• KSBB Journal
• /
• 제6권4호
• /
• pp.337-344
• /
• 1991

The liquid-liquid extraction of lipase A from Candide cylindracea and lipase B from porcine pancrease was carried out using reversed micellar organic solvents. Effects of various factors such as ionic strength, pH, and species and concentration of surfactant, on lipase solubilization were studied. A cationic surfactant cetyl-trimethyl ammonium bromide (CTAB) in isooctane/nhexanol(1:1) was found to be an effective solvent and its optimum concentration was 50 mM. KCl among various salts tested was the most effective and the efficiency of solubilization of lipase increased with decreasing the ionic strength of salts. The maximum activity and solubiliz ation of protein were obtained at pH 8. The stripping efficiency has a maximum value at pH 4 and increases with KCl concentration in the range of 0.2∼1.0 M. After the solubilization and stripping, the overall recovery efficiency of mass and specific activity of lipases was 62% and 66%, respectively.

• 대한토목학회논문집
• /
• 제29권2B호
• /
• pp.207-212
• /
• 2009

광물촉매에 의한 Fenton 산화에서 모래에 흡착된 phenanthrene을 대표적인 계면활성제인 SDS와 Tween 80을 사용하여 물질이동 영향을 조사하였다. 계면활성제 주입에 따라 액상과 고체상 사이 또는 산화물 표면으로 phenanthrene이 물질이동하였으며, 계면활성제 농도가 증가할수록 phenanthrene의 apparent solubility는 증가하는 경향을 나타내었다. Tween 80은 apparent solubility가 증가 하더라도, 계면활성제가 분해에 scavenger 작용을 하여 모래에 흡착된 phenanthrene 산화에는 영향을 주지 않았다. SDS를 주입하였을 때, Fenton-like 반응에서 SDS와 goethite가 착물을 형성하여 과산화수소 소모량을 지연시켰의며, 계면활성제를 주입 하지 않았을 때 보다 SDS 32 mM를 주입하였을 때 phenanthrene 처리효율이 증가하였다. 그러므로 최적농도의 SDS 주입은 액상과 고체상 사이 또는 산화물 표면에 phenanthrene 산화를 위한 적당한 조건을 제공 해주며, 과산화수소 소모량을 줄이고, phenanthrene 처리효율을 개선시킬 것이다.

• Preventive Nutrition and Food Science
• /
• 제3권2호
• /
• pp.143-151
• /
• 1998

Protein -surfactant interactions have been investigate by measuring ζ-potential of $\beta$-lactoglobulin-coated emulsion droplets and $\beta$-lactoglobulin in solution in the rpesenceof surfactant, with particular emphasis on the effect of protein heat treatment(7$0^{\circ}C$, 30min). When ionic surfactant (SDS or DATEM) is added to the protein solution, the ζ-potential of the mixture is found to increase with increasing surfactant concentration, indicating surfactant binding to the protein molecules. For heat-denatured protein,it has been observed that the ζ-potential tends to be lower than that of the native protein. The effect of surfactant on emulsions is rather complicated .With SDS, small amounts of surfactant addition induce a sharp increase in zeta potential arising from the specific interaction of surfactant with protein. With further surfacant addition, there is a gradual reductio in the ζ-potential, presumably caused by the displacement of adsorped protein (and protein-surfactant complex) from the emulsion droplet surfac by the excess of SDS molecules. At even higher surfactant concentrations, the measured zeta potential appears to increase slightly, possibly due to the formation of a surfactant measured zeta potential appears to increase slightly, possibly due to the formation of surfactant micellar structure at the oil droplet surface. This behaviour contrastswith the results of the corresponding systems containing the anionic emulsifier DATEM, in which the ζ-potential of the system is found to increase continuously with R, particularly at very low surfactant concentration. Overall, such behaviour is consisten with a combination of complexation and competitive displacement between surfactant and protein occurring at the oil-water interface. In addition, it has also been found that above the CMC, there is a time-dependent increase in the negative ζ-potential of emulsion droplets in solutions of SDS, possibly due to the solublization of oil droplets into surfactant micelles in the aqueous bulk phase.

• 설비공학논문집
• /
• 제19권2호
• /
• pp.133-141
• /
• 2007

The drag reduction (DR) and heat transfer efficiency reduction (HTER) of nonionic surfactant according to the fluid velocity, temperature and surfactant concentration were investigated experimentally. For this study, several kinds of new surfactant which contains amine-oxide and betaine were developed. And experimental apparatus equipped with two water storage tanks temperature controlled, pumps, testing pipe network, two flowmeters, two pressure gauges, heat exchanger, and data logging system was built. Results showed that existing alkyl ammonium surfactant (CTAC) had DR of $0.6{\sim}0.8$ for $1,000{\sim}2,000\;ppm$ in fluid temperature of $50{\sim}60^{\circ}C$ and had very low DR in fluid temperature over $70^{\circ}C$. And new amino oxide and betaine surfactant (SAOB) had lower DR in fluid temperature of $50{\sim}60^{\circ}C$ compared with CTAC but in fluid temperature of $70{\sim}80^{\circ}C$ DR was $0.6{\sim}0.8$ for 1$1,000{\sim}2,000\;ppm$.

