• Title/Summary/Keyword: catholyte

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Prevention of Power Overshoot and Reduction of Cathodic Overpotential by Increasing Cathode Flow Rate in Microbial Fuel Cells used Stainless Steel Scrubber Electrode (스테인리스강 수세미 전극을 사용한 미생물연료전지의 전력 오버슈트 예방과 환원조 유속 증가에 의한 환원전극 과전압 감소)

  • Kim, Taeyoung;Kang, Sukwon;Chang, In Seop;Kim, Hyun Woo;Sung, Je Hoon;Paek, Yee;Kim, Young Hwa;Jang, Jae Kyung
    • Journal of Korean Society of Environmental Engineers
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    • v.39 no.10
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    • pp.591-598
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    • 2017
  • Power overshoot phenomenon was observed in microbial fuel cells (MFCs) used non-catalyzed graphite felt as cathode. Voltage loss in MFCs was mainly caused by cathode potential loss. Cheap stainless steel scrubber, which has high conductivity, and Pt/C coated graphite felt as cathode were used for overcoming power overshoot and reducing the cathode potential loss in MFCs. The MFCs used stainless steel scrubber showed no power overshoot even slow catholyte flow rate and produced 29% enhanced maximum current density ($23.9A/m^3$) than MFCs used non-catalyzed graphite felt while the power overshoot phenomenon was existed in Pt/C coated MFCs. Increasing catholyte flow rate resulted in disappearing power overshoot of MFCs used non-catalyzed graphite felt. In addition, maximum power density and current density of both MFCs used non-catalyzed graphite felt and stainless steel scrubber increased by 2-3.5 times. Cathode potential losses in all region of activation loss, ohmic loss, and mass transport loss were reduced according to increase of catholyte flow rate. Therefore, stainless steel scrubber has advantages that are economical materials as electrode and prevents power overshoot, leading to enhance electricity generation. In addition, increasing catholyte flux is one of great solution when power overshoot caused by cathodic overpotential is observed in MFCs.

The Study of Cd and Pb Characteristics on Electrokinetic Remediation of Mine Deposit (Electrokinetic 기법에 의한 광산퇴적토내 Cd과 Pb의 제거 특성에 관한 연구)

  • 윤삼석;신현무;이창언
    • Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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    • 2001.09a
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    • pp.61-64
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    • 2001
  • In the remediation of contaminated soil by electrokinetic process, transport characteristics of contaminants are major factors. Pb is highly fixed to entire soil and not moved readily. High concentration of Cd was analyzed in the cathodic section but anodic section's concentration was lower than initial concentration. Although the Cd had high treatment effect, 50% of total mass was concentrated in cathodic section and was not flowed out readily. Most of transported Cd may be adsorbed in the cathodic side soil due to increased pH at adjacent to catholyte.

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The Remediation Characteristics of Natural Soil according to ElectroKinetic Remediation Systems under Unsaturated Conditions (불포화 자연토의 동전기 시스템에 따른 정화 특성)

  • Kim, Byung-Il;Kim, Ki-Nyun;Han, Sang-Jae;Kim, Soo-Sam
    • Proceedings of the Korean Geotechical Society Conference
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    • 2004.03b
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    • pp.873-881
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    • 2004
  • A serious of EK remediation tests on contaminated soil are performed under unsaturated conditions and analyzed for electrical potential, water content, pH and so on. The results indicated that electrical potential and pH distributions in the sample are dependent on the amount and inward/outward flow of hydrogen ion. Specially, for the closed system the water content is largely decreased with the flow of hydrogen. The maximum electrical conductivity is measured at the catholyte of CEM(Sealing) test and directly related to the remedial efficiency. Although pHs in the region near to the anode are similarly developed, the different concentration of lead is measured with the electrical gradient contrary to the lead concentration dependent on pH within the sample.

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Development of a Four-way Interface for Online Capillary Isoelectric Focusing-Electrospray-Mass Spectrometry (CIEF-ESI-MS)

  • Yu, Hai Dong;Kim, Byungjoo;Shin, Dae-Ho;Ahn, Seonghee
    • Mass Spectrometry Letters
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    • v.4 no.4
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    • pp.83-86
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    • 2013
  • A new interface for coupling CIEF and MS using a four-way cross has been developed in a single mechanical system. This new interface could be operated without the electric discontinuity and reinstallation of lines. Additionally, a bare fused silica capillary was facilitated as a spray needle to produce electrospray and to guide catholyte or sheath liquid. Focusing for CIEF was completed in a hanging droplet at the end of spray needle. This capillary spray needle also provided stable spray, enhanced the ionization efficiency and increased sensitivity. Results with carbonic anhydrase I showed that focusing and spraying were well completed with the new interface and the new spray needle.

Electrochemical Oxidation of Hydrazine in Membraneless Fuel Cells

  • Durga, S.;Ponmani, K.;Kiruthika, S.;Muthukumaran, B.
    • Journal of Electrochemical Science and Technology
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    • v.5 no.3
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    • pp.73-81
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    • 2014
  • This paper describes the continuous flow operation of membraneless sodium perborate fuel cell using acid/alkaline bipolar electrolyte. Here, hydrazine is used as a fuel and sodium perborate is used as an oxidant under Alkaline-acid media configuration. Sodium perborate affords hydrogen peroxide in aqueous medium. In our operation, the laminar flow based microfluidic membranleless fuel cell achieved a maximum power density of $27.2mW\;cm^{-2}$ when using alkaline hydrazine as the anolyte and acidic perborate as the catholyte at room temperature with a fuel mixture flow rate of $0.3mL\;min^{-1}$. The simple planar structured membraneless sodium perborate fuel cell enables high design flexibility and easy integration of the microscale fuel cell into actual microfluidic systems and portable power applications.

