• Title/Summary/Keyword: Graphite felt

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The Structure Improvement of Microbial Fuel Cell to Generate Electricity from swine wastewater (가축분뇨를 이용하는 미생물연료전지 개발을 위한 구조개선)

  • Jang, Jaekyung;Sun, RyouYoung;Lee, SungHyoun;Kim, JongGoo;Kang, YounKoo;Kim, Young Hwa
    • 한국신재생에너지학회:학술대회논문집
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    • 2010.06a
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    • pp.252.1-252.1
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    • 2010
  • These studies convert to useful electricity from swine wastewater and to treat this wastewater. In order to operate the microbial fuel cell(MFC) for the swine wastewater, the anode volume of MFCs was scaled up with 5L in the vacant condition. Graphite felts and low-priced mesh stainless-less as electrode had mixed up and packed into the anode compartment. The meshed stainless-less electrode could also be acted the collector of electron produced by microorganisms in anode. For a cathode compartment, graphite felt loaded Pt/C catalyst was used. Graphite felt electrode embedded in the anode compartment was punched holds at regular intervals to prevent occurred the channeling phenomenon. The sources of seeding on microbial fuel cell was used a mixture of swine wastewater and anaerobic digestion sludge(1:1). It was enriched within 6 days. Swine wastewater was fed with 53.26 ml/min flow rate. The MFCs produced a current of about 17 mA stably used swine wastewater with $3,167{\pm}80mg/L$. The maximum power density and current density was 680 $mW/m^3$ and 3,770 $mA/m^3$, respectively. From these results it is showed that treatment of swine wastewater synchronizes with electricity generation using modified low priced microbial fuel cell.

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Electricity Generation and De-contamination Effect for Characteristic Electrode Material in a Microbial Fuel Cell System Using Bay Sediment (MFC의 금속 및 탄소전극에 의한 전기생산 특성과 오염저감 효과)

  • Kwon, Sung-Hyun;Song, Hyung-Jin;Lee, Eun-Mi;Cho, Dae-Chul;Rhee, In-Hyoung
    • Journal of Environmental Science International
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    • v.19 no.8
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    • pp.951-960
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    • 2010
  • Sediment works as a resource for electric cells. This paper was designed in order to verify how sediment cells work with anodic material such as metal and carbon fiber. As known quite well, sediment under sea, rivers or streams provides a furbished environment for generating electrons via some electron transfer mechanism within specific microbial population or corrosive oxidation on the metal surfaces in the presence of oxygen or water molecules. We experimented with one type of sediment cell using different anodic material so as to attain prolonged, maximum electric power. Iron, Zinc, aluminum, copper, zinc/copper, and graphite felt were tested for anodes. Also, combined type of anodes-metal embedded in the graphite fiber matrix-was experimented for better performances. The results show that the combined type of anodes exhibited sustainable electricity production for ca. 600 h with max. $0.57\;W/m^2$ Al/Graphite. Meanwhile, graphite-only electrodes produced max. $0.11\;W/m^2$ along with quite stationary electric output, and for a zinc electrode, in which the electricity generated was not stable with time, therefore resulting in relatively sharp drop in that after 100 h or so, the maximum power density was $0.64\;W/m^2$. It was observed that the corrosive reaction rates in the metal electrodes might be varied, so that strength and stability in the electric performances(voltage and current density) could be affected by them. In addition to that, COD(chemical oxygen demand) of the sediment of the cell system was reduced by 17.5~36.7% in 600 h, which implied that the organic matter in the sediment would be partially converted into non-COD substances, that is, would suggest a way for decontamination of the aged, anaerobic sediment as well. The pH reduction for all electrodes could be a sign of organic acid production due to complicated chemical changes in the sediment.

