• Journal of Institute of Convergence Technology
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• v.3 no.2
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• pp.1-6
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• 2013

The ionic liquids are known to potential alternative solvents capable of replacing the commercial solvents in various processes including those in nuclear fuel cycle. As to the material, a number of studies have already reviewed the interesting results and addressed the spectroscopic as well as electrochemical behaviors of metal elements included in spent nuclear fuels. It has found that the important properties of metal ions in TBP dissolved ILs have led the development of alternative technologies to traditional solvent extraction processes. On the other hand, the electrochemical deposition of metal ions in ILs have been investigated for the application of the solvents to aqueous as well as to non-aqueous processes. In this work, a review on the application of ILs in nuclear fuel cycle is briefly presented to understand the notable researches on ILs focusing on aqueous processes.

• Journal of Environmental Science International
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• v.8 no.3
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• pp.393-397
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• 1999

Among various reactions which metal sulfides can undergo in the reducing environment, the lattice exchange reaction was examined in a attempt to selectively remove heavy metal ions contained in the Fe-Coagulants acid solution. We have examined Zeta potential along with pHs to investigate surface characteristics of ${FeS}_{(s)}$. As a result of this experiment, zero point charge(ZPC) of FeS is pH 7 and zeta potential which resulted from solid solution reaction between Pb(II) and ${FeS}_{(s)}$ is similar to that of ${PbS}_{(s)}$. Solubility characteristics of ${FeS}_{(s)}$ is appeared to that dissolved Fe(II) concentration increased in less than pH 4, and also increased with increasing heavy metal concentration. Various heavy metal ions(Pb(II), Cu(II), Zn(II)) contained in Fe-coagulants acid solution were removed selectively more than ninety-five percent in the rang of pH 2.5~10 by ${FeS}_{(s)}$. From the above experiments, therefore, We could know that the products of reaction between heavy metal ions and $FeS_{(S)}$ are mental sulfide such as $PbS_{(S)}$, $CuS_{(S)}$ and $ZnS_{(S)}$.

• Journal of the Korean Ceramic Society
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• v.56 no.4
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• pp.387-393
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• 2019

A N₂H₄-Cu(I)-HNO₃ solution was used to dissolve magnetite powders and a simulated oxide film on Inconel 600. The addition of Cu(I) ions to N₂H₄-HNO₃ increased the dissolution rate of magnetite, and the reaction rate was found to depend on the solution pH, temperature, and [N₂H₄]. The dissolution of magnetite in the N₂H₄-Cu(I)-HNO₃ solution followed the contracting core law. This suggests that the complexes of [Cu⁺(N₂H₄)] formed in the solution increased the dissolution rate. The dissolution reaction is explained by the complex formation, adsorption of the complexes onto the surface ferric ions of magnetite, and the effective electron transfer from the complexes to ferric ions. The oxide film formed on Inconel 600 is satisfactorily dissolved through the successive iteration of oxidation and reductive dissolution steps.

• Macromolecular Research
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• v.16 no.2
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• pp.108-112
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• 2008

Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) analysis of nonpolar polymeric materials is affected by the sample preparation as well as the matrix and cationizing agent. This study examined the influence of silver salt types on the MALDI analysis of polybutadiene (PB). Silver trifluoroacetate (AgTFA), silver benzoate (AgBz), silver nitrate ($AgNO_3$), and silver p-toluenesulfonate (AgTS) were used as the silver salts to compare the MALDI mass spectra of PB. The mixture solution of PB and 2,5-dihydroxybenzoic acid (DHB), as a matrix dissolved in THF, was spotted on the sample plate and dried. A droplet of the aqueous silver salt solution was placed onto the mixture. The mass spectrum with AgBz showed the clear $[M+Ag]^+$ ion distribution of PB while the mass spectrum with AgTFA did not show $[M+Ag]^+$ ions but only silver cluster ions. The mass spectra with $AgNO_3$ and AgTS did not show a clear $[M+Ag]^+$ ion distribution. The difference in the formation of $[M+Ag]^+$ ions of PB depending on the silver salts was attributed to the silver cation transfer reaction between the silver salt and the matrix (DHB). The mass spectrum showed a clear $[M+Ag]^+$ ion distribution of PB when the conjugate acid of the silver salt was less acidic than the matrix.

• Bulletin of the Korean Chemical Society
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• v.26 no.11
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• pp.1891-1894
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• 2005

• Bulletin of the Korean Chemical Society
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• v.16 no.5
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• pp.422-427
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• 1995

In a stream of water sample, trace metal ions are quantitatively coprecipitated with Indium hydroxide and filtered. The filtered precipitate is continuously dissolved in 3 M nitric acid and introduced to ICP directly. The lead, cadmium, and copper are concentrated more than 10-fold and determined with ICP-AES at a sampling frequency of 10/hour. The detection limits are 2.89, 1.43,0.52 ppb for lead, cadmium, and copper respectively. Recoveries of lead, cadmium, and copper are 98.7, 94.3, and 104.5% respectively. The RSD values for three elements are about 3-5% currently.

