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1.
K. V. Chetty P. M. Mapara Rajendra Swarup S. K. Patil 《Journal of Radioanalytical and Nuclear Chemistry》1988,121(1):149-159
The extraction of U(VI) by mixtures of HTTA and TBP from aqueous thiocyanate medium has been studied. From the data obtained it was observed that the predominant uranium species extracted, causing synergic enhancement in the extraction of U(VI), is UO2(SCN)TTA · 2TBP when benzene and cyclohexane are used as diluents, and that at a very low concentration of TBP the contribution of additional species, viz. UO2(TTA)2 · TBP becomes significant. With chloroform as diluent, however, both of these species are contributing to the synergic enhancement. The extraction of a quaternary uranium species, UO2(SCN)TTA · 2TBP, involving the participation of the aqueous anion is thus established. Equilibrium constants for the various extraction equilibria involved are calculated. 相似文献
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Study on the ternary synergistic extraction of uranium/VI/ by chelating-chelating-neutral extractant
Chen Yude Mao Jiajun Fu Lei Li Xintai 《Journal of Radioanalytical and Nuclear Chemistry》1987,108(1):41-53
The synergic extraction of uranyl nitrate from chloroform media with 1-phenyl-3-methyl-4-benzoyl-pyrazonole-5 /PMBP/, tributylphosphate /TBP/ and thenoyltrifluorylacetone /TTA/ was studied. It was found that synergic effect occurs during the extraction of uranyl nitrate with the chloroform solution of PMBP-TTA-TBP. The formation of the ternary extracted complex UO2AA'B was confirmed by the usual slope method. A method was proposed for the calculation of the ternary equilibrium constant which was evaluated to be 1gK111=2.65. Also the binary synergic extractions of uranyl nitrate with PMBP-TBP and TTA-TBP were studied. The binary equilibrium constants were found to be 1gK201=3.07 and 1gK021=1.39, respectively. An attempt has been made to interpret the data mainly on the basis of statistical factor. 相似文献
4.
Liu Wen-Tao Zeng Shan Yang Yan-Zhao Han Jian Zhu Tao Luo Chang-Hong 《Journal of Radioanalytical and Nuclear Chemistry》2004,261(2):315-317
The i-butyldodecylsulfoxide (BDSO) was synthesized. The extraction of uranium(VI) has been carried out with BDSO in toluene from various HNO3 concentrations. It was found that the distribution ratio increases with increasing nitric acid concentration up to 3.0 mol/l and then decreases. The distribution ratios also increase with increasing extractant concentration. The extracted species appears to be UO2(NO3)2·2BDSO and the equilibrium constant value is 15.2. The influence of temperature, sodium nitrate and oxalate concentrations on the extraction was also investigated, and the thermodynamic functions of the extraction reaction were obtained.This revised version was published online in November 2005 with corrections to the Cover Date. 相似文献
5.
Yang Yan-Zhao Sun Si-Xiu Feng Sheng-Yu 《Journal of Radioanalytical and Nuclear Chemistry》2002,251(3):503-506
The liquid-liquid extraction behavior of 2-ethylhexyltolylsulfoxide (EHTSO) towards uranium(VI) contained in nitric acid aqueous solution has been investigated. It was found that the extraction increases with increasing nitric acid concentration up to 5.0 mol/l and then decreases. Extraction also increases with increasing extractant concentration. The extracted species appears to be UO2(NO3)2
.2EHTSO. The influences of temperature, NH4NO3 and Na2C2O4 concentrations on the extraction equilibrium were also investigated and the thermodynamic functions of the extraction reaction were obtained. 相似文献
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Equilibrium distribution ratios have been determined for uranium(VI) with oxine between chloroform and 0.1M perchlorate as a function of pH and reagent concentration at 20 degrees . It is concluded that the extractable complex is UO(2)Ox(2)HOx. The equilibrium constants for the extraction of uranium have been determined as K(u,1) = [UO(2)Ox(2)HOx](0)/[UO(2)(2+)][Ox(-)](3)[H(+)] = 10(36.18) at low pH and K(U,2) = [UO(2)Ox(2)HOx](0)/[UO(2)Ox(2)OH(-)][Ox(-)][H(+)](2) = 10(25.40) at high pH. 相似文献
8.
