• Journal of environmental and Sanitary engineering
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• v.21 no.3 s.61
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• pp.52-60
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• 2006

The ion exchange resins have been synthesized from chlormethyl styrene-1,4-divinylbenzene(DVB) with 1%, 2%, and 20%-crosslinking and macrocyclic ligand of cryptand 21 by copolymerization method and the adsorption characteristics of uranium(VI), copper(II) and dysprosium(III) metallic ions have been investigated in various experimental conditions. The synthesis of these resins was confirmed by content of chlorine, element analysis, and IR-spectrum. The effects of pH, equilibrium time, dielectric constant of solvent and crosslink on adsorption of metallic ions were investigated. The metal ion was showed fast adsorption on the resins above pH 3. The optimum equilibrium time for adsorption of metallic ions was about two hours. The adsorption selectivity determined in ethanol was in increasing order uranium$(UO^{2+}_2)\;>\;copper(Cu^{2+})\;>\;dysprosium(Dy^{3+})$ ion. The adsorption was in order of 1%, 2%, and 20% crosslink resin and adsorption of resin decreased in proportion to order of dielectric constant of solvents.

• Journal of the Korean Chemical Society
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• v.53 no.6
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• pp.693-703
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• 2009

The complex formation of anti-inflamatory drug piroxicam (PX, 4-hydroxy-2-methyl-N-2--pridyl-2H-1,2-benzothiazine-3-carboxadiamide-1,1-dioxide) with transition metal ions Co(II), Ni(II), Cu(II) and Zn(II) in methanol(MeOH)/water binary mixtures were studied by spectrophotometric method at 25$^{\circ}C$, constant pH = 5.0 and I = 0.1 M. The computer program SQUAD was used to extract the desired information from the spectral data. The outputs of the fitting processes were stability constants, standard deviations of the estimated stability constants, concentration distribution diagrams and spectral profiles of all species. The sequence of the stability constants of PX complexes with Co(II), Ni(II), Cu(II) and Zn(II) follow the Cu(II) > Co(II) > Ni(II) ${\approx}$ Zn(II) order. This may be due to different geometry tendencies of these metal ions. The acidity constants of the PX were also determined under above condition from its absorption spectra at different pH values. The computer program DATAN was used for determination of acidity constants of PX. The validity of the obtained acidity constants was checked by a well known computer program SPECFIT/32. The effects of the different parameters like solvent nature, cations characteristics on the stability and acidity constants were thoroughly discussed.

• Analytical Science and Technology
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• v.9 no.4
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• pp.373-381
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• 1996

Algal biomass was used in our study in order to remove some metals. After packing of 40~60 mesh algae powder into column for use of metal adsorbent, the metal solution of 1mL/min of flow rate was eluted to adsorb in algae. More amount of Cu(II) or Zn(II) ion in green algae, Ulva pertusa Kjellman than in brown algae, Sargassum horneri (Turner) C. Agarch were adsorbed and Cu(II) ion was more adsorbed in both algae than Zn(II) ion. Recovery of metal from algae is showing higher in acidic or neutral than in alkalic conditions. Cu(II) ion is recovered relatively higher than Zn(II) ion in our system.

• Analytical Science and Technology
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• v.14 no.6
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• pp.530-534
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• 2001

Effect of stripping solutions on the Duolite GT-73 chelating resin for ten elements, Ag(I), Al(III), Ca(II), Cd(II), Cu(II), Fe(II), Hg(II), Mn(II), Pb(II), and Zn(II), was investigated. Relation between affinities of the metal ions and solubility products of metal sulfides was studied. The smaller the solubility product of metal sulfideis, the larger the affinitie with the ionsis. The ions which have the solubility products larger than $10^{-23}$ could be effectively desorbed with nitric acid. Complexation with chloride ion enhanced the desorption efficiencies of the ions having moderately strong affinity with the resin. The ions which have very strong affinity by the chelating resin can be desorbed by complextion with thiourea and hydrochloric acid.

