• 방사성폐기물학회지
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• 제15권2호
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• pp.101-116
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• 2017

KURT(KAERI Underground Research Tunnel) 지하수에 존재하는 천연 유기물질과 6가 우라늄(U(VI))화학종의 상호작용을 레이저 분광학 기술을 이용하여 조사하였다. 지하수 시료에 266 nm 파장의 레이저 빛을 입사시켜 자외선 및 파란색 파장 영역에서 방출되는 천연 유기물질의 발광 스펙트럼을 관측하였다. $0.034-0.788mg{\cdot}L^{-1}$ 농도 범위의 우라늄이 함유된 지하수에서는 녹색 파장 영역에서 방출되는 U(VI) 화학종의 발광 스펙트럼을 측정하였다. 지하수에 함유된 U(VI) 화학종의 발광 특성(피크 파장 및 발광 수명)이 실험실에서 제조한 표준용액에 함유된 $Ca_2UO_2(CO_3)_3(aq)$의 발광 특성과 매우 유사하다는 것을 확인하였다. 지하수에 존재하는 U(VI) 화학종의 발광 세기는 표준용액에 함유된 같은 농도의 $Ca_2UO_2(CO_3)_3(aq)$의 발광세기에 비해 약하다. 표준용액의 $Ca_2UO_2(CO_3)_3(aq)$를 천연 유기물질이 함유된 지하수에 섞었을 때에도 $Ca_2UO_2(CO_3)_3(aq)$의 발광 세기가 감소한다. 이러한 현상의 원인을 지하수의 천연 유기물질과 Ca-U(VI)-탄산염 화학종의 상호작용으로 인해 비발광성 U(VI) 착물이 형성되기 때문인 것으로 설명하였다.

• 한국의류학회지
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• 제14권2호
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• pp.98-103
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• 1990

Fibrous adsorbents containing amidoxime group which make chelate complexes with uranyl ions are studied for the recovery of uranium from sea water. Acrylic fibers are used as base Polymer. The adsorption properties of uranium are carried out to examine pH effect, concen-tration dependence, adsorption rate, separation, and chelate complex. The results obtained are as follows; 1. Metal capacity of U (VI) ion is in the range of pH $2\~10.2$. Amidoxime group-containing fiber recover U (VI) ions existed in sea water or waste water in extremely small quantities. 3. Using amidoxime group-containing fiber Cu (II) and U (VI) are separated with each other in dilute nitric acid solution (pH 2.3). 4. U (VI) chelate complexes are conformed by tridendate ligands, which are coordinated with one nitrogen and two oxygens onto amidoxime group-containing fiber.

• Advances in environmental research
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• 제2권3호
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• pp.245-260
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• 2013

Biosorption represents a technological innovation as well as a cost effective excellent remediation technology for cleaning up radionuclides from aqueous environment. In the present study, a bacteria strain FB12 with high adsorption rate of uranium ion was isolated from the vicinity of the nuclear power plant. It was tentatively identified as Bacillus sp.FB12 according to the 16S rDNA sequencing. Efforts were made to further improve the adsorption rate and genetic stability by UV irradiation and UV-LiCl cooperative mutagenesis. The improved strain named Bacillus sp.UV32 obtains excellent genetic stability and a high adsorption rate of 95.9%. The adsorption of uranium U (VI) by Bacillus sp.UV32 from aqueous solution was examined as a function of metal ion concentration, cell concentration, adsorption time, pH, temperature, and the presence of some foreign ions. The adsorption process of U (VI) was found to follow the pseudo-second-order kinetic equation. The adsorption isotherm study indicated that it preferably followed the Langmuir adsorption isotherm. The thermodynamic parameters values calculated clearly indicated that the adsorption process was feasible, spontaneous and endothermic in nature. These properties show that Bacillus sp.UV32 has potential application in the removal of uranium (VI) from the radioactive wastewater.

• Carbon letters
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• 제4권2호
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• pp.64-68
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• 2003

A study on the electrosorption of uranium ions onto a porous activated carbon fiber (ACF) was performed to treat uraniumcontaining lagoon sludge. The result of the continuous flow-through cell electrosorption experiments showed that the applied negative potential increased the adsorption kinetics and capacity in comparison to the open-circuit potential (OCP) adsorption for uranium ions. Effective U(VI) removal is accomplished when a negative potential is applied to the activated carbon fiber (ACF) electrode. For a feed concentration of 100 mg/L, the concentration of U(VI) in the cell effluent is reduced to less than 1 mg/L. The selective removal of uranium ions from electrolyte was possible by the electrosorption process.

• 환경위생공학
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• 제15권4호
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• pp.114-122
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• 2000

Several new ion exchange resins have been synthesized from chloromethyl styrene-1,4-divinylbenzine with 1%, 2%, 5% and 105-crosslink and macrocyclic ligands of cryptand type by interpolymerization method. The adsorption characteristics and the pH, time, solvents and concentration dependence of the adsorption of uranium ion by this resins were studied. The resins were very stable in both acidic and basic media and have good resistance to heat at $300^{\circ}C$. The uranium ion are not adsorbed on the resins below pH 3.0, but the power of adsorption of it increased rapidly above pH 4.0. The optimum equilibrium time for adsorption of uranium ion was two hours and adsorptive power decreased in proportion to crosslink size of the resins and order of dielectric constants of solvents used and the adsorption for uranium ion was bin the order of $OdienNtn-H_4$ > $OtnNen-H_4$ > $OtnNen-H_4$ > $OenNen-H_4$.

