• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2004.04a
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• pp.177-180
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• 2004

계면활성제를 이용한 오염된 토양을 복원하는데 있어 계면활성제의 회수하는 방법의 하나로 한외여과 방식의 타당성을 검토하였다. 계면활성제의 종류, 전해질과 첨가제로서의 알코올 및 휴믹 물질과 점토질에 의한 상대 플럭스의 변화와 투과액의 계면활성제의 농도 변화를 살펴보았다. 계면활성제의 경우 임계미셀농도 낮을수록 투과액의 농도가 낮았으며, 기타 첨가물은 농도에 비례하여 상대 플럭스가 감소하는 경향을 보였다.

• Journal of the Korean Electrochemical Society
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• v.13 no.3
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• pp.163-168
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• 2010

Effects of Cetyl Trimethyl Ammonium Bromide (CTAB), which is a kind of cationic surfactants, and Sodium Dodecyl Sulfate (SDS), which is a kind of anionic surfactants on the anodic formation of nanoporous niobium oxide were compared. The addition of SDS could protect the surface from dissolution for long time, leading to the formation of niobium oxide with a double thickness (~400 nm) compared to that prepared without surfactant, whereas dissolution seriously occurred in the solution containing CTAB. The different behaviors were attributed to the interaction between the surfactants with positive (or negative) charge and positively charged niobium oxide.

• Applied Chemistry for Engineering
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• v.8 no.4
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• pp.640-644
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• 1997

We investigated that how both the type and the concentration of coal and the surfactant and the electrolyte added to increase the fluidity of CWM influence rheological characteristics. According to the type of coal, the viscosity of CWM was increased with increasing O/C ratio. Also, the CWM was represented the property of non-Newtonian fluid, having yield stress which was linerarly increased with increasing coal concentration. According to the surfactant used as an additive, the rheological characteristics of CWM was represented the pseudoplastic property as n<1 without relating to the concentration of added surfactants. Also, according to the increase of the amount of electrolyte, n was nearly approached 1. Therfore, we found that CWM opproched Newtonian fluid and that when more than 0.05wt.% of electrolyte were added, yield stress was not shown up.

• Journal of Korea Soil Environment Society
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• v.3 no.1
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• pp.65-74
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• 1998

To enhance the washing efficiency of soil polluted by hydrophobic organic compounds, the effects of electrolytes and monomeric organic additives on micelle formation and washing efficiency of mixed surfactant solutions were investigated in this study. The surface tensions and critical micelle concentrations(CMCs) of the single and mixed surfactant solutions[$POE_5$/SDS] supplemented by NaCl were measured to investigate the effects on washing efficiency, and the composition ratios of surfactants and NaCl were optimized for the efficient soil washing system. As the mixing ratio of $POE_5$/SDS was increased to 80%, the mixed surfactant with 0.01M NaCl showed more proportional increase of washing efficiency than the mixed surfactant without any salts. The 3% solution of $POE_5$ and SDS(80%/2o%) with 0.01M NaCl showed the washing efficiency of 90%. However, the washing efficiency was not enhanced by NaCl addition to the single surfactant solution of $POE_5$. The CMC of SDS(0.049%) was higher than that of $POE_5$(0.016%), but the CMCs of mixed surfactants were decreased as the mixing ratio of $POE_5$ was increased. Alcohols having longer chain and branched carbon chain were found to be desirable for the soil washing additives.

• The Korean Journal of Rheology
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• v.9 no.1
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• pp.1-5
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• 1997

새로이 합성한 계면확성제와 대표적 분산용 계면활성제의 분산효과를 상호 비교해 보기 위하여 고농도 석탄-물 슬러리계에 대한 유변학ㅈ거 성질을 측정하였다. 0~$25^{\circ}C$ 온도 범위에서 얻어진 유동곡선으로부터 여러 가지 유동 파라미터를 구한 결과, PS가 상대적으로 structure factor, C2와 shear modulus, $\chi$2/$\alpha$2 값에 있어서 큰 감소를 보여 주엇으며 특히 shear modulus는 계면활성제의 종류에 따라 큰차이를 보여주었다. 이러한 현상을 PS가 다 가음이곤 고분자 전해질과 유사한 구조를 갖고있어서 석탄 입자에 흡착시 입자간 정전기적 반발과 입체장애를 초래하여 슬러리의 유동성을 향상시킨데 따른 결과로 해석된다.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.04a
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• pp.463-465
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• 2003

