• Korean Chemical Engineering Research
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• v.51 no.6
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• pp.733-738
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• 2013

Sediment contains a high fraction of organic matter, high buffering capacity, and a large portion of fine grained particles such as silt and clay, which are major barriers to remove heavy metals from sediments. In this study, a lab-scale electrokinetic (EK) technique was applied to remove heavy metals effectively from marine sediment at a constant voltage gradient of 2 V/cm. A concentration of 0.1 M of ethylenediaminetetraacetic acid (EDTA), citric acid (CA), $HNO_3$, and HCl were circulated in the cathode, and tap water was circulated in the anode. CA extracted 92.4% of Ni, 96.1% of Cu, 97.1% of Zn, and 88.1% of Pb from marine sediment. A higher voltage gradient enhanced the transport of citrate and EDTA into the sediment and, therefore, increased metal extraction from the marine sediment through a complexation reaction between metals and the chelates. Based on these results, the electrokinetic process using a high voltage gradient with EDTA and CA might be useful to extract heavy metals from marine sediment.

• Applied Chemistry for Engineering
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• v.22 no.2
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• pp.185-189
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• 2011

In this work, nano-sized M-ferrites (M=Co, Ni, Cu, Zn) for the decomposition of carbon dioxide were synthesized by the chemical co-precipitation. From the thermogravimetric analysis, it was clear that the maximum weight loss of each sample took place below $350^{\circ}C$. High temperature calcination resulted in more systematic crystallines, smaller specific surface area and larger particle size. An analysis by FTIR in the range of $375{\sim}406cm^{-1}$ revealed the presence of chelates at the octahedral site, which implies the formation of spinel structure in the ferrites. The current work showed that a $500^{\circ}C$ is the optimum heat treatment temperature of metal ferrites for $CO_2$ decomposition reaction.

• Analytical Science and Technology
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• v.7 no.3
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• pp.361-369
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• 1994

Voltammetric behavior of some light lanthanide ions($La^{3+}$, $Pr^{3+}$, $Nd^{3+}$, $Sm^{3+}$ and $Eu^{3+}$) in acetonitrile(AN) and dimethylformamide(DMF) has been investigated by direct current, differential pulse polarography and cyclic voltammetry. The reduction of $La^{3+}$, $Pr^{3+}$ and $Nd^{3+}$ in 0.1M TEAP proceeded directly to the metallic state through three-electron charge transfer of irreversible process where as $Sm^{3+}$ and $Eu^{3+}$ proceeded by charge transfer of two steps. As the results of the cyclic voltammetric investigation, the first step reduction of $Sm^{3+}$ and $Eu^{3+}$ were a quasireversible reaction, the second step reductions were an irreversible reaction. The cathodic peak currents of the differential pulse polarogram showed adsorptive properties at lower sweep rates and high concentrations of these metal ions. The peak potenital was shifted to a negative petential and the peak current decreased with the increase of percentage of water in AN. On the other hand, the peak potential was shifted to a positive potential and the peak current decreased with an increased percentage of water in DMF.

• Journal of the Korean Chemical Society
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• v.41 no.9
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• pp.465-470
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• 1997

A chiral pentadentate ligand, 1,9-bis(S)-prolyl-1,9-dioxo-2,5,8-triaza-nonane, (S,S-prochen) which shows the stereospecific reaction was synthesized from the reaction of S-proline and diethylenetriamine (dien). The red-violet $[Co(SS-prodien)H_2O]ClO_4$ was prepared by the oxidation of the aqueous solution dissolving $CoCl_2{\cdot}6H_2O$ and S,S-prodien. Elemental analysis, electronic absorption spectroscopy, and $^{13}C-NMR$ spectroscopy suggest that the geometrical structure of the Co(III) complex to be an ${\alpha}{\beta}$ (ffm) form, where the dien moiety of the ligand chelates the metal center to comprise a facial isomer, and an aqua ligand coordinates a cis site to the secondary nitrogens of the dien. Based upon the CD spectroscopic analysis, it seems that the absolute configuration of the ${\alpha}{\beta}$(ffm)-$[Co(SS-prodien)H_2O]ClO_4$ has the ${\Lambda}$-form.