Electricity Generation and Microbial Community variation in Microbial Fuel Cell with various Electrode Combinations. (다양한 탄소전극조합에 따른 미생물 연료전지의 전기발생량 및 미생물 군집변화)

  • Kwon, Jae-Hyeong;Choi, Soo-Jung;Cha, Jae-Hwan;Kim, Hyo-Soo;Kim, Ye-Jin;Yu, Jae-Cheul;Kim, Chan-Won
    • Journal of Korean Society of Environmental Engineers
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    • v.32 no.1
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    • pp.87-96
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    • 2010
  • The electrode material is one of the factors affecting the power production of microbial fuel cell. In this study, effects of carbon electrode material, thickness and configuration on the power density, biofilm formation and microbial community diversity of microbial fuel cell were investigated. To optimize the anode-cathode electrode assembly, seven lab-scale reactors which had various carbon electrode constructions were operated in continuous mode. Under the steady state condition, the electrode combination of graphite felt (6 mm) with hole showed the highest cell voltage of 238 mV and the coulombic efficiency of 37%. As a result of SEM analysis, the bacteria growing on surface of knitted type of carbon cloth and graphite felt electrode ncreased significantly. The change of dominant species between seeding sludge and biofilm on the surface of anode electrode, microbial analysis with PCR-DGGE showed that the dominant species of seeding sludge are quite different from those of biofilm on the surface of each anode electrode. Especially Geobacter sp., a well known electrochemical bacteria, was found as the dominant species of the electrode combination with graphite felt.

Optimization of Microbial Electrosynthesis Using Rhodobacter sphaeroides for CO2 Upcycling (CO2 고부가화를 위한 로도박터 스페로이데스를 활용한 미생물 전기합성 최적화 연구)

  • Hui Su Kim;Hwi Jong Jung;Danbee Kim;Samgmin Lee;Jiye Lee;Jin-Suk Lee;Myounghoon Moon;Chang Hyun Ko;Soo Youn Lee
    • New & Renewable Energy
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    • v.19 no.4
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    • pp.20-26
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    • 2023
  • Emitted CO2 is an attractive material for microbial electrochemical CO2 reduction. Microbial electrochemical CO2 reduction (i.e., microbial electrosynthesis, MES) using biocatalysts has advantages compared to conventional CO2 reduction using electrocatalysts. However, MES has several challenges, including electrode performance, biocatalysts, and reactor optimization. In this study, an MES system was investigated for optimizing reactor types, counter electrode materials, and CO2-converting microorganisms to achieve effective CO2 upcycling. In autotrophic cultivation (supplementation of CO2 and H2), CO2 consumption of Rhodobacter sphaeroides was observed to be four times higher than that with heterotrophic cultivation (supplementation of succinic acid). The bacterial growth in an MES reactor with a single-chambered shape was two times higher than that with a double chamber (H-type MES reactor). Moreover, a single-chambered MES reactor equipped with titanium mesh as the counter electrode (anode) showed markedly increased current density in the graphite felt as a working electrode (cathode) compared to that with a graphite felt counter electrode (anode). These results demonstrate that the optimized conditions of a single chamber and titanium mesh for the counter electrode have a positive effect on microbial electrochemical CO2 reduction.

Studies on a Feasibility of Swine Farm Wastewater Treatment using Microbial Fuel Cell (미생물연료전지의 가축분뇨 처리 가능성 연구)

  • Jang, Jae-Kyung;Kim, Se-Hee;Ryou, Young-Sun;Lee, Sung-Hyoun;Kim, Jong-Gu;Kang, Young-Goo;Kim, Young-Hwa;Choi, Jung-Eun
    • Microbiology and Biotechnology Letters
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    • v.38 no.4
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    • pp.461-466
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    • 2010
  • In this study the feasibility of simultaneous electricity generation and treatment of swine farm wastewater using microbial fuel cells (MFCs) was examined. Two single-chamber MFCs containing an anode filled with different ratio of graphite felt and stainless-steel cross strip was used in all tests. The proportion of stainless-steel cross strip to graphite felt in the anode of control microbial fuel cell (CMFC) was higher than that of swine microbial fuel cell (SMFC) to reduce construction costs. SMFCs produced a stable current of 18 mA by swine wastewater with chemical oxygen demand (COD) of $3.167{\pm}80\;mg/L$ after enriched. The maximum power density and current density of SMFCs were $680\;mW/m^3$ and $3,770\;mA/m^3$, respectively. In the CMFC, power density and current density was lower than that of SMFC. CODs decreased by the SMFC and CMFC from $3.167{\pm}80$ to $865{\pm}21$ and $930{\pm}14\;mg/L$, achieving 72.7% and 70.6% COD removal, respectively. The suspended solid (SS) of both fuel cells was also reduced over 99% ($4,533{\pm}67$ to $24.0{\pm}6.0\;mg/L$). The concentration of nutritive salts, ${NH_4}^+$, ${NO_3}^-$, and ${PO_4}^{3-}$, dropped by 65.4%, 57.5%, and 73.7% by the SMFC, respectively. These results were similar with those of CMFC. These results show that the microbial fuel cells using electrode with mix stainless-steel cross strip and graphite felt can treat the swine wastewater simultaneously with an electricity generation from swine wastewater.

