• Environmental Engineering Research
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• 제24권3호
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• pp.456-462
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• 2019

Hydrocarbon contamination is among the most challenging problems in soil remediation. Electrokinetic method can be a promising method to remediate hydrocarbon-contaminated soils. Electrokinetic method consists of different transport phenomena including electro-migration, electrophoresis, and electroosmotic flow. Electroosmotic flow is the main transport phenomenon for hydrocarbon removal in soil porous media. However, the main component of hydrocarbons is the hydrophobic organic which indicates low water solubility; therefore, it makes the electroosmotic flow less effective. The objective of the present study is to enhance electrokinetic remediation of diesel-contaminated silty sand by increasing the solubility of the hydrocarbons in the soil and then increase the efficiency. For this purpose, sodium dodecyl sulfate (SDS) was used as a catholyte. In this content, SDS 0.05 M was used as catholyte and $Na_2SO_4$ 0.1 M was used as an anolyte. Low (1 V/cm) and high (2 V/cm) voltage gradients were used in periodic and continuous forms. The best removal efficiency was observed for high voltage gradient (2 V/cm) in a periodic form, which was 63.86. This result showed that a combination of periodic voltage application in addition to the employment of SDS is an effective method for hydrocarbon removal from low permeable sand.

• 센서학회지
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• 제16권2호
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• pp.115-119
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• 2007

We report electrokinetic streaming potential detection in a microchannel. Streaming potential, one of the representative electrokinetic phenomena, becomes noticeable either when the channel size reduces or when the concentration of electrolyte reduces. We suggest a triangular-shaped microchannel to enhance streaming potential. The triangular-shaped microchannel shows better performance than the straight one in terms of streaming potential. Couple of possible methods to enhance streaming potential is also discussed. Moreover, this type of channel and phenomenon can be applied to biological sensor application and energy transduction.

• 한국지반공학회:학술대회논문집
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• 한국지반공학회 2008년도 추계 학술발표회
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• pp.1446-1451
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• 2008

The clay found in the river or in any waste water treatment plant usually have a very high content of water. A large amount of sediments hinder the navigation in river. In waste water treatment plant, there is requirement of settling the thick sludge. These problems are overcome by using rapid means of sedimentation and settling. This paper focus on how method of Electrokinetic sedimentation can be made faster. Sedimentation using Electrokinetic phenomenon has been discussed with varied voltage applied and effect and dose of coagulant in increasing the process. The experimental test has been carried out at water content that are generally present in the case of river and small canals carrying waste water. This paper also focus on different heavy metals concentration during the process and the power aspects of process. A series of experiment were done to support the proposed theory and how a bubble formation could hinder the purpose of experiment.

• 한국가시화정보학회지
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• 제8권4호
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• pp.38-42
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• 2010

Ion concentration polarization is an electrokinetic phenomenon which occurs in membrane systems, such as in an electrodialysis and fuel-cell system. But the phenomenon is not fully understood because hydrodynamics, electrokinetics and electrochemistry are coupled with each other. Here, we report that there occurs a change of pH value of buffer solution in concentration polarization phenomenon. To visualize the change of pH, the litmus solution which is one of the pH indicators was used. It is conjectured that the pH of solution changes because hydrogen ions were concentrated in cathodic side and hydroxide ions were concentrated in anodic side. We anticipate that this work may contribute to the fundamental understanding on the ion concentration polarization phenomenon.

• Korean Chemical Engineering Research
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• 제61권1호
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• pp.155-161
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• 2023

이온 농도 분극 현상은 전기투석, 전기화학 전지에서 일어나는 기초 이동 현상일 뿐만 아니라, 생체 물질 전처리용 농축 장치의 핵심 기작으로 활용된다. 외부 인가 전압에 의해 발생한 이온 농도 분극 현상은 분석 물질의 농축에 필요한 국소적으로 증폭된 전기장을 통해 물질의 농축을 가능케 한다. 그러나 기존의 농축 기작은 농축의 평형 지점이 불분명하며, 농축 플러그의 유체역학적 불안정성의 두가지 문제점을 가지고 있다. 본 연구에서는, 이온 농도 분극 기반의 농축 기작의 한계점을 해결하기 위해 막다른 미세유로와 양이온 교환막을 사용한 농축 방법을 연구하였다. 막다른 미세유로의 공간 제약적 구조를 통해 유체역학적 안정성을 확보할 수 있으며, 분석 물질의 농축 지점이 이온 공핍 영역의 충격 전단과 일치함을 수치적으로 확인하였다. 또한 농축 공정의 핵심 인자로써 인가 전압과 미세유로의 체적 전하 농도를 변화시켜가며, 농축 물질의 전기동역학적 거동을 연구하였다. 본 연구의 결과는 현장 진단 검사(point-of-care)와 같은 초단시간의 농축을 필요로 하는 미세유체역학 장치에 유효한 기작으로 사용될 수 있을 것이다.