• Analytical Science and Technology
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• v.9 no.4
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• pp.364-372
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• 1996

The sorption and desorption properties of U(VI), Th(IV), Zr(IV), Cu(II), Pb(II), Ni(II), Zn(II), Cd(II) and Mn(II) ions on XAD-16-[2-(2-thiazolylazo)-p-cresol](TAC) chelating resin were studied by elution method for selective separation, concentration and recovery of trace metal ions in sea water. The optimum conditions for the sorption of metal ions were examined with respect to flow rate, pH and concentration of buffer solution. The overall capacities of some metal ions on this chelating resin were 0.41mmol U(VI)/g resin, 0.55mmol Th(IV)/g resin, 0.43mmol Cu(II)/g resin, and 0.32mmol Zr(IV)/g resin, respectively. The elution order of metal ions obtained from breakthrough capacity and overall capacity at pH 5.0 was found as Th(IV)>Cu(II)>U(VI)>Zr(IV)>Pb(II)>Ni(II)>Zn(II)>Cd(II)>Mn(II). Desorption of characteristics for metal ions were investigated with desorption agents such as $HNO_3$, HCl, $HClO_4$, $H_2SO_4$, and $Na_2CO_3$. It was found that most of metal ions except Zr(IV) showed high desorption efficiency with 2M $HNO_3$. But, desorption and recovery of Zr(IV) ion were successfully performed with 1M $H_2SO_4$. The resin was applied for separation and preconcentration of trace amount of U(VI) ion from artificial sea water and the recovery of U(IV) was over 96%.

• Bulletin of the Korean Chemical Society
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• v.27 no.10
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• pp.1557-1561
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• 2006

The use of chemically modified silica-salen$(NEt_2)_2$ was studied for the separation and concentration of the metal ions from an aqueous solution by a solid phase extraction. After the salen(NEt2)2 was synthesized, it was chemically bonded to silica gel by a diazonium coupling reaction. The adsorption capacities and binding constants were obtained with respect to Cu(II), Mn(II), Pb(II) and Zn(II) by a graphical method. Some experimental conditions were optimized for the determination of the trace elements. After the silica-salen(NEt2)2 was pulverized in a sample solution of which the pH was adjusted, the solution was stirred to pre-concentrate the metal ions. The metal ions adsorbed were desorbed with nitric acid solution. And the concentrated analytes were determined by a flame AAS. The method proposed here was so rarely influenced by a sample matrix that the procedure was applied to 3 types of water samples. The reproducible results of less than 10% RSD were obtained at the concentration level of ca. 100 ng/mL and the recoveries of 95-109% were obtained in the spiked samples in which given amounts of analytes were added.

• Analytical Science and Technology
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• v.11 no.6
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• pp.440-447
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• 1998

Polydentate Schiff base ligands 5-Br-BSDT(bis(5-bromosalicylaldehyde)diethylenetriamine) having $N_3O_2$ atoms, 5-Br-BSTT(bis(5-bromosalicylaldehyde)triethylenetetramine) having $N_3O_2$ atoms, 5-Br-BSTP(bis(5-bromosalicylaldehyde)tetraethylenepentamine) having $N_3O_2$ atoms were synthesized. Stability constants of the complexes between these ligands and the metal ions such as Cu(II), Ni(II) and Zn(II) were measured in DMSO by a polarographic method. It was observed that all metal(II) ions employed in this study formed 1 : 1 complexes with Schiff base ligands. Stability constants for the ligands were in the order of Cu(II)>Ni(II)>Zn(II), and for complex formation were in the order of 5-Br-BSTP>5-Br-BSTT>5-Br-BSDT according to the increasing in the number of donor atoms. Both enthalpy and entropy changes are obtained in negative valves. Exothermicity for the complex formation indicated tight binding between the ligands and metal ions. The negative entropy change would be related to the fact that solvent molecules are strongly interacting with the metal complexes.

