• Title/Summary/Keyword: Anode

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Studies on the anodic oxidation of some volatile organic halogen compounds(THM) (휘발성 할로겐 화합물(THM)의 양극 산화에 관한 연구)

  • Yoo, K.S.;Park, S.Y.;Yang, S.B.;Woo, S.B.
    • Analytical Science and Technology
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    • v.10 no.4
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    • pp.264-273
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    • 1997
  • Anodic oxidation reaction was applied to remove trihalomethanes in an aqueous solution. Each component was determined by using solid phase microextraction(SPME) fiber and GC-ECD. Anodic and cathodic compartments were separated in order to protect contaminants and connected by $KNO_3$-agar bridge. The calibration graphs of the 6 THM components were shown good linearlity from a few ppb up to a few hundreds ppb concentration level. Anodes such as platinum(Pt), titanium(Ti). zircornium(Zr), titanium metal coated with iridium(Ti-Ir), and glassy carbon coated with mixed valence ruthenium(mv Ru) were tried to remove the THMs at different potentials. The best result was obtained on the Ti-Ir anode applied 9 volts DC. The electrode could effectively remove almost all the THM components from the stirring solution within about 1.5 hours. The glassy carbon electrode coated with mixed valence ruthenium showed excellent removing effect at the begining, but the maximum removing level was remained at 60% probably due to the destruction of the electrode surface. The concentration of chloroform, however, tends to be increased due to the electrode reaction producing the component at the condition.

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Development of Multiwire Proportional Counter for Measurement of Environmental-level Alpha Particles (환경준위 알파입자측정을 위한 다중선 비례계수기 개발(I))

  • Oh, Pil Jae;Park, Tae Soon;Lee, Min Kie;Kim, Kyung Hwa
    • Analytical Science and Technology
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    • v.9 no.3
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    • pp.262-269
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    • 1996
  • The muiltiwire proportional counter for the measurement of low-level and environmental $\alpha$ particles emitting nuclides was developed. External dimension of the devloped multiwire proportional counter is $350{\times}290{\times}30mm$ and the sensitivity area is $250{\times}200mm$. The wall material of the detector was selected the stainless steel to prevent the deformation by external impact and to obtain minimum background. The anode and cathode wires were used the stainless steel material of diameter $50{\mu}m$. The spacing of each wires are 10.0mm, 5.0mm and the numbers of total wire are 21, 42 lines, respectively. The multiwire proportional counter was designed that the measurement source is placed within the detector to prevent the wall absorption effect and the efficiency variation by various source heights. The characteristics of the developed detector have been investigated to obtain the plateau, operating voltage, background, counting efficiency, position sensitivity and energy resolution etc. For the $^{241}Am$ nuclide, the calculated LLD(Lower Limit of Detection) is 5.0mBq/L which is lower than 40mBq/L of recommended LLD value by ISO(International Organization for Standardization).

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Removal of Cr, Pb and Cd from Reservoir Sediment by Electrokinetic Technique (동전기를 이용한 유수지 오염 퇴적토내 Cd, Pb 및 Cr제거)

  • Shin, Hyun-Moo
    • Journal of Soil and Groundwater Environment
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    • v.14 no.1
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    • pp.68-77
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    • 2009
  • For the reservoir sediment highly contaminated with total Cr, Pb, and Cd, the applicability of electrokinetic remediation method was evaluated. Also, BCR sequential extraction method was adopted to compare the heavy metal speciation in between before and after electrokinetic reaction that is operated under constant current condition for the sediment. After reaction, total Cr and Pb moved toward the direction of anode, while Cd tended to cathode and stayed highest in the midst of sediment specimen. From the BCR sequential extraction analysis, it was known that for total Cr and Pb the residual fraction that showed high fraction before reaction decreased and changed to the oxidation fraction. On the other hand, for Cd the fraction of exchangeable/carbonate that dominated most fractions before reaction changed to the residual and oxidation fractions.

Properties of Polymer Electrolytes based on PEO-LiClO$_4$ Matrix Fabricated by Sol-Gel Process (솔-젤 법으로 만든 PEO-LiClO$_4$에 기초한 고분자 전해질의 물성)

  • 박영욱;이동성
    • Polymer(Korea)
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    • v.27 no.3
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    • pp.265-270
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    • 2003
  • In spite of high ionic conductivity, the polymer gels have poor mechanical properties and high reactivity with lithium metal anode. To solve these problems, the dry solid systems and polymer composites have been intensively studied, due to their good mechanical, thermal, chemical, and electrochemical stability. The objectives of this experiment were to improve ionic conductivity and mechanical properties of the solid polymer electrolytes based on PEO-LiClO$_4$. To obtain higher ionic conductivity and better mechanical properties, ceramic or rubber phase was added in the PEO-LiClO$_4$(8:1) matrix. The results showed that ionic conductivity and mechanical properties were improved. The ionic conductivity of the samples was as high as 10$\^$-5/ S cm$\^$-1/. This value is similar to the best ionic conductivity ever reported in the solid drying system. To obtain better results, we used PEO with various molecular weights (600∼8000) and changed the salt contents. By using DSC, we found that the addition of salt reduced the crystallinity of PEO. The mobility of polymer dependence on salt contents was examined by FT-IR.