R. N. Mohanty S. Singh V. Chakravortty K. C. Dash 《Journal of Radioanalytical and Nuclear Chemistry》1991,152(1):21-29
The order of extraction of Mo(VI) from 1M acid solutions by 5% (v/v) LIX 622 (HL) in benzene is HCl>HNO3>HClO4>H2SO4, and extraction decreases with increasing concentration of HCl and H2SO4, and increases slightly with increasing concentration of HNO3 and HClO4. The extracted species is shown to be MoO2L2 as established by IR data of organic extracts and the extracted species in the solid form. Extraction is almost quantitative at and above 10% LIX 622, and is found to be independent of [Mo(VI)] in the range of 10–4 to 10–3 M. The diluents CCl4, CHCl3 and C6H6 are found to be superior to solvents of high dielectric constant for extraction of Mo(VI). Extraction of uranium(VI) by 10% (v/v) LIX 622 in benzene was found to increase with increasing equilibrium pH (3.0 to 6.0), and becomes quantitative at pH 5.9. Tributyl phosphate acts as a modifier up to 2% (v/v). Thorium(IV) is almost not extracted by LIX 622 or its mixture. Separation of Mo(VI) and U(VI) is feasible. 相似文献
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Yang Yan-Zhao Yang Yong-Hui Jiang Xu-Chuan Sun Si-Xiu Bao Bo-Rong 《Journal of Radioanalytical and Nuclear Chemistry》1999,240(1):335-338
The effect of diluents on the extraction of uranium(VI) with petroleum sulfoxides (PSO) was studied. The decreasing order
of extraction ability of PSO is as follows: benzene, toluene, cyclohexane, heptane, kerosene, carbon tetrachloride and chloroform.
The effect of temperature on the extraction equilibrium was also investigated and enthalpy of the extraction was obtained.
The relationship between the extraction equilibrium constantsK
ex
and the physical parameters of diluents can be derived. 相似文献
10.
Li Lin Yang Yan-Zhao Zeng Shan Zhu Tao Sun Si-Xiu 《Journal of Radioanalytical and Nuclear Chemistry》2005,266(2):355-359
Summary The synergistic extraction of uranium(VI) from aqueous nitric acid solution with a mixture of tri-n-butyl phosphate (TBP)
and i-butyldodecylsulfoxide (BDSO) in toluene was investigated. The effects of the concentrations of extractant, nitric acid,
sodium nitrate and sodium oxalate on the distribution ratios of uranium(VI) have been studied. The values of enthalpy change
for the extraction reactions with BDSO, TBP and a mixture of TBP and BDSO in toluene were -23.2±0.8 kJ/mol, -29.2±1.4 kJ/mol
and -30.6±0.6 kJ/mol, respectively. It has been found that the maximum synergistic extraction effect occurs when the molar
ratio of TBP to BDSO is close to 1. The composition of the complex of the synergistic extraction is UO2(NO3)2 . BDSO . TBP. 相似文献
11.
Badri V. Agarwal Satendra P. Sangal Arun K. Dey 《Fresenius' Journal of Analytical Chemistry》1965,207(4):256-259
Summary Solvent extraction of uranium-sodium diethyldithiocarbamate with ethylmethyl ketone and separation from titanium, zirconium, thorium, lanthanum and cerium has been described. It has been found that 11.75 to 47.00 mg of uranium can be extracted from a binary mixture containing 4.78 to 19.04 mg of titanium, 9.12 to 36.48 mg of zirconium, 116.0 to 460.0 mg of thorium, 6.95 to 27.8 mg of lanthanum or 7.06 to 28.24 mg of cerium at pH 3.0. The pH range between which the separations may be carried out successfully is 2.0 to 3.5. The following cations interfere in the separations: CuII, FeIII, CoII, BiIII, NiII, CrVI, TeIV, SeIV, AgI, HgII, AsIII, SnIV, PbIV, CdII, MoVI, MnII, VV, ZnII, InIII, TlI, WVI, OsVIII and NbV.
Zusammenfassung Uran kann durch Extraktion als Diäthyldithiocarbamidat mit Methyläthylketon von Ti, Zr, Th, La oder Ce getrennt werden. Der günstigste pH-Bereich liegt zwischen 2,0 und 3,5. Die Trennungen wurden mit folgenden Mengen durchgeführt: U (11,75–47,00 mg); Ti (4,78 bis 19,04 mg), Zr (9,12–36,48 mg) Th (116,0–460,0 mg), La (6,95–27,8 mg), Ce (7,06–28,24 mg). Folgende Ionen verursachen Störungen: CuII, FeIII, CoII, BiIII, NiII, CrVI, TeIV, SeIV, AgI, HgII, AsIII, SnIV, PbIV, CdII, MoVI, MnII, VVI, ZnII, InIII, TlI, WVI, OsVIII sowie NbV.相似文献
12.
A method is described for the extractive separation and spectrophotometric determination of uranium(VI) from an aqueous solution of pH 5.0–7.0 using benzoylacetone (bzac) and pyridine (py) dissolved in toluene as extractants. The extracted species are UO2(bzac(2·2py. The method provides separation of uranium(VI) from lanthanum(III), samarium(III), neodymium(III), cerium(III) and thorium(IV). The method is precise, accurate, fast and selective. 相似文献
13.
