• Title/Summary/Keyword: Ionic Center

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Applications of Ionic Liquids: The State of Arts (이온성액체의 응용기술 동향)

  • Lee, Hyunjoo;Lee, Je Seung;Kim, Hoon Sik
    • Applied Chemistry for Engineering
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    • v.21 no.2
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    • pp.129-136
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    • 2010
  • Ionic liquids are expanding their applications in various fields of chemistry, due to their unique properties such as negligible volatility, immisciblity with hydrocarbons, high electrical conductivity, and tunable acidity and basicity. In this paper, the physical properties, synthesis, and commercial applications of ionic liquids are discussed. Recent research trends are also briefly reviewed, particularly on application of ionic liquids to catalysis, biomass, and $CO_{2}$ capture and utilization.

Effects of Ionic Strength, Background Electrolytes, Heavy Metals, and Redox-Active Species on the Reduction of Hexavalent Chromium by Ecklonia Biomass

  • PARK DONGHEE;YUN YEOUNG-SANG;JO JI HYE;PARK JONG MOON
    • Journal of Microbiology and Biotechnology
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    • v.15 no.4
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    • pp.780-786
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    • 2005
  • The biomass of the brown seaweed, Ecklonia, was used to remove Cr(VI) from wastewater. Previously, Cr(VI) was removed through its reduction to Cr(III) when brought into contact with the biomass. In this study, the effects of ionic strength, background electrolytes, and Cr(III), Ni(II), Zn(II), and Fe(III) on the Cr(VI) reduction were examined. An increased ionic strength inhibited the Cr(VI) reduction. The presence of other heavy metals, such as Cr(III), Ni(II), or Zn(II), only slightly affected the Cr(VI) reduction, while Fe(III) enhanced the reduction. Although the above various parameters could affect the reduction rate of Cr(VI) by Ecklonia biomass, these effects were relatively smaller than those of pH and temperature. In addition, the previously derived rate equation was found to be applicable over a range of ionic strengths and with different background electrolytes. In conclusion, Ecklonia, bioniass may be a good candidate as a biosorbent for the removal of Cr(VI) from wastewaters containing various other impurities, and scale-up to a practical process may be accomplished using the previously derived rate equation.

Effect of Metal Oxide Catalysts and Ionic Liquids on the Synthesis of Methyl Carbamate and Dimethyl Carbonate from Urea and Methanol under High Pressure Reaction System (고압반응 하에서 요소와 메탄올을 사용한 메틸카바메이트와 디메틸카보네이트 제조에 관한 금속산화물 촉매 및 이온성액체의 영향)

  • Kim, Yun-Min;Kim, Chul-Ung;Koh, Jae-Cheon;Park, Dae-Won;Koo, Kee-Kahb
    • Korean Chemical Engineering Research
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    • v.49 no.6
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    • pp.732-738
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    • 2011
  • Effect of metal oxide catalysts and ionic liquids on the synthesis of methyl carbamate(MC) and dimethyl carbonate (DMC) from urea and methanol was investigated in a high pressure reaction system. In closed system, MC yield from urea and methanol reached almost 100% at reaction temperature over $150^{\circ}C$ without catalyst, whereas DMC yield of 1.5% under was obtained irrespective of catalysts used. In DMC synthesis from MC and methanol, $ZnCl_{2}$ showed the highest catalytic activity and led to the DMC yield of 16.3% under optimal conditions. Furthermore, DMC yield can be enhanced by the simultaneous application of ionic liquids with nano-sized catalysts in semi-continuous reaction system.

Recent Progress in Nanoparticle Synthesis via Liquid Medium Sputtering and its Applications

  • Cha, In Young;Yoo, Sung Jong;Jang, Jong Hyun
    • Journal of Electrochemical Science and Technology
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    • v.7 no.1
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    • pp.13-26
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    • 2016
  • Nanoparticles (NPs), which have been investigated intensively as electrocatalysts, are usually synthesized by chemical methods that allow precise size and shape control. However, it is difficult to control the components and compositions of alloy NPs. On the other hand, the conventional physical method, sputtering with solid substrates, allows for facile composition control but size control is difficult. Recently, “liquid medium sputtering” has been suggested as an alternative method that is capable of combining the advantages of the chemical and conventional physical methods. In this review, we will discuss NP synthesis via the liquid medium sputtering technique using ionic liquid and low-volatile polymer media. In addition, potential applications of the technique, including the generation of oxygen reduction reaction electrocatalysts, will be discussed.

