• Journal of Korean Society of Environmental Engineers
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• v.37 no.3
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• pp.152-158
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• 2015

This paper investigated the membrane fouling potential at the state of passive adsorption which is no permeation with the test modules on COD (Chemical oxygen demand) loading rates, examined the recovery rate and resistance on membrane fouling by three cleaning manners of hydrophobic membrane in a bioreactor. The results showed that high COD loading led to the increase of extra-cellular polymeric substances and filtration resistance. The permeability resistance from 1st day to 63rd day was getting increased, however, the value of permeability resistance after 63th day during the operation period was almost same level at three COD loading rates, it was due that the biomass adhesion on membrane surface at the state of passive adsorption reached to the critical state. Also, the final recovery rates after three cleaning manners were 78%, 72% and 69% at the COD loading concentrations of 250 mg/L, 500 mg/L and 750 mg/L respectively, and then recovery rate by physical cleaning at Run 2 and Run 3 was decreased after 40th day, it proved that biomass cake, which is not easily removed, was formed on the membrane surface because of high COD loading rate and EPS concentration.

• Journal of Korean Society of Water and Wastewater
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• v.25 no.2
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• pp.231-240
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• 2011

The objectives of this research are to investigate coagulation efficiencies of two coagulants l.e., alum and polyaluminum chloride and to understand effects of the coagulants on membrane fouling in microfiltration. The turbidity of supernatant from alum coagulation was increased with increasing doses whereas the turbidity from PACl coagulation was maintained at the low values. The observed injection volume of PACl for the same removal was approximately 30 percent less than alum, which produced a low sludge volume. The settling velocity of PACl flocs was greater than alum flocs. The results corresponded well with floc size measurements. Flux decline from alum coagulation was significant due in part to small sizes of flocs. At the low dose, alum floc had less specific cake resistance than PACl floc. However, as the dosage was increased, the increases in specific cake resistances of alum was substantial. Alum coagulation pretreatment needs careful operation to reduce membrane fouling by flocs. In general, PACl coagulants were more effective than alum coagulants for pretreatment of membrane processes because PACl showed the better performance in coagulation and membrane fouling.

• Membrane Journal
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• v.22 no.5
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• pp.285-300
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• 2012

Vanadium redox flow battery is believed to be one of important energy storage technologies, because it has many advantages, including long cycle life, high energy efficiency, low cost of maintenance, and environmental friendship. As one of the key components of vanadium redox flow battery system, an ion exchange membrane is required to prevent cross-mixing of the positive and negative electrolytes while allowing ionic continuity. However, ion exchange membrane such as Nafion using in VRBs still face some challenges in meeting performance and cost requirements for broad penetration. Therefore, to resolve these problems, developed various ion exchange membranes are investigated and compared with Nafion membranes in terms of their performance in vanadium redox flow battery.

• Proceedings of the Membrane Society of Korea Conference
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• 1997.10a
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• pp.67-68
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• 1997

1. Introduction : Gas transport through dense polymeric membranes is predominantly determined by the chain packing density as well as the chain flexibility. Thus, improved permeation properties can be obtained by controlling these two factors. In this work, the introduction of bulky substituents was attempted to improve permeation properties. Polysulfone, widely used material for gas separation membrane, was the starting material of this modification. Gas transport properties of resulting modified polysulfones were examined, and the improved properties were explained by probing the change of physical properties.

• Membrane Journal
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• v.3 no.3
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• pp.117-125
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• 1993

The CA reverse osmosis membranes were prepared and were studied the effects of parameters in membrane performance. The dope solutions were composed of polymer, formamide, acetone and 2-methoxyethanol. And it was prepared flat type membranes. The membranes were measured flux and rejection. The experimental factors such as polymer concentration, additive type, solvent evporation period, annealing temperture, and applied pressure were changed to investigate the effects of these on the membranes. And the transport parameters were also calculated at reverse osmosis medel for prepared membranes.

• Membrane Journal
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• v.9 no.3
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• pp.151-156
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• 1999

Silicone was used in this study to enhance the oxygene permeability of gas separation membranes. PMP and PMMA were used to prepare the copolymers and IPN membranes, respectively. In the case of copolymers, there were two methodsCswelling and solvent evaporation) in this study and it was revealed that this preparation method affected the oxygene permeability. It was also shown that the IPN method brought the enhacement of oxygen permeability and slight decrease of separation factor. Regarding oxygen permeability 10 wt% of PMMA was the best composition of IPN membrane.

• Membrane Journal
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• v.6 no.4
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• pp.273-283
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• 1996

A cation-exchange membranes were prepared by polystyrene and poly(sodium 4-styrene sulfonate). The degree of crosslinking of polystyrene membranes was controlled by DVB. At the same time, the structure of PS membranes was changed from RO to MF by varying the concentration of PSS in the casting solution. Water flux increased with PS-PSS membranes due to the sulfonate groups, and final membrane cast from the solution containing 5% of DVB and 3% of PSS showed MF structure.

• Bulletin of the Korean Chemical Society
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• v.29 no.2
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• pp.398-404
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• 2008

A new solvent polymeric membrane electrode, based on N,N'-bis(salicylidene)-2,2-dimethylpropane-1,3-diamine Ni(II) as the ionophore, was designed. The oxalate-selective electrode has the dynamic range between 1.0 10-6 M and 1.0 10-1 M with a Nernstian slope of -28.7 1.0 mV per decade. The detection limit was 6.3 10-7 M. The proposed electrode revealed good selectivities for oxalate over a variety of other anions and could be used in a pH range of 2.0-7.8. The electrode can be used for at least two months without any considerable divergence in potential. The designed electrode was applied as an indicator electrode in the potentiometric determination of oxalate in real samples.

• Proceedings of the Membrane Society of Korea Conference
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• 1991.10a
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• pp.45-46
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• 1991

분리막 공정은 상변화를 일으키지 않기 때문에 장치비가 저렴하며, 열 및 화학적으로 민감한 물질, 특히 생체물질 등을 다루는데 적합하다. 또한 최종 생성물질을 정제하는 방법으로는 이온교환 크로마토그래피, 전기 영동 및 친화성 크로마토그래피(affinity chromatography)가 있다. 이중 친화성 크로마토그래피는 가장 선택적이고, 단일 장치로서 기존의 분리방법에 비해 약 1000배 가까이 정제할 수 있다. 본 실험에서는 트립신 억제제인 m-aminobenzamidine을 포함하고 있는 수용성 고분자를 제조하여 트립신을 선택적으로 분리하고자 하였으며, 본 연구 필요한 분리막은 막제조가 용이하며 비용이 저렴한 cellulose acetate막을 사용하였다. CA 막의 세공크기는 겔화매질의 에탄올 농도로 조절하였다. Casting 용액의 조성은 다음 표에 간략하게 나타내었다.

• Proceedings of the Membrane Society of Korea Conference
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• 2004.05a
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• pp.65-68
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• 2004

Molecular imprinting, which was first proposed by Wulff and Sarhan in 1972 [1], is a facile way to construct molecular recognition sites by applying a simple radical polymerization [2]. Since 1994, the authors have proposed an alternative molecular imprinting method in which polymeric materials are directly converted into molecular recognition materials [3].(omitted)