Bioelectrochemical Denitrification Using Permeabilized Ochrobactrum anthropi SY509

  • Choi Kyung-Oh;Song Seung-Hoon;Kim Yang-Hee;Park Doo-Hyun;Yoo Young-Je
    • Journal of Microbiology and Biotechnology
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    • v.16 no.5
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    • pp.678-682
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    • 2006
  • To remove nitrate from wastewater, a novel bioelectrochemical denitrification system is introduced. In this proposed system, biological reactions are coupled with reactions on the electrode, whereby the electrons are transferred to the bacterial enzymes via a mediator as an electron carrier. The denitrification reaction was achieved with permeabilized Ochrobactrum anthropi SY509 containing denitrifying enzymes, such as nitrate reductase, nitrite reductase, and nitrous oxide reductase, and methyl viologen was used as the mediator. The electron transfer from the electrode to the enzymes in the bacterial cells was confirmed using cyclic voltammetry. A high removal efficiency of nitrate was achieved when the bioelectrochemical system was used with the permeabilized cells. Furthermore, when the permeabilized cells were immobilized to a graphite felt electrode using a calcium alginate matrix containing graphite powder, a high removal efficiency was achieved (4.38 nmol/min mg cell) that was comparable to the result when using the free permeabilized cells.

용해 납 흐름 배터리용 여러 카본 전극의 에너지 효율 특성 비교

  • Min, Hyeong-Seop;Yang, Min-Gyu;Kim, Sang-Sik;Lee, Jeon-Guk
    • Proceedings of the Materials Research Society of Korea Conference
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    • 2009.05a
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    • pp.59.1-59.1
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    • 2009
  • 레독스 흐름 배터리 (Redox Flow Battery)는 외부의 탱크 등에 저장해 둔 활성물질(이온 가수가 변화는 금속) 의 용액을 펌프로 전해셀에 공급하여 충전 방전하는 배터리로 신재생 에너지인 풍력과 태양광 발전, 야간의 잉여 전력 저장 등 대용량 전력 저장 장치로 관심이 높아지고 있다. 대표적인 레독스 흐름 배터리로 알려진 바나듐 레독스 흐름 배터리는 이온 교환막 사용으로 인하여 전기전도도, 기계적 강도, 투과도 및 전해질 내의 화학적 안정성 등 여러 가지 문제점과 함께 비용 문제점을 야기한다. 하지만 새로운 용해 납 레독스 흐름 배터리는 이온 교환막을 사용하지 않아 바나듐 레독스 흐름 배터리의 문제점 및 시설비가 절약되는 장점이 있어 새로이 연구되지고 있다. 본 연구는 레독스 흐름 배터리에 주로 이용되는 카본 전극재료의 따라 형성되는 Pb, $PbO_2$ 박막의 미세 구조를 및 에너지 효율 특성을 분석하였다. 실험은 half-cell로 이루어졌으며 작업전극은 Carbon felt, Ordered Graphite, Disordered Graphite, Glassy Carbon 등을 여러 카본 재료를 사용하였고, 상대전극은 Pt, 기준전극으로 Ag/AgCl를 사용하여 Cyclic Voltammetry특성과 충방전 특성을 연구하였다. 전해질은 Lead Carbonate ($PbCO_3$)+Methanesulfonic acid ($CH_3SO_3H$) 들어간 수용성 전해질을 교반을 통해 이용하였다. 여러 carbon 전극재료와 생성된 Pb, $PbO_2$ 막의 표면구조, 미세구조, 상들의 변화는 XRD, SEM, EDX, Raman등을 통하여 분석하였으며, 전기화학 공정의 변수와 전극에 따른 에너지 효율특성에 대하여 고찰해 보았다.