• Bulletin of the Korean Chemical Society
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• v.33 no.3
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• pp.790-794
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• 2012

Trace metal ions such as $Cd^{2+}$, $Ni^{2+}$, and $Zn^{2+}$ in a highly saline sample were subjected to on-line complexation with 4-(2-thiazolylazo) resorcinol (TAR) dissolved in a background electrolyte (BGE) under transient isotachophoresis (TITP) conditions. A long plug of the saline sample, containing the trace metal ions but devoid of TAR, was injected into a coated capillary filled with a BGE composed of 150 mM 2-(cyclohexylamino) ethanesulfonic acid (CHES) and 110 mM triethylamine (TEA) at pH 9.7. Since the electrophoretic mobility of TAR fell between the mobilities of the anionic leading electrolyte ($Cl^-$ in the sample) and the anionic terminating background electrolyte ($CHES^-$), a highly concentrated zone of TAR from the BGE was formed at the rear of the sample matrix and then the metal cations toward the cathode were swept by isotachophoretically assisted on-line complexation (IAOC) between the metal ions and the isotachophoretically stacked TAR. As a result, anionic metal-TAR complexes were formed efficiently, which satisfy the TITP conditions between $Cl^-$ and $CHES^-$. The enrichment factors of metal ions including $Cd^{2+}$ were up to 780-fold compared to a conventional CZE mode using absorbance detection. The detection limits were 17 nM, 15 nM, and 27 nM for $Ni^{2+}$, $Zn^{2+}$, and $Cd^{2+}$ in a 250 mM NaCl matrix, respectively. Our method was successfully applied to the analysis of urine samples without desalting.

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

• Mass Spectrometry Letters
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• v.3 no.2
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• pp.54-57
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• 2012

Mass spectrometric analysis was carried out using multicollector inductively coupled plasma mass spectrometry (MC-ICP-MS) for the precise and accurate determination of the isotope ratios of ultratrace levels of uranium dissolved in 3% $HNO_3$. We used the certified reference material (CRM) 112-A at a trace level of 100 pg/mL for the uranium isotopic measurement. Multiple collectors were utilized for the simultaneous measurement of uranium isotopes to reduce the signal uncertainty due to variations in the ion beam intensity over time. Mass bias correction was applied to the measured U isotopes to improve the precision and accuracy. Furthermore, elemental standard solution with certified values of platinum, iridium, gold, and thallium dissolved in 3% $HNO_3$ were analyzed to investigate the formation rates of the polyatomic ions of $Ir^{40}$ $Ar^+$, $Pt^{40}$ $Ar^+$, $Tl^{40}$ $Ar^+$, $Au^{40}$ $Ar^+$ for the concentration range of 50-400 pg/mL. Those polyatomic ions have mass-to-charge ratios in the 230-245 m/z region that it would contribute to the increase of background intensity of uranium, thorium, plutonium, and americium isotopes. The effect of the polyatomic ion interference on uranium isotope measurement has been estimated.

• Proceedings of the Korea Water Resources Association Conference
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• 2023.05a
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• pp.247-247
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• 2023

Coastal lagoons play a crucial role in water exchange, water quality, and biodiversity. It is essential to monitor and understand the dynamics of hydrogeochemistry in lagoon water and its groundwater to preserve and sustainably manage the groundwater-dependent ecosystems like coastal lagoons. This study investigated the spatial and temporal hydrogeochemical characteristics of coastal lagoon (Songjiho) and groundwater on the east coast of Korea. The concentrations of major ions, water isotopes, and nutrients (nitrogen and dissolved organic carbon) in lagoon water and groundwater were periodically monitored for one year. The study revealed that major ions and total dissolved solids (TDS) concentration were higher at deeper depths of aquifers and closer to the coastal area. The hydrogeochemical characteristics of coastal lagoon and groundwater chemistry were classified into two types, Ca-Mg-HCO₃ and Na-Cl, based on their spatial location from inland to coastal area. Moreover, the hydrogeochemical characteristics of coastal lagoons and groundwater varied significantly depending on the season. During the wet season, the increased precipitation and evaporation lead to changes in water chemistry. As a result, the total organic carbon (TOC) of coastal lagoons increases during this season, likely due to increased runoff by rainfall whereas the variation of chemical compositions in the lagoon and groundwater were not significant because there is reduced precipitation, resulting in stable water levels and during the dry season. The study emphasizes the impact of spatial distribution and seasonal changes in precipitation, evaporation, and river discharge on the hydrogeochemical characteristics of the coastal aquifer and lagoon system. Understanding these impacts is crucial for managing and protecting coastal lagoons and groundwater resources.