• Journal of Soil and Groundwater Environment
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• v.8 no.1
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• pp.9-16
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• 2003

A new method has been proposed and developed that solves the problem of decreasing electroosmotic flow rate by excess $H^{+}$ and precipitation of heavy metal by $OH^{-}$. An electrolytic solution was circulated between the anode and cathode compartments that enabled the pH at the anode and cathode to be controlled. The change of the soil pH by circulation systems affects the operation time, by lowering the rate of increase of the electric potential gradient, and the removal efficiency of heavy metals, by affecting the soil pH. Since there was no effluent from the cathode compartment in circulation system, there was no need to treat the wastewater after the experiment, which resulted in the reduction of influent electrolyte volume.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.1C
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• pp.1-8
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• 2006

The purpose of this study is to experimentally analysis the eletrokinetic phenomena and remediation characteristics developed during the application of electrokinetic remediation technique to unsaturated soils contaminated by heavy metals. In the laboratory a series of column tests are performed on degree of saturation for shooting range soil. The test results indicated that Pb is mainly removed under unsaturated conditions by electromigration within diffuse double layer, and if the initial containment concentration is below cation exchange capacity and equals to adsorption per unit soil solid weight, the remedial efficiency decreases with the decreasing of transport efficiency due to the changes in the degree of saturation in the electric gradient of 1V/cm.

• Journal of Soil and Groundwater Environment
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• v.13 no.6
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• pp.17-22
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• 2008

The feasibility of acid-enhanced electrokinetic remediation on zinc and nickel-contaminated soil was investigated in the laboratory. Simple extraction efficiency using 1M HCl was 24% for Zn and 9% for Ni, as a result, the acid washing is not effective to remove Zn and Ni from the soil. The effiencey of normal electrokinetic treatment during 28 days was less than simple soil washing. Catholyte circulation with a strong acid enhanced dramatically the removal of Zn and Ni and pretreatment of soil with acid increased more the removal. Based on the result, acid-enhanced electrokinetic remediation is effective to remove Zn and Ni from the contaminated soil.

• Journal of the Korean Geotechnical Society
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• v.19 no.3
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• pp.83-91
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• 2003

The electrokinetic technique has been applied to remove mainly the heavy metal and the ultrasonic technique to remove mainly organic substance in contaminated soil. In this study, the combined electrokinetic and ultrasonic remediation technique was studied far the removal of heavy metal and organic substance in contaminated soils. This study emphasized the coupled effects of electrokinetic and ultrasonic techniques on migration as well as remediation of contaminants in soils. The laboratory soil flushing tests combining electrokinetic and ultrasonic technique were conducted using specially designed and fabricated devices to determine the effect of both of these techniques. A series of laboratory experiments involving the simple, electrokinetic, ultrasonic, and electrokinetic & ultrasonic flushing test were carried out. A soil admixed with sand and kaolin was used as a test specimen, and Pb and ethylene glycol were used as contaminants of heavy metal and organic substance. An increase in out flow, permeability and contaminant removal rate was observed in electrokinetic and ultrasonic flushing tests. Some practical implications of these results are discussed in terms of technical feasibility of in situ implementation of electrokinetic ultrasonic remediation technique.

• Journal of Soil and Groundwater Environment
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• v.9 no.1
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• pp.47-53
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• 2004

Feasibility of electrokinetic process combined with Fenton-like reaction was investigated for the removal of phenanthrene from contaminated soil. Transport of hydrogen peroxide by electroosmosis and decomposition of phenanthrene by Fenton-like reaction were observed in a model system. Electrical potential gradient and electroosmotic flow (EOF) at 10 mA were higher than those at 5 mA. High accumulated EOF resulted in high removal efficiency of phenanthrene because the large amount of hydrogen peroxide was transfered through the soil. Removal efficiency of phenanthrene by water washing was 8.5% for 7 days. The highest removal efficiency including phenanthrene decomposition was 95.6% for 14 days. After the operation, soil samples with removal efficiency of 95.6% showed low concentrations of phenanthrene and its intermediates. From this result, it was presumed that phenanthrene was decomposed to small molecules or mineralized to water and carbon dioxide due to continuous supply of hydrogen peroxide by electroosmotic flow.

