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1.
Yang Yan-Zhao Sun Si-Xiu Zhang Lei Yang Yong-Hui Bao Bo-Rong 《Journal of Radioanalytical and Nuclear Chemistry》1999,240(1):383-385
The liquid-liquid extraction of uranium(VI) from aqueous nitric acid with bis(octylsulfinyl)methane (BOSM) has been studied
over a wide range of conditions. The extracted species appear to be UO2(NO3)2·2BOSM. It was found that the extraction increased with increasing nitric acid concentration up to 8.5 mol/l and then descreased.
Extraction also increased with increasing extractant concentration. The influence of temperature and salting-out agent concentration
on the extraction equilibrium has also been investigated, and the enthalpy of the extraction reaction was estimated. 相似文献
2.
Yang Yan-Zhao Zeng Shan Bao Li-Ping Liu Wen-Tao Sun Si-Xiu 《Journal of Radioanalytical and Nuclear Chemistry》2003,258(2):403-408
The synergistic extraction of uranium(VI) from aqueous nitric acid solution with mixtures of bis(hexylsulfinyl)ethane (BHxSE) and petroleum sulfoxides (PSO) in 1,1,2,2-tetrachloroethane was studied. It has been found that the maximum synergistic extraction effect occurs when the molar ratio of PSO to BHxSE is close to 1. The composition of the complex of synergistic extraction was estimated as UO2(NO3)2
.BHxSE.PSO. The formation constant of the complex was equal to KBP = 4.23±0.03. The effects of extractant, nitric acid, salting-out agent, and complex anion concentrations and temperature on the extraction equilibrium of uranium(VI) were also studied. 相似文献
3.
Yang Yan-Zhao Yang Yong-Hui Xong Jun Sun Si-Xiu Bao Bo-Rong 《Journal of Radioanalytical and Nuclear Chemistry》1999,241(1):235-238
The liquid-liquid extraction behavior of uranium(VI) from aqueous nitric acid with bis(octylsulfinyl)ethane (BOSE) in 1,1,2,2-tetrachloroethane
has been studied over a wide range of conditions. The extracted species appears to be UO2(NO3)2·2BOSE. It was found that the extraction increases with increasing nitric acid concentration up to 7 mol/l and then decreased.
Extraction also increases with increasing extractant concentration. The influence of temperature and salting-out agent concentration
on the extraction equilibrium and stripping of uranium(VI) was also investigated and the enthalpy of the extraction reaction
was obtained. 相似文献
4.
The liquid-liquid extraction of uranium(VI) from aqueous nitric acid with n-octyldecylsulfoxide (ODSO) in toluene has been studied over a wide range of conditions. The extracted species appears to be UO2(NO3)2·2ODSO. The extraction increased with increasing nitric acid concentration up to 2.0 mol/l and then decreased. Extraction also increased with increasing extractant concentration. The influence of temperature, salting-out agent concentration and complex anion concentration on the extraction equilibrium were also investigated, and the enthalpy of the extraction reaction was calculated. 相似文献
5.
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
6.
The thermodynamic extraction of uranium(VI) with hexyloctylsulfoxide (HxOSO) has been studied. It was found that the distribution ratio increases with increasing nitric acid concentration up to 2.3 mol/l and then decreases. The distribution ratio also increases with increasing extractant concentration. The extracted species appears to be UO2(NO3)2
.2HxOSO. The influences of temperature, sodium nitrate and oxalate concentrations on the extraction were also investigated, and the thermodynamic functions of the extraction reaction were obtained. 相似文献
7.
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
8.
K. A. Venkatesan K. V. Shyamala M. P. Antony T. G. Srinivasan P. R. Vasudeva Rao 《Journal of Radioanalytical and Nuclear Chemistry》2008,275(3):563-570
Batch and dynamic extractions of uranium(VI) in 10−3–10−2M concentrations in 3–4M nitric acid medium have been investigated using a commercially available phosphinic acid resin (Tulsion
CH-96). The extraction of uranium(VI) has been studied as a function of time, batch factor (V/m), concentrations of nitric acid and uranium(VI) ion. Dual extraction mechanism unique to phosphinic acid resin has been established
for the extraction of uranium(VI). Distribution coefficient (K
d
) of uranium(VI) initially decreases with increasing concentration of nitric acid, reaches a minimum value at 1.3M, followed
by increases in K
d
. A maximum K
d
value of ∼2000 ml/g was obtained at 5.0M nitric acid. Batch extraction data has been fitted into the linearized Langmuir
adsorption isotherm. The performance of the resin under dynamic extraction conditions was assessed by following the breakthrough
behavior of the system. Effect of flow rate, concentrations of nitric acid and uranium ion in the feed on the breakthrough
behavior of the system was studied and the data was fitted using Thomas model. 相似文献
9.
