• Journal of Korean Society of Environmental Engineers
• /
• v.22 no.4
• /
• pp.755-764
• /
• 2000

Fate and transport of hydrophobic organic contaminants can be influenced by naturally-existing humic substances and surfactants applied to wash polluted soils in the subsurface environment. The objective of this paper is to study the solubility enhancement of four PAHs (polycyclic aromatic hydrocarbon) and p,p'-DDT in humic acid and surfactant solutions. As the number of aromatic ring is increased, the extent of solubility enhancement of PAHs by humic acid increased. Although the hydrophobicity of p,p'-DDT was the largest among five organic compounds used, the extent of solubility enhancement of p,p'-DDT by humic acid was lower than that of pyrene. In case of anionic surfactants, the extent of the increased solubility of five organic compounds by SDS and SDDBS was increased linearly, but the extent of the increased solubility of p,p'-DDT by MADS-12 was lower than that of perylene.

• Korean Chemical Engineering Research
• /
• v.45 no.6
• /
• pp.669-676
• /
• 2007

The raw water was fractionated into hydrophobic (HPO), transphilic (TPI), and hydrophilic portions (HPI) using XAD resins. The raw water DOC contains 39% of hydrophilics, 43% of hydrophobics, and 18% of transphilics. When fractionated NOM (natural organic matter) was passed through hydrophilic membrane with 100 kDa, hydrophobic portion (HPO) caused the most fouling and hydrophilic portion (HPI) caused the least fouling. This could be related to size and adsorption capability of organics. Small sized organics would pass through membrane pores, but large sized organics would be attracted to either membrane pores or surface, which led to the fouling. An effect of membrane pore size on membrane fouling is related to the availability of organics at membrane pores. As the pore size became larger, the more organics were transported into the membrane pore. Some organics caused pore blocking, and others caused pore adsorption, which resulted in membrane fouling. Membrane material is also important for membrane fouling. More fouling occurred at hydrophobic membrane than hydrophilic membrane regardless of its pore size. Hydrophobic interaction caused more fouling at hydrophobic membrane.

• Journal of Korea Soil Environment Society
• /
• v.5 no.1
• /
• pp.65-73
• /
• 2000

Surfactants have been extensively considered for decontamination of the subsurface polluted with hydrophobic organic compounds. In order to investigate the effect of molecular structures on the solubilization of hydrophobic organic compounds, solubility enhancement of two PAHs in solutions of three different surfactants-conventional, dianionic, and gemini. The batch experimental results showed that the gemini was the most effective and the dianionic was the least, indicating that organic carbon content of the surfactants was the major factor which determines the sorption capacity of surfactant aggregates in water, unlike some of the previous reports.

• Journal of Korean Society of Environmental Engineers
• /
• v.27 no.12
• /
• pp.1321-1326
• /
• 2005

As a results of this research, the Nakdong River consisted of 43% of hydrophobic fraction, 39% of hydrophilic fraction, and 18% of transphilic fraction. The hydrophobic fraction in this raw water was mostly fulvic acid. Fulvic acid comprised of 62% and the rest was humic acid(38%). There was more carboxylic acid functional roup(64%) than phenolic group(36%). HPI-N and HPI-C comprised of 17% and 22% in the hydrophilic portion, respectively. The results of the membrane fouling test using UF membrane according to NOM fractions. HPI-N caused more fouling than HPI-C. Humic acid caused more fouling than fulvic acid probably due to higher adsorption capacity. Since humic acid has higher adsorption capacity than fulvic acid, it would be more adsorbed onto the membrane pores. The carboxylic acid functional group caused more fouling than the phenolic group.

