共查询到20条相似文献,搜索用时 15 毫秒
1.
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
2.
Guo-Xin Sun Jian-Kang Zhu You-Shao Wang Bo-Rong Bao 《Journal of Radioanalytical and Nuclear Chemistry》1998,227(1-2):183-186
Natural zeolitic materials (sedimentary zeoliferous rocks) were organo-modified using polyhexamethyleneguanidine-chloride
in order to enhance their anionic sorptive properties. The sorption of As(V)-anions from aqueous solutions [As(V) concentration
range from 10 to 1000 mg/l] was investigated using radiochemical techniques. The samples exhibited an elevated tendency to
sorb As(V)-anions (up to 6.73 mg/g) and the relative uptake was found to be much higher for solutions of low initial concentrations
(up to 99.8% removal). The different As(V) species (mainly HAsO4
2−) are principally sorbed through ion-exchange reactions by the net of the polymeric, compound covering the mineral aggregates
of the samples. The investigated materials could be considered for the removal of As(V) anionic species present in industrial
or municipal wastewaters. 相似文献
3.
Phosphoorganic solvents such as OPPA, DEPA/TOPO and OPAP are commonly used to extract uranium from wet phosphoric acid. They are used in concentrations between 1–10% wt/wt in organic diluents. These inert organic substances serve to dilute the solvent, decrease its viscosity and secure a greater contact between the acid and the solvent. The diluents should also be cheap, readily available, immiscible with water and volatile at the temperature of the extraction which is from 30–50°C. They should not reduce the extraction coefficient of the solvent and separate well at the temperature of separation as an organic phase. This study was carried out to investigate the effect of various organic diluents in order to select the most suitable one. It is established that paraffinic diluents are better than aromatic ones. Since kerosene is cheap, available and not very volatile at the temperature of extraction, it is commonly used in extraction. However, the kerosene used should be treated to reduce the aromatic content to a minimum. 相似文献
4.
Reza Davarkhah Fereshteh Khanramaki Mehdi Asgari Bahram Salimi Parviz Ashtari Mojtaba Shamsipur 《Journal of Radioanalytical and Nuclear Chemistry》2013,298(1):125-132
To go through the first stage of industrial solvent extraction process in order to recover uranium from phosphate rocks by liquid membrane techniques, as a simple model, the kinetics of facilitated transport of uranium(VI) from a dilute phosphoric acid medium into more concentrated phosphoric acid media as a receiving phase through a bulk liquid membrane containing di-2-ethylhexyl phosphoric acid as a carrier was studied. The influence of phosphoric acid concentration in the source and receiving phases, carrier concentration, type of solvent, stirring speed and temperature were investigated. The kinetic parameters (k e, k s, t max, J max) were calculated for the interface reactions assuming two consecutive, irreversible first-order reactions. The activation energy values were calculated as 29.40 and 19.51 kJ mol?1 for extraction and stripping, respectively. The values of calculated activation energy indicated that both the extraction and stripping processes were controlled by mixed regime (both kinetic and diffusion). In addition, the influence of adding trioctyl-phosphine oxide into the membrane phase as a synergic agent on the transport kinetics was determined. 相似文献
5.
6.
Zu-Ming Zhou Yong-Xia Sun Shao-Ning Yu Hui-Fang Du 《Journal of Radioanalytical and Nuclear Chemistry》1996,214(5):369-379
The kinetics of solvent extraction of U (IV), Th (IV) and U (VI) from nitric acid solution with tributyl phosphate (TBP) in kerosene and cyclohexane have been studied using the single drop technique. The effects of concentrations of U (IV), Th (IV), U (VI), nitric acid, nitrate, TBP and temperature on the extraction rates of U (IV), Th (IV) and U (VI) have been examined. The mechanisms for the three extraction processes are discussed. 相似文献
7.
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
8.
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
9.
The extraction of iron(III) from aqueous phosphoric acid was studied using di-(2-ethylhexyl)phosphoric acid and trioctylphosphine oxide in nonaromatic hydrocarbon diluent. Distribution ratios have been investigated as a function of concentration of iron(III), phosphoric acid concentration, extractant concentration and extraction temperature. The apparent enthalpy change for the extraction reaction has been calculated from the temperature dependence data. It was found that the extractant dependency for iron(III) is first power indicating hydrolysis of iron(III) in the aqueous phase. 相似文献
10.
The extraction of vanadium(IV) from hydrochloric acid solutions by di-(2-ethylhexyl)-phosphoric acid
《Journal of Inorganic and Nuclear Chemistry》1978,40(5):853-856
The distribution of vanadium(IV) between hydrochloric acid solutions and solutions of di-(2-ethylhexyl)-phosphoric acid (DEHPA; HX) in organic solvent has been investigated under different conditions. Both the aqueous and organic phases have been examined spectrophotometrically. IR and electron spin resonance spectroscopies have been applied to the organic extracts. The mechanism of extraction is discussed on the basis of the results obtained. 相似文献
11.
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
12.
