• Environmental Engineering Research
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• v.12 no.1
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• pp.1-7
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• 2007

Most of the herb residue producing from oriental medical clinics(OMC) and hospitals(OMH) is wasted in Korea. To develop of adsorbent for removing heavy metal from wastewater, the various pre-treatment methods of the herb residue were evaluated by potentiometric titration, Freundlich isotherm adsorption test and the kinetic adsorption test. The herb residue was pre-treated for increasing the adsorption capacity by cleaning with distilled water, 0.1 N HCl and 0.1 N NaOH and by heating at $370^{\circ}C$ for 30 min. It showed a typical weak acid-weak base titration curve and a short pH break like commercial activated carbon during photentiometric titration of pre-treated herb residue. The log-log plots in the Freundlich isotherm test were linear on the herb residue pre-treated with NaOH or HCl like commercial activated carbon. The adsorption capacity(qe) in the Freundlich isotherm test for $Cr^{6+}$ was 1.5 times higher in the pre-treated herb residue with HCl than in activated carbon. On the other hand the herb residue pre-treated with NaOH showed the good adsorption capacities for $Pb^{2+}$, $Cu^{2+}$ and $Cd^{2+}$ even though those adsorption capacities were lower than that of activated carbon. In kinetic test, most of heavy metals removed within the first 10 min of contact and then approached to equilibrium with increasing contact time. The removal rate of heavy metals increased with an increase of the amount of adsorbent. Likewise, the removal rates of heavy metals were higher in the herb residue pre-treated with NaOH than in that pre-treated with HCl. The adsorption preference of herb residues pre-treated with NaOH or HCl was $Pb^{2+}>Cu^{2+}$ or $Cd^{2+}>Cr^{6+}$ in the order. Conclusively, the herb residue can be used as an alternative adsorbent for the removal of heavy metals depending on pr-treatment methods.

• Journal of the Korean Society of Tobacco Science
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• v.28 no.2
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• pp.83-93
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• 2006

The aim of this study is to develop a simple and rapid field method for the determination of chloride content in tobacco green or cured leaves. To set up a practical process, several factors such as the proper sampling position of each leaf, the size of leaf lamina pieces for blending, the substitution of deionized water fur the extracting solution, 0.1N $HNO_3$, the submerging durations before blending, and the standing times before measuring were studied using flue-cured and burley tobacco with a stable and reproducible Chloride Meter, KRK CL-2Z. From the results, chloride contents of tobacco leaves could be analyzed with the Chloride Meter(CL-2Z) using the suspension of 14 mm diameter leaf disks after soaking in distilled water for 30 min., blending with a mini-blender for 30 seconds. The chloride contents measured in this way showed highly significant correlations with ones by the conventional potentiometric method using an ion meter-chloride electrode and $AgNO_3$ titration. In our method, the procedures such as drying, powdering and weighing samples, and using chemical reagents for extraction (0.1N $HNO_3$) and titration(0.028N $AgNO_3$) could be eliminated. These results suggest that the newly constructed method using the Chloride Meter is more efficient to determine the chloride content of tobacco leave in comparison with the one by the Ion $Meter:AgNO_3$ titration.

• Bulletin of the Korean Chemical Society
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• v.23 no.1
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• pp.53-58
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• 2002

A new PVC-membrane electrode for $Ag^+$ ion based on a thia-substituted macrocyclic diamide has been prepared. The electrode exhibited a Nernstian response for $Ag^+$ over a wide concentration range $(1.7{\times}10^{-6}-1.0{\times}10^{-1}M)$. It has a response time <15 s and can be used for at least 3 months without divergence. The proposed membrane sensor revealed good selectivities for $Ag^+$ over a variety of metal ions and can be used in a pH range 3.0-7.5. It has been used successfully for direct determination of $Ag^+$ in different real samples and, as an indicator electrode, in the titration of silver ion.

• Journal of Environmental Science International
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• v.12 no.4
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• pp.497-501
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• 2003

The new tridentate ligands of nitrogen donor atoms N,N-Bis(2-amino-ethyI)-benzyl-amine 2HCI(BABEA. 2HCI) and 2,6-Bis(amino-methyl)-pyridien. 2HCI(BAMP. 2HCI) were synthesized as their dihydrochloride salts and characterized by TA, IR. Mass and NMR spectroscopy. The protonation constants of the ligands and stability constants for Cd$^{2+}$, Pb$^{2+}$, Zn$^{2+}$and Cu$^{2+}$ ions were determined by potentiometric titration in aqueous solutions and compared with those of analogous ligands. The effect stability constants of ligands and metal ions for removal of heavy metals in aqueous solution were described.