• 대한화학회지
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• 제38권7호
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• pp.502-508
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• 1994

염의 농도가 큰 시료용액중에 미량으로 함유되어 있는 U(VI)과 Th(VI)을 액상크로마토그래피로 동시에 분리, 정량하였다. 약 2ml의 시료를 pH5.5의 0.11M ${\alpha}$-HIBA 용리액과 함께 C_{18}$ 역상농축컬럼에 통과시켜 U(VI)과 Th(VI)을 농축시켰으며, 농축된 이들 원소들을 다시 비활성 C_{18}$ 역상분리컬럼에서 pH3.0의 0.17M ${\alpha}$-HIBA/0.0038 M 1-pentanesulfonate 용리액으로 각각 분리하였다. 분리된 이들 원소들은 Arsenazo III를 사용하는 postcolumn반응으로 검출되었으며, 검출한계는 두 원서 모두 1ppb이었다.

• 방사성폐기물학회지
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• 제18권4호
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• pp.497-508
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• 2020

In the geochemical field, the chemical speciation of hexavalent uranium (U(VI)) has been widely investigated by performing measurements to determine its luminescence properties, namely the excitation, emission, and lifetime. Of these properties, the excitation has been relatively overlooked in most time-resolved laser fluorescence spectroscopy (TRLFS) studies. In this study, TRLFS and continuous-wave excitation-emission matrix spectroscopy are adopted to characterize the excitation properties of U(VI) surface species that interact with amorphous silica. The luminescence spectra of U(VI) measured from a silica suspension and silica sediment showed very similar spectral shapes with similar lifetime values. In contrast, the excitation spectra of U(VI) measured from these samples were significantly different. The results show that distinctive excitation maxima appeared at approximately 220 and 280 nm for the silica suspension and silica sediment, respectively.

• 환경위생공학
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• 제18권2호
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• pp.9-15
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• 2003

Resins have been synthesized from chlormethyl styrene 1,4- divinylbenzene(DVB) with 1%, 4%, and 20%-crosslinked and macrocyclic ligand of cryptand type by copolymerization method and the adsorption of uranium(VI), nickel(II) and lutetium(III) ions have been investigated in various experimental conditions. The correlation between the adsorption characteristics of rare earths and transition metal on the resins and stability constants of complexes with macrocyclic ligand have been examined. The uranium ion was not adsorbed on the resins below pH 2.0, but the power of adsorption of uranium ion increased rapidly above pH 3.0. The adsorption power was in the order of 1%, 4% and 20%-crosslinked resin, but adsorptive characteristics of resins decreased in proportion to the order of dielectric constants of solvents.

• Journal of Radiation Protection and Research
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• 제48권2호
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• pp.77-83
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• 2023

Background: The purpose of this study is to purify uranium (U[VI])-contaminated soil-flushing effluent using the precipitation-distillation process for clearance. Precipitation and distillation are commonly used techniques for water treatment. We propose using a combination of these methods for the simple and effective removal of U(VI) ions from soil-flushing effluents. In addition, the U concentration (Bq/g) of solid waste generated in the proposed treatment process was analyzed to confirm whether it satisfies the clearance level. Materials and Methods: Uranium-contaminated soil was decontaminated by soil-flushing using 0.5 M sulfuric acid. The soil-flushing effluent was treated with sodium hydroxide powder to precipitate U(VI) ions, and the remaining U(VI) ions were removed by phosphate addition. The effluent from which U(VI) ions were removed was distilled for reuse as a soil-flushing eluent. Results and Discussion: The purification method using the precipitation-distillation process proposed in this study effectively removes U(VI) ions from U-contaminated soil-flushing effluent. In addition, most of the solid waste generated in the purification process satisfied the clearance level. Conclusion: The proposed purification process is considered to have potential as a soil-flushing effluent treatment method to reduce the amount of radioactive waste generated.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2005년도 춘계 학술대회
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• pp.239-247
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• 2005

본 연구에서는 현재 국내에서 잠재적인 완충재 물질로 고려되고 있는 경주산 칼슘벤토나이트에서 발생되는 벤토나이트 콜로이드를 대상으로 대표적인 악티나이드 핵종이며 고준위 핵종인 우라늄(VI)에 대한 수착특성에 대한 실험적 연구를 수행하였다. 실험에 사용될 벤토나이트 콜로이드의 농도 및 크기를 여과법을 사용하여 측정한 결과 벤토나이트 콜로이드 원액의 농도는 약 5100ppm 이고 $98\%$ 이상의 콜로이드들이 200-450nm 크기 사이에 존재하는 것으로 나타났다. 우라늄 수착실험에 대한 공시험을 수행하여 수착반응 용기 벽면에 의해, 침전에 의해, 한외여과 또는 콜로이드 형성에 의해 손실된 우라늄 양을 평가하였다. 한외여과에 의한 우라늄 손실의 경우 이온강도가 낮은 경우에(즉, 0.001M $NaClO_4$의 경우) 한외여과 필터의 표면전하 역전에 의한 양이온 수착 영향으로 매우 높은 핵종 손실을 유발하였다. 벤토나이트 콜로이드에 대한 우라늄(VI)의 수착 분배계수(의사콜로이드 형성상수)는 pH에 따라 $10^4^{\sim}10^6$ mL/g 정도의 값을 가지는 것으로 관측되었으며 중성 영역인 pH 6.5 근처에서 최대값을 가지는 것으로 나타났다.