Solvent extraction of thorium from nitric acid solutions using di-N-butyl sulfoxide (DBSO) in xylene
Muhammad Haleem Khan Syed Moosa Hasany Akbar Ali Muhammad Ali Khan 《Journal of Radioanalytical and Nuclear Chemistry》1995,198(2):409-421
The extraction of thorium(IV) from nitric acid solutions by di-n-butyl sulfoxide (DBSO) in xylene has been investigated as a function of acid, extractant and the metal concentration. The effect of contact time and diverse ions on the extraction has been examined. Phosphate, fluoride, oxalate and perchlorate reduce the extraction to some extent. The extraction of other metal ions, especially impurities associated with thorium in ores, has been measured under optimised conditions selected for thorium extraction. Na(I), K(I), Ca(II), Sr(II), Mn(II), Fe(II), Ni(II), Zn(II), Pb(II), Al(III), Ti(IV) and Hf(IV) are not extracted. Among the stripping solutions employed for back-extraction, deionized water is found to be the best and more than 99% thorium can be back-extracted in three stages. The extracted species is supposed to be Th(NO3)4·2DBSO. The extraction is found to be almost independent of the thorium concentration in the range between 4.3·10–4–4.3·10–2M and inversely dependent upon the temperature. The values of thermodynamic functions H, G and S for extraction equilibrium have been evaluated to be –19.6±2.9 kJ·mole–1, –18.1±2.0 kJ·mole–1 and –5.0±2.9 J·mole–1·K–1, respectively. 相似文献
13.
《Journal of Coordination Chemistry》2012,65(9):1449-1456
The liquid–liquid extraction of copper(II) from sulfate medium with di(2-ethylhexyl)phosphoric acid (D2EHPA, HL) at 25°C is studied with the following parameters: pH, concentration of the extractant, and the nature of diluent. The effect of the diluent using polar and nonpolar solvents in the extraction of copper(II) is discussed. The extracted copper(II) species were CuL2 in 1-octanol and methyl isobutyl ketone and CuL2 · 2HL in toluene, carbon tetrachloride, and cyclohexane. The extraction constants are evaluated for different diluents. 相似文献
14.
《Journal of Inorganic and Nuclear Chemistry》1978,40(8):1571-1574
The rate of the extraction of aluminium(III) from sulphuric acid solutions by di-(2-ethylhexyl)-phosphoric acid (DEHPA) has been investigated under non-equilibrium conditions. The rate of forward reaction is proportional to first order with respect to the concentrations of aluminium and DEHPA and to inverse first order with respect to the hydrogen ion concentration. The rate constant and activation energy are 4.11 X 10−5 sec−1 at 20°C and 79.4kJ/mol, respectively. 相似文献
15.
The extraction of actinium by HDEHP solutions in n-heptane as a function of mineral acids and some lanthanides (Ln) in the aqueous phase has been studied. It was found that the actinium extraction coefficient in the absence of Ln decreased linearly with acid concentration with the slope of –3 in the whole investigated range of its concentration. In the presence of Ln the extraction coefficient decreased with a smaller slope than in the absence of Ln. This slope decreased with the Ln salt concentration. The extraction coefficient of Ac decreased with a slope of –3 at acid concentrations above 0.1N, regardless of the Ln concentration in the extraction system. 相似文献
16.
Y. X. Xia B. R. Bao J. F. Yang 《Journal of Radioanalytical and Nuclear Chemistry》1988,125(1):165-173
Solvent extraction of uranyl nitrate in nitric acid medium with the binary system of DMHMP and DOSO has been investigated. It was found that synergistic effect occurs during the extraction of uranyl nitrate with benzene solution of DMHMP and DOSO, the binary species extracted UO2 (NO3)2·DMHMP·DOSO has been confirmed. From the data the equilibrium constants have been determined. 相似文献
17.
The extraction behavior of tervalent rare-earth metals (Ln) using a heptane solution containing bis(2-ethylhexyl)phosphinic
acid (PIA-8, HR) from 0.1 mol/dm3 sodium perchlorate media was studied. The pH0.5 values and separation factors obtained were compared among the metals. The stoichiometry of the extracted species and the
extraction constants for the present aqueous/heptane system were determined by slope analysis. It is demonstrated that the
rare-earth metals were extracted as monomers LnR3⋅mHR (m=3, 4, 5 or 6), and the extracted species could be stripped into a relatively low concentrated hydrochloric acid. PIA-8
was found to be the most selective extractant for the mutual separation of rare-earth metals among the other phosphinic acids
reported.
Received: 27 February 1996/Revised: 13 May 1996/Accepted: 21 May 1996 相似文献
18.
G. X. Sun Y. S. Wang S. X. Sun B. R. Bao 《Journal of Radioanalytical and Nuclear Chemistry》1997,221(1-2):219-220
The partition of uranium(VI) between nitric acid solutions and solutions of N,N-dibutyldodecanamide (DBDA) in kerosene has been investigated at varying concentrations of nitric acid, extractant, salting-out agent LiNO3 and at different temperatures. The mechanism of extraction is discussed in the light of the results obtained. 相似文献
19.
Polarographic determination of uranium (VI) has been studied in the organic extraction phase TBP—diluent along with a selected
aprotic solvent (i. e. dimethyl sulfoxide or N,N-dimethylformamide). DMF was found more suitable because it dissolves the
organic extraction phase better than DMSO. U (VI) extracted in TBP-kerosene, n-hexane, cyclohexane, n-dodecane, benzene, from
nitric acid medium can be determined in an organic solution (e. g. 50% DMF-30% TBP-20% kerosene) where it gives a well defined
wave. In the organic solution, nitric acid added and/or extracted from the aqueous phase was found as an excellent supporting
electrolyte for uranium determination. 相似文献