• Membrane Journal
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• v.13 no.4
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• pp.211-218
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• 2003

The removal characteristics of cadmium in micellar enhanced ultrafiltration (MEUF) were investigated by using an anionic biosurfactant, deoxycholic acid (DCA). The ultrafiltration experiments were performed in a batch-type stirred cell. The ultrafiltration membranes used were Millipore YM1, YM3, YM10, and YM30 which had a difference in molecular weight cut-off. The presence of cadmium ion in DCA solution tends to reduce the critical micell concentration considerably and increase the micell size. The molecular weight cut-off of ultrafiltration membrane had a minimal effect on cadmium removal whereas DCA/Cd ratio had a substantial influence. When DCA/Cd ratio was 3, the removal efficiency of cadmium was more than 99.6%. A relative flux, which is defined as ratio of the flux for a separation trial to that of deionized water run using the same piece of membrane, decreased in the order of YM3 > YM1 > YM10 > YM30.

• Proceedings of the Membrane Society of Korea Conference
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• 1998.04a
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• pp.83-86
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• 1998

1. Introduction : Low molecular harmful organics such as 1-naphthol and phenol are widely used in industries, and pose serious environmental problems. Wastewater containing low molecular harmful organics may be ejected from various sources including metal-plating industries, circuit-board manufacturing process, photographic and photo-processing industries, refineries and metal-tailing leachate. The pollution of nation harbors, waterways and ground water resources with these organics has reached critical portions, and might also give hazardous influence on human health. Micellar enhanced ultrafiltration(MEUF) is a recently developed process to remove dissolved organics and/or heavy metals present in small or trace quantities from aqueous solution. In this system, the fatal defect is leakage of surfactants especially at low concentration below CMC(critical micelle concentration), which becomes a secondary pollution. Our group proposed to use biosurfactant and polymeric micelle to solve problems mentioned above. In this study we investigated a modified MEUF using PEO-PPO-PEO (polyethyleneoxide-polypropyleneoxide-polyethyleneoxide) block copolymers for the removal of organic solutes such as 1-naphthol and phenol from aqueous wastewater. We proposed PEO-PPO-PEO block copolymers as new surfactants for forming micelles in MEUF, and investigated the solubilization characteristics and efficiency for the removal of 1-naphthol and phenol. PEO-PPO-PEO block copolymers are, environmentally mild and safe as biosurfactants.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2002.09a
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• pp.103-106
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• 2002

Solubilization isotherms for methyl tort-butyl ether (MTBE) in sodium dodecyl sulfate(SDS), dowfax 8390, sodium dodecylbenzenesulfonate and cetylpyridinium chloride (CPC) were investigated for application to micellar enhanced remediation. Dowfax 8390 showed maximum extent of solubilization among surfactants tested in this study. It seems that sulfate group in anionic surfactants playes a important role in solublization of MTBE. Chemical shiftes in NMR of surfactant and MTBE supports this point.

• Proceedings of the Membrane Society of Korea Conference
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• 2004.11a
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• pp.267-270
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• 2004

• Proceedings of the Membrane Society of Korea Conference
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• 2004.11a
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• pp.271-274
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• 2004

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.04a
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• pp.307-310
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• 2004

Micellar enhanced ultrafiltration (MEUF) is a surfactant-based separation process and it can remove heavy metal ions from aqueous stream effectively. However, it is necessary to recover and reuse surfactants for economic feasibility because surfactant is expensive. Foam fractionation was investigated for both anionic and cationic surfactant recovery. Chelating agent such as ethylenediaminetetraacetic acid (EDTA) was studied for the separation of heavy metals from surfactant solution. Anionic surfactants bound with heavy metals can be recovered by lowering pH (acidification). In this study, citric acid and imminodiacetic acid (IDA) were applied to release copper from sodium dodecyl sulfate (SDS) micellar solution and compared with EDTA. Precipitation of copper by ferricynide and sodium sulfide were also investigated. As a result, ca. 100 % of copper was released from SDS micellar solution by 5 mM of EDTA and citric acid. And 3.3 mM of ferricyanide formed precipitate with 82.7 % of copper. 5 mM of IDA and sodium sulfide released or formed precipitate 82.5 % and 58.9 % of copper, respectively. Citric acid is harmless to environments and ferricyanide precipitates with Cu easily. Therefore, it is considered that citric acid and ferricyanide have competiveness over a famous chelating agent, EDTA, for the separation of Cu from SDS solution.

• Proceedings of the Membrane Society of Korea Conference
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• 1994.10a
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• pp.12-13
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• 1994

막분리 공정을 이용하여 수용액상에 존재하는 유기 오염물질을 제거하기 위해서는 역삼투나 투과중발법의 도입이 필요하다. 그러나 두가지 공정 모두 대단위의 처리를 위해서는 막대한 시설$\cdot$가동비를 필요로 한다. 특히 물속에 녹아 있는 방향족 유기물들은 심각한 환경오염의 주범이 되고 있음에도 불구하고 효율적이고 경제적인 처리가 거의 이루어지지 않고 있다. Micllar enhanced ultrafiltration (MEUF) 공정은 오염물이 녹아있는 수용액에 계면활성제를 투입하여 오염물이 포함된 micelle을 형성시킨 후 이를 한외여과함으로써 계면활성제와 유기물을 동시에 제거하는 공정이다[1]. 이 공정을 이용함으로써 한외여과막의 종류, 유기 오염물의 특성에 다른 제거 효율의 변화나 최적 조업 조건 등에 대한 체계적인 연구[3,4]가 미흡한 실정이다.

• Membrane Journal
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• v.16 no.1
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• pp.59-67
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• 2006

Biodegradable amphiphilic polymer was synthesized for removing hydrophobic pollutants(phenol, 4-nitrophenol, benzene, and toluene) and metal ions ($Cs^{+},\;Mg^{2+},\;Cu^{2+},\;Ni^{2+}$, and $Cr^{3}$). The methoxy poly(ethylene glycol)s with different molecular weights (1,100 and 5,000) were used as a hydrophilic segment. The rejection ratio improved in the relatively high molecular weight of MPEG. The rejection ratio of biodegradable nanoparticles without pollutants was over 98%. In removal of hydrophobic pollutants, the rejection ratio increased with the hydrophobic properties. The electron valence affects the rejection ratio of metal ions, indicating rejection ratio was ordered as $3^{+}>2^{+}>1^{+}$.