• Journal of the Korean Chemical Society
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• v.44 no.6
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• pp.518-525
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• 2000

The open-chain hexadentate N$_4$, O$_2$ ligands 1,13-bis(2-hydroxybenzyl)-2,5,9,12-tetraazatridecane-tetrahydrochloride (BSATD${\cdot}$4HCl) and 1,14-bis (2-hydroxybenzyl)-2,6,9,12-tetraazatetradecane-tetrahydrochloride (BSATED${\cdot}$ 4HCl) have been synthesized as their tetrahydrochloride salt and characterized by EA, IR, NMR and Mass. Their proton dissociation constants(log$K^{n}_{H}$) and stability constants(log$K_{ML}$) for Cu(II), Ni(II), Co(II), and Zn(II) ions were determined in aqueous solution by potentiometry and compared with those of analogous N$_4$, O$_2$ ligands contain ethylenic spacers or propylenic spacers, which make six-membered chelate rings between the aliphatic nitrogen atoms. Synthesis and characterization of [Cu(BSATD)]ClO$_4$ and [Cu(BSATED)](ClO$_4$)$_2$ complexes are described.

• Bulletin of the Korean Chemical Society
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• v.21 no.4
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• pp.393-400
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• 2000

2,2￠-Dihydroxyazobenzene (DHAB) was attached to poly(ethylenimine) (PEI) to obtain DHAB-PEI. Spectral titration revealed that uranyl, Fe(III), Cu(II), and Zn(II) ion form 1 : 1-type complexes with DHAB attached to PEI. Formation constants for the metal complexes formed by the DHAB moieties of DHAB-PEI were mea-sured by using various competing ligands. The results indicated thatthe concentrations of uranyl, Fe(III), and Cu(II) ions can be reduced to 10 -16 -10 -23 M at p 8 with DHAB-PEI when the concentration of the DHAB moiety is 1 residue M. By using cyanuric chloride as the coupling reagent, DHAB-PEI was immobilized on Sephadex G-25 resin to obtain DHAB-PEI-Seph. Binding of uranyl,Fe(III), Cu(II), and Zn(II) ion by DHAB-PEI-Seph was characterized by using competing ligands. A new method has been developed for characteriza-tion of metal sequestering ability of a chelating resin. Formation constants and metal-binding capacity of two sets of binding sites on the resin were estimated for each metal ion. DHAB-PI-Seph was applied to recovery of metals such as uranium,Fe, Cu, Zn, Pb, V, Mn, and W from seawater. The uranium recovery from seawaterby DHAB-PEI-Seph does not meet the criterion for economical feasibility partlydue to interference by Fe and Zn ions. The seawater used in the experiment was contaminated by Fe and Zn and, therefore, the efficiency of uranium extractionfrom seawater with DHAB-PEI-Seph could be improved if the experiment is carried out in a cleaner sea.

• Bulletin of the Korean Chemical Society
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• v.32 no.11
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• pp.4021-4026
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• 2011

Functions of the luteinizing hormone releasing hormone (LHRH) and its induced release by divalent metal ions have received great attention because this neurotransmitter subsequently regulates the secretion of luteinizing hormone (LH). Metal-LHRH complexes were synthesized by addition of various Cu(II),Ni(II),Zn(II) ions into LHRH in order to understand how the induced release of LHRH is possible. The degree of complexation was monitored by $^1H$, $^{13}C$-NMR chemical shifts, and final products were identified by Mass spectrometry. Solutionstate structure determination of Zn(II)-LHRH out of metal-complexes was accomplished by using NMR and NMR-based distance geometry (DG). Interproton distance information from nuclear Overhauser effect spectroscopy was utilized for structure determination. Structure obtained in this study has a cyclic conformation exhibiting a specific ${\alpha}$-helical turn with residue numbers His[2]-Leu[7] out of 10 amino acids. Comparison of chemical shifts and EPR studies of Ni(II),Cu(II)-LHRH complexes exhibit that these metal complexes have 4-coordination geometry.