• 한국미생물·생명공학회지
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• 제21권3호
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• pp.269-275
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• 1993

The aims of the present study are to examine the precipitation of uranyl ion in the culture of Desulfovibrio desulfricans for the sedimentary recovery of aqueous uranium. D. desulfricans had the highest utilization rate of lactate and precipitated iron ion in the three sulfate reducing bacteria. So, subsequent experiments were conducted using lactate as an energy source. The normal growth was observed with increased pH and lactate utilization. During the culture, the amounts of SO42- consumed and S2- produced in aqueous phase were 8.5 and 7.5 mmol/m3-broth, respectively.

• 환경위생공학
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• 제22권3호
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• pp.77-87
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• 2007

The ion exchange resins have been synthesized from chlormethyl styrene - 1,4 - divinylbenzene(DVB) with 1%, 3%, and 5%-crosslinking and macro cyclic ligand of OenNen-$H_4$ by copolymerization method and the adsorption characteristics of uranium(VI), iron(II) and samarium(III) metallic ions have been investigated in various experimental conditions. The synthesis of these resins was confirmed by content of chlorine, element analysis, and IR-spectrum. The effects of pH, time, dielectric constant of solvent and crosslink on adsorption of metallic ions were investigated. The uranium ion was showed fast adsorption on the resins above pH 3. The optimum equilibrium time for adsorption of metallic ions was about two hours. The adsorption selectivity determined in ethanol was in increasing order uranium ${UO_2}^{2+}>Fe^{2+}>Sm^{3+}$ ion. The adsorption was in order of 1%, 3%, and 5% crosslink resin and adsorption of resin decreased in proportion to order of dielectric constant of solvent.

• 환경위생공학
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• 제20권3호
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• pp.27-35
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• 2005

The ion exchange resins have been synthesized from chlormethyl styrene - 1,4 -divinyl-benzene(DVB) with $1\%,\;4\%,\;and\;10\%$-crosslinking and macrocyclic ligand of cryptand type by copolymerization method and the adsorption characteristics of uranium(VI), calcium(II) and lutetium(III) metallic ions have been investigated in various experimental conditions. The synthesis of these resins was confirmed by content of chlorine, element analysis, and IR-spectrum. The effects of pH, time, dielectric constant of solvent and crosslink on adsorption of metallic ions were investigated. The uranium ion was showed fast adsorption on the resins above pH 3. The optimum equilibrium time for adsorption of metallic ions was about two hours. The adsorption selectivity determined in ethanol was in increasing order uranium $(UO_2^{2+})>calcium(Ca^{2+})>lutetium(Lu^{3+})$ ion. The adsorption was order of $1\%,\;4\%,\;and\;10\%$ crosslink resin and adsorption of resin decreased in proportion to order of dielectric constant of solvents.

• Bulletin of the Korean Chemical Society
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• 제21권4호
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• pp.393-400
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• 2000

2,2￠-Dihydroxyazobenzene (DHAB) was attached to poly(ethylenimine) (PEI) to obtain DHAB-PEI. Spectral titration revealed that uranyl, Fe(III), Cu(II), and Zn(II) ion form 1 : 1-type complexes with DHAB attached to PEI. Formation constants for the metal complexes formed by the DHAB moieties of DHAB-PEI were mea-sured by using various competing ligands. The results indicated thatthe concentrations of uranyl, Fe(III), and Cu(II) ions can be reduced to 10 -16 -10 -23 M at p 8 with DHAB-PEI when the concentration of the DHAB moiety is 1 residue M. By using cyanuric chloride as the coupling reagent, DHAB-PEI was immobilized on Sephadex G-25 resin to obtain DHAB-PEI-Seph. Binding of uranyl,Fe(III), Cu(II), and Zn(II) ion by DHAB-PEI-Seph was characterized by using competing ligands. A new method has been developed for characteriza-tion of metal sequestering ability of a chelating resin. Formation constants and metal-binding capacity of two sets of binding sites on the resin were estimated for each metal ion. DHAB-PI-Seph was applied to recovery of metals such as uranium,Fe, Cu, Zn, Pb, V, Mn, and W from seawater. The uranium recovery from seawaterby DHAB-PEI-Seph does not meet the criterion for economical feasibility partlydue to interference by Fe and Zn ions. The seawater used in the experiment was contaminated by Fe and Zn and, therefore, the efficiency of uranium extractionfrom seawater with DHAB-PEI-Seph could be improved if the experiment is carried out in a cleaner sea.

• 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.

