• Journal of Electrochemical Science and Technology
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• v.2 no.2
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• pp.63-67
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• 2011

To examine the effects of a two-cation ionic liquid as an electrolyte component of a supercapacitor, 1,4-bis(3-methylimidazolium-1-yl)butane tetrafluoroborate ($MIBBF_4$), dissolved in propylene carbonate (PC) or acetonitrile (ACN), is newly synthesized and tested here for potential use as an electrolyte of capacitor. The $MIBBF_4$ salt exhibits higher ionic conductivity in ACN than in PC. The supercapacitive properties of capacitors containing an activated carbon electrode and various electrolytes are evaluated using cyclic voltammetry and electrochemical impedance spectroscopy. The capacitor adopting the $MIBBF_4$/ACN electrolyte shows the largest specific capacitance at low scan rates, whereas the capacitor adopting the 1-ethyl-3-methylimidazolium tetrafluoroborate $(EMIBF_4)$/ACN electrolyte shows the largest specific capacitance at high scan rates.

• Membrane and Water Treatment
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• v.4 no.3
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• pp.203-214
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• 2013

Laboratory tests were performed to determine the efficiency of dye solution desalination by electrodialysis. The study involved anionic dye and mineral salt recovery by obtaining two streams from a salt and dye mixture - dye-rich solution and salt solution. A standard anion-exchange and cation-exchange membranes or monovalent selective anion-exchange membranes were used in the ED stack. It was found that the separation efficiency was strongly dependent on the dye molecular weight. The best results for standard ion-exchange membranes were achieved for the desalination of Direct Black solution. Furthermore, the obtained results implied that the application of monovalent selective anion-exchange membranes improved the recovery of dye and salt solutions - the dye concentration in the diluate remained constant irrespective of the molecular weight of anionic dyes, whereas the salt recovery remained very high (99.5%).

• Journal of the Korean Electrochemical Society
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• v.18 no.1
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• pp.24-30
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• 2015

To desalinate the aqueous solutions with high salt concentration using the capacitive deionization technology, two resin/membrane capacitive deionization(RMCDI) cells were fabricated by filling mixed ion exchange resins in two different flow channels (spacer and spiral type). The salt removal efficiency of the spacer- and spiral-RMCDI was 77.21 and 99.94%, respectively. Many ions were significantly removed in a spiral RMCDI cell because the feed solution could be more evenly contacted with the ion exchange resins filled on the spiral type flow channel. As the result of the changes of pH and accumulative charges, it was observed that Faradaic reaction was diminished for a spiral RMCDI cell filled by the mixture of cation and anion exchange resins. Therefore, the desalination of the aqueous solutions with high salt concentration by the capacitive deionization technology was proven. In addition, further studies on the optimization of the mixing ratio with ion exchange resins and the introduction of the regeneration process generally occurred in the continuous electrodeionization (CEDI) technology are required to improve the RMCDI technology.

• Journal of Korean Society for Atmospheric Environment
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• v.15 no.4
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• pp.385-392
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• 1999

This study was carried out to investigate the constituents of inorganic ions of precipitation in Mokpo and Yeochon area from Jan. 1996 to Dec. 1997. The volume-weighted mean pH of precipitation was 5.7(4.8~7.8) at Mokpo, and 5.6(5.1~7.4) at Yeochon area, respectively. The non-seasalt(nss) anion concentrations were found in order of $nss-SO^{2-}_4>NO^-_3>nss-Cl^-$ at two areas. The portion of $nss-SO^{2-}_4;and;NO^-_3$ was 71~84% out of anions. The the non-seasalt cation concentrations were found in order of $NH^+_4>nss-Ca^{2-}>nss-Mg^{2+}>nss-K^-$ at two areas. The portion of $NH^+_4;and; nss-Ca^{2+}$ was 85~92% out cations. Compared regionally the year concentraton of $nss-SO^{2-}_4$, the result of Yeochon was 3 times higher than that of Mokpo in 1996, while the results of two regions were almost similar in 1997. The reason was that Yeochon was restricted area of the use of 0.5% sulfur B-C oil, controlled air pollution emission area, controlled semitotal amounts of air pollution emission area and partial operating of factories in 1997. There were no ions having high correlation with $H^+,;but;nss-SO^{2-}_4,;NO^-_3,;NH^+_4;and;nss-Ca^{2+}$ showed high correlation coefficient each other. It seems that these ions have little correlation with $H^+$ because they are washed out on binding state. Factor analysis showed that the first factor was complicated factor containing anthropogenic and soil resource, the second factor was sea-salt resource and the third factor was independent behavior of hydrogen at Mokpo. While, the first factor was complicated factor containing anthropogenic and sea-salt resource, the second factor was $Ca(NO_3)_2$ salt and the third factor was $NH^+_4;and;SO^{2-}_4$ synergied by resource and combination at Yeochon.

• Applied Chemistry for Engineering
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• v.21 no.1
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• pp.87-92
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• 2010

Desalination experiments were carried out with two types of cell configuration; a CDI cell constructed with carbon electrodes only and a membrane capacitive deionization (MCDI) cell having a cation-exchange membrane on the cathode surface. The salt removal rate and desalination efficiencies increased linearly with increasing the cell potential. Although the same carbon electrodes were used in the desalination experiments, the MCDI cell showed higher salt removal efficiency than that of the CDI cell. The amount of salt removal for the MCDI cell was enhanced by 33.1~135% compared to the CDI cell, depending on the applied cell potential in the range of 0.8~1.2 V. In addition, the current efficiency for the MCDI cell was about 80%, whereas the efficiency was under 40% for the CDI cell. The higher salt removal efficiency in the MCDI cell was attributed to the fact that ions were selectively transported between the electric double layer and the bulk solution in the MCDI cell configuration.