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Development of Composite Bipolar Plate for Vanadium Redox Flow Battery (바나듐 레독스 흐름 전지용 복합재료 분리판 개발)

  • Lim, Jun Woo
    • Composites Research
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    • v.34 no.3
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    • pp.148-154
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    • 2021
  • Carbon/epoxy composite bipolar plate (BP) is a BP that is likely to replace existing graphite bipolar plate of vanadium redox flow cell (VRFB) due to its high mechanical properties and productivity. Multi-functional carbon/epoxy composite BP requires graphite coating or additional surface treatment to reduce interfacial contact resistance (ICR). However, the expanded graphite coating has the disadvantage of having low durability under VRFB operating conditions, and the surface treatments incur additional costs. In this work, an excessive resin absorption method is developed, which uniformly removes the resin rich area on the surface of the BP to expose carbon fibers by applying polyester fabric. This method not only reduces ICR by exposing carbon fibers to BP surfaces, but also forms a unique ditch pattern that can effectively hold carbon felt electrodes in place. The acidic environmental durability, mechanical properties, and gas permeability of the developed carbon/epoxy composite BP are experimentally verified.

Characteristics of Organic Material Removal and Electricity Generation in Continuously Operated Microbial Fuel Cell (연속류식 미생물연료전지의 유기물 제거 및 전기 발생 특성)

  • Kim, Jeong-Gu;Jeong, Yeon-Koo;Park, Song-In
    • Journal of the Korea Organic Resources Recycling Association
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    • v.18 no.1
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    • pp.57-65
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    • 2010
  • Two types of microbial fuel cells(MFC) were continuously operated using synthetic wastewater. One was conventional two-chambered MFC using proton exchange membrane(PEM-MFC), the other was upflow type membraneless MFC(ML-MFC). Graphite felt was used as a anode in PEM-MFC. In membraneless MFC, two MFCs were operated using porous RVC(reticulated vitreous carbon) as a anode. Graphite felt was used as a cathode in all experiments. In experiment of PEM-MFC, the COD removal rate based on the surface area of anode was about $3.0g/m^2{\cdot}d$ regardless of organic loading rate. And the coulombic efficiency amounted to 22.4~23.4%. The acetic acid used as a fuel was transferred through PEM from the anodic chamber to cathodic chamber. The COD removal rate in ML-MFC were $9.3{\sim}10.1g/m^2{\cdot}d$, which indicated the characteristics of anode had no significant effects on COD removal. Coulombic efficiency were 3.6~3.7 % in both cases of ML-MFC experiments, which were relatively small. It was also observed that the microbial growth in cathodic chamber had an adverse effects on the electricity generation in membraneless MFC.

Performance of Carbon Cathode and Anode Electrodes Functionalized by N and O Doping Treatments for Charge-discharge of Vanadium Redox Flow Battery (탄소전극의 질소 및 산소 도핑에 따른 바나듐 레독스-흐름전지 양극 및 음극에서의 촉매화학적 특성 연구)

  • Lim, Hyebin;Kim, Jiyeon;Yi, Jung S.;Lee, Doohwan
    • Clean Technology
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    • v.23 no.3
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    • pp.308-313
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    • 2017
  • In this study, we investigated the electrocatalytic effects of the N and O co-doping of Graphite Felt (GF) electrode for the vanadium redox flow battery (VRFB) at the cathode and the anode reaction, respectively. The electrodes were prepared by chemical vapor deposition (CVD) with $NH_3-O_2$ at 773 K, and its effects were compared with an electrode prepared by an O doping treatment. The surface morphology and chemical composition of the electrodes were characterized by scanning electron microscopy (SEM) and photoelectron spectroscopy (XPS). The electrocatalytic properties of these electrodes were characterized in a VRFB single cell comparing the efficiencies and performance of the electrodes at the cathode, anode, and single cell level. The results exhibited about 2% higher voltage and energy efficiencies on the N-O-GF than the O-GF electrode. It was found that the N and O co-doping was particularly effective in the enhancement of the reduction-oxidation reaction at the anode.