• Korean Journal of Agricultural Science
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• v.46 no.4
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• pp.799-811
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• 2019

The aim of this study was to evaluate heavy metal contamination and pollution index of agricultural soils around industrial complexes in the Jeon-Buk Regions of Korea. Soil samples near industrial complexes in 2017 were collected at two depths (0 - 15 and 15 - 30 cm) within a 500- and 1000-meter radius before planting. Eight heavy metals (Arsenic (As), cadmium (Cd), chromium (Cr), Cupper (Cu), nickel (Ni), lead (Pb), mercury (Hg) and zinc (Zn)) and the pollution index (PI), geoaccumulation index (Igeo) and soil pollution index (SPI) were evaluated based on soil contamination warning standard (SCWS). Overall, the heavy metal concentrations were below the SCWS. The PI ranged from 0.1 to 0.9 and categorized into Group 1 which is not polluted with any heavy metals. The average Igeo values of all the soil samples ranged from - 2.56 to 3.22. The Igeo values of Cd and Hg may not represent well the pollution index because the heavy metal concentrations in the soil is lower compared to the SCWS. In fact, based on the heavy metal concentrations, the Igeo for monitored soils should be categorized into Group 1, uncontaminated to moderately contaminated. However, the Igeo of Cd and Hg are classified into heavily contaminated. These results suggest that for calculating the Igeo, the heavy metal concentration and background concentration should be used very carefully if the heavy metal concentration in the soil is lower than the background concentration. SPI for all the soil samples ranged from 0.00 to 0.11 which indicates no heavy metal pollution was observed.

• Journal of the Korean Chemical Society
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• v.12 no.3
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• pp.121-127
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• 1968

In the oligomerization of p-aminophenol under the catalytic action of the metallic complexes, the effects of the ligands are studied. When the initial velocity of $O_2$ uptake at pH 8 using Fe(Ⅲ) as the central metal and N-hydroxylethylethylenediaminetriacetic acid (HEDTA), ethylenediaminetetraacetic acid (EDTA), diethylenetriaminepentaacetic acid (DTPA), 1,2-cyclohexanediaminetetraacetic acid(CyDTA) as the ligands respectively are compared, the velocities are as the following order: HEDTA > EDTA > DTPA > CyDTA. Further when the effect of the ligands, nitrilotriacetic acid (NTA), HEDTA, EDTA, and DTPA, on the yields of oligomers are compared, the result shows as the following order: NTA > HEDTA > EDTA > DTPA. These are nearly reverse order of the stability constants of the complexes. In order to determine the composition of the mixed complexes at the initial step, the method of continuous variation is used, and it is found that the composition ratio of Fe-EDTA complex to monomer in the mixed complexes is one at pH 5-8 range. It is also found that at pH 9 or in the more alkaline range, side reactions occur to form water soluble dimer of quinone type and the catalytic action of the metallic complex markedly decreases on account of the hydrolysis of the central metal by the $OH^-$ ion.

• YAKHAK HOEJI
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• v.18 no.2
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• pp.133-144
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• 1974

The metal indicator, acidic azo dyes NN, EBT and Calcon are utilized to analyse quantitatively chlorpheniramine, tripelenamine and diphenhydramine forming insoluble ion pair in aqueous solution at proper pH values between the acidic azo dyes and the sample molecules, these compexes are extracted by organic polar solvents, and organic layer is determined spectrophotometrically. Generally, the absorption maxima of the complexes are shifted to longer wavelengths compare to the absorption maxima of the dyes themselves. The binding ratio of the ion pair forming complex molecules in chloroform soln, are as follows ; NN-antihistamines (chlorpheniramine, tripelennamine, diphenhydramine) are NN-1 to antihisamine-1, EBT-antihistamines are EBT-2 to antithistamines a and Calcon-antihistamines are Calcon-3 to antithistamines-1. These coomplexes in chloroform soln. are very stable, and show higher absorbance than the other organic polar solvents. The binding state of complexes were presumed intermolecular hydrogen bond by their infrared spectra. In the mixture solution of three samples, the aqueous phase is buffered at pH 1.0, and benzene is used to extract ion pair of diphenhydramine EBT complex selectively. At pH 1.0 of aqueous layer, Calon-diphenhydramine complex is also extracted selectively by benzene. However, in this case very small amount of chlorpheniramine-calcon calcon simultaneously. The binding state of diphenhydramine-EBT and diphenhydramine-calcon in benzene are smae as the complexes in chloroform. But the absorption maxima of the complexes in benzene are shifted to shorter wavelenlgths than the complexes in chloroform.

• Bulletin of the Korean Chemical Society
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• v.28 no.6
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• pp.921-928
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• 2007

Three different phosphonated trisbipyridine ruthenium complexes, [(4-CH3-4'-CH2PO(OH)2-2,2'-bipyridine)- (bpy)2Ru]·(PF6)2 (Ru-P1), [(4-CH3-4'-CH2PO(OH)2-2,2'-bipyridine)3Ru]·(PF6)2 (Ru-P2), and [(4,4'-CH2PO- (OH)2-2,2'-bipyridine)3Ru]·(PF6)2 (Ru-P3) were synthesized and their photochemical and electrochemical properties were studied. These ruthenium complexes were strongly adsorbed on the surface of the layered metal oxide semiconductor K4Nb6O17 that was partially acid-exchanged and sensitized up to pH 10, while the carboxylated ruthenium complex, (4,4'-COOH-2,2'-bipyridine)3Ru·Cl2 (Ru-C) that was previously studied was sensitized only below pH 4. The visible light water reduction at K4Nb6O17 that was internally platinized and sensitized by these phosphonated Ru-complexes was comparatively studied using a reversible electron donor iodide.