• Journal of Soil and Groundwater Environment
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• v.10 no.5
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• pp.11-17
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• 2005

Characteristics of phenanthrene removal in the Electrokinetic (EK)-Fenton process were investigated in a 2-dimensional test cell in a viewpoint of the effect of gravity and electrosmotic flow (EOF). When the constant voltage of 100 V was applied to this system, the current decreased from 1,000 to 290 mA after 28 days, because soil resistance increased due to the exhaustion of ions in soil by electroosmosis and electromigration. Accumulated EOF in two cathode reservoirs was 10.3 L and the EOF rate was kept constant for 28 days. At the end of operation, the concentration of phenanthrene was observed to be very low near the anode and increased in the cathode region because hydrogen peroxide was supplied from anode to cathode region following the direction of EOP. Additionally, the concentration of phenanthrene decreased at the bottom of the test cell because the electrolyte solution containing hydrogen peroxide was largely transported toward the bottom due to a low capillary action in the soil with high porosity. Average removal efficiency of phenanthrene by EK-Fenton process was 81.4% for 28 days. In-situ EK-Fenton process would overcome the limitations of conventional remediation technologies and effectively remediate the contaminated sites.

• KSCE Journal of Civil and Environmental Engineering Research
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• v.26 no.5C
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• pp.291-301
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• 2006

In this study the characteristics of electrokinetic remediation, which is dependent on a various electrode configuration, was predicted from 2-D numerical analysis program (HERO-2D). Based on the predicted results for one dimensional and two dimensional electrode configurations, the optimized electrode configuration was determined by analyzing remediation efficiency, consumed electric power, installation cost of electrode and so on. When proposed electrode configurations were applied for in-situ remediation of the soils contaminated by heavy metals, the electrode configuration of high remediation efficiency should be chosen in case the high removal effect would be required, and one dimensional electrode configuration should be chosen in case the hard field works would be expected. Because the rectangular electrode configuration is better than others for consumed electric power, remediation efficiency per unit power, installation cost of electrode and so on, it can obtain the best results for the cost reduction.

• Journal of Soil and Groundwater Environment
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• v.14 no.1
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• pp.36-43
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• 2009

The feasibility of electrokinetic remediation was investigated in the laboratory to treat contaminated soil with Zn, Ni and F. Electro-migration and electro-osmosis are the major removal mechanisms because fluorines desorbed from soil exist as an anionic form in soil pores, and Zn and Ni exist as a cationic form. Desorption of fluorine was enhanced under the alkaline condition, but that of Zn and Ni increased under the acidic condition. Sequential pH control was effective to control the mixed wastes from contaminated soil. 2 V/cm was applied to reactor to evaluate the effect of constant voltage gradient, after two weeks, the removal efficiency of Zn, Ni and F was 20.5%, 2.5% and 57.4%, respectively. Even though the removal of Zn and Ni was very low, the pH control enhanced transport of Zn and Ni significantly. As a result, sequential pH control is a effective method to remediate mixed waste-contaminated soil.

• Journal of the Korean GEO-environmental Society
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• v.3 no.1
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• pp.37-45
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• 2002

EDTA-enhanced electrokinetic removal of copper and zinc from contaminated sandy soil was carried out. In desorption equilibrium tests, the required mass ratio of EDTA to metal was 10:1 to obtain over 90% of desorption from soil. The removal of heavy metals with chelating agent EDTA below pH 3 was limited because of EDTA precipitation. In electrokinetic experiments, the pH control at anode chamber was essential and 38% Cu and 56% Zn were removed under 30 mA for 1.5 days. Heavy metal removal was greatly improved by controlling anode and soil pH with circulation of anolyte with NaOH solution, in which >50% heavy metal was removed for 4 days and >70% for 9 days.

• Bulletin of Korea Environmental Preservation Association
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• s.382
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• pp.46-48
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• 2009