• 한국의류학회지
• /
• 제17권3호
• /
• pp.380-390
• /
• 1993

Effect of interfacial electrical conditions on adhesion of ${\alpha}-Fe_2O_3$ particles to PET fabric and the removal of ${\alpha}-Fe_2O_3$ particles from PET fabric, were investigated as functions of pH, electrolyte and ionic strength. The ${\zeta}$ potential of PET fiber and ${\alpha}-Fe_2O_3$ particles in the electrolyte solution were measured by streaming potential and microelectrophoresis methods respectively. The potential energy of interaction between ${\alpha}-Fe_2O_3$ particles and PET fabric were calculated by using the heterocoagulation theory for a sphere-plate model. The negative ${\zeta}$ potential of ${\alpha}-Fe_2O_3$ particle and PET fiber increased with pH, and then decreased certain pH and isoelectric points of ${\alpha}-Fe_2O_3$ particles and PET fiber were pH 6.5 and pH 3.5, respectively. The negative ${\zeta}$ potential of ${\alpha}-Fe_2O_3$ particle and PET fiber affected by electrolytes, were relatively high with polyanion electrolytes in solutions and were low with neutral salts. However, at surfactant solution, ${\zeta}$ potential was levelled off. The influence of the ionic strength on the ${\zeta}$ potential of ${\alpha}-Fe_2O_3$ particle was small but the negative ${\zeta}$ potential of PET fiber increased with the ionic strength. In the presence of anionic surfactant, the ${\zeta}$ potential of ${\alpha}-Fe_2O_3$ particle and PET fiber increased regardless of solution conditions. The interaction energy between ${\alpha}-Fe_2O_3$ particle and PET fabric increased with pH. The interaction energy was relatively high with polyanion electrolytes in solution, and the influence of ionic strength on the interaction energy was small, and the effective thickness of electrical double layer increased with decreasing the ionic strength.

• 한국진공학회:학술대회논문집
• /
• 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
• /
• pp.434-434
• /
• 2012

Despite recent efforts for fabricating flexible transparent conducting films (TCFs) with low resistance and high transmittance, several obstacles to meet the requirement of flexible displays still remain. Indium tin oxide (ITO) thin films, which have been traditionally used as the TCFs, have a serious obstacle in TCFs applications. SWNTs are the most appropriate materials for conductive films for displays due to their excellent high mechanical strength and electrical conductivity. Recently, it has been demonstrated that acid treatment is an efficient method for surfactant removal. However, the treatment has been reported to destroy most SWNT. In this work, the fabrication by the spraying process of transparent SWNT films and reduction of its sheet resistance by Au-ionic doping treatment on PET substrates is researched. Arc-discharge SWNTs were dispersed in deionized water by adding sodium dodecyl sulfate (SDS) as surfactant and sonicated, followed by the centrifugation. The dispersed SWNT was spray-coated on PET substrate and dried on a hotplate. When the spray process was terminated, the TCF was immersed into deionized water to remove the surfactant and then it was dried on hotplate. The TCF film was then was doped with Au-ionic doping treatment, rinsed with deionized water and dried. The surface morphology of TCF was characterized by field emission scanning electron microscopy. The sheet resistance and optical transmission properties of the TCF were measured with a four-point probe method and a UV-visible spectrometry, respectively. This was confirmed and discussed on the XPS and UPS studies. We show that 87 ${\Omega}/{\Box}$ sheet resistances with 81% transmittance at the wavelength of 550 nm. The changes in electrical and optical conductivity of SWNT film before and after Au-ionic doping treatments were discussed. The effects of hole transport interface layer using Au-ionic doping SWNT on the performance of organic solar cells were investigated.

• 자원환경지질
• /
• 제34권4호
• /
• pp.417-422
• /
• 2001

계면활성제는 소수성 화합물로 오염된 토양과 대수층을 복원하는데 사용할 수 있다. 본 연구의 목적은 톨루엔으로 오염된 사질토양을 복원하는데 사용될 수 있는 적당한 계면활성제들의 선택과 선택된 계면활성제들이 얼마나 효과적으로 톨루엔을 제거하는가를 연구하는데 있다. 사용된 토양은 Ottawa 사질 토양이며, 이용된 유기오염물질은 톨루엔이었다. 6종의 계면활성제의 선택은 독성도, 용해도 등에 따라 이루어졌으며, 이들을 이용한 계면활성제들의 선택실험 방법은 separatory funnel 실험과 shaker table agitation and centrifugation 실험이다. HLB 및 표면장력과 본 연구의 실험 결과에 의하여 6종의 계면활성제 중 가장 효율적인 종으로 Sandopan JA36(an anionic surfactant)과 Pluronic L44(a nonionic surfactant)가 선택되었다. 최고의 톨루엔 회수율 96%는 Sandopan JA36를 사용한 shaker table agitation and centrifugation 실험에서 얻었다.

