• Journal of Microbiology and Biotechnology
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• 제14권6호
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• pp.1129-1133
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• 2004

The effects of Pluronic F-68, a non-ionic surfactant, on the growth and physical characteristics of Digitalis lanata suspension cultures were investigated in aqueous two-phase systems (ATPSs) composed of $4.5\%$ polyethylene glycol (PEG) 20,000 and $2.8\%$ crude dextran. In the range of 0.1-10.0 g $1^{-1}$, Pluronic F-68 enhanced the maximum cell density in a medium with ATPSs, even though Pluronic F-68 did not affect cell growth in a normal growth medium. In terms of physical properties of ATPSs with cell suspension cultures, 0.2 g $1^{-1}$ of Pluronic F-68 reduced viscosity by up to $40\%$, while 0.1 g $1^{-1}$ of Pluronic F-68 significantly enhanced the oxygen transfer rate. In addition, we successfully performed aqueous two-phase cultivation in a 5-1 stirred tank bioreactor with 0.5 g $1^{-1}$ of Pluronic F-68, and discovered that cell growth in ATPSs was similar to that in normal growth medium.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2004년도 임시총회 및 추계학술발표회
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• pp.186-190
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• 2004

The electrokinetic bioremediation employing electrolyte circulation method was carried out for the cleanup of phenanthrene-contaminated kaolinite, and microorganism used in the biodegradation of phenanthrene was Sphingomonas sp. 3Y. The electrolyte circulation method supplied ionic nutrientsand the microorganism into soil, and inhibited the significant pH change of soil by increasing the soil buffering capacity by providing phosphate buffer compounds. When the remediation process was conducted without surfactant, the removal efficiency of phenanthrene, at the initial concentration of 200 ppm, was 69% for only 7 days. Higher microbial population and lower phenanthrene concentration were observed in the anode and middle regions of soil specimen than in the cathode region. The higher density of microorganism was because the microbial movement was in the direction of the anode part due to the negative surface charge. When Triton X-100 and APG of 20 g/1 were used to improve the bioavailability of phenanthrene strongly adsorbed onto soil surface, about 90 and 39% of phenanthrene removal were obtained. Consequently, it was confirmed that the microorganism preferred APC to phenanthrene as carbon source and so the removal efficiency with APG decreased less than that without APG.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2004년도 임시총회 및 추계학술발표회
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• pp.68-71
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• 2004

Effects of surfactants and natural organic matter (NOM) on the sorption and reduction of tetrachloroethylene (PCE) and chromate with iron were examined in this study. PCE and chromate reduction by iron depended on the ionic type of the surfactants in this study. The apparent reaction rate constants of PCE with Triton X-100 and hexadecyltrimethyl ammonium (HDTMA) at one half and two times of the critical micelle concentration (CMC) were relatively higher than without surfactants because of the enhanced PCE partitioning and surface concentration. In the presence of sodium dodecyl benzene sulfonate (SDDBS) at 2000 mg/L and NOM at 50 mg/L, the apparent reaction rate constants of PCE increased, but TCE production decreased. The enhanced removal rate of PCE was not due to the dechlorination, and the sorption was dominant iron with SDDBS and NOM. The apparent reaction rate constants of chromate by iron with Triton X-100 and NOM were 1.4-3.1 times lower than without surfactants while that with HDTMA was two times higher than without HDTMA, When the sorbed HDTMA molecules form admicelles, negatively-charged chromate has an affinity for the positively-charged HDTMA head group.

• Toxicological Research
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• 제17권3호
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• pp.167-171
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• 2001

Oral mucous membrane test using Syrian hamsters was performed to evaluate the reliability as a model system for the assessment of the potentially irritating substances intended for the mucous membranes, and to determine the irritating potential of a new emulsion-type formulated toothpaste. After test substances were implanted into the cheek pouches of hamsters with diluents (20 mg/kg) under pento-barbital sodium anesthesia, we made the comparison in irritation between emulsion-type and dispersion-type of triclosan (TCS) formulations in the range of 0.2% to 0.3%. The emulsion-type formulations using non-ionic surfactant showed less mucosal lesion than other commercial toothpastes with 0.3% TCS, or dispersion-type ones. However, no significant difference in irritation was detected between 0.2% and 0.3% TCS. We report that this hamster cheek pouch method could be a reliable approach for the evaluation slight difference in the irritating potentials of cosmetics and hygiene products intended for the lips or other mucous membranes, and this method showed that the new emulsion-type formulation significantly lowered the TCS-induced toxicity, compared with other commercial toothpastes.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제41회 하계 정기 학술대회 초록집
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• pp.200-200
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• 2011

Hierarchical mesoporous ZSM-5 with enhanced mesoporosity was synthesized by microwave through the rapid assembly via ionic interaction between sulfonic acid functionalized ZSM-5 nano particles and cationic surfactant. The catalytic performance of enhanced accessibility due to mesoporosity and acidity were investigated in the alkylation of mesitylene with benzyl alcohol as alkylating agent. The effect of mole ratio of aromatic with benzyl alcohol, reaction time and alkylation agent were also studied. The enhanced mesoporosity and acidity of sulfonic acid functionalized mesoporous ZSM-5 induced activity enhancement compared with non-functionalized mesoporous ZSM-5, sulfonic functionalized mesoporous ZSM-5 synthesized by hydrothermal method and conventional microporous ZSM-5. The sulfonic acid functionalized mesoporous ZSM-5 showed much higher chemoselectivity of benzylated mesitylene than others, whereas the others mainly show dibenzyl ether as product. This significant difference in catalytic selectivity was resulted from the existence of mesopores, which definitely allowed the benzylation in mesopores.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2003년도 가을 학술논문집
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• pp.650-654
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• 2003

원자력분야에서 방사성폐기물 처리 및 처분은 해결해야 할 중요한 문제가 된다. 보다 청정한 방법을 사용한 제염법이 요구되고 있다. 이산화탄소를 이용한 제염법은 두가지로 나눠지는데-킬레이트제를 이용한 방법과 에멀젼을 이용한 방법이다. 킬레이트제 방법은 시너지효과를 낼 수 있는 방안이 중요하다. 마이크로 에멀젼을 사용한 방법은 에멀젼 코어속에 산을 넣어 금속표면이나 토양에서 오염물질을 직접 꺼내는 방법이다. 표면제거율을 QCM을 사용하여 측정하였다. 에멀젼을 만드는데 사용된 계면활성제의 회수 방법에 대하여 아울러 논의하였다.