A Study on Process Performances of Continuous Electrodeionization with a Bipolar Membrane for Water Softening and Electric Regeneration (바이폴라막을 이용한 연수용 전기탈이온의 공정 효율 및 전기적 재생에 관한 연구)

  • Moon, Seung-Hyeon;Hong, Min-Kyoung;Han, Sang-Don;Lee, Hong-Joo
    • Membrane Journal
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    • v.17 no.3
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    • pp.210-218
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    • 2007
  • CEDI-BPM(Continuous Electrodeionization-Bipolar Membrane) has advantages due to high ion permselectivity through ion exchange membranes and the production of $H^+$ and $OH^-$ ions on the bipolar membrane surfaces for regeneration of ion exchange resin during electrodeionization operation. In this study, hardness materials were removed by the CEDI-BPM without scale formation and the ion exchange resins were electrically regenerated during the operation. The adsorption characteristic of ion exchange resin surface, the influence of flow rate on the hardness removal and electric regeneration were investigated in the study. The removal efficiency of Ca was higher than that of Mg in the CEDI-BPM, which was related to the high adsorption capacity of Ca on the cation exchange resin. With increasing flow rate, the flux of Ca and Mg was enhanced by the permselectivity of a cation exchange membrane. In the electric regeneration of CEDI-BPM, it was shown that the regeneration efficiency was higher with a lower regeneration potential applied between cathode and anode.

Effect of Cathode Porosity of Mixed Conducting (La0.6Sr0.4Co0.2Fe0.8O3) on the Power Generating Characteristics of Anode Supported SOFCs (혼합전도체 LSCF(La0.6Sr0.4Co0.2Fe0.8O3) 양극의 기공률에 따른 음극지지형 단전지의 출력특성 평가)

  • Yun, Joong-Cheul;Kim, Woo-Sik;Kim, Hyoungchul;Lee, Jong-Ho;Kim, Joosun;Lee, Hae-Weon;Kim, Byong-Ho
    • Journal of the Korean Ceramic Society
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    • v.42 no.4
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    • pp.269-275
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    • 2005
  • We analyzed the unit cell performance against the cathode porosity, which is supposed to be closely related with active sites for the cathode reaction. In order to fabricate the unit cells with different porosity in the cathode layer we changed the mixing ratio of fine and coarse LSCF cathode powders. The final porosity of each cathode layer was 14, 23, 27, $39\%$ respectively. According to the electrochemical analysis of unit cell performance via DC current interruption and AC impedance method, the electrodic polarization resistance was diminished as the cathode porosity increased. The decrease of polarization resistance was attributed due to the increase of active reaction sites and the enhancement of overall unit cell performance could be explained in the same line.

Comparison of Dye Removal Performance and Oxidants Formation of Insoluble Electrode (불용성 전극의 Dye 제거 성능과 산화제 생성 비교)

  • Yoo, Young-Eok;Kim, Dong-Seog
    • Journal of Environmental Science International
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    • v.20 no.10
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    • pp.1273-1284
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    • 2011
  • The aim of this research was to evaluate the performance of insoluble electrode for the purpose of degradation of Rhodamine B (RhB) and oxidants generation [N,N-Dimethyl-4-nitrosoaniline (RNO, indicator of OH radical), $O_3$, $H_2O_2$, free Cl, $ClO_2$)]. Methods: Four kinds of electrodes were used for comparison: DSA (dimensional stable anode; Pt and JP202 electrode), Pb and boron doping diamond (BDD) electrode. The effect of applied current (0.5~2.5 A), electrolyte type (NaCl, KCl and $Na_2SO_4$) and electrolyte concentration (0.5~3.5 g/L) on the RNO degradation were evaluated. Experimental results showed that the order of RhB removal efficiency lie in: JP202 > Pb > BDD ${\fallingdotseq}$ > Pt. However, when concerned the electric power on maintaining current of 1 A during electrolysis reaction, the order of RhB removal efficiency was changed: JP202 > Pt ${\fallingdotseq}$ Pb > BDD. The total generated oxidants ($H_2O_2$, $O_3$, free Cl, $ClO_2$) concentration of 4 electrodes was Pt (6.04 mg/W) > JP202 (4.81 mg/W) > Pb (3.61 mg/W) > BDD (1.54 mg/W), respectively. JP202 electrode was the best electrode among 4 electrodes from the point of view of performance and energy consumption. Regardless of the type of electrode, RNO removal of NaCl and KCl (chlorine type electrolyte) were higher than that of the $Na_2SO_4$ (sulfuric type electrolyte) RNO removal. Except BDD electrode, RhB degradation and creation tendency of oxidants such as $H_2O_2$, $O_3$, free Cl and $ClO_2$, found that do not match. RNO degradation tendency were considered a simple way to decide the method which is simple it will be able to determinate the electrode where the organic matter decomposition performance is superior. As the added NaCl concentration was increases, the of hydrogen peroxide and ozone concentration increases, and this was thought to increase the quantity of OH radical.