Yang Yan-Zhao Sun Si-Xiu Yang Yong-Hui Zhang Lei Yu Shao-Ning Bao Bo-Rong 《Journal of Radioanalytical and Nuclear Chemistry》1999,241(1):231-234
The synergic extraction of uranium(VI) from nitric acid solution with petroleum sulfoxides (PSO) and tri-n-butyl phosphate (TBP) mixture has been studied. It has been found that maximum synergic extraction effect occurs if the molar
ratio of PSO to TBP is two to three. The composition of the complex of synergic extraction is UO2(NO3)2·TBP·PSO. The formation constant of the complex isK
PT=8.19. The effect of extractant concentration, nitric acid concentration, salting-out agent concentration and temperature
on the extraction equilibrium of uranium(VI) was also studied. 相似文献
10.
Yang Yonghui Sun Sixiu Xue Shuyun Yang Yanzhao Bao Borong 《Journal of Radioanalytical and Nuclear Chemistry》1998,237(1-2):171-173
The extraction of uranium(VI) from sulfuric acid medium with tri-octylphosphine oxide (TOPO) in n-heptane was studied. Accompanied
with the increase in the concentration of H2SO4, the distribution coefficient of uranium(VI) increased in the region of dilute sulfuric acid. When the concentration of H2SO4 surpassed 3.5 mol·dm−3, the distribution coefficient of uranium(VI) was at maximum. This result was due to the competition extraction between uranium(VI)
and H2SO4. From the data, the composition of extracted species and the equilibrium constant of extraction reaction have been evaluated,
which were (TOPOH)2UO2(SO4)2 (TOPO) and 107.6±0.15, respectively. 相似文献
11.
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
12.
Ashok Kumar Ashoke Chandra Deb S. K. Mukerjee V. N. Vaidya D. D. Sood 《Journal of Radioanalytical and Nuclear Chemistry》1999,240(1):375-377
Solvent extraction of plutonium(VI) from nitric acid (1 to 5M) into 20% and 30% TBP in dodecane saturated with uranium(VI)
(0% to 80%) has been studied. For a particular nitric acid concentration, the distribution coefficient (K
d
) is found to decrease with the increase in saturation of organic phase with uranium(VI). At a fixed organic phase the saturationK
d
increased with increase in nitric acid concentration, however, the magnitude of this increase inK
d
decreased with the increase in saturation. 相似文献
13.
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
14.
D. R. Prabhu G. R. Mahajan M. S. Murali J. P. Shukla G. M. Nair P. R. Natarajan 《Journal of Radioanalytical and Nuclear Chemistry》1992,162(1):91-97
The liquid-liquid extraction behavior of plutonium(IV) from aqueous nitric acid media into n-dodecane by di(2-ethylhexyl)sulfoxide (DEHSO) was investigated over a wide range of conditions. Optimum-parameters such as the aqueous phase acidity, reagent and metal concentrations, etc., were established for efficient extraction-separation of tracer as well as macro levels of plutonium. It was found that the extraction increased with increasing nitric acid concentration up to 6M HNO3 and then decreased. Extraction also increased with increasing extractant concentration. After loading of the organic phase with 2 to 50 mg/ml of U(VI), extractability of Pu(IV) became considerably lower. Recovery of Pu(IV) from the organic phase was accomplished using dilute uranium(IV) nitrate as the strippant. 相似文献
15.
K. Shakir Sh. G. Beheir M. Aziz 《Journal of Radioanalytical and Nuclear Chemistry》1992,162(2):371-380
The effect of added TBP on the extraction of uranium(VI) with a solution of di-(2-ethylhexyl)-phosphoric acid (HDEHP) in o-dichlorobenzene from nitric acid solutions has been investigated at varying concentrations of nitric acid, HDEHP, TBP and uranium(VI). The mechanism of the synergistic effect of TBP is discussed on the basis of the results and can be summarized in the following equation: UO
2(aq)
2+
+0.67(HX)3(o)+2TBP(o)UO2X2·2TBP(o)+2H
(aq)
+
where HX denotes HDEHP and the HDEHP loaded on the foam is trimerized. 相似文献
16.