• 한국지하수토양환경학회지:지하수토양환경
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• 제19권5호
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• pp.26-34
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• 2014

A $1.5m(L){\times}1.0m(W){\times}1.1m(H)$ polypropylene (PP) field scale electroniketic system coupled with stainless steel electrodes was designed to examined metal removal performance applied 0.2-0.35 V/cm potential gradient and 0.05-0.5M lactic acid for 20 day. Electroosmosis permeabilities of $2.2{\times}10^{-5}cm^2/V-s$ to $4.8{\times}10^{-5}cm^2/V-s$ were observed and it increased with the potential gradient increased. The reservoir pH controlled at $7.0{\pm}1.0$ has been effectively diminished the clogging of most metal oxides. The best removal efficiency of Zn, Pb, and Ni was 78.4%, 84.3%, and 40.1%, respectively, in the field scale EK system applied 0.35 V/cm and 0.05M lactic acid for 20 days. Increasing potential gradient would more effectively enhance metal removal than increasing concentration of processing fluid. The reservoir and soil temperatures were majorly related to potential gradient and power consumptio. A $4-16^{\circ}C$ above room temperature was observed in the investigated system. It was found that the temperature increase in soil transported the pore water and metals from bottom to the topsoil. This vertical transport phenomenon is critical for the electrokinetic process to remediate in-situ deep pollution.

• 멤브레인
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• 제27권5호
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• pp.399-405
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• 2017

계면동전위라 불리는 제타전위(zeta potential)란 표면 전하적 특성을 정량화 한 값으로 전기동역학적 현상으로 발생하는 전위차를 말한다. 제타전위는 막오염(fouling)과 표면전하 분석을 통한 개질 확인 및 치환기 확인에 대한 연구가 활발히 진행되어 왔다. 그리고 제타전위를 측정하는 방법으로는 전기영동(electrophoresis), 전기삼투(eletrosmosis), 유동전위(streaming potential)를 기초로 개발되었고, 그중에서도 평막은 유동전위 측정이 적합하다고 알려졌다. 따라서, 본 연구에서는 poly(styrene-ethylene-butylene-styrene) 고분자에 암모늄을 도입하여 아민화된 SEBS 평막 형택의 분리막을 제조하고, 계면동전위 측정기를 이용하여 제조된 분리막들의 유동전위를 측정하여 결과를 분석하였다.

• 대한토목학회논문집
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• 제30권1C호
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• pp.17-25
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• 2010

전기영동기술은 사용중인 폐기물 매립지(MSW) 지오멤브레인 차수층의 누출 복원을 위한 새로운 기술로서 음으로 대전된 점토입자는 동전기(Electrokinetic) 현상에 의해 누출이 발생되는 차수층까지 이동되고, 누출구 주변에 침출수의 외부유출 방지를 위한 점토 케이크를 형성한다. 본 연구에서는 3차원 누출구 모사실험을 수행하여 전기영동기술의 현장 적용성과 1차원 전기영동 실험을 통해 도출된 최적 인자들의 적절성을 평가하였다. 결과적으로 누출구의 반경이 증대되거나 또는 양전극간의 거리가 가까울수록 누출구 근처에서 형성된 점토 케이크의 크기(두께 및 폭)는 증가하였다.

• 한국지반공학회논문집
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• 제18권4호
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• pp.349-356
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• 2002

본 연구는 유류 화합물 중 phenol을 대표적인 친수성 유기 화합물로, phenanthrene을 대표적인 소수성 유기오염물로 선정하여 실내에서 인위적으로 오염시킨 세립질 지반에 EK 정화 실험을 실시하였다. 또한, 유기 오염물의 제거효율을 높이기 위해 기존의 양수처리에서 향상기법으로 사용하는 계면활성제를 이용한 향상기법을 연구하였다. 실내 bench 스케일 실험결과, 물에 대한 용해도가 높은 phenol은 비교적 쉽게 제거되었지만, 용해도가 낮은 phenanthrene은 거의 제거되지 않음을 알 수 있었다. 또한, 계면활성제를 적용한 향상기법에서 phenanthrene이 음극부 근처에서 누적되는 지연현상을 보였지만, 농도가 증가할수록 제거효율은 증가하였다. 가동시간을 증가시킨 실험을 통해 시간을 증가시키는 것이 계면활성제의 농도를 증가시키는 것보다 효과적인 것을 알 수 있었다.

• Membrane and Water Treatment
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• 제4권2호
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• pp.127-142
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• 2013

In order to investigate the significance of "salting-out" and "pore swelling" effects on the nanofiltration of neutral solutes, rejection properties of two NF ceramic and polymeric membranes were studied with single polyethyleneglycol (PEG) solution and mixed PEG/inorganic electrolyte solutions. For both membranes, the rejection rate of PEG was found to decrease significantly in the presence of ions. In the case of the ceramic membrane (rigid pores), this phenomenon was imputed to the sole partial dehydration of PEG molecules induced by the surrounding ions. This assumption was confirmed by the lowering of the PEG rejection rates which followed the Hofmeister series. Experimental data were used to compute the resulting decrease in the Stokes radius of PEG molecules in the presence of the various salts. Concerning the polymeric membrane, the decrease in the rejection rate was found to be systematically higher than for the ceramic membrane. The additional decrease was then ascribed to the swelling of the pores. The experimental data of rejection rates were then used to compute the variation in the mean pore radius in the presence of the various salts. The pore swelling phenomenon due to accumulation of counterions inside pores was supported by electrokinetic charge density measurements.