Development of Slurry Flow Control and Slot Die Optimization Process for Manufacturing Improved Electrodes in Production of Lithium-ion Battery for Electric Vehicles (전기자동차 리튬이온 배터리 제조공정에서 Loading Level 산포최소화 코팅을 통한 전극 품질개선에 관한 연구)

  • Jang, Chan-Hee;Lee, Jae-Chon
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.19 no.3
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    • pp.14-20
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    • 2018
  • Electric vehicles are environmentally friendly because they emit no exhaust gas, unlike gasoline automobiles. However, since they are driven by the electric power from batteries, the distance they can travel based on a single charge depends on their energy density. Therefore, the lithium-ion battery having a high energy density is a good candidate for the batteries of electric vehicles. Since the electrode is an essential component that governs their efficiency, the electrode manufacturing process plays a vital role in the entire production process of lithium-ion batteries. In particular, the coating process is a critical step in the manufacturing of the electrode, which has a significant influence on its performance. In this paper, we propose an innovative process for improving the efficiency and productivity of the coating process in electrode manufacturing and describe the equipment design method and development results. Specifically, we propose a design procedure and development method in order to improve the core plate coating quality by 25%, using a technology capable of reducing the assembly margin due to its high output/high capacity and improving the product capacity quality and assembly process yield. Using this method, the battery life of the lithium-ion battery cell was improved. Compared with the existing coating process, the target loading level is maintained and dispersed to maintain the anode capacity (${\pm}0.4{\rightarrow}{\pm}0.3mg/cm^2r$ reduction).

Electricity Production by Metallic and Carbon Anodes Immersed in an Estuarine Sediment (퇴적토에 담지된 금속 및 탄소전극에 의한 전기 생산 특성)

  • Song, Hyung-Jin;Rhee, In-Hyoung;Kwon, Sung-Hyun;Cho, Dae-Chul
    • Journal of the Korea Academia-Industrial cooperation Society
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    • v.10 no.12
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    • pp.3731-3739
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    • 2009
  • One-chambered sediment cells with a variety of anodic electrodes were tested for generation of electricity. Material used for anodes was iron, brass, zinc/iron, copper and graphite felt which was used for a common cathode. The estuarine sediment served as supplier of oxidants or electron-producing microbial habitat which evoked electrons via fast metal corrosion reactions or a complicated microbial electron transfer mechanism, respectively. Maximum power density and current density were found to be $6.90\;W/m^2$ (iron/zinc) and $7.76\;A/m^2$ (iron), respectively. Interestingly, copper wrapped with carbon cloth produced better electric performance than copper only, by 60%, possibly because the cloth not only prevented rapid corrosion on the copper surface by some degrees, but also helped growing some electron-emitting microbes on its surface. At anodes oxidation reduction potential(ORP) was kept to be stationary over time except at the very initial period. The pH reduction in the copper and copper/carbon electrodes could be a sign of organic acid production due to a chemical change in the sediment. The simple estimation of interfacial, electrical resistances of electrodes and electrolyte in the sediment cell that a key to the electricity generation should be in how to control corrosion rate or microbial electron transfer activity.

Effect of External Resistance on Electrical Properties of Two-Chamber type Microbial Fuel Cells (이형반응기 미생물연료전지의 전기적 특성에 미치는 외부저항의 영향)

  • Lee, Myoung-Eun;Jo, Se-Yeon;Chung, Jae-Woo;Song, Young-Chae;Woo, Jung-Hui;Yoo, Kyu-Seon;Lee, Chae-Young
    • Journal of Korean Society of Environmental Engineers
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    • v.33 no.3
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    • pp.167-173
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    • 2011
  • The Effects of external resistance on electrical properties such as current density, power density and coulombic efficiency were investigated in two-chamber type MFCs using a ferricyanide as reducing agent. A stable electricity was produced when a constant time elapsed after innoculation of mixed cultures into the anode compartment; voltages from 0.13 to 0.16 V was measured at $50{\Omega}$ of external resistance. When the external resistance was increased, the current density decreased and the power density rapidly increased and then slowly decreased. Big variation of electrical properties was observed in high-current density region due to the concentration loss related with substrate consumption in repeated experiments changing the external resistance. The maximum power density ($175.8mW/m^2$) and coulombic efficiency (46.1%) were obtained at $100{\Omega}$ of the external resistance which is nearest with the internal resistance ($134{\Omega}$) of MFC system.