• Journal of the Korean Chemical Society
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• v.18 no.1
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• pp.31-39
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• 1974

Solutions of $Mn^{++}, Co^{++} and Zn^{++}$ were mixed with various dibasic organic acids in the presence of cation exchange resin at room temperature. The distribution ratios of the metal ions between resin and solution were measured, using radioactive metal ions as tracer. From the observed variation of the distribution ratios with acid anion concentrations, it was concluded that $Mn^{++}, Co^{++}$ and $Zn^{++}$ formed one-to-one complexes with succinate, malonate, o-phthalate and tartrate ions in aqueous, 20 % ethanol-water and 20 % acetone-water solutions. The results of the present investigation indicated that the relative stabilities of the complexes increased in the order: $Mn^{++} < Co^{++} < Zn^{++} complexes, Succinate < malonate < o-phthalate < tartrate complexes, Aqueous < mixed solvent systems.$

• Bulletin of the Korean Chemical Society
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• v.15 no.5
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• pp.374-378
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• 1994

Square planar nickel(II) complexes with various 1-alkyl derivatives of the 14-membered pentaaza macrocycle 8-methyl-8-nitro-1,3,6,10,13-pentaazacyclotetradecane can be readily prepared by two-step metal template condensation reactions of ethylenediamine, nitroethane, formaldehyde, and appropriate primary alkylamines. In coordinating solvents the nickel (II) complexes form octahedral species containing two axially coordinated solvent molecules and thus show square planar-octahedral equilibrium. The properties of the pentaaza macrocyclic complexes are considerably different from those of the complexes of analogous hexaaza and tetraaza macrocyclic complexes. Synthesis, characterization, and spectroscopic and chemical properties of the new complexes are described.

• Membrane Journal
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• v.24 no.6
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• pp.472-483
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• 2014

This study is preparation of microporous membranes by using macrocyclic metal ion complexes and extended cage complexes. It is a more favorable way to existing methods because polymer and metal ion-ligand complex system provides a fine control over the phase transition behavior. Chemical functionalization of the polar surface can be obtained. Metal-templated condensation of cyclohexanedione dioxime, hydroxyphenylboronic acid in the presence of metal salts proceeds cleanly in methanol to furnish the metal clathrochelate complexes. Organic/inorganic hybrid membranes were prepared with polyethersulfone (PES), polyvinylpyrrolidone (PVP), ethyleneglycol butyl ether (BE), metal clathrochelate s and DMF by using nonsolvent induced phase inversion method. The structure of membranes was characterized with scanning electron microscopy (SEM) and microflow permporometer. The addition of Fe(II) clathrochelate complex with p-hydroxyphenyl group leads to changes of membrane morphology such as narrow mean pore size distribution, increase of surface pore density and decrease of the largest pore size.

• Journal of Environmental Science International
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• v.8 no.2
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• pp.205-209
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• 1999

Iron hydroxides are good adsorbents for uncomplexed metals, some metal-ligand complexes and many metal oxyanions. However, their adsorption properties of these precipitations are not fully exploited in wastewater treatment operations because of difficulties associated with their separation from the aqueous phase. This study describes experiments in which iron hydroxides were coated onto the surface of ordinary adsorbents(Sea sand) that are very resistant to acids, The coated adsorbents were used in adsorption of oxyanionic metals. The process was successful in removing some anions such as $SeO_3(-II)$ over a wide range of metal concentrations and sorption of oxyanionic metals increased with decreasing pH. Formation of two surface complexes for oxyanionic metals adsorption on iron hydroxides comprise (1) complexation of the free anion by a positively charged surface site, and (2) protonation of the adsorbed anion (or alternatively adsorption of a protonated form from solution) The coated adsorbents are inexpensive to prepare and could serve as the basis of a useful oxyanionic metal removal.

• Bulletin of the Korean Chemical Society
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• v.31 no.4
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• pp.781-788
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• 2010

Experimental and theoretical studies show that all covalent azides possess a nonlinear azide group. They also rationalize this remarkable structural feature. We have seen that the most important non-covalent contributions in the covalently bound azides system (X-N1-N2-N3) are the $\pi$-delocalization over the entire molecule and a strong negative hyperconjugation which donates electron density from the filled $\sigma$ (X-N1) orbital into the unfilled, antibonding $\pi^*$ (N2-N3) orbital. For transition metal azide complexes, a bent configuration and a small difference between the N-N bond lengths, generally the longer one being adjacent to the transition metal, were observed.

• Bulletin of the Korean Chemical Society
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• v.22 no.12
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• pp.1316-1322
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• 2001

Transition metal complexes of novel mono- and di-ferrocene-substituted porphyrins have been synthesized and characterized by structural and electrochemical methods. The X-ray structures of Mn(FPTTP)Cl and Mn(DFTTP)Cl showed the distorted square pyramidal coordination geometry with syn configuration of chloride and ferrocenyl substituents. The electrochemistry of ferrocene-substituted porphyrins and their metal complexes has been determined to elucidate the ${\pi}-conjugation$ effect of the porphyrin ring. The ferrocenyl group of H2FPTTP underwent a reversible one-electron transfer process at 0.30 V, indicating the good electron donating effect of the phorphyrin ring to the ferrocene substituent. The redox potential of the ferrocenyl subunit and porphyrin ring was affected by the central metal ions of the metalloporphyrins, that is, Zn(II) and Ni(II) made the oxidation of ferrocene much easier and Mn(III) made it harder. The ferrocene subunits of H2DFTTP interacted electrochemically with each other with peak splitting of 0.21 V. The strength of the electrochemical interactions between the two ferrocenyl substituents can be controlled by central metal ions of metalloporphyrins.