• Journal of Korea Soil Environment Society
• /
• v.2 no.1
• /
• pp.99-107
• /
• 1997

In this study, a series of batch-scale tests were conducted to optimize the design parameters for the application of soil washing techniques to the hydrophobic organic compounds(HOCs)-contaminated soil and to find the effective methods for the recovery of surfactants from washing effluent by using solvent. Several nonionic surfactants (polyoxyethylene oleyl ester) and sophorolipid were applied to the artificially contaminated soil (4,000 mg n-dodecane/kg dry soil). The effects of washing time, concentration of surfactant solution, dilution ratio, and temperature on washing efficiencies were examined. Hydrophile-liphophile balance (HLB) number was proven to be one of the important parameters for soil washing. The HLB numbers of OA-5 and sophorolipid are too low to form a stable soil-water emulsion. They showed very low washing efficiencies less than 10e1o. If HLB number is in the proper range to form a stable soil-water emulsion, surfactant having higher solubility for HOCs shows higher washing efficiency. OA-14 having higher HLB number than OA-9 formed more stable soil-water emulsion. But its washing efficiency was about 20% due to a lower molar solubility ratio (MSR) than OA-9. OA-9, which forms a stable soil-water emulsion and has comparatively high sotubility for HOCs, showed about 60% washing efficiency by itself. To recover anthracene effectively from OA-9 washing effluent by using benzene as an organic solvent, desirable temperature and pH were $30^{\circ}C$ and 2, respectively.

• Proceedings of the Materials Research Society of Korea Conference
• /
• 2011.05a
• /
• pp.41.1-41.1
• /
• 2011

초소수성 표면은 $150^{\circ}$ 이상의 높은 접촉각을 가지며 표면에 오염물질이 묻지 않게 하는 anti-contamination, anti-fingerprint, self-cleaning 기능을 갖고 있는 것이 특징이다. 재료표면의 친/소수성을 제어하기 위해서는 고체 표면의 화학적인 요인과 물리적인 요인 두 가지를 조절함으로써 이루어지는데 즉 물질의 표면에너지와 표면 거칠기를 변화시켜 친/소수성을 부여할 수 있다. 초소수성 표면을 구현하기 위해서는 고체 표면의 에너지를 낮춰야 하며 이는 일반적으로 불소화합물을 사용한다. 불소는 지구상의 원소 중 가장 낮은 표면에너지를 가지고 있어 주로 후라이팬이나 치아 표면에 코팅되며 오염을 방지하는 특성을 지닌다. 실리카는 박막소재로 이용하기 위한 우수한 특성을 가진 물질로서 자연계에서 매우 풍부하게 존재하고 있으며, 생체무해하며 내구성과 내마모성, 화학적 안정성, 고온 안정성 등을 지니고 있어 여러 가지 종류의 전자기기 및 부품의 내외장 코팅에 적용이 적극 검토되고 있다. 이러한 실리카 코팅소재를 바탕으로 초소수성 코팅층을 구현하는 하나의 방법으로서 본 연구에서는 전기분무법을 사용하여 실리카 코팅층을 형성하였으며, 표면에너지를 제어하기 위해 플루오린 처리를 하여 초소수성 실리카 코팅층을 제조하였다. 합성된 실리카 코팅층은 물 뿐만이 아니라 표면장력이 낮은 다른 용액에서도 초소유성을 나타내었다. 이러한 코팅층에 대한 고온 안정성과 UV 저항성, 내구성(durability) 등을 조사하여 실제 응용 가능성을 타진하였다.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 1997.05a
• /
• pp.74-78
• /
• 1997

• Proceedings of the Korean Institute of Electrical and Electronic Material Engineers Conference
• /
• 2009.06a
• /
• pp.56-56
• /
• 2009

