• Bulletin of the Korean Chemical Society
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• 제31권5호
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• pp.1143-1148
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• 2010

We investigated the separation of nitrogen heterocyclic compound (NHC) contained in a model coal tar fraction comprising four kinds of NHC [indole (In), quinoline (Q), iso-quinoline (iQ), quinaldine (Qu)], three kinds of bicyclic aromatic compound (BAC) [1-methylnaphthalene (1MN), 2-methylnaphthalene (2MN), dimethylnaphthalene (DMN) mixture with ten structural isomers (DMNs; regarded as one component)], biphenyl (Bp) and phenyl ether (Pe) by liquid membrane permeation (LMP). A batch-stirred tank was used as the permeation unit. An aqueous solution of saponin and n-hexane were used as the liquid membrane and the outer oil phase, respectively. Yield and selectivity of individual NHC was much larger than that of BAC, Bp and Pe. Increasing the initial mass fraction of the saponin to the membrane solution ($C_{sap,0}$) and the initial volume fraction of O/W emulsion to total liquid in a stirred tank (${\phi}_{OW,0}$) resulted in deteriorating the yield of individual NHC, but increasing the stirring speed (N) resulted in improving the yield of each NHC. With increasing $C_{sap,0}$, the selectivity of each NHC based on DMNs increased. Increasing ${\phi}_{OW,0}$ and N resulted in decreasing the selectivity of individual NHC based on DMNs. At an experimental condition fixed, the sequence of the yield and selectivity in reference to DMNs for each NHC was Q > Qu = iQ > In. Furthermore, we compared LPM method with methanol extraction method in view of the separation efficiency (yield, selectivity) of NHC.

• 한국막학회:학술대회논문집
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• 한국막학회 1991년도 추계 총회 및 학술발표회
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• pp.1-3
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• 1991

A novel membrane separation process for the separation of liquid mixture is Pervaporation. The term, 'pervaporation', is a combination of permeation and evaporation, and was first introduced by kober[1] in 1917. In this technique, the liquid mixture in feed is in contact with one side of a dense non-porous membrane and after diffusing through the membrane is removed from the downstream side in the vapor phase, but is usually condensed afterwards to obtain a permeate in liquid from.

• Bulletin of the Korean Chemical Society
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• 제22권10호
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• pp.1076-1080
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• 2001

• Membrane and Water Treatment
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• 제5권2호
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• pp.109-122
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• 2014

Polyvinylidene fluoride (PVDF) hollow fiber membrane is widely used for water treatment. However, the weak mechanical strength of PVDF limits its application. To enhance its tensile strength, a double-layer composite hollow fiber membrane, with PVDF and polyetherimide as the external and inner layers, respectively, was successfully prepared through phase inversion technique. The effects of additive content, air gap distance, N,N-dimethyl-acetamide content in the inner core liquid, and the temperature of external coagulation bath on the membrane structure, permeation flux, rejection, tensile strength, and porosity were determined. Experimental results showed that the optimum preparation conditions for the double-layer composite hollow fiber membrane were as follows: PEG-400 and PEG-600, 5 wt%; air gap distance, 10 cm; inner core liquid and the external coagulation bath should be water; and temperature of the external coagulation bath, 40 C. A single layer PVDF hollow fiber membrane (without PEI layer) was also prepared under optimum conditions. The double-layer composite membrane remarkably improved the tensile strength compared with the single-layer PVDF hollow fiber membrane. The permeation flux, rejection, and porosity were also slightly enhanced. High-tensile strength hollow fiber PVDF ultrafiltration membrane can be fabricated using the proposed technique.

• 한국막학회:학술대회논문집
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• 한국막학회 1997년도 추계 총회 및 학술발표회
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• pp.5-8
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• 1997

Introduction : Membranes made from inorganic materials are generally superior to organo-polymeric materials in thermal and mechanical stability, and chemical resistance. Among inorganic materials zeolite is a promising candidate for a high performance membrane because of the unique characteristics of zeolite crystals such as molecular sieving, ion exchange, selective adsorption and catalysis. Although there are many recent reportsl on the preparation of zeolitc membranes and the gas permeation through the membranes, only a limited number of publications deal with pervaporation studies. Recently, we have reported a high pervaporation performance of NaA zeolite membrane for the separation of water/organic liquid mixtures. and of NaY zeolite menlbrane for the separation of methanol/MTBE. Here, preparation of zeolite (LTA, ZSM-5 and FAU) membranes and their permeation properties are discussed.

• 한국막학회:학술대회논문집
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• 한국막학회 1994년도 춘계 총회 및 학술발표회
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• pp.51-52
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• 1994

High permeability, selectivity and stability are the basic properties also required for membrane gas separations. The $CO_2$ separation by liquid membranes has been developed as a new technique to improve the permeability and selectivity of polymeric membranes. Sirkar et al.(1) have atlempted the hollow-fiber contained liquid membrane technique under four different operational modes, and permeation models have been proposed for all modes. Compared to a conventional liquid membrane, the diffusional resistance decreased by the work of Teramoto et al.(2), who referred to a moving liquid membrane. Recently, Shelekhin and Beckman (3) considered the possibility of combining absorption and membrane separation processes in one integrated system called a membrane absorber. Their analysis could be predicted effectively the performance of flat sheet membrane, however, there are restrictions for considering a flow effect. The gas absorption rate is determined by both an interfacial area and a mass transfer coefficient. It can be easily understood that although the mass transfer coefficients in hollow fiber modules are smaller than in conventional contactors, the substantial increase of the interfacial area can result in a more efficient absorber (4). In order to predict a performance in the general system of hollow-fiber membrane absorber, a gas-liquid mass transfor should be investigated inevitably. The influence of liquid velocity on both a mass transfer and a performance will be described, and then compared with experimental results. A present study is attempted to provide the fundamentals for understanding aspects of promising a hollow-fiber membrane absorber.