Nanofiltration of Dye Solutions Through Polyamide Composite Membranes

  • Jonggeon Jegal;Baek, Kyung-Sook;Lee, Kew-Ho
    • Korean Membrane Journal
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    • v.4 no.1
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    • pp.12-19
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    • 2002
  • Nanofiltration of aqueous dye solutions was carried out using polyamide (PA) nanofiltration (NF) composite membranes. The PA composite membranes were prepared by the interfacial polymerization of piperazine (PIP) and trimesoyl chloride (TMC) on the surface of microporous polysulfone (PSf) ultrafi1tration (UF) membranes. After characterization in terms of their permeation performance and surface ionic property, they were used for the separation of dye solutions such as Direct Red 75, 80, 81, and Direct Yellow 8 and 27. The separation conditions were varied to study the factors affecting on the permeation performance of the membranes: different concentrations of dye solutions, operating temperature and time, and flow rate of a feed solution. The surface property of the membrane, especially its ionic property, as a function of operating time was examined with a zeta-potentiometer and the relationship between the surface chemistry of the membrane and its permeation properties was also studied.

Effect of Surface Roughness on the Actuation of Ionic Polymer Metal Composites (표면 조도에 따른 이온성 고분자-금속 복합체의 구동특성)

  • Jung, Sunghee;Song, Jeomsik;Kim, Guoosuk;Lee, Sukmin;Mun, Museong
    • Applied Chemistry for Engineering
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    • v.17 no.6
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    • pp.586-590
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    • 2006
  • As one of electro active polymers for soft smart materials, the ionic polymer metal composites (IPMC) are easy to produce through chemical reduction processing and show high displacements at low voltage. When the IPMC actuates, the deformation depends on a few factors including the structure of based membrane, species and morphology of the metal electrodes, the nature of cations and the level of hydration. As previously published, we have been studying on improvement of actuation through surface electrode modification of IPMC to grasp the effect of electrode morphology on actuation. This study is comparative experiments through the chemical reaction and deposition by ion beam assisted deposition (IBAD) in order to prepare the very thin and homogeneous surface electrode of IPMC. The IPMCs were prepared with different surface roughness of polymer membrane, and the influence of the surface roughness on the actuation was studied. By investigating the electrical properties and driving displacement, the actuating properties of IPMC with different surface roughness were studied.

A Series of N-Alkylimidazolium Propylhexanamide Iodide for Dye-Sensitized Solar Cells

  • Lim, Sung-Su;Sarker, Subrata;Yoon, Sun-Young;Nath, Narayan Chandra Deb;Kim, Young-Jun;Jeon, Heung-Bae;Lee, Jae-Joon
    • Bulletin of the Korean Chemical Society
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    • v.33 no.5
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    • pp.1480-1484
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    • 2012
  • We report a series of novel imidazolium iodides based ionic liquids (NMIPHI, NAIPHI, and NBIPHI) with different functional groups for the development of a quasi-solid type electrolyte for dye-sensitized solar cells (DSSCs). The diffusion coefficients of redox ions ($I^-$ and $I_3{^-}$) are dependent on the molecular weight and it was higher for lighter salts. Among the three ionic liquids, NMIPHI showed highest efficiency of 4.18% when it was used in a liquid electrolyte of a DSSC with $ca$. 6 ${\mu}m$ thick $TiO_2$ mesoporous film. Even though the efficiency was $ca$. 19% lower than that obtained from a liquid electrolyte composed of PMII. When NMIPHI was mixed with PMII with a molar ratio of 1:1 in a solvent free electrolyte, the efficiency of the DSSCs was enhanced compared to that based on pristine PMII.