• Membrane Journal
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• v.29 no.2
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• pp.80-87
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• 2019

Dye-sensitized solar cells (DSSCs) have attracted great attention as sustainable energy devices. The efficiency and long-term stability of DSSCs are greatly influenced by electrode materials and electrolytes. In this review, we focused on the electrolytes of DSSCs. Polymer electrolyte membranes have been proposed as an alternative to conventional liquid electrolytes in DSSCs. Conventional liquid electrolytes can exhibit a high efficiency, but due to some problems such as poor long-term stability of device and leakage of liquid, much interest in polymer electrolyte membranes continues to rise and the papers on polymer electrolytes membranes have been extensively reported recently. This review covers the concept and development of polymer electrolyte membranes for DSSCs, and discusses the efficiency and electrochemical properties of DSSCs, highlighting the modification of polymer matrix, the introduction of additives such as organic-inorganic plasticizers and ionic liquids.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.17 no.8
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• pp.722-727
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• 2016

In this study, we attempted to reduce the generation of waste acids in the electropolishing process by improving the current efficiency. The optimum conditions of the electropolishing process when using the round bus bar were determined by the Taguchi method. The current density, polishing time, electrolyte temperature and flow rate were selected as the control factors for the current efficiency in the electropolishing process. An orthogonal array was created by considering three levels for each factor and experiments were carried out. The larger-the-better SN ratios were calculated by the Taguchi method. The current density was the most important factor affecting the current efficiency and the polishing time was the least important one. The optimum conditions to minimize the generation of waste acids were a current density of $45A/dm^2$, polishing time of 4 min, electrolyte temperature of $65^{\circ}C$ and flow rate of 7 L/min. The results of the ANOVA confirmed that the effects of the current density, electrolyte temperature and flow rate are significant at the 95% confidence level. The increase in the contact area and contact force afforded by using the round bus bar improved the current efficiency which, in turn, reduced the amount of waste acids generated. Further research is planned to investigate the effect of the type of bus bar on the current efficiency.

• Resources Recycling
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• v.16 no.6
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• pp.52-60
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• 2007

Denitrification from aqueous solution was investigated through patent analysis and electrochemical denitrification experiment. Among several candidates, biological treatment and oxidation/reduction method are mainly discussed. Recently, patent pending concerning to electrochemical treatment is increasing. Based on basic electrochemical study, total nitrogen was removed up 47% by 1-hour galvanostatic electrolysis with Fe cathode and Pt anode. More applicable technique to industry could be mentioned combination of two or more technologies suitable to waste water characteristics. In the case of small and concentrate effluent, combination of chemical and electrochemical treatment would be recommendable because nitrate could be easily converted to nitrite by chemical treatment, and in that case denitrification by electrolysis becomes more efficient and metal ions from chemical treatment can be recovered during electrolysis.

• Applied Chemistry for Engineering
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• v.16 no.2
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• pp.206-211
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• 2005

Mediated electrochemical oxidation (MEO) of polyethylene glycols (PEGs) of molecular weight of 1000, 4000 and 20000, was carried out on both platinum (Pt) and titanium-iridium electrodes in 8.0 M nitric acid solution containing 0.5 M Fe(II) and Co(II) ion. The electrochemical parameters such as current densities, kinds of electrode, electrolyte concentration and removal efficiency were investigated in both Fe(III)/Fe(II) and Co(III)/Co(II) redox systems. The PEGs was decomposed into carbon dioxide by MEO in Fe(III)/Fe(II) and Co(III)/Co(II) redox system during 180 min and 210 min at the current density of $0.67A/cm^2$ on the Pt electrode. Removal efficiency of PEGs by MEO was better in Co(III)/Co(II) redox system than Fe(III)/Fe(II) redox system, indicating mediated electrochemical removal efficiency was 100%.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.04a
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• pp.463-465
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• 2003

전기분해에 의한 부상현상을 이용하여 유류로 오염된 토양 세정 후 발생되는 유출수 중 유분 등을 분리하기 위한 적정 운전조건을 찾고자 하였다. 전기분해 반응조(200 $\times$ 10 $\times$15cm)에 혼합 계면활성제 (POE5 : POE14, 1:1) 1% 용액에 디젤을 1,000mg/L 농도로 용해시켜 실험하였다. 양극에는 티나늄 코팅전극, 음극으로는 스테인레스 스틸전극을 이용하였다. 반응시간은 62분( 반응: 60분, 부상시간: 2분) 이었으며 전압은 6V였다. 전해질 첨가에 의한 영향을 알아보기 위하여 실험한 결과, 전해질을 첨가하였을 경우 첨가하지 않았을 때보다 40% 정도의 효율이 증가하였다. 적정 전해질, 주입농도 및 반응시간을 알아보기 위하여 1N NaCl과 NaOH의 농도를 변화시켜 가면서 실험하였다. NaCl의 경우 더 좋은 효율을 나타내었다. 전해질의 농도는 0.2 - 1.0% 의 농도 범위에서 NaCl와 NaOH 모두 농도에 따라 순차적으로 효율이 증가하였다. 두 전해질 모두 0.4 - 1.0% 농도 범위에서 평형에 도달하는 시간은 20분으로 나타났다.

