• Title/Summary/Keyword: electrokinetic flow

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동전기-펜턴 토양정화공정에서 공정변수에 따른 분해성능 비교

  • 양지원;박지연;김상준;이유진
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • 2002.09a
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    • pp.239-242
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    • 2002
  • Removal of phenanthrene by electrokinetic (EK) method combined with Fenton-like process was studied in a model system. Sand and phenanthrene were selected as a model soil and a representative PAH. Sand was contaminated at the concentration of 500 mg phenanthrene/kg dry sand. Bentonite and kaolinite were inserted into the space between reservoir and contaminated soil. When hydrogen peroxide supplied to a soil system from the anode reservoir was transported through the soil by EK process, the Fenton-like reaction was occurred by naturally existing iron minerals in soil. When hydrogen peroxide was supplied into the system, it showed higher removal efficiency than when just water was used. Maximum removal efficiency of phenanthrene was 81.2 % for 7 days.

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Competitive Adsorption of Dispersant and Binder on Alumina and Its Effect on the Electrokinetic Behavior in Aqueous Media

  • Paik, Un-Gyu
    • The Korean Journal of Ceramics
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    • v.4 no.4
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    • pp.292-296
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    • 1998
  • In wet powder processing of alumina, a number of organic molecules such as dispersant and binder are used to produce the flow behavior and properties requisite for shape forming. In this study, interparticle forces of alumina particles suspended in aqueous media were controlled by suspension pH, poly (methacrylic acid) (PMAA, used as dispersant) and poly (vinyl alcohol) (PVA, used as binder). The combined adsorption isotherms of the dispersant and binder additives on alumina were determined by total organic carbon analyzer, while the adsorption of dispersant was differentiated from binder in the mixed additive system by ultraviolet spectroscopy. The electrokinetic behavior of alumina suspensions were then correlated with the adsorption characteristics of dispersant and binder onto alumina particles. It was found that the isoelectric ($pH_{iep}$) of alumina shifted from pH 8.9${\pm}$0.1 to acidic pH as PMAA concentration increased, while PVA adsorption did not affect the $pH_{iep}$ but caused a decrease in the near surface potential.

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Electrochemical Characteristics of Fine Soils in the Application of Electrokinetic Remediation (동전기력 복원공정 적용에 따른 세립토양의 전기화학적 특성 변화)

  • 고석오
    • Journal of Soil and Groundwater Environment
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    • v.7 no.3
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    • pp.85-94
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    • 2002
  • Overall objective of this study was to evaluate the electrochemical characteristics of fine soils during the electrokinetic(EK) remediation. Zeta potential of kaolinite as a function of solution pH and surfactant concentration was investigated to make a relationship with electroosmotic flow direction and rate. During the EK experiments, pH of pore solution, electroosmotic permeability($k_e$), electric conductivity($\delta_e$) and voltage distribution was measured, respectively, The point of zero charge(PZC) of kaolinite was estimated to be about 4.2 and the zeta potential of kaolinite above PZC was more negative as solution pH increased. Sorption of surfactants on the kaolinite altered the zeta potential of kaolinite. resulting from the variation of electrochemical characteristics of kaolinite surface. hs the EK experiment progressed, low pH was predominant over most of the kaolinite specimen and thus resulted in very low mass and charge flow. The $k_e$ and $\delta_e$ was also affected by the variation of voltage drop across the EK column with time. Results from this study implied that zeta potential of kaolinite affected by the pH variation of pore solution and voltage distribution in soil column played important role in the determination of mass and charge flow during EK process. It was also suggested that pH adjustment or addition of suitable sorbates could alter the electrochemical characteristics of soil surface and thus maintain high mass and charge flow rate with time.

Electrohydrodynamic Flow around a Circular-Cylindrical Rod Submerged in a Dielectric Liquid (비전도성 액체에서의 실린더 막대 주변에 생기는 전기동역학적 유체흐름)

  • Park, Hyun-Jin;Ryu, Jae-Chun;Kang, Kwan-Hyoung
    • 한국가시화정보학회:학술대회논문집
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    • 2007.11a
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    • pp.51-54
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    • 2007
  • The induced-charge electroosmosis (ICEO) is a kind of electroosmotic flow which is generated by the electrical charge induced by an externally-applied electric field. That kind of electrokinetic phenomenon provides a nonmechanical technique to handle microscale flows and particles. In this work, we report that the ICEO-like flow is observed around two kinds of circular-cylindrical rod submerged in a dielectric liquid. The conductivity of the solution is varied by adding a surfactant. The flow field is visualized by the PIV method, and average flow speed shows a remarkable dependence on electrical input frequency. Interestingly, the characteristics of the flow are quite different from the conventional ICEO with respect to the flow direction and the locations of center of vortices.

