• Title/Summary/Keyword: electrokinetics

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Improved Migration of Arsenic by Bio-Electrokinetics in Soil (토양에서 생물학적 동전기법의 영향에 의한 As의 이동)

  • Kim, Hong Tae;Lee, Tae-Ryong
    • Journal of Environmental Impact Assessment
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    • v.24 no.4
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    • pp.344-351
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    • 2015
  • In this study, bio-electrokinetics was used to increase migration of arsenic by activating endemic microorganisms in the soil. In this technology, bio-electrokinetics which the cultured soil microorganisms and nutrients injected combines with biological technology. This technology using electrical movement of microorganisms could overcome the weakness of late degradation speed and low removal efficiency. And, various soil microorganisms reduce ferreous, manganese, etc., using organic matter by as an electron donor by injecting mixture of soil microorganisms and nutrients instead of using electrolyte of the electrode. Accordingly, surrounding metal oxide microorganisms convert arsenic (III) to arsenic (V) to increase migration of arsenic (III), in consequence, migration of arsenic increased in 60 to 70% compared to about 30% of conventional electrokinetics.

A Study for Remediation of Heavy Metal Contaminated Soil Using Electrokinetics with Swappable Electrode (전극변환 동전기를 이용한 중금속 오염토양 처리에 관한 연구)

  • Choi, Heechol;Lee, Tae-Jin
    • Journal of Soil and Groundwater Environment
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    • v.17 no.5
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    • pp.75-81
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    • 2012
  • In this study, remediation of heavy metal contaminated soil was attempted by the electrokinetic process equipped with fixed or swappable electrode. Copper was more effectively removed with EDTA than citric acid. Zinc was much more removed than copper with both detergents. When electrokinetic with fixed electrode and detergents were applied to the contaminated soil, copper was removed about 28.52%~35.25% and zinc was removed about 63.44%~71.48%. When electrokinetics with swappable electrode and detergents were applied to the contaminated soil, the pseudo-first order reaction constants was higher about 16~50% than with fixed electrode in the case of zinc. It is conclusive that electrokinetics with swappable electrode could be an effective method for the remediation of heavy metal contaminated soil.

Simple Fabrication of Micromixer Based on Non-Equilibrium Electrokinetics in Micro/Nano Hybrid Fluidic System (단순공정으로 제작된 마이크로/나노 하이브리드 채널의 불균형 동전기성을 이용한 미세혼합기 연구)

  • Yu, Samuel;Kim, Sun-Min
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.35 no.4
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    • pp.385-390
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    • 2011
  • In this study, we developed a micromixer based on the non-equilibrium electrokinetics at the junction of a microchannel and nanochannel. Two fluid streams were mixed by an electro-osmotic flow and a vortex flow created as a result of the non-equilibrium electrokinetics at the junction of the microchannel and nanochannel. Initially, the microchannel was fabricated using Polydimethylsiloxane (PDMS) by the general soft lithography process and the nanochannel was created at a specific position on the microchannel by applying a high voltage. To evaluate the mixing performance of the micromixer, fluorescent distribution was analyzed by using the fluorescent dye, Rhodamine B. About 90% mixing was achieved with this novel micromixer, and this micromixer can be used in microsystems for biochemical sample analysis.

Remediation of Arsenic Contaminated soils Using a Hybrid Technology Integrating Bioleaching and Electrokinetics (생용출과 전기동력학을 연계한 통합기술을 이용한 비소 오염 토양의 정화)

  • Lee, Keun-Young;Kimg, Kyoung-Woong;Kim, Soon-Oh
    • Journal of Soil and Groundwater Environment
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    • v.14 no.2
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    • pp.33-44
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    • 2009
  • The objective of the study was to develop a hybrid technology integrating biological and physicochemical technologies to efficiently remediate arsenic contaminated lands such as abandoned mine area. The tailing soil samples contaminated with As at a high level were obtained from Songchon abandoned mine, and the content of arsenic and heavy metals as well as physicochemical properties and mineral composition were investigated. In addition, two sets of sequential extraction methods were applied to analyze chemical speciations of arsenic and heavy metals to expect their leachability and mobility in geoenvironment. Based on these geochemical data of arsenic and heavy metal contaminants, column-type experiments on the bioleaching of arsenic were undertaken. Subsequently, experiments on the hybrid process incorporating bioleaching and electrokinetics were accomplished and its removal efficiency of arsenic was compared with that of the individual electrokinetic process. With the results, finally, the feasibilty of the hybrid technnology was evaluated. The arsenic removal efficiencies of the individual electrokinetic process (44 days) and the hybrid process incorporating bioleaching (28 days) and electrokinetics (16 dyas) were measured 57.8% and 64.5%, respectively, when both two processes were operated in an identical condition. On the contrary, the arsenic removal efficiency during the bioleaching process (28 days) appeared relatively lower (11.8%), and the result indicates that the bioleaching process enhanced the efficacy of the electrokinetic process as a result of mobilization of arsenic rather than removed arsenic by itself. In particular, the arsenic removal rate of the electrokinetics integrated with bioleaching was observed over than 2 times larger than that obtained by the electrokinetics alone. From the results of the study, if the bioleaching which is considered a relatively economic process is applied sufficiently prior to electrokinetics, the removal efficiency and rate of arsenic can be significantly improved. Consequently, the study proves the feasibility of the hybrid process integrating both technologies.

