• Transactions of the Korean hydrogen and new energy society
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• v.14 no.2
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• pp.155-170
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• 2003

$Cu-Ce/{\gamma}-Al_2O_3$ based catalysts were prepared and tested for selective oxidation of CO in a $H_2$-rich stream(1% CO, 1% $O_2$, 60% $H_2$, $N_2$ as balance). The effects of Cu loading and weight ratio(=Cu/(Cu+Ce)) upon both activity and selectivity were investigated upon the change in temperatures, It was also examined how the activity and selectivity of catalysts were varied with the presence of $CO_2$ and $H_2O$ in the reactant feed. Among the various Cu-Ce catalysts with different catalytic metal composition, Cu-Ce(4 : 16 wf%) /${\gamma}-Al_2O_3$ catalyst showed the highest activity(>$T_{99}$) and selectivities(50-80%) under wide range of temperatures($175-220^{\circ}C$). However, in the Cu-Ce(4 : 16 wt%)/ ${\gamma}-Al_2O_3$, the presence of $CO_2$ and $H_2O$ in the reactant feed decreased the activity and the maximum activity(>$T_{99}$) in terms of reaction temperature moved by about $25^{\circ}C$ toward higher temperature, the $T_{>99}$ window was seen between $210-230^{\circ}C$ (selectivity 50-75%). From $CO_2-/H_2O-TPD$, it can be concluded that the main cause for the decrease in catalytic activity may be attributed to the blockage of the active sites by competitive adsorption of water vapor and $CO_2$ with the reactant at low temperatures.

• Bulletin of the Korean Chemical Society
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• v.30 no.5
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• pp.1093-1096
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• 2009

Two new chemosensors 1 and 2 derived from 5,12- and 5,7-dioxocyclams were prepared and their signaling behaviors toward transition metal ions were investigated. Chemosensors 1 and 2 showed very efficient responses toward $Cu_{2+}$ and $Hg_{2+}$ ions. Ratiometric analysis of the fluorescence changes in pyrene monomer and excimer emissions clearly demonstrated the $Cu_{2+}$- and $Hg_{2+}$-selective signaling behavior. The signaling mechanism of the chemosensors is due to conformation changes upon complexation with metal ions and the inherent quenching nature of the complexed $Cu_{2+}$ and $Hg_{2+}$ ions themselves.

• Bulletin of the Korean Chemical Society
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• v.34 no.4
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• pp.1061-1064
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• 2013

A known $Hg^{2+}$ selective rhodamine B derivatised probe 1 was reinvestigated as a colorimetric and fluorescent probe for $Cu^{2+}$ through changing the applied solvent media. Probe 1 exhibited good selectivity and sensitivity to $Cu^{2+}$ in $CH_3CN-H_2O$ (7:3, v/v, HEPES 10 mM, pH 7.0) solution with a detection limit of $9.74{\times}10^{-7}$ M. The $Cu^{2+}$ sensing event was proved to be irreversible through hydrolysis of 1 to release rhodamine B.

• Journal of the Korea Academia-Industrial cooperation Society
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• v.3 no.2
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• pp.156-159
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• 2002

Ion exchange is the most reliable process to remove the ionic impurities and the economic operation. ion exchange is widely used in water and wastewater treatment, especially softening and demineralization. ion selectivity depends on the hydrated radius, charge of ions and concentration. The objective of this study was to determine the selectivity order of cations with equilibrium and column ion exchanges and to investigate the effect of the background anion on selectivity. Cation selectivity increases with decreasing concentration and increasing charge ( $H^+$ < $K^+$ << $Cu^{2+}$ < $Co^{2+}$ < TEX>$Ca^{2+}$ << $Ce^{3+}$)in equilibrium and column cation adsorptions.

• KSBB Journal
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• v.13 no.4
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• pp.444-448
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• 1998

Biosorption of Pb and Cu was evaluated for 23 species of marine algae collected from a Korean coast. Among a variety of species for biosorbent potential, Hypnea charoides showed the highest capacity for Pb. An adsorption equilibrium was reached in about 2 hr for Pb and 30 min for Cu. The uptake capacity was 192.8 mg Pb/g biomass and 256 mg Cu/g biomass, respectively. The adsorption parameters for Pb and Cu were determined according to Langmuir model. With an increase in pH value, more negative sites are becoming avaliable for adsorption of pH and Cu, thus the removal of Pb and Cu increases at alkaline conditions. The selectivity of mixture solution shows the uptake order of Pb>Cu>Cr>Cd. When Ca concentration increases in Pb solution, Pb was selectively adsorbed.

