• 한국전산유체공학회:학술대회논문집
• /
• 2003.10a
• /
• pp.123-125
• /
• 2003

Understanding the physics of electroosmotic flow is important to the optimum design and operation of microfluidic systems. Recent development on the topic in our group is summarized in this presentation. Applications to the variable-volume-Injection, micro flow switch, electrokinetic focusing, and flow cytometer will be presented with our novel design and control.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2003.09a
• /
• pp.310-313
• /
• 2003

The precipitation of heavy metals within the region of pH jump is inevitable in the conventional electrokinetic remediation technology. This study prevents the interest species from precipitating through the injection of flushing solutions in which HCl, acetic acid, citric acid, EDTA and SDS dissolved. The cumulative flow resulted from electroosmosis appear in order of Citric acid

• Proceedings of the PSK Conference
• /
• 2003.04a
• /
• pp.294.1-294.1
• /
• 2003

At pH 7.4 (physiological pH), skin is permselective to cations, due to the net negative charge of the current passing channels (pores) in skin. This causes the convective solvent flow (electroosmotic flow) from anode to cathodal direction. In this work, we have investigated several factors (pH. current density and ionic strength) that can affect the electroosmotic flow. (omitted)

• Geomechanics and Engineering
• /
• v.1 no.4
• /
• pp.275-289
• /
• 2009

Electroosmosis (EO) is the movement of water in a porous medium under the influence of a direct current (dc). In past decades, electro-osmosis has been successfully employed in many soil improvement and other geotechnical engineering projects. Metal electrodes, such as steel, copper and aluminum have been used traditionally to conduct current. The shortcoming of these electrodes is that they corrode easily during an EO treatment, which results in reduced effectiveness and environmental concerns. More recently, conductive polymers are developed to replace metal electrodes in EO treatment. Electrical vertical drainages (EVDs) are one of these products under trial. The goal of this study is to assess the performance of EVDs for soil improvement and to further understand the scientific principle of the EO process, including the voltage drop at the soil-EVD interface, electrical current density, polarity reversal, and changes in soil physico-chemical properties generated by electroosmosis. It is found from the study that after 19 days of EO treatment with a constant applied dc electric field intensity of 133 V/m, the soil's moisture content decreased by 28%, the shear strength and pre-consolidation pressure increased more than 400%. It is also found that the current density required triggering the water flow in the soil tested, the Korean Yulchon marine clay, is 0.7 $A/m^2$. The project demonstrates that EVDs can serve as both electrodes and drains for soil improvement in short term. However, the EVDs, as tested, are not suitable for polarity reversal in EO treatment and their service life is limited to only 15 days.

• Proceedings of the KIEE Conference
• /
• 2001.11a
• /
• pp.69-71
• /
• 2001

본 논문에서는 FACS(fluorescence activated cell sorting)의 초소형화를 위한 미세 유체소자들을 플라스틱 기판에 집적하여 제작하고 전기삼투를 이용해서 세포가 일렬로 이송되는 특성을 시험한다. 제작된 미세 유체 소자는 유리 하부 기판과 플라스틱 상부 기판 및 전원장치로 구성된다. 상부기판은 세포를 주입하기 위한 샘플 측 레저버와 세포를 운반 및 일렬 이송이 가능하게 하는 버퍼를 저장할 두 개의 레저버가 있고 이들이 배출되는 레저버로 구성된다. 마이크로머시닝 기술을 이용하여 실리콘 기판 위에 미세 채널 몰드를 제작한 후 PDMS(polydimethylsiloxane)로 주물을 제작한다. $O_2$ 플라즈마를 이용하여 유리 기판과 PDMS 주물을 접합하며 제작된 채널에 적색 잉크와 bead를 샘플 측에 충전하고 버퍼 측에 sodium borate를 충전한 후 전기삼투로 구동시킨다. bead가 일렬로 이송되도록 전장을 조절하고 이때의 유속과 유량을 측정한다. 다양한 전장에 따른 실험을 통하여 채널의 구조를 최적화한다.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2000.05a
• /
• pp.121-124
• /
• 2000

In-situ soil remediation using electrokinetics has been investigated and the attempts for the removal of hydrocarbons have been continued. In this study, the electrokinetic remediation using three different kinds of surfactnats was conducted for the removal of phenanthrene from clay The used surfactnats were APG, Brij30 and SDS. In the solubility test for phenanthrene, the experimental result was APG

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2001.09a
• /
• pp.131-134
• /
• 2001

This research was carried out to evaluate the effects of humic acid on contaminated kaoline with cadmium when electrokinetic remediation. Electrokinetic remediation test was performed depending on humic acid concentrations(0.005, 0.01, 0.05, 0.083, 0.1, 0.5, 5.0mg/g) in contaminated kaoline with cadmium and time(4, 8, 12days). In the absence of humic acid, Cd at the anode showed the highest concentration while Cd concentrations were lower as the concentration of humic acid increased. The removal of Cd to the anode reservoir was increased with increasing humic acid concentration by electroosmosis or ion migration.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2004.03b
• /
• pp.890-896
• /
• 2004

This study is intended as an investigation of the EK remediation characteristics of natural soil with treatment time under unsaturated conditions. EK tests are performed under the voltage gradient of 1V/cm, the degree of saturation of 82.8%, and the installing of cation exchange membrane. It was found from the results that the acid front is initially transported at 0.75cm/day and then continuously degreased until the transport velocity of the acid front is balanced to the velocity of the base front. The residual lead concentration indicated the maximum value at the treatment time of lOdays, then the increasing of treatment time largely decreases the concentration within the sample though electromigration than electroosmosis.

• Proceedings of the KSME Conference
• /
• 2003.04a
• /
• pp.1992-1997
• /
• 2003

This study is to develop the pretreatment for the excess and digested sludge by electro-coagulation and dewatering. Electrocoagulation is applied to excess and digested sludge before transferring to the piston type press for dewatering. Piston type filter press as a laboratory scale plant was used to estimate the dewaterability. MMD of excess sludge was increased from initial diameter of particles(34.16 ${\mu}m$) to the 87%(64.01 ${\mu}m$) after electrocoagulation. AI electrode is more effective than Fe electrode for the dewaterability of excess sludge. Electrodewatering after electrocoagulation as pretreatment makes the water content of sludge cake $50{\sim}60$ wt%.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
• /
• 2003.09a
• /
• pp.158-161
• /
• 2003

Removal of phenanthrene by electrokinetic method combined with Fenton-like process was studied in a model system. The scale of reactor was 100cm in length, 100cm in width, and 70cm in height. The distance between electrodes was 70cm. Indonesia kaoline was selected as a model soil. When constant voltage of 100 V was applied to this system, current decreased from 200 mA to 100 mA for 14 days. Total accumulated EOF was about 55,000 mL. The concentration of phenanthrene near anode was very low because direction of electroosmosis was from anode to cathode and hydrogen peroxide was supplied to anode reservoir. Phenanthrene concentration was increased as the location was far from anode because hydrogen peroxide was gradually decomposed and then the rate of hydroxyl radical production was decreased.