• Bulletin of the Korean Chemical Society
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• v.23 no.11
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• pp.1635-1639
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• 2002

A new solvent polymeric membrane sensor based on tetra(p-chlorophenyl)porphyrinato manganese (III) acetate is described which demonstrates excellent selectivity toward the triiodide ion. The electrode has a linear dynamic range between 1.0 ${\times}$ $10^{-2}$ M and 7.0 ${\times}$$10^{-6}$M with a Nernstian slope of $-59.6{\pm}1$ mV per decade and a detection limit of 5.0 ${\times}$$10^{-6}$M. The proposed sensor revealed good selectivities for triiodide over a wide variety of other anions and could be used in a pH range 2-9. The electrode can be used for at least two months without any considerable divergence in potential. It was applied as indicator electrode in potentiometric titration of the triiodide and As(III) ions.

• Journal of Pharmaceutical Investigation
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• v.9 no.4
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• pp.23-28
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• 1979

The effect of maltitol admininstration to rat was studied on breakdown of ${\alpha}-glycoside$ linkage with intestinal mucosa or pancreatic enzymes and induction of hepatic polyol dehydrogenase activities. Maltitol was contained as 13% or 26% in diet, and was administrated to rat for 9 weeks. This report carried out that ${\alpha}-glycoside$ linkage of maltitol was not hydrolyzed with pancreatic enzymes and intestinal mucosa. Maltitol dehydrogenase was not obeserved in liver cytoplasm, and hepbtic sorbitol dehydrogenase was not induced by maltitol administsation. Also, the effect of maltitol on aging of aluminum hydroxide gel, prepared by the reaction of aluminum chloride solution with strong ammonia solution to final pH 7.0, was studied by potentiometric titration, pH and acid-consuming capacity. Gel containing 1% or 2% maltitol was lost less than 2% of their acid-consuming capacity during a 120 days aging period compared with a loss of more than for an identical gel without maltitol and gel containing 0.5% maltitol.

• Journal of the Korean Society of Clothing and Textiles
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• v.20 no.4
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• pp.682-689
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• 1996

A preparative method has been proposed for obtaining chitosan products which have a desired degree of deacetylation (DD, %) without much decrease in molecular weight. Deacetylation was prepared by two methods. The method I which was proposed by Domard etc. was that DMSO/thiophenol was used repeatedly only during the deacetylation, the method II was that DMSO/thiophenol was used after the alkali treatment. Then, effective deacetylation was performed by the method ll. To determine the degree of deacetylation, potentiometric titration method was adopted. According to the increase of DD, the viscosity average moleclar weght $(\overline{M\upsilon}$) and the DP of the chitosan products were decreased. The intensity of FT-lR peak appeared at $1655cm^{-1}, which was characteristic peak of amide I (Nacetyl secondary amide group), was gradually decreased with deacetylation. X-ray analysis showed that the lattice-spacing in the chitosan film increased with the degree of deacetylation, but the difference of the transparency of the chitosan products was not diverged significantly.

• Journal of the Korean Chemical Society
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• v.39 no.3
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• pp.213-217
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• 1995

Infrared Spectra of aqueous solution of BUDDA(Butyldithiodiacetic acid), BMDDA(Benzmethyldithiodiacetic acid), and CHDDA(Cyclohexyldithiodiacetic acid) are reported at various pH values. On the basis of the antisymmetric stretching bands of the ionized and un-ionized carboxyl group, the structures of the free-ligand are inferred. An approach to the study of these structures are compared with the results of potentiometric titration curve and IR Spectra studies.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.09a
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• pp.293-297
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• 2003

A series of laboratory experiments was conducted to investigate the fixation characteristics of poly(vinylalcohol)-poly(methacrylic acid)(PVA-PMAA) mixed solution on the soluble (equation omitted)-radionuclides. Using the potentiometric titration technique, it was found out that the PVA and PMAA in a solution form intermacromolecular complex. The mobilized portion of each radionuclide by water from sand surface treated with a fixative was measured by ${\gamma}$-ray spectroscopy, The mobilized portion of minor radionuclides such as $^{241}$ Am, $^{154}$ Eu, $^{155}$ Eu and $^{144}$ Ce were higher than those of $^{134}$ Cs and $^{137}$ Cs. The capability of PVA-PMAA system was better among the candidate solutions for the fixation of total (equation omitted)-radioactivity, $^{134,137}$Cs which is composed of more than 85 % of total ${\gamma}$-radioactivity could be fixed effectively by the PVA-PMAA solution.

• Bulletin of the Korean Chemical Society
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• v.29 no.2
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• pp.372-376
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• 2008

The hydrolysis of gallium(III) has been studied using potentiometric techniques under physiological conditions of temperature 37 C and ionic strength 0.15 moldm-3 NaCl and at different metal ion concentrations. Changes in pH were monitored with a glass electrode calibrated daily in hydrogen ions concentrations. The titration data within the pH range of 2.5-9.99 were analyzed to determine stability constants of hydroxide species using the SUPERQUAD program. Several different species were considered during the calculation procedure and the following hydroxides have been characterized: Ga(OH)3, Ga(OH)4- Ga3(OH)112-, Ga4(OH)11+ and Ga6(OH)153+. Speciation calculations based on the determined constants were then used to simulate the species distribution.