• Journal of the Korean institute of surface engineering
• /
• v.16 no.4
• /
• pp.199-214
• /
• 1983

Up to this date, numerous methods of analysis of electroplating solutions are published. Some, however, need lots of works before reaching final results, or require high technique and special instruments, and also some are unaccurate due to unclearnes of end point. Like our undevelope countries, technicians of electoplating shops are most high school gradutes or under, and have not much knowledge on chemistry. Furthermore, those technicians have to control their plating solutions by themselves without having enough analytical laboratory equiIJment. Therefore, in this paper the simplest, besides accurate method is investigated after comparing nu.merous methods published. Among the methods of 'copper determinations from acid and alkaline copper plating baths, EDT A titration method are chosen, due to these methods are the simplest and fastest for the evaluation of metal content, without requiring any special instrument. For acid copper solutions, chelate titrations were accurate enough. Since the end point of titration of chelate method is variable according to the kind of .indicators androther metal's coexsistence as well as solution comIJonent, many difficulties were encountered from cyanide' copper, on the contrary of acid copper bath. PAN, PV, and MX indicators were tried, but it is found that MX is the best. In cyanide solution, due to cyanide is the masking reagent, elimination of this component is essential, and finally found that elimination eN- by precipitation with AgN03 solution was the simplest and the most accurate way among others. This method was very accurate for the new plating solutions even coexistence with organic brightners. However used solutions for long months running have to be predetermined the accurate copper value by thiosulfate method from time to time, before chelate titration by means of AgN03 precipitation. Always some constant deviatioJ;ls will be seen according to the solutions nature. Therefore those deviation values have to be compensated each time.

• Journal of the Korean Crystal Growth and Crystal Technology
• /
• v.23 no.2
• /
• pp.114-118
• /
• 2013

Separation/recovery of valuable metals such as nickel or tin from copper based alloys has recently attracted from the viewpoints of environmental protection and resource recycling. In this report, preliminary study on concentration and separation of nickel from copper based alloy dross using selective adsorption by chelate resin was performed. The chelate resin used in this study has absorbed copper ions more easily than nickel ions in the metal solution, which could allow the concentration/separation of the nickel from the copper base alloy solution. The final molar ratios of Ni and Cu ions in the two concentrated solutions were 70 and 99 % respectively after three-time flowing the solution through the chelate resin column.

• The Research Journal of the Costume Culture
• /
• v.11 no.3
• /
• pp.431-440
• /
• 2003

The purpose of this study is to investigate the feasibility of applying the chitosan for a natural mordant. The chitosan, a natural chelate macromolecule, is acquired from the crustacean. Investigation was focused on the change of the dyeability according to the chitosan treatment based on the Caesalpinia sappan and the color change of the dyed fabric according to the application of heavy metal mordant. The change of air permeability of the fabric with the dyeing condition was also investigated systematically. The effect of dyeing with/without mordant on the air permeability of the fabric after the chitosan treatment. It seems that the increase in the dye-uptake is attributable to the fact that chitosan forms a complex with the Caesalpinia sappan and Al during mordant dyeing of cotton fabric. For nylon fabric, the darkest color was achieved on the occasion of non-mordant dyeing of the fabric. The mordant treatment or chitosan treatment, however, reduced the dyeability. While the dyed nylon fabric could maintain the same air permeability as the grey nylon fabric, the cotton fabric lowered the air permeability after dyeing.

• Journal of Applied Biological Chemistry
• /
• v.49 no.1
• /
• pp.8-10
• /
• 2006

Compositions of methionine-metal chelates have been investigated by FT-IR and XRD studies to elucidate their molecular structures. It was concluded that Copamin and Zincamin contain a high percentage of crystalline products, presumably 2:1 Methionine-Cu or Zn complexes. On the contrary, FT-IR and XRD spectra of Ferramin didn't show any characteristics of the chelate and it was concluded to contain major components of starting $FeSO_4$ and methionine without chelation.

• Bulletin of the Korean Chemical Society
• /
• v.16 no.3
• /
• pp.211-214
• /
• 1995

The catalytic activities of palladium(0,Ⅰ,Ⅱ)-diphosphine complexes were investigated in styrene oxidation using H2O2 as terminal oxidant. The rates showed a dependence on the chelate ring patterns of complexes (PdCl2L); 5-membered ring (L=dppe: 1,2-bis(diphenylphosphino)ethane) < 6-membered ring (L=dppp: 1,3-bis(diphenylphosphino)propane) < 4-membered ring (L= dppm: bis(diphenylphosphino)methane). This sequence correlates with the ligand field strength and interactions between metal and phosphine ligands. Pd(Ⅱ,Ⅰ)-diphosphine complexes which are capable of making 4-membered chelate ring showed an enhancement of catalytic activities for styrene oxidation. The catalytic activities of Pd(0,Ⅰ,Ⅱ)-diphosphine complexes are described in terms of electronic and steric factors.