The extraction of thorium(IV) and uranium(VI) from nitric acid solutions has been studied using mixtures of 3-phenyl-4-benzoyl-5-isoxazolone (HPBI) and dicyclohexano-18-crown-6, benzo-18-crown-6, dibenzo-18-crown-6 or benzo-15-crown-5. The results demonstrate that these metal ions are extracted into chloroform as Th(PBI)(4) and UO(2)(PBI)(2) with HPBI alone and as Th(PBI)(4) . CE and UO(2)(PBI)(2) . CE in the presence of crown ethers (CE). The equilibrium constants of the above species have been deduced by non-linear regression analysis. The addition of a CE to the metal chelate system enhances the extraction efficiency and also improves the selectivities between thorium and uranium. IR spectral data of the extracted complexes were used to further clarify the nature of the complexes. The binding to the CEs by Th(PBI)(4) and UO(2)(PBI)(2) follows the CE basicity sequence but with DC18C6 and DB18C6, steric effects become more important. 相似文献
14.
B. S. Mohite J. M. Patil D. N. Zambare 《Journal of Radioanalytical and Nuclear Chemistry》1993,170(1):215-224
Uranium(VI) was quantitatively extracted with 0.01M DB-24-crown-8 in nitrobenzene from 6 to 10M hydrochloric acid. From the organic phase uranium was stripped with 2M nitric acid and determined spectrophotometrically with PAR at 530 nm. Uranium(VI) was separated from a large number of elements in binary mixtures as well as from multicomponent mixtures. The method was extended to the analysis of uranium in geological samples and animal bone. 相似文献
15.
Yang Yan-Zhao Liu Wen-Tao Han Jian Zeng Shan Sun Si-Xiu 《Journal of Radioanalytical and Nuclear Chemistry》2004,260(3):647-651
The kinetics and mechanism of uranium(VI) extraction from nitric acid solution by bis(octylsulfinyl)methane (BOSM) are studied
with the method of stationary interface cell. The effects of temperature, extractant and nitric acid concentrations are discussed.
The results showed that the extraction process is controlled by the following reaction: UO2(NO3)2 + BOSM(i)⇄k1
k-1UO2(NO3)2BOSM(i). The variation of enthalpy associated with the extraction is -22.1±2.1 kJ/mol.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
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V. K. Manchanda J. P. Shukla M. S. Subramanian 《Journal of Radioanalytical and Nuclear Chemistry》1976,29(1):69-75
The equilibrium constants for coordination of methyl substituted pyridine N-oxides with plutonium(VI) thenoyl trifluoroacetonate
in chloroform (Ks) follow an order similar to those of the analogous uranium(VI) complexes indicating steric hindrance to bonding in the case
of ortho substituted pyridine N-oxides. The extraction constants (k) of Pu(VI) chelates with various β-diketones are found
to be only marginally higher than the values for the corresponding uranium(VI) chelates which is in conformity with the close
similarity of the ionic radii of PuO
2
2+
and UO
2
2+
. 相似文献
19.
Cross-linked chitosan resins with catechol (catechol-type chitosan, type 1 and type 2), iminodiacetic acid (IDA-type chitosan), iminodimetylphosphonic acid (IDP-type chitosan), phenylarsonic acid (phenylarsonic acid-type chitosan), or serine (serine-type chitosan) were prepared for the collection and concentration of uranium(VI). The adsorption behavior of U(VI) and other ionic species, such as metal ions and oxo-acid ions, on the cross-linked chitosan (base material) and chitosan resins modified with chelating moieties was examined using a column procedure. Especially, the catechol-type chitosan (type 2) adsorbed U(VI) at pH 2-7, and selectively collected U(VI) at acidic pH regions by forming a stable chelate with hydroxyl groups of catechol moiety introduced to the chitosan. Also, the adsorption properties of cationic and anionic species present in aquatic media were elucidated. The adsorption ability for U(VI) was in the order: catechol-type chitosan (type 2) > serine-type chitosan > phenylarsonic acid-type chitosan > the others. The catechol-type chitosan (type 2) was useful for the collection and concentration of uranium(VI). 相似文献
20.
Ye Tianzhen Liu Zhirong Cai Zhiwang 《Journal of Radioanalytical and Nuclear Chemistry》2020,323(1):223-232
Journal of Radioanalytical and Nuclear Chemistry - The main structure of polystyrene-divinylbenzene (PSD) was synthesized by suspension method, and chlorinated resin (PSD-Cl) obtained by... 相似文献