• 대한화학회지
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• 제5권1호
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• pp.84-87
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• 1961

A polarographic method for rapid determination of Uranium in the presence of foreign ions was proposed. The method is based on the measurement of polarogram in the sulfuric acid as supporting electrolyte. In this medium Uranyl ions give well defined reduction waves, and half-wave potentials are -0.19V vs. S.C.E. as first wave, and uncertain volt. vs. S.C.E. as second wave in $2.4 N-H_2SO_4.$ The first wave has a linear relationship between the concentration of Uranyl ion and wave height. The author also studied a method for rapid determination of Uranium in Korean monazite sand without eliminating the foreign ions. The Korean monazite sands were analyzed by this method and satisfactory result were obtained.

• Nuclear Engineering and Technology
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• 제31권5호
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• pp.445-454
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• 1999

This work describes the adaptation of extractive scintillation by URAE $X^{TM}$ with a photon-electron rejecting alpha liquid scintillation (PERAL $S^{)}$ spectrometer to the analysis of uranium in aqueous samples. The extraction efficiency of the system was evaluated under varing chemical conditions including pH, and sample-cocktail volume ratio. Isotopic information from the (PERAL $S^{)}$ spectrum of natural uranium was obtained using a curve fitting routine. Comparisons of the result with that obtained from alpha spectrometry method using ion implanted silicon detector showed good agreement.t.

• 대한화학회지
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• 제27권5호
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• pp.361-367
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• 1983

이온 교환수지에 의한 국산모나자이트 중에 함유된 우라늄을 분리, 회수하기 위하여 강염기성 이온교환수지(Amberlite IRA-900)에 S$O_4^{2-}$ 및 P$O_4^{3-}$ 이온을 흡착시켜 황산우라닐착이온, 인산우라닐착이온 형태로 우라늄을 흡착시켜 적당한 용리액(HN$O_3$ : N$NH_4NO_3$)으로 우라늄을 분리 회수하는 실험을 하였다. 표준우라늄을 사용하였을 때 황산형수지에서 99.3%, 인산형수지에서 99.2%까지 회수하였으며 모자나이트를 황산분해한 모나자이트 황산분해용액 중의 희토류원소들을 제거한 용액을 사용하였을 때는 약 92%까지 회수하였다. 모나자이트 중에 함유된 인산이온의 방해가 없는 것으로 나타났다. 인산형수지에서 우라늄의 회수율이 51% 정도인 것으로 보아 모나자이트를 황산으로 분해하였을 때는 대부분의 우라늄은 황산우라닐착이온으로 된다는 사실도 확인하였다.

• Nuclear Engineering and Technology
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• 제55권2호
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• pp.523-529
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• 2023

Cemented uranium tailings backfill created from alkali-activated slag (CUTB) is an effective method of disposing of uranium tailings. Using some environmental functional minerals with ion exchange, adsorption, and solidification abilities as backfill modified materials may improve the leaching resistance of the CUTB. Natural zeolite, which has good ion exchange and adsorption characteristics, is selected as the backfill modified material, and it is added to the backfill materials with cementitious material proportions of 4%, 8%, 12%, and 16% to prepare CUTB mixtures with environmental functional minerals. After the addition of natural zeolite, the uniaxial compressive strength (UCS) of the CUTB decreases, but the leaching resistance of the CUTB increases. When the natural zeolite content is 12%, the UCS reaches the minimum value of 8.95 MPa, and the concentration of uranium in the leaching solution is 0.28-8.07 mg/L, the leaching rate R₄₂ is 9.61×10^-7 cm/d, and cumulative leaching fraction P₄₂ is 8.53×10^-4 cm, which shows that the alkali-activated slag cementitious material has a good curing effect on the CUTB, and the addition of environmental functional minerals helps to further improve the leaching resistance of the CUTB, but it reduces the UCS to an extent.

• 폴리머
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• 제25권1호
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• pp.49-55
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• 2001

비닐계 단량체인 아크릴로니트릴과 스티렌을 E-beam 전조사법에 의해 폴리프로필렌 섬유에 그라프트 반응시켜 PP-g-(AN/St) 공중합체를 제조한 후 아미드옥심기와 슬폰기를 도입하여 이관능성 이온교환섬유를 제조하였다. 그라프트율은 단량체 내에 아크릴로니트릴의 조성이 감소할수록 증가하였으며 최대 101.1%이었고 최대 아미드옥심화율은 7.2 mmol/g이었다. 또한 섬유상 이온교환체의 초기 열분해 온도는 120 ${\circ}C$ 이었고 함수율은 공중합체 내에 아미드옥심화율이 증가할수록 감소하였고 슬폰화율이 증가할수록 증가하는 경향을 나타냈다. APP-g-AN, SPP-g-St, ASPP-g-(AN/St) 이온교환체의 우라늄 흡착량은 각각 12.4, 34, 38mg/g이었으며 최적 흡착시간은 약 50시간이었다. 우라늄 흡착 실험결과, 본 실험에서 합성한 이온교환체 ASPP-g-(AN/St)는 $UO_2^{2+}$에 대하여 우수한 성능을 보였다.