• Journal of environmental and Sanitary engineering
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• v.15 no.4
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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 $OdienNtn-H_4$ > $OtnNen-H_4$ > $OtnNen-H_4$ > $OenNen-H_4$.

• Journal of environmental and Sanitary engineering
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• v.23 no.2
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• pp.47-53
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• 2008

The ion exchange resins have been synthesized from chloromethyl styrene (dangerous matter) 1, 4-divinylbenzene(DVB) with 1%, 5%, and 15%-crosslinked and macrocyclic ligand of cryptand type by copolymerization method and the adsorption of uranium(VI), cobalt(II) and europium(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%, 5% and 15%-crosslinked resin, but adsorptive characteristics of resins decreased in proportion to the order of dielectric constants of solvents.

• Analytical Science and Technology
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• v.21 no.2
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• pp.143-147
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• 2008

U(IV) ion, the valance state of uranium presumed at in a deep-depth disposal of a spent fuel, was prepared and separated from U(VI) ion. In order to prepare U(IV) ion, tests were performed by adding several reducing agents into a uranyl solution or by dissolution of uranium oxide in a mixed acid added with a reducing agent. The valance states of the uranium in the prepared solutions were identified by separating two ions with a Dowex AG 50W-X8 cation exchange resins and measuring the solutions using a laser-induced fluorescence spectroscopy. However, U(IV) and U(VI) were not separated by a Lichroprep Si60 exchange resin in the same separation condition of Pu(IV) and Pu(VI).

• Applied Chemistry for Engineering
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• v.9 no.4
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• pp.475-480
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• 1998

A study on the electrochemical reduction of uranium (VI) to uranium (IV) was carried out in the mixed phases of an organic phase with uranium (VI) and aqueous phase of nitric acid by use of a highly packed glassy carbon (GC) fiber column electrode system, and a model for in-situ electrolytic stripping of uranium (VI) was suggested. The electrochemical reduction of uranium (VI) occurred faster in organic phase than in aqueous phase of the mixed phases. The uranium stripping yield increased and then became constant with the increase of organic flow rate of the electrolytic system due to the increase of diffusion resistance of uranium ions in the organic phase into the aqueous phase. Aqueous flow rate, on the other hand, didn't affect the total uranium (VI) reduction current in the system. The system combined with electrochemical reduction was confirmed to be much more effective than the simple system without it in stripping uranium.

• Journal of environmental and Sanitary engineering
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• v.18 no.2
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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 Integrative Natural Science
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• v.6 no.2
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• pp.104-110
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• 2013

1-Aza-12-crown-4 macrocyclic ligand was combined with styrene (2th petroleum in 4th class hazardous materials) divinylbenzene copolymer having 1%, 2%, 3%, and 6% crosslinks by a substitution reaction, in order to synthesize resin. These synthetic resins were confirmed by chlorine content, elementary analysis and IR-spectrum. As the results of the effects of pH, equilibrium arrival time, crosslink of synthetic resin, and dielectric constant of a solvent on uranium ion adsorption for resin adsorbent, the uranium ion showed high adsorption at pH 3 or over and adsorption equilibrium of uranium ion was about 2 hours. In addition, adsorption selectivity for the resin in methanol solvent was the order of uranium ($UO_2{^{2+}}$) > iron ($Fe^{3+}$) > lutetium ($Lu^{3+}$) ions, adsorbability of the uranium ion was in the crosslinks order of 1%, 2%, 3%, and 6% was increased with the lower dielectric constant.

• Advances in environmental research
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• v.2 no.3
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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.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.18 no.4
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• pp.457-464
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• 2020

In this study, extraction of uranium(VI) from an aqueous nitric acid solution was investigated using tri-n-butyl phosphate (TBP) as an extractant in an ionic liquid, 1-alkyl-3-methylimidazolium bis (trifluoromethylsulfonyl)imide ([Cnmim][Tf2N]). The distribution ratio of U(VI) in 1.1 M TBP/[Cnmim][Tf2N] was significantly high when the concentration of nitric acid was low. The value of the distribution ratio decreased as the concentration of the nitric acid increased at lower acidities, and then increased with a nitric acid concentration of up to 8 M. This can be attributed to the different extraction mechanisms of U(VI) based on nitric acid concentrations. Thus, a cation exchange at low acidity levels and an ion-pair extraction at high acidity levels were suggested as the extraction mechanism of U(VI) in the TBP/[Cnmim][Tf2N] system.

• Journal of environmental and Sanitary engineering
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• v.22 no.3
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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.

• Journal of the Korean Society of Clothing and Textiles
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• v.14 no.2
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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.