• Journal of the Society of Cosmetic Scientists of Korea
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• v.38 no.4
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• pp.271-276
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• 2012

In this study, the dispersion ability of powder in low viscosity solubilization system that depends on variety and amount of additives and powders was investigated. A PMMA powder shows outstanding dispersion ability because of its repulsive force of partially charged chain and low density of porous structure. A sample, which contains salts, showed better dispersion tendency than a sample without any additives. The dispersion ability was quantity of salts dependent. Furthermore, a sample with divalent ion salts, like $MgSO_4$, showed better dispersion tendency than that of monovalent ion salts, like NaCl or KCl. The reason for the better dispersion tendency was due to the existence of ionized salts around the powders which significantly improves repulsive force between powders and consequently reduces powder aggregation. The sample with chelating agent, like EDTA as an additive, had improved dispersion ability. EDTA chelates and blocks metal cation therefore anion's character is maximized and repulsive force between powders is improved. As a result, salts and EDTA help to improve the powder dispersion ability and the stability of product.

• Applied Chemistry for Engineering
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• v.3 no.3
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• pp.412-421
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• 1992

The superconducting thin films have shown a growing possibility for practical application in microelectronic fields in recent years. In this study, the high Tc superconducting Y-Ba-Cu-O thin films were prepared on various substrates by chemical vapor deposition method using organic metal chelates of $Y(thd)_3$, $Ba(thd)_2$, and $Cu(thd)_2$ as source materials. The deposition reactions were carried out on single crystalline MgO(100), YSZ(100), $SrTiO_3(100)$, and polycrystalline $SrTiO_3$ substrates. Deposition thickness of thin films was linearly increased with the increase of deposition time. It turned out that the Y-Ba-Cu-O thin films on MgO(100), YSZ(100), and $SrTiO_3(100)$ single crystal substrates showed superconductivities above liquid nitrogen temperature($T_{c,onset}=87{\sim}89K$, $T_{c,zero}=85{\sim}86K$), but the one on polycrystalline $SrTiO_3$ substrate did not.

• Nuclear Medicine and Molecular Imaging
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• v.43 no.4
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• pp.330-336
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• 2009

Purpose: We established radiolabeling conditions of NOTA and DOTA with a generator-produced PET radionuclide $^{68}$Ga and studied in vitro characteristics such as stability, serum protein binding, octanol/water distribution, and interference with other metal ions. Materials and Methods: Various concentrations of NOTA 3HCl and DOTA 4HCl were labeled with 1 mL $^{68}$GaCl$_3$ (0.18$\sim$5.75 mCi in 0.1 M HCl in various pH. NOTA 3HCl (0.373 mM) was labeled with $^{68}$GaCl$_3$(0.183$\sim$0.232 mCi/0.1 M HCl 1.0 mL) in the presence of CuCl$_2$, FeCl$_2$, InCl$_3$, FeCl$_3$, GaCl$_3$, MgCl$_2$ or CaCl$_2$ (0$\sim$6.07 mM) at room temperature. The labeling efficiencies of $^{68}$Ga-NOTA and $^{68}$Ga-DOTA were checked by ITLC-SG using acetone or saline as mobile phase. Stabilities, protein bindings, and octanol distribution coefficients of the labeled compounds also were investigated. Results: $^{68}$Ga-NOTA and $^{68}$Ga-DOTA were labeled optimally at pH 6.5 and pH 3.5, respectively, and the chelates were stable for 4 hr either in the reaction mixture at room temperature or in the human serum at 37$^{\circ}C$. NOTA was labeled at room temperature while DOTA required heating for labeling. $^{68}$Ga-NOTA labeling efficiency was reduced by CuCl$_2$, FeCl$_2$, InCl$_2$, FeCl$_3$ or CaCl$_3$, however, was not influenced by MgCl$_2$ or CaCl$_2$. The protein binding was low (2.04$\sim$3.32%). Log P value of $^{68}$Ga-NOTA was -3.07 indicating high hydrophilicity. Conclusion: We found that NOTA is a better bifunctional chelating agent than DOTA for $^{68}$Ga labeling. Although, $^{68}$Ga-NOTA labeling is interfered by various metal ions, it shows high stability and low serum protein binding.