전기분해에 의한 부상현상을 이용하여 유류로 오염된 토양 세정 후 발생되는 유출수 중 유분 등을 분리하기 위한 적정 운전조건을 찾고자 하였다. 전기분해 반응조(200 $\times$ 10 $\times$15cm)에 혼합 계면활성제 (POE5 : POE14, 1:1) 1% 용액에 디젤을 1,000mg/L 농도로 용해시켜 실험하였다. 양극에는 티나늄 코팅전극, 음극으로는 스테인레스 스틸전극을 이용하였다. 반응시간은 62분( 반응: 60분, 부상시간: 2분) 이었으며 전압은 6V였다. 전해질 첨가에 의한 영향을 알아보기 위하여 실험한 결과, 전해질을 첨가하였을 경우 첨가하지 않았을 때보다 40% 정도의 효율이 증가하였다. 적정 전해질, 주입농도 및 반응시간을 알아보기 위하여 1N NaCl과 NaOH의 농도를 변화시켜 가면서 실험하였다. NaCl의 경우 더 좋은 효율을 나타내었다. 전해질의 농도는 0.2 - 1.0% 의 농도 범위에서 NaCl와 NaOH 모두 농도에 따라 순차적으로 효율이 증가하였다. 두 전해질 모두 0.4 - 1.0% 농도 범위에서 평형에 도달하는 시간은 20분으로 나타났다.

• Korean Journal of Materials Research
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• v.8 no.2
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• pp.135-140
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• 1998

Drag reduction produced by dilute solution of water soluble ionic polymer-surfactant complex under turbulent flow in a rotating disk apparatus(RDA) was investigated in this study. Three different molecular weights of polyacrylic acid(PAA) were adopted as drag reducing additives, and distilled water was used as a solvent. Experiments were undertaken to observe the dependence of drag reduction on various factors such as polymer molecular weight, molecular expansions and flexibility, rotating speed of the disk and polymer concentration. Specific considerations were put on conformational difference between surfactant and polymer, and effect of pH on ionic polymer possessing various molecular conformation through pH. The complex of ionic polymer and surfactant(Sodium Dodecyl Sulfate) behaves like a large polyelectrolyte. Surfactant changes the polymer conformation and then increases the dimension of the polymer. The radius of gyration, hydrodynamic volume and relative viscosity of the polymer-surfactant system are observed to be greater than those of polymer itself. Such surfactant-polymer complex has enhanced drag reduction properties.

• Journal of the Korean Electrochemical Society
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• v.4 no.1
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• pp.10-13
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• 2001

Effects of an anionic surfactant pentadecafluorooctanoic acid on the photoluminescence of porous silicon was investigated, which was prepared by photoelectrochemical etching at 4V of single crystalline n-type silicon (100) with the specific resistivity of $0.4\~0.8{\Omega}{\cdot}cm$. Photoluminescence shifted to shorter wavelength and its intensity decreased when the concentration of the surfactant increased. FT-IR and contact angle data supported the presence of the surfactant lying on the surface of porous silicon.

• Korean Chemical Engineering Research
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• v.51 no.4
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• pp.527-530
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• 2013

I present the behavior of colloidal adsorption to an oil-water interface in the presence of electrolyte in an aqueous subphase. The optical laser tweezers and the piezo controller are used to trap an individual polystyrene microsphere in water and forcibly transfer it to the interface in the vertical direction. Addition of an electrolyte (i.e., NaCl) in the aqueous subphase enables the particle to attach to the interface, whereas the particle escapes from the trap without the adsorption in the absence of the electrolyte. Based on the analytical calculations of the optical trapping force and the electrostatic disjoining pressure between the particle and the oil-water interface, it is found that a critical energy barrier between them should exist. This study will provide a fundamental understanding for applications of colloidal particles as solid surfactants that can stabilize the immiscible fluid-fluid interfaces, such as emulsions (i.e., Pickering emulsions) and foams.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.26 no.1
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• pp.139-148
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• 2000

The osmotic pressure is a one of the most important factor affecting stabilization of multiple emulsion in a law hours after experiment. To understand and decrease osmotic pressure between Wl phase and W2 phase, a kinds of humectants were introduced in outer water phase. As a result, Betaine and Glucose had an excellent effect reducing osmotic pressure and NaCl made W/O/W emulsion more stable than MgSO4 did when introduced in inner water phase.