• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2017년도 춘계학술논문요약집
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• pp.301-302
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• 2017

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2018년도 춘계학술논문요약집
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• pp.291-292
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• 2018

• Journal of Electrochemical Science and Technology
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• 제7권3호
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• pp.199-205
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• 2016

We present the electrochemical performance of electric double layer capacitors (EDLCs) assembled with pyrrolidinium (Pyr)-based ionic liquid electrolytes at 55 ℃. Cations with various alkyl chain lengths were employed in Pyr-based ionic liquids to investigate the effect of cation structure on the cycling stability of EDLCs. The EDLCs exhibited initial specific capacitances ranging from 122.4 to 131.6 F g⁻¹ based on activated carbon material at 55 ℃. Cycling data and XPS results demonstrate that Pyr-based ionic liquid with longer alkyl chain is more effective for enhancing the cycling stability of EDLC by suppressing the reductive decomposition of pyrrolidinium cations during cycling at high temperatures.

• 한국환경과학회지
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• 제26권7호
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• pp.859-868
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• 2017

In this study, the reductive dechlorination of triclosan using zero-valent iron (ZVI, $Fe^0$) and modified zero-valent iron (i.e., acid-washed iron (Aw/Fe) and palladium-coated iron (Pd/Fe)) was experimentally investigated, and the reduction characteristics were evaluated by analyzing the reaction kinetics. Triclosan could be reductively decomposed using zero-valent iron. The degradation rates of triclosan were about 50% and 67% when $Fe^0$ and Aw/Fe were used as reductants, respectively, after 8 h of reaction. For the Pd/Fe system, the degradation rate was about 57% after 1 h of reaction. Thus, Pd/Fe exhibited remarkable performance in the reductive degradation of triclosan. Several dechlorinated intermediates were predicted by GC-MS spectrum, and 2-phenoxyphenol was detected as the by-product of the decomposition reaction of triclosan, indicating that reductive dechlorination occurred continuously. As the reaction proceeded, the pH of the solution increased steadily; the pH increase for the Pd/Fe system was smaller than that for the $Fe^0$ and Aw/Fe system. Further, zero-order, first-order, and second-order kinetic models were used to analyze the reaction kinetics. The first-order kinetic model was found to be the best with good correlation for the $Fe^0$ and Aw/Fe system. However, for the Pd/Fe system, the experimental data were evaluated to be well fitted to the second-order kinetic model. The reaction rate constants (k) were in the order of Pd/Fe > Aw/Fe > $Fe^0$, with the rate constant of Pd/Fe being much higher than that of the other two reductants.

• Bulletin of the Korean Chemical Society
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• 제26권1호
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• pp.43-46
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• 2005

Reaction energies were determined for reductive ring-opening reactions of Li$^+$-coordinated ethylene carbonate (EC) and vinylene carbonate (VC) by a density functional method. We have also explored the ring-opening of Li$^+$-EC and Li$^+$-VC by reaction with a nucleophile (CH$_3$O$^-$.) thermodynamically. Our thermodynamic calculations led us to conclude that the possible reaction products are CH$_3$OCH$_2$CH$_2$OCO$_2$Li (O$_2$-C$_3$ cleavage) for Li$^+$-EC +CH$_3$O$^-$., and CH$_3$OCHCHOCO$_2$Li (O$_2$-C$_3$ cleavage) and CH$_3$OCO$_2$CHCHOLi (C$_1$-O$_2$ cleavage) for Li$^+$-VC +CH$_3$O$^-$.. The opening of VC would occur at the C$_1$-O$_2$ side by a kinetic reason, although the opening at the O$_2$-C$_3$ side is more favorable thermodynamically.

• Membrane and Water Treatment
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• 제11권3호
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• pp.195-200
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• 2020

In this study, a biocatalyst composite was prepared by immobilizing oxidoreductases onto Cu-activated zeolite to facilitate biochemical decomposition of 4-chlorophenol (4-CP). 4-CP monooxygenase (CphC-I) was cloned from a 4-CP degrading bacterium, Pseudarthrobacter chlorophenolicus A6, and then overexpressed and purified. Type X zeolite was synthesized from non-magnetic coal fly ash using acetic acid treatment, and its surfaces were coated with copper ions via impregnation (Cu-zeolite). Then, the recombinant oxidative and reductive enzymes were immobilized onto Cu-zeolite. The enzymes were effectively immobilized onto the Cu-zeolite (79% of immobilization yield). The retained catalytic activity of CphC-I after immobilization was 0.3423 U/g-Cu-zeolite, which was 63.3% of the value of free enzymes. The results of this study suggest that copper can be used as an effective enzyme immobilization binder because it provides favorable metalhistidine binding between the enzyme and Cu-zeolite.

