• Title/Summary/Keyword: Anode Application

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Application of Galvanic Oxidation and Pyrite Dissolution for Sustainable In-Situ Mine Tailings Treatment (갈바닉 산화와 황철석 용해를 이용한 친환경 원위치 광미 무해화 기술)

  • Ju, Won Jung;Jho, Eun Hea;Nam, Kyoungphile
    • Ecology and Resilient Infrastructure
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    • v.3 no.4
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    • pp.279-284
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    • 2016
  • Mine tailings generated during mining activity often contain high concentrations of heavy metals, with pyrite-containing mine tailings in particular being a major cause of environmental problems in mining areas. Chemical cell technology, or fuel cell technology, can be applied to leach heavy metals in pyrite-containing mine tailings. As pyrite dissolves through spontaneous oxidation (i.e. galvanic oxidation) in the anode compartment of the cell, $Fe^{3+}$, sulfuric acid are generated. A decrease in pH due to the generation of sulfuric acid allows heavy metals to be leached from pyrite-containing mine tailings. In this study, pyrite was dissolved for 4 weeks at $23^{\circ}C$ in an acidic solution (pH 2) and in a galvanic reactor, which induces galvanic oxidation, and total Fe leached from pyrite and pH were compared in order to investigate if galvanic oxidation can facilitate pyrite oxidation. The change in the pyrite surface was analyzed using a scanning electron microscope (SEM). Comparing the total Fe leached from the pyrite, there were 2.9 times more dissolution of pyrite in the galvanic reactor than in the acidic solution, and thus pH was lower in the galvanic reactor than in the acidic solution. Through SEM analysis of the pyrite that reacted in the galvanic reactor, linear-shaped cracks were observed on the surface of the pyrite. The study results show that pyrite dissolution was facilitated through the galvanic oxidation in the galvanic reactor, and also implied that the galvanic oxidation can be one remediation option for pyrite-containing mine tailings.

Progress in Composite Polymer Membrane for Application as Separator in Lithium Ion Battery (리튬 이온 전지의 분리막으로 사용하기 위한 복합 고분자 막의 동향)

  • Oh, Seok Hyeon;Patel, Rajkumar
    • Membrane Journal
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    • v.30 no.4
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    • pp.228-241
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    • 2020
  • Separators, which produces physical layer between a cathode and anode, are getting enormous attention as the quality of the separator determines the performance of lithium ion batteries (LIBs). Porous membranes based on polyethylene (PE) and polypropylene (PP) are generally utilized as the separator of LIBs because of their high electrochemical stability and suitable mechanical strength. However, low thermal resistance and wettability of PE and PP membranes limited the potential of LIBs. Operating at the temperature exceeding the melting point of membranes, the separators change their structures which lead to short circuit of LIBs. Low wettability of the separators corresponds to low ionic conductivity which increases the cell resistance. To overcome these weaknesses of PE and PP separators, different types of separator were prepared by co-electrospinning, applying coating layer, forming core shell around membrane, and papermaking method. The synthesized separator greatly enhanced the heat resistance and wettability of separator and mechanical properties like flexibility and tensile strength. In this review different type of polymer membrane used as separator in lithium ion battery are discussed.

Influence of Gd0.1Ce0.9O2-δ Interlayer between La0.6Sr0.4Co0.2Fe0.8O3-δ Cathode and Sc-doped Zirconia Electrolyte on the Electrochemical Performance of Solid Oxide Fuel Cells (La0.6Sr0.4Co0.2Fe0.8O3-δ 공기극과 Sc이 도핑된 지르코니아 전해질 사이에 삽입한 Gd0.1Ce0.9O2-δ 중간층이 고체산화물 연료전지의 전기화학적 성능에 미치는 영향)

  • Lim, Jinhyuk;Jung, Hwa Young;Jung, Hun-Gi;Ji, Ho-Il;Lee, Jong-Ho
    • Ceramist
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    • v.21 no.4
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    • pp.378-387
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    • 2018
  • The optimal fabrication conditions for $Gd_{0.1}Ce_{0.9}O_{2-{\delta}}$(GDC) buffer layer and $La_{0.6}Sr_{0.4}Co_{0.2}Fe_{0.8}O_{3-{\delta}}$ (LSCF) cathode on 1mol% $CeO_2-10mol%\;Sc_2O_3$ stabilized $ZrO_2$ (CeScSZ) electrolyte were investigated for application of IT-SOFCs. GDC buffer layer was used in order to prevent undesired chemical reactions between LSCF and CeScSZ. These experiments were carried out with $5{\times}5cm^2$ anode supported unit cells to investigate the tendencies of electrochemical performance, Microstructure development and interface reaction between LSCF/GDC/CeScSZ along with the variations of GDC buffer layer thickness, sintering temperatures of GDC and LSCF were checked, respectively. Electrochemical performance was analyzed by DC current-voltage measurement and AC impedance spectroscopy. Microstructure and interface reaction were investigated by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). Although the interfacial reaction between these materials could not be perfectly inhibited, We found that the cell, in which $6{\mu}m$ GDC interlayer sintered at $1200^{\circ}C$ and LSCF sintered at $1000^{\circ}C$ were applied, showed good interfacial adhesions and effective suppression of Sr, thereby resulting in fairly good performance with power density of $0.71W/cm^2$ at $800^{\circ}C$ and 0.7V.

Research of Cross-linked Hydrocarbon based Polymer Electrolyte Membranes for Polymer Electrolyte Membrane Fuel Cell Applications (고분자 전해질 막 연료전지 응용을 위한 탄화수소계 기반 가교 전해질 막의 연구동향)

  • Ko, Hansol;Kim, Mijeong;Nam, Sang Yong;Kim, Kihyun
    • Membrane Journal
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    • v.30 no.6
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    • pp.395-408
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    • 2020
  • Polymer electrolyte membrane fuel cells (PEMFCs) have gained much attention as eco-friendly energy conversion devices without emission of environmental pollutant. Polymer electrolyte membrane (PEM) that can transfer proton from anode to cathode and also prevent fuel cross-over has been regarded as a key component of PEMFCs. Although perfluorinated polymer membranes such as Nafion® were already commercialized in PEMFCs, their high cost and toxic byproduct generated by degradation have still limited the wide spread of PEMFCs. To overcome these issues, development of hydrocarbon based PEMs have been studied. Incorporation of cross-linked structure into the hydrocarbon based PEM system has been reported to fabricate the PEMs showing both high proton conductivity and outstanding physicochemical stability. This study focused on the various cross-linking strategies to the preparation of cross-linked PEMs based on hydrocarbon polymers with ion conducting groups for application in PEMFCs.