The biofuel cell: development of new materials for composing electron mediator-free and electrochemical active bacteria-free biofuel cell

  • Park Doohyun;Park Yongkeun;Kim Sikyun;Lee Daesik;Shin Inho
    • Proceedings of the Microbiological Society of Korea Conference
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    • 2000.10a
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    • pp.92-99
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    • 2000
  • In this study biofuel cell is classified into 5 generation fuel cell system based on structural and structural difference. I optionally named the biofuel cell with electron mediators prototype, that with electrochemical active bacterium 2nd generation, that with modified electrode with NR 3rd generation, that with catalytic active electrode 4th generation, and that using air as a catholyte instead of ion selective membrane and cathode, respectively. The electricity production was compared among 5 types biofuel cell and was confirmed to be $50-100\%$ higher in 4th and 5th generation than in 1st to 3rd generation.

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The effect of pore structure and surface properties of carbon nanotube films on the performance of a lithium sulfur battery

  • Song, Hyeonjun;Hwang, Yunjae;Kumar, Vimal Tiwari;Jeong, Youngjin
    • Carbon letters
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    • v.27
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    • pp.12-17
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    • 2018
  • We fabricated a Li-S battery with post-treated carbon nanotube (CNT) films which offered better support for sulfur, and investigated the effect of the surface properties and pore structure of the post-treated CNT films on Li-S battery performance. Post-treatments, i.e., acid treatment, unzip process and cetyltrimethylammonium bromide (CTAB) treatment, effectively modified the surface properties and pore structure of the CNT film. The modified pore structure impacted the ability of the CNT films to accommodate the catholyte, resulting in an increase in initial discharge capacity.

Performance of Microbial Fuel Cell Integrated with Anaerobic Membrane Filter for Continuous Sewage Treatment with Stable Effluent Quality (안정적 유출수질의 연속 하수처리를 위한 혐기성 멤브레인 필터와 통합된 미생물연료전지의 성능 평가)

  • Lee, Yunhee;Oa, Seong-Wook
    • Journal of Korean Society on Water Environment
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    • v.29 no.6
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    • pp.808-812
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    • 2013
  • A new type of microbial fuel cell (MFC) with anaerobic membrane filter was designed to produce bioelectricity and to treat domestic sewage at relatively high organic loading rate (OLR) of $6.25kgCOD/m^3/day$ and short hydraulic retention time (HRT) of 1.9 h. A following aeration system was applied to ensure effluent water quality in continuous operation. Glucose was supplemented to increase the influent concentration of domestic sewage. Influent substrate of 95% was removed via the MFC and following aeration system and the corresponding maximum power density was $25.6mW/m^3$. External resistor of $200{\Omega}$ and air-cathode system contributed better MFC performance comparing to $2000{\Omega}$ and dissolved oxygen as a catholyte.

Analysis of Vanadium Ions and SOC in the Electrolytes of VRFB-ESS (VRFB-ESS용 전해질의 이온가수 분석방법 및 SOC 분석)

  • Seo, Hai-Kyung;Park, Wonshik;Kim, Kangsan
    • KEPCO Journal on Electric Power and Energy
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    • v.7 no.2
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    • pp.309-316
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    • 2021
  • For the detection of the state of charge in VRFB-ESS, the analyses of UV-Visible spectrometry and the measurements of potential between the anolyte and catholyte were used in parallel. This paper includes the production of 4-valant ion from VOSO4 powder, 3- and 5-valant ions from electrochemical charge of 4-valant ion and 2-valant ion from 3-valant ion. It also includes the analyses of these valance ions and unknown electrolyte at any time using UV-Visible spectrometry. Through the analyses of the valance ions in samples, the SOCs of the samples at any charge-discharge times were verified.

A Study on the Performance and Operation Limit of Electrodialysis Cell for HI Concentration (HI 농축에 대한 전기투석 셀의 성능 및 운전한계조건 연구)

  • Lee, Byung-Woo;Jeong, Seong-Uk;Cho, Won-Chul;Kang, Kyoung-Soo;Park, Chu-Sik;Bae, Ki-Kwang;Kim, Young-Ho;Kim, Chang-Hee
    • Transactions of the Korean hydrogen and new energy society
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    • v.22 no.6
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    • pp.749-758
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    • 2011
  • The present work explores the performance and operation limit of electrodialysis cell for HI concentration in sulfur iodine thermochemical hydrogen production process, For this purpose, the electrodialysis cell was assembled with Nafion 117 as a PEM membrane and two activated carbon papers as the electrodes. HIx solution was prepared with composition of HI: $I_2$: $H_2O$ = 1: 0.5~2.5: 5.2 in molar ratio. The cell and its peripheral apparatus were placed in the specially designed convective oven in order to uniformly maintain the operation temperature. As operation temperature increased, the amount of water transport from anode to cathode increased, thus reducing HI molarity in catholyte. Meanwhile, the current efficiency was constant as about 90 %, irrespective of temperature change. The cell voltage increased with initial $I_2$ mole ratio as well as anolyte to catholyte mole ratio. Moreover the cell voltage overshot took place within 10 h cell operation, which is due to the $I_2$ precipitation inside the cell. From the analysis of $I_2$ mole ratio in the anolyte, it is noted that operation limit (in $I_2$ mole ratio) of the electrodialysis cell, arising from was measured to be 3.2, which is much lower than bulk solubility limit of 4.7.