共查询到20条相似文献,搜索用时 15 毫秒
1.
The extraction of uranium(VI) with di-2-ethylhexyldithiophosphoric acid (HEhdtp) in benzene from aqueous solutions containing nitrate, chloride, sulfate and phosphate anions was investigated. The data obtained show hat the mechanism of extraction is similar to that established for perchlorate media. The inorganic anions present in the aqueous phase do not participate in the extraction process but affect the magnitude of the distribution ratio by the complexation phenomena which occur in the aqueous phase. In benzene the extracted species is a 12 complex of uranium(VI) with HEhdtp. 相似文献
2.
D2HEDTPA和D2EHPA萃取汞(II)的研究 总被引:1,自引:0,他引:1
The extration of Hg2+ from HNO3 solution with (D2EHPA) and bis(2-ethylhexyl dithiophosphate (D2EHDTPA) was studied. The composition of extracted complex was determine by saturation and mol. ratio methods. The bonding of the extracted species is discussed on the basis of IR and NMR data. EHMO calcns. show that the extration capacities of the 2 extractants for Hg2+ are quite different. 相似文献
3.
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
4.
N. M. Sundaramurthi G. S. Desai V. M. Shinde 《Journal of Radioanalytical and Nuclear Chemistry》1990,144(6):439-445
A solvent extraction method is proposed for the extraction and separation of uranium from salicylate media using tris-/2-ethyl hexyl/ phosphate dissolved in xylene as an extractant. The optimum conditions were evaluated from a critical study of pH, salicylate concentration, extractant concentration, period of equilibration and diluent. The method permits the separation of uranium from thorium, cerium, titanium, zirconium, hafnium, copper, vanadium and chromium from binary mixtures and is applicable to the analysis of uranium in synthetic samples. The method is precise, accurate, fast and selective. 相似文献
5.
S. S. V. Ramakumar O. V. Singh S. N. Tandon 《Journal of Radioanalytical and Nuclear Chemistry》1987,119(4):283-289
Mössbauer spectra of hexakis/alkylurea/iron/III/ complexes were measured to investigate the paramagnetic relaxation in ionic compounds. The effects of iron-iron distance and temperature on Mössbauer line shape were studied in these compounds, and the results are discussed in comparison with our previous data on tris/\-diketonato/iron/III/. 相似文献
6.
B. S. Chandravanshi Temam Juhar 《Journal of Radioanalytical and Nuclear Chemistry》1996,210(1):171-181
Uranium(VI) reacts withN-phenylcinnamohydroxamic acid to form an orange-yellow complex in the pH range 5.5–8.5. The orange-yellow complex, having the composition of 12 (metal:ligand), is quantitatively extractable into ethyl acetate. The spectrum of the complex exhibits a maximum absorption at 400 nm with a molar absorptivity of 6500 M–1·cm–1. The coloured system obeys Beer's law in the concentration range 2–40g·ml–1 of uranium(VI). The photometric sensitivity of the colour reaction is 0.037 g·cm–2 of uranium(VI). Most of the common ions do not interfere and the method has been found to be simple, precise, and free from the rigid control of experimental conditions. The method has been applied to the determination of uranium in synthetic matrices and potable water. 相似文献
7.
A. Hermann B. Suhr B. Liebscher 《Journal of Radioanalytical and Nuclear Chemistry》1979,51(2):253-266
An elution scheme has been developed for obtaining separate fission product and uranium fractions using extraction chromatographic
techniques with di-(2-ethylhexyl)phosphoric acid as a stationary phase and HCl of varying concentration as eluting agent.
The investigations have been concentrated on the fission products cerium, europium, molybdenum and zirconium. The elution
of zirconium by oxalic acid is characterized by a peak broadening and has been explained by considering extraction kinetics.
Experiments on column performance with different support materials have proved Ftoroplast-4 and Celite Hyflo Super Cel to
be capable of giving column fillings with equal separation ability. 相似文献
8.
9.
D. V. Bryk R. G. Makitra E. Ya. Pal’chikova 《Russian Journal of Applied Chemistry》2006,79(7):1096-1099
Extraction of Carpathian menilite shales with 18 solvents at 20°C was examined. 相似文献
10.
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
11.
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
12.
13.
Phthalic acid, a ubiquitous organic compound found in soil, water, and in domestic and nuclear wastes can affect the mobility and bioavailability of metals and radionuclides. We examined the complexation of uranium with phthalic acid by potentiometric titration, electrospray ionization-mass spectroscopy (ESI-MS), and extended X-ray absorption fine structure (EXAFS) analysis. Potentiometric titration of a 1:1 U/phthalic acid indicated uranyl ion bonding with both carboxylate groups of phthalic acid; above pH 5 the uranyl ion underwent hydrolysis with one hydroxyl group coordinated to the inner-sphere of uranium. In the presence of excess phthalic acid, ESI-MS analysis revealed the formation of both 1:1 and 1:2 U/phthalic acid complexes. EXAFS studies confirmed the mononuclear biligand 1:2 U/phthalic acid complex as the predominant form. These results show that phthalates can form soluble stable complexes with uranium and may affect its mobility. 相似文献
14.
15.
P. Tkac B. Matteson J. Bruso A. Paulenova 《Journal of Radioanalytical and Nuclear Chemistry》2008,277(1):31-36
The advanced separation extraction process based on tri-n-butyl phosphate organic phase called UREX is being developed to
separate uranium from fission products and other actinides, and the acetohydroxamic acid (AHA) is employed to reduce and complex
plutonium and neptunium in order to decrease their distribution to the TBP-organic phase. In this study, the extraction of
uranium was performed from various aqueous matrices with different concentrations of HNO3, LiNO3, and AHA. Extraction of uranium increases with increasing both initial HNO3 and total nitrate concentration. UV-VIS spectrophotometry confirmed that AHA is involved in the complex of uranium with TBP. 相似文献
16.
17.
E. V. Novikova V. M. Smychenko A. A. Iozep 《Russian Journal of Applied Chemistry》2007,80(7):1151-1153
Solutions of chlorosulfonic acid in dichloroethane and formamide are suggested for incorporation of sulfo groups into macromolecules of polysaccharides. The influence of temperature, reaction duration, and reactant ratio on the yield of sulfated dextran and also the influence of the reaction conditions on hydrolytic stability of the polymer were studied. 相似文献
18.
G. H. Rizvi 《Journal of Radioanalytical and Nuclear Chemistry》1986,106(5):309-317
Tropolone reacts with uranium/VI/ and forms orange yellow precipitate extractable in chloroform. The maximum absorption occurs at 405 nm and the absorbance is found to remain constant in the pH range of 5.5 to 7.0. Beer's law is obeyed upto 37.6 ppm of U/VI/. The sensitivity of the colour reaction is 0.034 g cm–2. Most of the common ions do not interfere. The method becomes more selective by masking some of the interfering cations with EDTA. The method was applied to determine uranium in monazite sand.This work is a part of the Ph.D. Thesis. 相似文献
19.
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
20.
Yang Yan-Zhao Tian Sheng-Jun Sun Si-Xiu Feng Sheng-Yu 《Journal of Radioanalytical and Nuclear Chemistry》2002,252(1):171-173
Complexes of Hf with polyaminopolycarboxylic acids viz. diethylene-triamine-penta-acetic acid (DTPA) and its dimethoxy derivative DMDTPA have been studied using paper chromatography at different acidities. Kinetic stabilities of the complexes have also been looked at. Behaviors of these two ligands in complexing with Hf(IV) have been found to be similar. The extent of complexation reduces slowly with acidity and increase with time and reaches a maximum around 70-80% after about 24 hours. 相似文献