencies of turbidity and humic acid were above 98.9% and 88.7%, respectively, those did not depend on the humic acid concentration. However, the treatment efficiency of humic acid increased a little as the humic acid concentration increased in the previous results.

• Membrane and Water Treatment
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• v.15 no.1
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• pp.21-29
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• 2024

1H,1H,2H,2H-perfluorodecytriethoxysilane (C₁₆H₁₉F₁₇O₃Si) be successfully applied to the hydrophobic modification of Al₂O₃ tubular ceramic membrane. Taking the concentration of modification solution, modification time, and modification temperature as factors, orthogonal experiments were designed to study the hydrophobicity of the composite membranes. The experiments showed that the modification time had the greatest impact on the experimental results, followed by the modification temperature, and the modification solution concentration had the smallest impact. Concentration of the modified solution 0.012 mol·L^-1, modification temperature 30 ℃ and modification time 24 h were considered optimal hydrophobic modification conditions. And the pure water flux reached 274.80 kg·m^-2·h^-1 at 0.1MPa before hydrophobic modification, whereas the modified membrane completely blocked liquid water permeation at pressures less than 0.1MPa. Air gap membrane distillation experiments were conducted for NaCl (2wt%) solution, and the maximum flux reached 4.20 kg·m^-2·h^-1, while the retention rate remained above 99.8%. Given the scarcity of freshwater resources in coastal areas, the article proposed a system for seawater desalination using air conditioning waste heat, and conducted preliminary research on its freshwater production performance using Aspen Plus. Finally, the proposed system achieved a freshwater production capacity of 0.61 kg·m^-2·h^-1.

• Proceedings of the Membrane Society of Korea Conference
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• 1996.04a
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• pp.46-47
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• 1996

막분리 공정의 공업적인 이용을 위해서는 막을 특정 용기에 적재한 모듈의 형태가 요구되는데 모듈의 형태에 따라 평판형(plate and frame), 나권형(spiral wound), 관형(tubular), 중공사형(hollow fiber)모듈 등이 있다. 이 중에서 관형 시스템은 내경이 12.5~25 mm, 길이 0.6~6.4 m에 이르는 비교적 큰 open channel로 되어 있으며 공급액 유로가 일반적으로 커서 전처리를 행하지 않고도 fouling이 적으며, 또한 막 표면의 세정이 약품에 의한 것 이외에 스폰지 볼 등에 의한 물리적 세정도 가능하므로 응용 범위가 넓다는 것이 특징이다. 한외여과 공정의 가장 큰 문제점은 농도분극 및 fouling 현상에 의한 플럭스 감소이다. 농도분극 현상은 경계층에서 용질의 대류,확산적인 전달에 기인하여 막 표면으로 갈수록 진해지는 용액층의 형성을 의미한다. 이 현상은 가역적인 과정으로서 감압함으로 원상태로 회복이 가능하며 조작 압력에서 정상상태가 되면 막투과 플럭스는 일정한 값을 유지한다.

• Proceedings of the Membrane Society of Korea Conference
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• 1996.04a
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• pp.42-43
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• 1996

고분자 분미막을 이용한 분리기술은 기존의 분리기술에 비하여 에너지의 절약과 높은 분리효율 등의 장점이 있어 거의 모든 산업에 이용되고 있다. 분리막의 용도가 다양화됨에 따라서 내열성, 내약품성, 내유기용매성을 갖는 막소재의 개발이 필요하게 되었다. polyimide(PI)게의 고분자는 물리, 화학적 성능이 우수하고 내열성과 내유기용매성 등이 우수한 열가소성수지로서 film, sheet, tubular형으로 만들 수 있어 한외여과막이나 역삼투막, 기체분리막 등에 이용되고 있다. 그러나 투과속도를 높디고, fouling을 줄이기 위해서는 화학적 개질을 통해 친수성을 높이는 방법이 필요하다. 본 실험에서는 내열성과 내유기용매성이 우수한 polyetherimide계 고분자를 chlorosulfonic acid(CSA)를 이용하여 술폰화시킴으로써, 극성기의 도입에 의해 친수성이 향상된 sulfonated polyetherimide(SPEI)를 합성하였다.

• Applied Microscopy
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• v.21 no.2
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• pp.29-38
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• 1991

Ventral nephrocytes in the larva of the Lucilia illustris comprise ellipsoid cells situated onto the salivary glands. The cells are $60{\sim}100{\mu}m$ in diameter. Junctional complex beneath the basement membrane hold the plasma membrane in a even contour. Intracellular channels from the juntion complex are well developed at the cortex part of the cell. Coated vesicles pinched off from the channels seems to be connected with the ${\alpha}$-vacuoles via the tubular elements, which is regared as selective absorption system from the hemolymph. Two nuclei are sometimes observed in the medulla part of the cell. Ventral nephrocytes contain well-developed rough endoplasmic reticulum and Golgi complex, and numerous mitochondria. These cellular organelles synthesize lysosome. The lysosome not only digest some cell organells but also seems to be related with the ${\beta}$-vacuoles.