• 멤브레인
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• 제13권2호
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• pp.65-72
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• 2003

본 연구는 액상유기성 슬러지로부터 용존 유기물을 회수하기 위한 막결합형 발효 시스템의 여과특성의 검토에 초점을 두었다. $0.1 {\mu}m{\sim}5 {\mu}m$ 범위에서 6종류의 막공경을 대상으로 한 슬러지 발효액의 정밀여과 특성으로 막공경이 작을수록 전체저항이 큰 값을 나타내었고 케？층의 형성에 의한 저항이 전체저항의 68~88%를 차지하여 막투과유속의 저하는 주로 입자간의 물리화학적 상호작용에 의한 막표면에의 강한 입자침전에 기인함을 알 수 있었다. 발효액의 고형물 농도가 증가함에 따라 막투과유속은 감소하였으나 일정이상의 고형물 농도에서는 비례관계를 보이지 않았다. 막면유속이 증가할수록 그리고 5.0~6.0의 pH범위에서 높은 막투과유속이 얻어졌고 에너지 효율측면에서는 가능한 낮은 압력에서 여과하는 것이 유리한 것으로 나타났다. $0.1{\mu}m$과 $0.2{\mu}m$의 막공경에서는 100%의 미생물 제거율을 보였다 액상 유기성 슬러지로부터 용존 유기물을 효율적으로 회수하기 위한 최적 막공경은 제안된 기준의 관점에서 볼 때 $1{\mu}m$ 정도라 판단되어진다.

• 한국물환경학회지
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• 제20권2호
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• pp.183-189
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• 2004

The performance of a membrane-coupled anaerobic fermenter system for the recovery of volatile fatty acids (VFAs) from liquid organic sludge was experimentally investigated. Permeation flux was stably kept around $0.2(m^3/m^2/day)$ during operational period. The membrane-coupled fermenter showed 2.2 times higher VFAs concentration and higher VFAs forming rate than those of fermenter without membrane. The fermenter with membrane proved to be an effective system for the recovery of soluble organic materials from liquid sludge.

• 멤브레인
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• 제10권3호
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• pp.148-154
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• 2000

본 연구에서는 sulfur-succinic acid의 가교제를 이용한 가교된 폴리비닐알코올(poly(vinyl alcohol), PVA) 가교막을 이용하여 MTBE-methanol 혼합액에 대하여 조업온도, 가교제의 조성에 따른 증기투과 공정의 투과 특성을 조사 하였다. 팽윤 실험을 통해 PVA/SSA 가교막에 대하여 가교제 조성에 따른 막의 구조와 PVA의 하이드록실기(-OH), SSA의 설폰기(-$SO_3$H)와 용매와의 수소결합의 두 가지 인자가 상호 보완적으로 작용하고 있음을 알 수 있었다. 투과 특성에 있어 SSA의 설폰기가 중요한 인자로 작용하였다. 예를 들면 7% SSA 막에 대해서는 수소결합의 효과보다는 가교도의 효과가 투과 특성에 중요한 요인으로 작용하며 5% SSA에 대해서는 수소결합의 효과가 중요하게 작용하였다. 증기투과 공정에 있어 막과 직접 접촉하는 증기상이 액상에 비하여 methanol의 농도가 낮아 PVA의 하이드록실기와 methanol과의 수소결합 확률이 감소함에 따라 투과 특성에 영향을 미친다. 결과적으로 7% SSA 막에 대하여 MTBE/mthanol=80/20 혼합액에 대하여 공급액의 온도 3$0^{\circ}C$에서 선택도 2187, 투과도 4.84g/$m^2$hr를 보여 주었다.

• Korean Membrane Journal
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• 제2권1호
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• pp.36-47
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• 2000

This paper deals with the separation of MTBE-methanol mixtures using crosslinked Poly(vinyl alcohol)(PVA) membranes with sulfur-succinic acid(SSA) as a crosslinking agent by pervaporation and vapor permeation technique. The operating temperatures, methanol concentration in feed mixtures, and SSA concentrations in PVA membranes were varied to investigate the separation performance of PVA/SSA membranes and the optimum separation characteristics by pervaporation and vapor permeation. And also, for PVA/SSA membranes, the swelling measurements were carried out to study the transport phenomena. The swelling measurements were carried out for pure MTBE and methanol, and MTBE/methanol=90/10, 80/20 mixtures using PVA/SSA membranes with varying SSA compositions. There are two factors of the membrane network and the hydrogen bonding. In pervaporation separation was also carried out for MTBE/methanol=90/10, 80/20 mixtures at various temperatures. The sulfuric acid group in SSA took an important role in the membrane performance. The crosslinking effect might be over the hydrogen bonding effect due to the sulfuric acid group at 3 and 5% SSA membranes, and this two factors act vice versa on 7% SSA membrane. In this case, the 5% SSA membrane shows the highest separation factor of 2,095 with the flux of 12.79g/㎡$.$hr for MTBE/methanol=80/20 mixtures at 30$^{\circ}C$ which this mixtures show near the azeotopic composition. Compared to pervaporation, vapor permeation showed less flux and similar separation factor. In this case, the flux decreased significantly because of compact structure and the effect of hydrogen bonding. In vapor permeation, density or concentration of methanol in vaporous feed is lower than that of methanol in liquid feed, as a result, the hydrogen bonding portion between the solvent and the hydroxyl group in PVA is reduced in vapor permeation. In this case, the 7% SSA membranes shows the highest separation factor of 2,187 with the flux of 4.84g/㎡$.$hr for MTBE/methanol=80/20 mixtures at 30$^{\circ}C$.