• 한국염색가공학회지
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• 제5권4호
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• pp.10-19
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• 1993

Broad, mercerized broad, mercerized twill cotton fabrics and rayon fabric were treated with cellulase for 30~480 minutes at different temperature, concentration, time, and also treating methods such as continuously-treated or repeatedly-treated, and dyed with two direct dyes before or after enzyme treatment. From the experimental result by treating under the various conditions above, it was obtained that the weight loss increased more in thin fabric than thick one. In addition, it was considered that the treatment in 5$0^{\circ}C$ for 240 minutes brought about the ideal weight loss and flexible hand of the specimens. For both broad and mercerized broad, repeated treatment showed more weight loss than continuous. Direct dye on cotton fabric apparently inhibited hydrolysis. Ionic surfactants showed the inhibition effect of the catalytic hydrolysis of enzyme, on the other hand, nonionic surfactant did not.

• Macromolecular Research
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• 제14권5호
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• pp.545-551
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• 2006

Aqueous dispersions of pristine and functionalized (COOH- and $NH_2$-) multi-walled, carbon nanotubes (MWNTs) were prepared by using three types of surf act ants: sodium dodecyl sulfate (SDS, anionic), PEO-PPO-PEO (Pluronic P84, non-ionic), and poly(styrene/$\alpha-methyl$ styrene/acrylic acid) random terpolymer, i.e., alkali-soluble resin (ASR). The aggregate size, $\zeta-potential$, and storage stability of the MWNT aqueous dispersions were investigated by using dynamic light scattering and the turbidity method at room temperature. The exfoliation of the MWNT aggregates was determined by a UV-visible spectrophotometer and the morphology of the surfactant-coated MWNTs was observed by transmission electron microscopy (TEM). In all cases, ASR showed better dispersion stability with the smallest aggregate size, compared with the other surfactants, because of its unique molecular structure, i.e., randomly incorporated carboxylic acid groups and planar phenyl groups that can be irreversibly and effectively adsorbed on the MWNT surface. A predominantly-exfoliated morphology of MWNTs was observed in the presence of ASR from the strong intensity of the UV-vis spectrum at 263 nm.

• 한국표면공학회지
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• 제37권6호
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• pp.344-349
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• 2004

Emulsions were formed through putting small quantity of nickel electroplating solution into supercritical carbon dioxide, and then electroplating in the $sc-CO_2$ emulsions was conducted. It is an environmental-friendly technology that can solve the treatment of a large quantity of toxic plating wastewater, which is a big problem in the existing wet plating, and also can reduce secondary waste generation fundamentally. Supercritical carbon dioxide emulsions enhanced by ultrasonic horn were formed by non-ionic surfactant and nickel solution. Plating condition within emulsions was set up as 120bar and $55^{\circ}C$ through measurement of electrical conductivity following the pressure change. Experiments were conducted respectively against supercritical carbon dioxide emulsions electroplating and general chemical electroplating, and then their results were compared and analyzed. As the experiment result utilizing emulsions, plating surface was formed very evenly even with a small quantity of electroplating solution, and fine particles were plated compactly without any pinhole or crack due to hydrogenation, which occurs in general electroplating. Used electroplating solution can be reused through recovery process. Therefore, this technology will be able to be applied as new clean technology in electro-plating.

• 한국막학회:학술대회논문집
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• 한국막학회 1998년도 추계 총회 및 학술발표회
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• pp.153-155
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• 1998

PTFE 합성공정에서 대량으로 사용하는 고가의 음이온계 유화제를 분리/회수하는 것은 경제적인 문제 뿐만 아니라 환경적으로도 매우 중요하다. 음이온계 유화제의 회수에는 Water-evaporation, ion-exchange, freezing, electrodialysis등의 방법을 사용할 수 있다. 그러나 회수에 드는 경비가 높고 장치가 복잡하다는 단점이 잇다. 반\ulcorner에 막분리 공정은 장치가 간단하고 상대적으로 경비가 적게 든다는 장점이 있다. 본 연구에서는 음이온계 유화제를 분리/회수하기 위해서 역삼투 공정을 사용하였다. 그러나 역삼투 공정과 같이 압력을 분리의 구동력으로 하는 막분리 공정에서는 농도분극 및 막오염 현상에 의한 투과량의 감소가 심각하게 일어나며 전체적으로 막분리 공정의 경제성을 떨어뜨리는 주된 요인이 된다. 특히 이온성 막을 사용할 경우 막과 이온성 용질간의 정전기적 포텐셜이 화학적 포텐셜과 함께 투과분리의 구동력을 이루게 되므로 투과거동이 매우 달라지게 된다. 본 연구에서는 막 재료의 이온특성과 음이온성 용질의 농도에 따른 막오염 현상의 관찰 및 이것이 투과거동에 미치는 영향을 관찰하였다. 이를 위해 Sodium alginate, Chitosan, Poly(vinyl alcohol)을 이용하여 각각 음이온성, 양이온성, 중성 막을 제조하여 투과거동을 관찰하였다.