Insights into the Mechanism of Extraction of Uranium (VI) from Nitric Acid Solution into an Ionic Liquid by using Tri‐n‐butyl phosphate 下载免费PDF全文
Dr Clotilde Gaillard Dr. Maria Boltoeva Dr. Isabelle Billard Sylvia Georg Valérie Mazan Dr. Ali Ouadi Dr. Dariia Ternova Dr. Christoph Hennig 《Chemphyschem》2015,16(12):2653-2662
We present new results on the liquid–liquid extraction of uranium (VI) from a nitric acid aqueous phase into a tri‐n‐butyl phosphate/1‐butyl‐3‐methylimidazolium bis(trifluoromethylsulfonyl)imide (TBP/[C4mim][Tf2N]) phase. The individual solubilities of the ionic‐liquid ions in the upper part of the biphasic system are measured over the whole acidic range and as a function of the TBP concentration. New insights into the extraction mechanism are obtained through the in situ characterization of the extracted uranyl complexes by coupling UV/Vis and extended X‐ray absorption fine structure (EXAFS) spectroscopy. We propose a chemical model to explain uranium (VI) extraction that describes the data through a fit of the uranyl distribution ratio DU. In this model, at low acid concentrations uranium (VI) is extracted as the cationic complex [UO2(TBP)2]2+, by an exchange with one proton and one C4mim+. At high acid concentrations, the extraction proceeds through a cationic exchange between [UO2(NO3)(HNO3)(TBP)2]+ and one C4mim+. As a consequence of this mechanism, the variation of DU as a function of TBP concentration depends on the C4mim+ concentration in the aqueous phase. This explains why noninteger values are often derived by analysis of DU versus [TBP] plots to determine the number of TBP molecules involved in the extraction of uranyl in an ionic‐liquid phase. 相似文献
17.
Sujoy Biswas K. N. Hareendran D. K. Singh J. N. Sharma S. B. Roy 《Journal of Radioanalytical and Nuclear Chemistry》2010,283(3):665-668
Extraction behavior of U(VI) and Th(IV) from nitric acid medium is investigated using organo-phosphorous extractant, tri(butoxyethyl)
phosphate in n-paraffin at room temperature (27 ± 1 °C). The effect of diluents, nitric acid concentration as well as extractant concentration
on extraction of U(VI) and Th(IV) are evaluated. Extraction of U(VI) and Th(IV) from nitric acid medium proceeds via solvation
mechanism. Slope analysis technique showed the formation of neutral complexes of the type of UO2(NO3)2·2TBEP and Th(NO3)4·3TBEP with U(VI) and Th(IV) respectively in the organic phase. The FTIR data showed shifting of P=O stretching frequency
from 1,282 to 1,217 cm−1 indicating the strong complexation of P=O group with UO2
2+ ions in the organic phase. Effect of stripping agents, other metal ions and their separation with respect to U(VI) extraction
has also been investigated. 相似文献
18.
Extraction behavior of Th(IV) and U(VI) has been investigated with bis(2-ethylhexyl) phosphinic acid (PIA-8) and bis(2-ethylhexyl) phosphoric acid (HDEHP) from nitric acid media in toluene. The optimum conditions for extraction of these metals have been established by studying various parameters like acid concentration, pH, reagent concentration, diluents and shaking time. The extraction of Th(IV) was found to be quantitative with 0.3-2.5M HNO3 by 2.5.10-2M HDEHP and in the pH range 0.1-2.5 with 2.3.10-2M PIA-8 in toluene. U(VI) was completely extracted in the acidic range of 0.1-2.0M HNO3 with 2.2.10-2M HDEHP and in the pH range of 1.0-3.0 with 2.0.10-2M PIA-8 in toluene. The probable extracted species have been ascertained by log D-log c plot as UO2 R2
.2HR with both the reagents and Th (NO3)2R2
.2HR with PIA-8 and Th (NO3)3R.3HR with HDEHP, respectively. Temperature dependence of the extraction equilibrium is examined by the temperature variation method. Separation of U(VI) and Th(IV) was also carried out from commonly associated metals. 相似文献
19.
Shen Chao-Hong Bao Bo-Rong Wang Gao-Dong Qian Jun Bao Ya-Zhi Cao Zheng-Bai 《Journal of Radioanalytical and Nuclear Chemistry》1992,162(2):207-216
Extraction of uranium(VI), thorium(IV) from nitric acid has been studied with N-octylcaprolactam and N-(2-ethyl)hexylcaprolactam. Distribution coefficients of U(VI), Th(IV) and HNO3 as a function of aqueous NHO3 concentration, extractant concentration and temperature have been studied. The compositions of extracted species, thermodynamic parameters of extraction have been evaluated. Third phase formation in extraction of U(VI) has been studied. Back extraction behavior of U(VI) and Th(IV) from the organic phase has also been tested. The results obtained are compared with those obtained by using TBP under the same experimental conditions. 相似文献
20.
Si-Xiu Sun 《Journal of Radioanalytical and Nuclear Chemistry》2001,249(3):625-628
By using stirred-cell method as experimental technique, the kinetictransfer mechanism of UO2
2++ with N,N,N',N'-tetrabutyladipicamide(TBAA) from nitric acid solutions into toluene was studied. The differentconditions effecting the extraction rate constants (k'f and k'b ) were investigated, such as UO2
2+ concentration,HNO3 concentration, TBAA concentration, temperature and agitationspeed. It was found that the extraction process was controlled by the diffusionof UO2 (NO3 )2 . 2TBAA from the liquid-liquidsurface into the organic phase in the range of the experimental concentrationof HNO3. The extraction rate was found to be of pseudo-first orderwith respect to the concentration of uranium(VI). 相似文献