• Bulletin of the Korean Chemical Society
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• v.25 no.11
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• pp.1635-1640
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• 2004

The cyclophanes 1a-d containing two benzo[b]furan rings connected by various bridges have been prepared and their binding behaviors with N-benzylphenethylammonium cation 2 were examined by NMR titration method. The successive alkylation reactions of 4-hydroxyl groups and then 2-hydroxyl groups of 2,4-dihydroxybenzophenonse gave macrocycles 5a-c. Photoirradiation of the macrocycles 5a-c with 350 nm mercury lamp followed by dehydration afforded the cyclophanes 1a-c. Hydrolysis of two ester groups pendant on a bridge of 1b produced the carboxyl group-containing cyclophane 1d. The cyclophane 1a having a p-xylene bridge showed 1 : 1 binding with 2 with the binding constant of $36{\pm}6M^{-1}$ in 3 : 1 $CDCl_3$/methanol-$d_4$ solvent, while 1b and 1c which have neutral flexible bridges exhibited no appreciable binding with 2. The disodium salt of 1d showed much higher binding affinity for 2 forming 1 : 1 and 1 : 2 complexes.

• Nuclear Engineering and Technology
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• v.12 no.2
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• pp.99-105
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• 1980

The distribution of $^{55}$ Mn and $^{38}$ Cl recoil species following radiative neutron capture in permanganates, chlorates and perchlorates has been investigated by using ion-exchange chromatography method. The whole of the $^{55}$ Mn radioactivity in permanganates appeared in two valence states, the $^{38}$ Cl radioactivity in chlorates in two valence states and also the $^{38}$ Cl radioactivity in perchlorates in three valence states. Recoil energy was calculated. The internal conversion of $^{38}$ Cl isomer transition affects the retention value. The greater the radii of the cation, the higher is the probability of the recoil atom breaking through the secondary cage. In ammonium salt, the ammonium ion behaves as a reducing agent. Crystal structures with their greater free space have shown low retention.

• Journal of Integrative Natural Science
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• v.10 no.3
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• pp.131-136
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• 2017

The chemical shifts in the $^{13}C$ NMR spectra of 2,3,4,5-tetraphenyl-1-silacyclopentdienide dianion $[SiC_4Ph_4]^{2-}{\cdot}2[K^+]$ (3) and 2,3,4,5-tetraphenyl-1-germacyclopentdienide dianion $[GeC_4Ph_4]^{2-}{\cdot}2[K^+]$ (4) were compared to those of $[SiC_4Ph_4]^{2-}{\cdot}2[Li^+]$ (5), $[SiC_4Ph_4]^{2-}{\cdot}2[Na^+]$ (6), and $[GeC_4Ph_4]^{2-}{\cdot}2[Li^+]$ (7). The average polarizations in two phenyl groups of two potassium salts are decreased over 15% to 20% comparing to those of the lithium salts and sodium salt {$[EC_4Ph_4]^{2-}{\cdot}2[M^+]$ (E=Si, Ge, M=Li, Na) due to the effect of the counter potassium cation.

• The Korean Journal of Nuclear Medicine
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• v.28 no.3
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• pp.331-337
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• 1994

In order to develop a $^{18}F$-labelled myocardial perfusion agent(flow tracer) for PET, $^{18}F$-labelled organic ammonium cations were synthesized and evaluated in relation to their biodistribution. Five quaternary organic ammonium compounds were labelled with $^{18}F$ in a side chain with moderate to good yields by direct introduction of $^{18}F$-fluoride. Radiochemical yields have been achieved in 30-40min by the precursors (tosylates) in dimethylsulfoxide 15-60% (decay corrected). The reaction was found to be autocatalyzed. A remote controlled procedure was developed in these synthesis. $^{18}F$-Labelling and HPLC-purification of com-pounds needed about 60 min(Yield; 7-20%). Up to now the two compounds N-4-[$^{18}F$]fluorobutyl-pyridinium cation(1) and N, N dibenzyl-4(2-[$^{18}F$]fluoroethyl)piperidinium cation(2) were investigated in relation to their biodistribution in mice. Compound 1 showed at 1 min post injection the high uptake of 19.22% ID/g organ in the myocardium but a following fast decline to 1.12% ID/g organ after 40min. Uptake of compound 2 was after 1min in the heart 5.90% ID/g organ but after 40min at the relative high value of 4.33% ID/g organ. Heart:blood ratio for compound(1) at 1 min was 8.3, at 40 min 2.6 for compound II 2.0(1min) and 15.0(40 min). As data of compound 2 showed greater heart uptake, slower myocardial release, and higher heart: blood ratios, compound 2 is a good candidate for further evaluation.

• Journal of the Korean Chemical Society
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• v.42 no.6
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• pp.696-702
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• 1998

The effect of alkali metal salt on the activity of Co-Mo catalyst which has high resistance to sulfur poisoning for water gas shift reaction(WGSR) was studied. Two groups of catalysts were prepared to investigate the effects of anion and cation in alkali metal salts. For K-doped catalysts made with various potassium salts having different anion, the catalytic activity was explained to depend mainly on the BET surface area. Among the catalysts prepared by various nitrates of alkali metal as precursor, the Li-doped catalyst showed the best activity, and the others did not make significant differences giving relatively low activities. And the change of BET surface area by varying the loading of alkali metal showed a similar trend to that of activity. In this case, the activity was dependent on both BET surface area and the ratio of $Mo^{6+}$ with a tetrahedral coordination symmetry to $Mo^{6+}$ with an octahedral one, $Mo^6+[T]/Mo^{6+}[O]$ value.