• Proceedings of the KIPE Conference
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• 2012.07a
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• pp.598-599
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• 2012

본 논문은 전압제한 고효율 AC입력 LED 드라이버에 연구에 관한 것이다. 최근 이산화탄소 배출 저감과 고효율 LED 조명이 일반화 되면서 고효율, 장수명, 소형화에 대한 요구가 커지고 있다. LED를 구동하기 위해 SMPS (Switching Mode Power Supply)를 사용하는 경우 역률을 높이기 위해서 별도의 역률 개선부를 포함하고 있어야 하며 전해커패시터 역시 사용되어야 한다. 이 방식은 가격의 상승과 전해커패시터 사용에 의해 수명 저하라는 단점이 있다. 본 연구에서는 이러한 단점을 보완하여 수명 저하를 일으키는 전해커패시터와 별도의 역률 개선부 없이 LED에 정전류를 공급하고 역률을 향상시킬 수 있는 LED 드라이버 회로를 제안하고 이를 실험으로 검증한다.

• Applied Chemistry for Engineering
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• v.16 no.5
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• pp.635-640
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• 2005

Mediated electrochemical oxidation (MEO) is an aqueous process which oxidizes organics electrochemicallly at low temperatures and pressures. The useful process can be used to treat mixed wastes containing hazardous organics. This paper have studied MEO of ethylene glycol (EG) in nitric acids by Fe(III)/Fe(II) and Co(III)/Co(II) system. It investigated current density, supporting electrolyte concentration, hydraulic retention time, removal efficiency of EG by MEO. Removal efficiency of EG by MEO was superior in Co(III)/Co(II) redox system than Fe(III)/Fe(II) redox system, where MEO removal efficiency was 100 percent. In case of EG, the reactions were fast and good yields of carbon dioxide formation was observed.

• Journal of the Korean Chemical Society
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• v.17 no.5
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• pp.378-384
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• 1973

To investigate the mechanism of the reaction of electrolytic oxidation of iodide to iodate ions, polarization curves are determined in various kinds of solution using electrodeposited lead peroxide and platinum anodes. It was observed from the polarization curves that the limiting current is exists at concentration 1.5 M of potassium iodide, and these limiting current disappeared as potassium hydroxide was added up to concentration of 0.1 M. while in case of platinum anode, limiting current did not appear in dilute potassium iodide solution. These results are owing to the chemical reaction, $PbO_2+2I^{-}+2H^+{\to}PbO+I_2+H_{2}O$ ocurring at the surface of lead peroxide anode. Also, we studied to obtain the optimum conditions of electrolytic preparation of iodate from iodide solution using a cell without the diaphragm. The results are that; (a) addition of potassium dichromate at the anti-reducing agent is proper in concentration of 0.1 g/l, (b) electrolytic temperature is not so much effective in raising the current efficiency, (c) current efficiency is increased with current density, and (d) electrolysis is the most effective in weak alkaline solutions.

• Journal of the Korean Institute of Illuminating and Electrical Installation Engineers
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• v.16 no.4
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• pp.101-107
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• 2002

A novel oxidant generation and ion precipitation cell with slits on parallel plate electrodes was proposed instead of the conventional parallel plate type. An investigation was carried out on the effect of the number and size of slits on ion precipitation and oxidant generation characteristics, evidenced by eliminated space charge limiting action and by elevated electric fields in active interelectrode sparing. Consequently, very high ion precipitation and dense oxidant generation characteristics can be realized by having slits un the electrodes of conventional cells as these slits increase the electric fields and decrease the space charge limiting actions in interelectrode spacing.

• Proceedings of the Korean Institute of Resources Recycling Conference
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• 2005.10a
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• pp.256-260
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• 2005

마그네슘은 자동차 엔진 경량화재료, 휴대폰케이스 등 기능성 경량재료로서의 용도개발과 함께 수요가 증가하고 있다. 마그네슘 제련법은 원료광의 특성에 따라 달라지는데 크게 용융염전해법과 열환원법 두 가지로 구분할 수 있다. 본 연구에서는 염화마그네슘을 사용하여 용융염전해법에 의해 전해 마그네슘을 얻고자 하였다. 전해전압 7V로 일정한 전극침지 깊이에서 두 가지 염욕을 비교 실험하였으며, $KCl/NaCl/MgCl_2$ 혼합 염욕을 $760^{\circ}C$에서 전해한 결과 약 47%의 전류효율을 달성할 수 있었다. 회수된 전해 마그네슘의 순도는 98% 이상이었다. 본 연구를 통하여 용융염 전해장치를 스케일엎하거나 상용화시에 장치설계 등에 필요한 기초 자료들을 축적할 수 있었다.