• Nuclear Engineering and Technology
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• v.13 no.4
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• pp.237-244
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• 1981

The preliminary concentration of trace elements in uranium dioxide using an anion exchange resin is presented for neutron activation analysis. The uranyl solution in sulfuric acid is adjusted to the acidity of about pH 2.7 and loaded on a column of the anion exchange resin. An appropriate volume of eluates obtained from the column shows good recoveries of trace elements. By combining this preconcentration with a radiochemical separation scheme, which was developed for the determinations of impurities in aluminum, it is possible to determine 21 trace elements in reactor grade uranium dioxide.

• Journal of the Korean Chemical Society
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• v.37 no.9
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• pp.813-819
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• 1993

An ICP-AES system directly connected with a separation column was used in order to determine the trace elements in $UO_2$ powder promptly and reduce the volume of the waste solution. The outlet of a separation column, which was filled with Teflon powder ($330\;{\mu}m$) coated with tri-n-butyl phosphate (TBP) as extractant, was directly connected with sample injection tube of ICP-AES. Eleven elements including molybdenum in $UO_2$ powder were separated and determined simultaneously. Recoveries of these elements were $91{\sim}110%$ and these results were agreed with those of solvent extraction methods. This method was applicable to quality control in manufacturing nuclear fuel.

• Journal of the Korean Society for Marine Environment & Energy
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• v.8 no.4
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• pp.213-219
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• 2005

In this study, we try to Quantitatively assess the micropollutants in Gwangyang bay, Gamag bay and Yeoa bay, using simultaneous analytical method fir 310 chemicals. In the results, several dozen organic pollutants were detected in sampling sites, and the major chemicals detected were CH type chemicals, such as aliphatic and polycyclic compounds, and CHN(O) type chemicals, such as aromatic ammines and nitro compounds. The concentration of organic pollutants was higher in summer than in winter. However, there was no association of species of organic pollutants with season. The total concentration of pesticides at each sampling site was measured within the range of $ND{\sim}9.11{\mu}g/L$. Insecticides and fungicides of pesticide type were detected in Gwangyang bay and Gamag bay, while six kinds of endocrine disrupter were detected in southern coastal waters. From the results of this study, we should estimated that the insecticides, the fungicides, and a few of the endocrine disrupters are major pollutant factors in southern coastal waters.

• The Sea:JOURNAL OF THE KOREAN SOCIETY OF OCEANOGRAPHY
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• v.19 no.2
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• pp.155-163
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• 2014

Total concentration and chemical speciation of trace metals (Cu, Pb, Zn, Cd, and Ni) were determined to evaluate pollution level and potential ecological risk in surface sediments of the Masan Bay. The results showed that the trace metal concentrations, except for Ni, were high in the inner Masan Bay. Based on the chemical speciation of metals in sediments, the percentage of total concentrations of Cd and Pb in non-residual fraction was 92% and 88%, respectively, indicating that these metals originated mainly from anthropogenic sources. However, Ni (70%) was dominant in residual fraction. Pollution load index (PLI) and ecological risk index (ERI) values in the inner bay indicate the presence of anthropogenic pollution and considerable-moderate ecological risk, respectively. Ecological index (Ei) value for Cd was high at most stations in the Masan Bay, and Cd content was the highest in acid soluble fraction, which presents the highest ecological risk. The results obtained in this study indicate that Cd presents a high potential ecological risk to benthic biota in the Masan Bay.

• Economic and Environmental Geology
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• v.39 no.3 s.178
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• pp.213-227
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• 2006