• Proceedings of the Membrane Society of Korea Conference
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• 1997.10a
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• pp.129-130
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• 1997

1. 서론 : 반도체 제조공정중 wafer가공 공정에 사용되는 많은 양의 RO 초순수는 미세한 규소입자를 비롯하여 비교적 낮은 농도의 불순물을 포함하고 있으나, 현재 1차세정후 공정폐수로 전량 희석되어 폐기되고 있다. 반도체 제조공정에서 발생되는 이러한 세정폐수를 적절한 전처리와 분리막 처리를 통하여 유가물질인 Si 입자를 회수하고, 처리수를 재이용함으로써 환경오염의 감소 및 공업용수의 증대를 도모할 수 있다. 본 연구에서는 고분자 분리막을 이용하여 반도체 제조공정중 발생한 세정중의 유가물질인 Si를 회수하고, 용수를 재이용하기 위하여 한외여과용 평막을 제조하여 Si 함유 폐수에 대한 막성능을 평가하였으며, 또한 상용 tubular 및 hallow fiber막의 성능과도 비교하였다.

• Proceedings of the Membrane Society of Korea Conference
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• 2004.05a
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• pp.98-101
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• 2004

Utilization of biomass resources has considerable contribution to the reduction of carbon dioxide emission. Ethanol is one of the biomass products and is used as an additive to gasoline in several countries. Conventional process to produce ethanol involves energy-intensive azeotropic distillation. Pervaporation (PV) or vapor permeation (VP) is considered to be an alternative separation process to the conventional process.(omitted)

• Proceedings of the Korean Society of Plant Pathology Conference
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• 1997.06a
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• pp.5-21
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• 1997

Unique virus-like particles were associated with five eriophyid mite-borne plant diseases of unknown etiology; fig mosaic, redbud yellow ringspot, rose orsette, thistle mosaic, and high plains disease of corn and wheat. Quasi-spherical, double membrane-bound particles (DMPs), 120 - 200 nm in diameter, were observed in the cytoplasm of all cell types in symptomatic leaves of infected plants. No DMPs were observed in symptomless plants. The DMPs in symptomatic thistles were associated with two types of inclusions, electron-dense amorphous material and tubular aggregates. Similar amorphous inclusions were also found in corn and wheat with high plains disease, while tubular inclusions were observed in figs with mosaic symptoms. The particles and inclusions were similar in some aspects to immature particles associated with viroplasms of animal and insect poxviruses and also to the double-enveloped particles of tomato spotted wilt virus associated with viroplasms during early stages of infection, but were unique and unlike any known plant viruses. The DMPs and associated viroplasm-like inclusions in the high plains disease were specifically immunogold labeled in situ with the disease-specific antiserum. Thread-like structures, similar to tenuivirus particles, present in the partially purified virus preparations were also immunogold labeled with the antiserum. It is suggested that the thread-like structures are derived from the DMP. In many cells of symptomatic corn and wheat samples, DMPs occurred together with flexuous rod-shaped particles and cylindrical inclusions of wheat streak mosaic potyvirus (WSMV), suggesting that the disease is caused by a mixed infection of WSMV and the agent represented by the DMPs. Based on cytopathology, symptomatology and mite and/or graft-transmissibility, the five diseases described in this paper are potentially caused by virus(es) and the DMPs associated with these diseases may represent virus particles. If the DMPs are indeed viral in nature, they would comprise a new group of plant viruses.

• Korean Chemical Engineering Research
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• v.48 no.5
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• pp.598-602
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• 2010

In this paper, we carried out CFD modelling and simulation for the membrane system to separate H2 gas from the multi-component feed gas. The membrane system is of the annulus tubular type consisting of the external lumen side for the feed gas and the internal permeation side for the sweeping gas. The operating temperature and pressure of the lumen side inlet flow are $374^{\circ}C$ and 7 bar respectively and those of the sweeping gas are $374^{\circ}C$ and 3 bar, and considering these conditions, Pd membrane system was employed. CFD simulations were performed for the co-current flow and counter-current flow membrane system based on the flow directions between the feed and the sweeping gas. Comparisons and discussions were made for the H2 partial pressure, H2 mole fraction and H2 flux for both cases. Furthermore, we executed CFD simulations for the each case of the various inlet flow rates of the feed gas at the lumen side. Accordingly, we reviewed the effects of the flow rate and residence time on the performance of the membrane system.