• Journal of Electrochemical Science and Technology
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• 제7권3호
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• pp.214-217
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• 2016

In this study, we studied the enhancement of the energy densities of electrochemical capacitors by improving the working voltage range of the electrolyte. To prevent the decomposition of the electrolyte, stable SEI layers were formed by reductive degradation of additive materials such as fluoro-ethylene carbonate (FEC) and vinyl ethylene carbonate (VEC) before degradation of the base electrolyte. As a result, the solution resistance (R_s) of EC:DMC + SL 20 % + VEC 1 % electrolytes observed 1.47 Ω and the charge transfer resistance (R_ct) was 2.64 Ω at the open circuit voltage. Additionally, a cycle retention of 94 % was observed for EC:DMC + SL 20 % + VEC 1 % after 500 cycles at 3.5 V.

• 한국환경과학회지
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• 제32권1호
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• pp.57-65
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• 2023

The advanced oxidation treatment using persulfate and zero-valent iron (ZVI) has been evaluated as a very effective technology for remediation of soil and groundwater contamination. However, the high rate of the initial reaction of persulfate with ZVI causes over-consumption of an injected persulfate, and the excessively generated active species show a low transfer rate to the target pollutant. In this study, ZVI was modified using selenium with very low reactivity in the water environment with the aim of controlling the persulfate activation rate by controlling the reactivity of ZVI. Selenium-modified ZVI (Se/ZVI) was confirmed to have a selenium coating on the surface through SEM/EDS analysis, and low reductive reactivity to trichlroethylene (TCE) was observed. As a result of inducing the persulfate activation using the synthesized Se/ZVI, the persulfated consumption rate was greatly reduced, and the decomposition rate of the model contaminant, anisole, was also reduced in proportion. However, the final decomposition efficiency was rather increased, which seems to be the result of preventing persulfate over-consumption. This is because the transfer efficiency of the active species (SO4-∙) of persulfate to the target contaminant has been improved. Selenium on the surface of Se/ZVI was not significantly dissolved even under oxidation conditions by persulfate, and most of it was present in the form of Se/ZVI. It was confirmed that the persulfate activation rate could be controlled by controlling the reactivity of ZVI, which could greatly contribute to the improvement of the persulfate oxidation efficiency.

• 대한화학회지
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• 제25권5호
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• pp.311-317
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• 1981

새로운 니켈(II) 화합물, 비스(트리메틸실릴메틸)1,2-(비스디페닐포스피노) 에탄니켈(II)(1)이 디클로로-1,2-비스(디페닐포스피노)에탄니켈(Ⅱ)와 트리메틸실릴메틸리튬의 반응으로부터 합성되었다. 화합물 1은 질소하, 상온에서 안정하다. 화합물 1은 열분해하여 환원성짝지음 생성물, 1,2-비스(트리메틸실릴)에탄을 생성한다. 화합물 1은 상온에서 일산화탄소 및 산소와, 그리고 80${\circ}$C에서 1,2-비스(디페닐포스피노)에탄과 반응하여 역시 1,2-비스(트리메틸실릴)에탄을 생성한다.

• 전기화학회지
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• 제20권1호
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• pp.13-17
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• 2017

본 연구에서는 고전압용 전기화학 커패시터에 응용을 위한 유기 전해액 개발에 관한 연구를 실시하였다. 사용한 기준 전해액으로는 1M의 $SBPBF_4$염이 포함된 EC:DMC(1:1) 복합 전해액을 사용하였으며, 고전압 안정성을 위해 기준 전해액에 첨가제 GBL을 5 wt.% 첨가했다. 0-3.5 V 전압 범위에서 초기 250 사이클까지의 효율이 약 2.5배 향상된 것을 확인할 수 있었으며, 2000 사이클 이후에는 약 3배 이상의 커패시턴스 효율이 유지되는 것을 확인하였다. 고전압에서 GBL이 전해액 보다 먼저 분해를 일으켜 전해액이 분해되는 현상을 억제하며 안정성을 향상시키는 효과가 있는 것으로 판단된다. 또한 분해된 GBL이 전극 표면에 흡착하여 안정한 SEI 층을 형성해줌으로서, 전극 표면을 보호하여 전해질과의 부반응을 억제해주는 역할을 하는 것으로 판단된다.