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Electrokinetically Flow-Induced Streaming Potential Across the Charged Membrane Micropores: for the Case of Nonlinear Poisson-Boltzmann Electric Field (하전된 멤브레인 미세기공에서의 계면동전기적 유동에 의한 흐름전위: 비선형 Poisson-Boltzmann 전기장을 갖는 경우)

  • Myung-Suk Chun
    • Membrane Journal
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    • v.13 no.1
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    • pp.37-46
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    • 2003
  • The electrokinetic effect can be found in cases of the fluid flowing across the charged membrane micropores. The externally applied body force originated from the electrostatic interaction between the nonlinear Poisson-Boltzmann field and the flow-induced electrical field is taken into the equation of motion. The electrostatic potential profile is computed a priori by applying the finite difference scheme, and an analytical solution to the Navier-Stokes equation of motion for slit-like pore is obtained via the Green's function. An explicit analytical expression for the flow-induced streaming potential is derived as functions of relevant physicochemical parameters. The influences of the electric double layer, the surface potential of the wall, and the charge condition of the pore wall upon the velocity profile as well as the streaming potential are examined. With increasing of either the electric double layer thickness or the surface potential, the average fluid velocity is entirely reduced, while the streaming potential increases.

Lifetime Prolongation of Poly (dimethylsiloxane) Surface Modification via 2-Hydroxyethyl Methacrylate Grafting for Electroosmotic Flow

  • Park, Eun-Soo;Yang, Sang-Sik
    • KIEE International Transactions on Electrophysics and Applications
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    • v.4C no.4
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    • pp.142-144
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    • 2004
  • To use Poly-dimethylsiloxane (PDMS) for the electrokinetic flow channel, the PDMS surface must be modified to be hydrophilic. With $O_2$ plasma treatment, it is difficult to maintain hydrophilicity for more than one day. In this paper, we present the chemical modification of the PDMS surface using 2-Hydroxyethyl methacrylate (HEMA) to prolong hydrophilicity lifetime. The oxide radicals generated temporarily on the PDMS surface by $O_2$ plasma are grafted with HEMA. Once the PDMS samples have been grafted, they demonstrate improved hydrophilicity retainment and electroosmotic flow characteristics compared to the untreated PDMS and the oxidized PDMS following the $O_2$ plasma process. This phenomenon was verified by the contact angles, Fourier transform infrared (FTIR) spectra and electro osmotic flow rates observed for more than 300 hours.

A Technical Review on Principles and Practices of Self-potential Method Based on Streaming Potential (흐름 전위에 기초한 자연 전위 탐사법의 원리 및 활용)

  • Song, Seo Young;Nam, Myung Jin
    • Geophysics and Geophysical Exploration
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    • v.21 no.4
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    • pp.231-243
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    • 2018
  • Streaming potential (SP) arises from fluid flow through effectively connected pores. From this potential, formation water information as well as fluid flow properties can be estimated. As micro particles being located in boundary between subsurface porous media and fluid are charged to form electrical double layer, fluid flow caused by several reasons generates SP, one of electrokinetic phenomena. Occurrence mechanism of SP is complex and signal strength is relatively weak compared to noise. However, application of self potential survey using SP to monitoring of formation fluid is expanding because of its' convenience of exploration without artificial source and repetitiveness of signal. This paper accounts for the occurrence mechanism of SP studied before, including governing equations and analyzes previous various case studies of SP according to the change of physical properties of materials. It helps to increase understanding about SP and also lays the foundations of the application of SP to fields.

Dispersion of Silicon Nitride Particles and Sintering Additives of AlN and Nd$_2$O$_3$ in Nonaqueous Suspending Media (비수계분산매체에서 질화규소와 소결첨가제 AlN 및 Nd$_2$O$_3$의 분산)

  • 김재원;백운규;윤경진
    • Journal of the Korean Ceramic Society
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    • v.36 no.2
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    • pp.210-219
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    • 1999
  • The fundamental dispersion property of Si2N4 and a combination of AlN and Nd2O3 as sintering additives in a variety of organic solvents such as alcohols, hydrocarbons, ketones, and ethers was investigated. The stabilization mechanism and interaction between organic functional groups of the various organic additives were studied to clarify the dispersibility of the ceramic particles in the nonaqueous suspending medium. characterization of the suspensions was based mainly on electrokinetic sonic amplitude(ESA) measurements and the flow curves obtained from the rheological studies as well as estimated Hamaker constants. It was found that the contribution of electrostatic repulsive forces to the Si3N4, AlN and Nd2O3 stabilization in organic media is appreciably greater than anticipated and is dependent on the physicochemical properties of organic solvents.

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Dewatering of Sewage Sludge by Electrokinetics (동전기를 이용한 슬러지 탈수에 관한 연구)

  • Kim, Ji Tae;Won, Se Yeon;Cho, Won Cheol
    • KSCE Journal of Civil and Environmental Engineering Research
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    • v.26 no.6B
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    • pp.661-667
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    • 2006
  • In this study, an experiment of sewage sludge dewatering is carried by using electrokinetic method, and the electrokinetic dewatering efficiency of digested sludge is analyzed. Digested sludge without coagulants is selected and gravitational and pressing dewatering methods are applied in combination with electro-osmotic and electro-osmotic pulse technology. After the test of digested sludge, dewatering test of thickened sludge is carried to evaluate the electrokinetic dewatering feasibility of thickened sludge. Under the condition of constantly applied voltage, however, electrical resistance increases with decreasing of water content so that dewatering rate decreases with time. To reduce such a hindrance caused by constantly applied voltage, electro-osmotic pulse technology which is considered to reduce the difference of water content with height, is applied. For the application of electro-osmotic pulse, the dewatered flow rate and the dewatered volume became more increasing from the middle of the dewatering process than that of continuous voltage. Through the test of thickened sludge, electro-osmotic dewatering combined with gravitational and expression also showed high dewatering rate, which proved the possibility of using electrokinetic dewatering.