• Journal of the Korean Chemical Society
• /
• v.12 no.3
• /
• pp.81-84
• /
• 1968

Stabilities of chelates of 7-nitroso-8-hydroxyquinoline-5-sulfonate have been determined for divalent transition metal ions, Mn(Ⅱ), Fe(Ⅱ), Co(Ⅱ), Ni(Ⅱ), Cu(Ⅱ), and Zn(Ⅱ) by means of the Calvin-Bjerrum technique. Comparison of these stability constants with those obtained for 8-hydroxyquinoline, and 8-hydroxyquinoline-5-sulfonate shows that the observed differences are essentially the results of the lower basicity of the sulfonated group and different metal-ligand bond. The divalent metal chelate stability sequence is not in agreement with the reported metal orders for other chelating agents. The stabilities were found to follow the order Mn(Ⅱ) < Fe(Ⅱ) ${\approx}$ Co(Ⅱ) > Ni(Ⅱ) < Cu(Ⅱ) > Zn(Ⅱ).

• Journal of Environmental Health Sciences
• /
• v.18 no.2
• /
• pp.106-116
• /
• 1992

In order to examine the influences of diluent, DVB, and ligand content, in the adsorption velocities and capacities of chelating resins to heaw metal ions, the chelating resins containing the PO$_3$H, amide, and PO$_3$H+amide were prepared from AN-STR-DVB copolymer. The adsorption capacities of chelating resins were measured by ICP-AES. The major results of the studies are as follows: The optimized compositions of the chelating resins having the highest adsorptivity for the heavy metal ions were found to be DVB=7 wt%, toluene= 100 vol%. The adsorption rate of the chelating resins to the heaw metal ions was PO$_3$H > PO$_3$H+Amide > Amide in order.

• Korean Journal of Soil Science and Fertilizer
• /
• v.40 no.4
• /
• pp.311-325
• /
• 2007

The concept of metal bioavailability, rather than total metal in soils, is increasingly becoming important for a thorough understanding of risk assessment and remediation. This is because bioavailable metals generally represented by the labile or soluble metal components existing as either free ions or soluble complexed ions are likely to be accessible to receptor organismsrather than heavy metals tightly bound on soil surface. Consequently, many researchers have investigated the bioavailability of metals in both soil and solution phases together with the key soil properties influencing bioavailability. In order to study bioavailability changes various techniques have been developed including chemical based extraction (weak salt solution extraction, chelate extraction, etc.) and speciation of metals using devices such as ion selective electrode (ISE) and diffusive gradient in the thin film (DGT). Changes in soil metal bioavailability typically occur through adsorption/desorption reactions of metal ions exchanged between soil solution and soil binding sites in response to changes in environment factors such as soil pH, organic matter (OM), dissolved organic carbon (DOC), low-molecular weight organic acids (LMWOAs), and index cations. Increasesin soil pH result in decreases in metal bioavailability through adsorption of metal ions on deprotonated binding sites. Organic matter may also decrease metal bioavailability by providing more negatively charged binding sites, and metal bioavailability can also be decreases as concentrations of DOC and LMWOAs increase as these both form strong chelate complexeswith metal ions in soil solution. The interaction of metal ions with these soil properties also varies depending on the soil and metal type.

• Environmental Sciences Bulletin of The Korean Environmental Sciences Society
• /
• v.10 no.S_3
• /
• pp.139-148
• /
• 2001

Heavy metals such as Cu, Ni, Cd, and Pb were chemically extract from the contaminated soils using the chelating agents, EDTA and DTPA. These chemical extraction have been focused on its applicability to a wide range of soils. Results of extractive efficiency for heavy metal follow the order : Cu-EDTA $\geq$ Ni-EDTA > Pb-EDTA > Cd-EDTA > Cu-DTPA> Pb-DTPA. This result is coincided with order of conditional formation constants(Kr) of metal-chelate agent. The second study involved the recovery of the metals and EDTA from complex solutions by an electromembrane process. The overall processes of regeneration, recovery, and reuse were evaluated. The electrochemical studies showed that copper could be chosen as an electrode to plate Cd, Cu, and Pb. At least 95% of 75 of EDTA and associated Cu or Pb could be recovered by the electromembrane process. Recovery of Cd by electodeposition was not possible with the copper electrode. The percent EDTA recovery is equal to the percentage of metal electroplated from the chelates.

• Bulletin of the Korean Chemical Society
• /
• v.12 no.2
• /
• pp.219-224
• /
• 1991

New binuclear Ni(Ⅱ) and Cu(Ⅱ) complexes with various alkyl derivatives of 1,2-bis(1,3,6,8,10,13-hexaaza-1-cyclotetradecyl) ethane, in which two fully saturated 14-membered hexaaza macrocyclic subunits are linked together by an ethylene chain, have been synthesized by the one step template condensations of formaldehyde with ethylenediamine and appropriate primary alkyl amines in the presence of the metal ions. Each macrocyclic subunit of the double-ring macrocyclic complexes contains one alkyl pendant arm and has a square planar geometry with a 5-6-5-6 chelate ring sequence. The visible spectra and oxidation properties indicate that the metal-metal interaction of the binuclear complexes are not significant. Synthesis, characterization, and the properties of the complexes are presented.