반도체 device가 점점 고집적화, 다층화 되면서 막질의 평탄화를 위한 CMP (chemical mechanical planarization) 공정은 반도체 제작 공정에서 필수 요건이 되었다. 특히 pad conditioning은 CMP 공정 중, 막질의 제거율과 균일도를 유지시키기 위한 중요한 공정이다. 하지만, conditioner를 장시간 사용할 경우 slurry residue와 같은 잔류 오염물질들이 conditioner의 표면의 오염을 유발할 수 있고 이로 인해 conditioner의 수명이 단축되거나 웨이퍼 표면에 결함을 유발할 수도 있다. 본 연구에서는 이를 방지하기 위해 vapor SAM을 이용하여 Ni conditioner 표면에 소수성 박막을 증착하여 오염여부를 평가해 보았다. 먼저, Ni wafer를 이용하여 증착 온도와 압력에 따라 소수성 박막을 증착하여 표면특성을 평가해 보았다. 증착전과 후에 Ni wafer 표면의 접촉각은 contact angle analyzer (Phoenix 400, SEO, Korea)를 이용하여 측정하였다. 박막 표면 형상과 거칠기는 AFM (XE-100, PSIA, Korea)를 이용하여 평가되었고 묘면 성분 분석을 위해 FT-IR (Nicolet 6700, Thermo Scientific, USA)이 사용되었다. SEM (S-4800, Hitach, Japan)은 박막 증착 전과 후의 conditioner를 이용하여 실제 conditioning후 conditioner 표면의 particle 오염정도를 관찰하기 위해 사용되었다. 또한, conditioner 표면에 실제 오염되어있는 particle 개수를 평가하기 위해 particle size analyzer (Accusizer 780A, Particle Sizing Systems Co., USA)을 사용하였다. 본 실험을 통해 최적 증착 조건을 확립하였으며 실제 conditioner 표면에 소수성 박막을 증착 후 $100^{\circ}$ 이상의 높은 contact angle을 확인할 수 있었다. 또한, 소수성 박막이 증착된 conditioner의 경우 실제 conditioning후 표면 particle 오염이 현저히 감소되었음을 확인할 수 있었다.

• Journal of the Korean Society of Groundwater Environment
• /
• v.4 no.2
• /
• pp.103-108
• /
• 1997

A series of batch tests were conducted to evaluate the design parameters for the application of soil washing techniques to the hydrophobic organic compounds (HOCs)-contaminated soil using mixed surfactants. Because the mixed surfactants form different structures of molecular aggregates from single surfactant, they were applied to improve the washing efficiency. Kinds of surfactants added, mixing ratio, and total concentration of mixed surfactants were evaluated. The uncontaminated soil was obtained from a country hill near Nock-Chun Station in Seoul. The portion of soil passing #4 (4.75 mm) sieve was used. The pH, organic contents and cation exchange capacity were 4.4, 1.6% and 4.08 meq/100 g, respectively The soil was artificially contaminated by n-dodecane. The 5% solution of OA-5 and OA-14 (1:1) showed 86% washing efficency. The 4% solution of SDS and OA-5 (1:1) showed 95% washing efficiency.

• Journal of Korean Society of Environmental Engineers
• /
• v.28 no.10
• /
• pp.1046-1054
• /
• 2006

The raw water DOC contained 39.3% of hydrophilics, 42.9% of hydriophobic, and 17.8% of transphilic. The hydrophobic fraction in this raw water was mostly fulvic acid. Fulvic acid comprised of 62% and the rest was humic acid(38%). There was more carboxylic acid functional group(64%) than phenolic group(36%). HPI-N and HPI-C comprised of 17% and 22% in the hydrophilic portion, respectively. The fouling mechanisms on the membrane surface and into its porous structure were analyzed in terms of several kinetic models. In order to analyze the fouling kinetics, the various kinetic models described in this paper were used to fit the experimental results. The kinetic models and kinetic constants obtained for each operation condition. The permeate flux was rapidly declined by simultaneous pore blocking and cake formation. Also, the permeate flux declined with decreasing internal pore size resulted from organic deposition into the membrane pore. The results of the membrane fouling test using UF membrane according to NOM fractions. HPI-N caused more fouling than HPI-C. Humic acid caused more fouling than fulvic acid probably due to higher adsorption capacity. Since humic acid has higher adsorption capacity than fulvic acid, it would be more adsorbed onto the membrane pores.