동전기 기술과 계면활성제를 이용한 clay에서의 Phenanthrene 제거

  • 박지연;이현호;조현정;양지원
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • 2000.05a
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    • pp.121-124
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    • 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

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Electrokinetic Sedimentation and Remediation of River Dredged Contaminated Soil (오염된 하천준설토의 동전기적 침강 및 오염물질 제거)

  • 정하익;오인규;진현식
    • Proceedings of the Korean Geotechical Society Conference
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    • 2001.03a
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    • pp.559-562
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    • 2001
  • There are many engineering applications that demand settling acceleration and volume reduction of fine solid suspensions. It is a matter to Improve the dredged soil thickening as well as the dewatering characteristic, because settling acceleration of dredged soil decreases the scale of industrial process and volume reduction of dredged soil decreases environmetal challenge to the disposal sites. Direct electric current induces the movement of fine solid particles suspended in water. Upon formation of a soil structure, the current further induces the movement of water and contaminant in the soil skeleton. Theses phenomena are known as electrokinetics. This study investigates the viability, of using the technique of electrokinetic dewatering to river dredged soil for settling acceleration and volume reduction. The aspect, such as sedimentation velocity, final volume and current variation are discussed.

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Removal of Heavy Metal Contaminants from Cohesive Soil by Electrokinetics (Electrokinetic 기술에 의한 점성토의 중금속 오염물 제거)

  • 정하익;강병희
    • Geotechnical Engineering
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    • v.13 no.6
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    • pp.123-138
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    • 1997
  • Electroosmotic tests were performed on saturated marine clay specimens contaminated with lead to investigate the efficiency of the electrokinetic technique for removal of heavy metals from the cohesive soils. For this purpose, testing program included variable conditions such as the concentration of lead (500, 5, 000, 50, 000mg/kg), the level of electrical current (10, 50, 100 mA), operating duration (5, 15, 30days), and the application of three dirtferent chemicals for enhancement in efficiency. The pH of inflow and outflow, electroosmotic flow and electrical conductivity during the test, and the pH and the concentration of lead across the specimen after the test are presented. Test results came to the conclusion that the electrokinetic technique was very effective to remove heavy metals such as lead from the contaminated cohesive soil. Adding ecetic acid at the cathod to dissolve the procipitates of lead hydroxide as found to be effective for the enhancement of the efficiency in remediation.

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Settling behaviour of clay slurries enhanced by using electrokinetics (동전기에 의한 점토슬러리의 침강 촉진에 관한 연구)

  • Kim, Dae-Ho;Kim, Soo-Sam;Lee, Myung-Ho
    • Proceedings of the Korean Geotechical Society Conference
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    • 2008.03a
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    • pp.1061-1064
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    • 2008
  • A completion of settling process takes a lot of time for dredged materials of high moisture content, such as contaminated sludge, in landfill site. In general, additives (e.g. flocculants) are used for reducing settling time of such colloidal material, which results in the increase of sludge volume, and hence much space is required in landfill site. This study is to suggest alternative method in order to enhance the settling process of cohesive clayey soils. A number of gravitational sedimentation tests as well as electrokinetic experiments were conducted to investigate the variation of initial moisture content on the settling behaviour of clay slurry. Surface settlement, electric current and local voltage gradient were monitored during the experiment, and moisture content and soil pH were measured after the experiment. From the results, the application of electrokinetics was found to be effective in volume reduction (i.e. increase of settling velocity and decrease of final moisture content) by comparison with gravitational settling process.

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Economic Analysis on Desalination Technology for Saline Agricultural Land on the Basis of Crop Production (염류집적 농경지 제염기술에 대한 경제성분석 - 작물생산량을 기준으로)

  • Kim, Do-Hyung;Choi, Jeong-Hee;Kim, Lee-Yul;Nam, Chang-Mo;Baek, Ki-Tae
    • Journal of Soil and Groundwater Environment
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    • v.17 no.5
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    • pp.40-48
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    • 2012
  • In this study, economic analysis of five desalination technologies for saline agricultural land was carried out. The analysis was comprehensively evaluated by calculating changes in crop production and benefit/cost (B/C) ratio. The analysis of crop production was in the order of tomato > cucumber > a (musk) melon > watermelon > cabbage, and economical efficiency for desalination technology was in the order of soil exchange > soil addition > electrokinetics > under-drainage > subsoil reversal. In cost benefit analysis, B/C ratio was in the order of under-drainage > soil exchange > electrokinetics > soil addition > subsoil reversal, and all desalination technologies used in this study have the ratio higher than 1, which means economical efficiency was high. Based on the net production considering B/C ratio, the general economic analysis was exactly order from that of crop production analysis. As a result, economical efficiency of soil exchange was highest, and economical efficiency of soil addition and electrokinetic was relatively higher than others.