• Bulletin of the Korean Chemical Society
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• v.29 no.3
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• pp.571-574
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• 2008

The well-known Cu2+-selective chemodosimetric behavior of rhodamine B hydrazide was successfully switched to selectivity for Hg2+. The fluorescence signaling is remarkably selective toward Hg2+ ions compared to other common biologically and environmentally important metal ions, including Cu2+ ions. The detection limit was 0.2 mM in an acetate-buffered aqueous 10% methanol solution at pH 5. The OFF-ON type of signaling is due to the selective Hg2+-induced hydrolysis of the lactam ring of the hydrazide as has been reported for the standard Cu2+-signaling process of the same compound. A simple change in medium resulted in clear switching of selective signaling from Cu2+ to Hg2+, which extends the applicability of the easily accessible hydrazide derivative.

• Journal of Applied Biological Chemistry
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• v.42 no.1
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• pp.25-28
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• 1999

For investigating the effectiveness of Korean natural zeolite for removal of $NH_4{^+}$ in waste waters containing $NH_4{^+}$ and $Cu^{2+}$, the adsorption of $NH_4{^+}$ and $Cu^{2+}$ by three Korean natural zeolite samples, which contained mordenite and/or clinoptilolite, was measured by adding solutions containing $NH_4{^+}$ and $Cu^{2+}$ or both at a concentration range from 1 to 7 mmol(+)/L of each cation. In the solutions, the zeolite samples adsorbed more amounts of $NH_4{^+}$ than $Cu^{2+}$. By seven successive equilibrations, Korean natural zeolites adsorbed $NH_4{^+}$ corresponding to 23~33% of those cation exchange capacity from the solution containing both $NH_4{^+}$ and $Cu^{2+}$ at 3 mmol(+)/L of each cation. Whereas, the corresponding adsorption of $Cu^{2+}$ was 17-27% of the CEC. Korean natural zeolite exhibited selectivity for $NH_4{^+}$ but not for $Cu^{2+}$. Nevertheless, it using as a soil amendment after removing of $NH_4{^+}$ in waste waters should be carefully controlled on the application rate.

• Analytical Science and Technology
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• v.8 no.4
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• pp.529-534
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• 1995

The metal ion selective resins were prepared by surface template polymerization using monooleyl phosphoric acid (1), oleyl methyl phosphoric acid (2) or oleyl ethyl phosphoric acid (3) as an amphiphilic host surfactant. The $Cu^{2+}$-imprinted resins prepared in the presence of $Cu^{2+}$ adsorbed $Cu^{2+}$ much more effectively than did their reference resins. On the other hand, the $Cu^{2+}$-imprinted resins showed much less binding ability to $Zn^{2+}$. The template-dependent selectivity should be ascribed to a favorable placement of the surface-anchored metallophilic groups for multidentate coordination to specific metal ion.

• Clean Technology
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• v.19 no.1
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• pp.65-72
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• 2013

In this study, we investigated the activity of Pd and Cu co-incorporated on mesoporous silica support such as MCM-41 and SBA-15 for catalytic nitrate reduction in water. In pure hydrogen flow, nitrate concentration was gradually decreased with the reaction time, but nitrogen selectivity was too low due to very high pH of reaction medium after the reaction. In order to acquire high nitrogen selectivity, we utilized carbon dioxide as a pH buffer, which resulted in higher nitrogen selectivity (about 40%). For the above reaction conditions, Pd-Cu/MCM-41 showed better performance than Pd-Cu/SBA-15. The physicochemical properties of both catalysts were investigated to figure out the relationship between the characteristics of the catalysts and the catalytic activity on the catalytic nitrate reduction by $N_2$ adsoprtion-desorption, X-ray diffraction (XRD), $H_2$-temperature programmed reduction, X-ray photoelectron spectroscopy (XPS) techniques.

• Journal of the Institute of Electronics Engineers of Korea SD
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• v.37 no.3
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• pp.27-33
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• 2000

The selective chemical vapor deposition techniques for Cu metallization were studied. For enhancing the selectivity, furnace annealing and N$_{2}$ plasma were treated on patterned TiN/BPSG prior to the copper deposition. As a result, Cu did not deposited lead to suppressing the nucleation on BPSG singificantly. With the increasement the plasma treatment temperature, copper nucleation on BPSG was suppressed mote effectively, From TOF-SIMS(Time-of-Flight Secondary ion Mass Spectrometry), it is considered that annealing and N$_{2}$ plasma treatment remove hydroxyl(0-H) group so that eliminating the nucleation site for copper precursor enhance the selectivity.