The geochemical evolution of mine drainage and leachate from waste rock dumps and stream water in Pb-As-rich abandoned Sechang mine area was investigated to elucidate mechanisms of trace metals. Total and sequential extractions were applied to estimate the distribution of trace metals in constituent phases of the waste rocks and to assess the mobility of trace metals according to physicochemical conditions. These discharged waters varied largely in chemical composition both spatially and temporally, and included cases with significant]y low pH (in the range 2.1-3.3), and extremely sulphate (up to 661 mg/l and metal contents (e.g. up to 169 mg/l for Zn, 27 mg/l for As, 3.97 mg/l for Pb, 2.99 mg/l for Cu, and 1.88 mg/l for Cd). Arsenic and heavy metal concentrations at the down-stream of Sechang mine have been decreased nearly to the background level in downstream sites (sites 8 and 16) without any artificial treatments. The oxidation of Fe-sulfides and the subsequent hydrolysis, of Fe(II), with precipitation of poorly crystallized minerals, constituted an efficient mechanism of natural attenuation which reduces considerably the transference of trace metals (i.e. Fe and As) to rivers. The dilution of drainage by mixing with pristine waters provoked an additional decrease of trace metal concentrations and a progressive pH increase. On the other hand, the most soluble cations (i.e. Zn) remained significantly as dissolved solutes until the pH was raised to approximately neutral values. With respect to ecotoxicity, it is likely that the Zn pollution is of particular concern in Sechang mine area. This was confirmed by the sequential extraction experiment, where Zn in wet waste-rock samples occurred predominantly in the exchangeable fraction (65-89% of total), while Pb was the highest in the reducible and carbonate fractions, and Cd, Cu and As in the residual fraction. Pb concentration in the readily available exchangeable fraction (34-48% of total) was dominated for dried waste rock samples. Considering the proportion of metals bound to the exchangeable and carbonate fractions, the comparative mobility of metals probably decreased in the order of Zn>Pb>Cd>As=Cu.

• Resources Recycling
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• v.7 no.5
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• pp.52-57
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• 1998

Effect of Si in the electrochemical corrosion characteristics of Mg-Li-Al light alloy has been investigated by means of potentiodynamic polarization study. The elecrochemical behaviors were evaluated in 003% NaCl solution and the solution buffered with KH$_{2}PO_{5}{\cdot}$NaOH at room temperature. It was found that the addition of very small quantity of Si (0.48 wt%) in Mg-Li-Al light alloy increased corrosion rates and amount of corrosion products and decreated the pitting resistance of the alloy. From the results it was concluded that Si which is added to increase the strength of Mg-Li-Al alloy is harmful to corrosion properties of the alloy.

• Proceedings of the Korea Air Pollution Research Association Conference
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• 2003.05b
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• pp.320-321
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• 2003

대기중에 존재하는 입자상물질은 광범위한 입경역에 걸쳐서 다종다양한 미량화학성분으로 구성되는 분산체이고, 그 성상은 공간적으로도 시간적으로도 크게 변동한다. 입자상 물질의 화학분석법은 발생원 동정을 위한 자료로 적합하며 일반적으로는 습식의 파괴적인 원소분석으로 하는 경우가 많다. 일반적으로 화학적 분석법은 개별입자의 정보가 무시되며 필터에 포집된 bulk 시료에 의한 분석이 진행되므로 장시간 포집에 의한 단시간의 시간변동과 개개의 입자가 가지는 정보가 무시되고 평균화 되어버린다. (중략)

• Korean Chemical Engineering Research
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• v.51 no.6
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• pp.645-654
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• 2013

In this study, the management polices of micropollutants (MPs) were reviewed and the future management strategy was discussed considering climate change and etc. In Korea, the investigation of drinking water has been actively carried out for the priority contaminants as well as MPs. Recently river and lake waters have been also examined for MPs. However, the coverage and depth of the investigation is limited. Moreover, climate change is likely to increase air & water temperature and it will affect the hydrological cycle. Such changes may increase the residual concentrations of MPs in water system. As water reuse increases, the residual MPs of the recycled water may create public concerns. Thus, in a viewpoint of the precautionary principle, more stringent management of MPs is recommended for the drinking water and the body-contact water use. For the surface water, more studies are necessary to understand the ecological risk by MPs.

• Journal of the Korean Chemical Society
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• v.16 no.6
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• pp.373-377
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• 1972

The analytical conditions for the fluorescence X-ray determination of small amount of cupper in solution were established. Copper in solution was extracted by diethyldithiocarbamate ethyl acetate and adsorbed by zinc powder. After drying, it was pressed to tablet under the pressure of $250Kg/cm^2.$$K_{\alpha}2(2{\theta}_{LiF} = 45.08^{\circ})$. The limit of detection was estimated to be about $10{\mu}g$ by the method of standard addition with an error of 10 %.

• The Microorganisms and Industry
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• v.15 no.2
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• pp.50-53
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• 1989

이 글은 물질의 분리과정과 구조결정에 관련되는 단계, 방법들에 대하여 개술하였다. 물질의 분리에서는 분리매질에 있어서 분리하고자 하는 물질의 특이한 물성을 이용할 수 있는 매질의 개발이 지속될 것으로 생각되며, 구조결정의 각방법들에서도 software의 발달로 미량의 물질로부터 구조를 결정할 수 있는 방향으로 진전할 것이다.