• 한국환경과학회지
• /
• 제19권2호
• /
• pp.247-254
• /
• 2010

Ultrasound and Surfactant aided soil washing process has been shown to be an effective method to remove diesel from soils. The use of surfactants can improve the mobility of diesel in soil-water systems by increasing solubility of adsorbed diesel into surfactant micelles. However, a large amount of surfactant is required for treatment. In addition, synthetic surfactants, specially anionic, are more toxic and the surfactant wastewater is hard to treat by conventional wastewater treatments even by AOPs. Ultrasound improves desorption of the diesel adsorbed on to soil. The mechanisms are based on physical breakage of bonds by hot spot, directly impact onto soil particle surface, the fragmentation of long-chain hydrocarbons by micro-jet and microstreaming in the soil pores. The use of ultrasound as an enhancement method in both anionic and nonionic surfactant aided soil-washing processes were studied. And all experiments were examined proceeded under CMC surfactant concentration, frequency 35 khz, power 400 W, Soil-water ratio 1:3(wt%), particle size 0.24 ~ 2mm and initial diesel concentration. 20,000 mg/kg. Combination with ultrasound showed significant enhancements on all the processes. Especially, nonionic surfactant Triton-X100 with ultrasound showed remarkable enhancements and diesel removal rate enhanced by ultrasound helps desorpting of surfactant adsorbed onto soils which prevented decreasing surfactant activity.

• 공업화학
• /
• 제30권5호
• /
• pp.606-614
• /
• 2019

본 연구에서는 palm oil과 서로 다른 HLB (hydrophile-lipophilie balance) value를 갖는 Tween-Span계 비이온성 계면활성제를 혼합하여 O/W (oil in water) 유화액을 제조하고, 유화액의 유화안정성을 향상시키기 위한 최적 유화조건을 결정하였다. 이를 위해 CCD-RSM (central composite design model-response surface methodology)을 이용하여 각 계량인자의 주효과 및 교호효과를 해석하였으며, 두 가지 반응치를 동시에 만족하는 최적조건을 결정하였다. CCD-RSM의 계량인자로는 유화시간, 유화속도, HLB value, 계면활성제의 첨가량 등을 설정하고, 반응치로는 O/W 유화액의 점도와 평균액적크기를 설정하였다. CCD-RSM 최적화 분석결과 반응치인 O/W 유화액이 점도와 평균액적크기의 목표치를 동시에 부합하는 최적조건은 유화시간(12.7 min), 유화속도(5,551 rpm), HLB value (8.0), 계면활성제의 첨가량(5.7 wt.%)으로 산출되었으며, 이 조건에서의 CCD-RSM 예측결과는 점도(1,551 cP)와 평균액적크기(432 nm)이었다. 이 조건의 실제 실험 결과 오차율은 2.5% 이하로 나타나 O/W 유화액 제조과정에 CCD-RSM 최적화 분석을 적용할 경우 비교적 높은 유의수준의 만족하는 결과를 얻을 수 있었다.

• KSBB Journal
• /
• 제22권1호
• /
• pp.43-47
• /
• 2007

신문지와 같은 폐지의 가수분해에 미치는 계면활성제의 영향을 조사하였다. 전처리 공정에 적합한 계면활성제는 사용한 9종의 비이온 계면활성제 중 NP 계열 계면활성제가 가장 좋은 전처리 효과를 나타내었다. NP-20을 사용하여 전처리 공정을 최적화한 결과 계면활성제 농도, 교반속도, 전처리 온도와 시간이 0.5%, 100 rpm, 30$^{\circ}C$와 1시간일 때 최적조건이었다. 당화율을 최대화하기 위하여 기질을 NP-20으로 전처리하고 전처리된 기질을 TW-80을 첨가하여 가수분해하였다. 계면활성제를 사용하여 전처리된 기질을 계면활성제를 첨가하여 가수분해하면 가수분해에서 계면활성제의 효과가 거의 없었다. 그래서 가수분해 공정에서만 계면활성제를 사용하여 효소와 계면활성제의 첨가 순서에 따른 당화율을 조사하였다. 조사결과 기질에 효소를 넣고 난 후 계면활성제의 첨가시기가 늦을수록 당화율이 낮아지는 경향을 나타내었다.