共查询到20条相似文献,搜索用时 15 毫秒
1.
April R. Gillens Brian A. Powell 《Journal of Radioanalytical and Nuclear Chemistry》2013,296(2):859-868
Tri-n-butyl phosphate (TBP) is the key complexant within the plutonium and uranium reduction extraction process used to extract uranium and plutonium from used nuclear fuel. During reprocessing TBP degrades to dibutyl phosphate (DBP), butyl acid phosphate (MBP), butanol, and phosphoric acid over time. A method for rapidly monitoring TBP degradation is needed for the support of nuclear forensics. Therefore, a Fourier transform infrared spectrometry-attenuated total reflectance (FTIR-ATR) technique was developed to determine approximate peak intensity ratios of TBP and its degradation products. The technique was developed by combining variable concentrations of TBP, DBP, and MBP to simulate TBP degradation. This method is achieved by analyzing selected peak positions and peak intensity ratios of TBP and DBP at different stages of degradation. The developed technique was tested on TBP samples degraded with nitric acid. In mock degradation samples, the 1,235 cm?1 peak position shifts to 1,220 cm?1 as the concentration of TBP decreases and DBP increases. Peak intensity ratios of TBP positions at 1,279 and 1,020 cm?1 relative to DBP positions at 909 and 1,003 cm?1 demonstrate an increasing trend as the concentration of DBP increases. The same peak intensity ratios were used to analyze DBP relative to MBP whereas a decreasing trend is seen with increasing DBP concentrations. The technique developed from this study may be used as a tool to determine TBP degradation in nuclear reprocessing via a rapid FTIR-ATR measurement without gas chromatography analysis. 相似文献
2.
Model studies on TBP—diluent—aqueous HNO3 extraction systems were performed to establish the mechanism of emulsyfying during the reprocessing of spent reactor fuel
with mixtures of TBP solutions. The systems of interest were emulsified under fixed conditions. The rate of separation of
the primary emulsion as well as the turbidity of each phase were determined. The experiments were performed on mixtures of
pure components of the extraction systems. Emulsion stability was investigated in terms of the influence of such factors as
main products of TBP decay, the type of diluents, HNO3 concentration and concentration of TBP in different diluents. 相似文献
3.
J. N. Mathur M. S. Murali M. V. Balarama Krishna R. H. Iyer R. R. Chitnis P. K. Wattal A. K. Bauri A. Banerji 《Journal of Radioanalytical and Nuclear Chemistry》1996,213(6):419-429
The partitioning and recovery of237Np from three types of simulated high level waste solutions originating from PUREX processing of spent nuclear fuels such as sulfate bearing high level waste (SB-HLW), HLW from a pressurised heavy water reactor (PHWR-HLW) and from a fast breeder reactor (FBR-HLW) have been carried out using a mixture of 0.2M CMPO and 1.2M TBP in dodecane. Quantitative extraction of neptunium was possible by either oxidizing it to the hexavalent state keeping K2Cr2O7 at 0.01M concentration or by reducing it to tetravalent state keeping Fe2+ at 0.02M concentration. Stripping of neptunium was carried out using different reagents, such as dilute nitric acid, oxalic acid and sodium carbonate. Almost quantitative recovery of neptunium has been achieved during these studies. 相似文献
4.
Paula Cable-Dunlap Lee Trowbridge Debra Bostick Denise Lee Brian Anderson Andrew Harter Roger Kapsimalis Lindsay Sexton Jeff De Gange Daniel Radford 《Journal of Radioanalytical and Nuclear Chemistry》2013,295(2):943-949
Towards development of electrical conductivity based sensors for online detection of formation of third phase during reprocessing of Pu rich spent nuclear fuels, laboratory studies were carried out using U4+ solutions in various experimental conditions. Third phases were generated by extracting U4+ from nitric acid medium by 1.09 M TBP at different A/O (A: aqueous, O: organic) ratios. The results of this study indicate that the third phase is nearly 100–300 times more conducting than lean organic phase and saturated phase. The higher conductivity of third phase as compared to that of other two phases is explained based on the principle of reverse micelle formation and charge movement between the micro emulsion globules by percolation phenomenon. 相似文献
5.
P. N. Pathak 《Journal of Radioanalytical and Nuclear Chemistry》2014,300(1):7-15
Reprocessing of spent nuclear fuel is vital for the long-term global nuclear power growth and is the major motivation for developing novel separation schemes. Conventionally, PUREX and THOREX processes have been proposed for the reprocessing of U and Th based spent fuels employing tri-n-butyl phosphate (TBP) as extractant. However, based on the experiences gained over last five–six decades on the reprocessing of spent fuels, some major drawbacks of TBP have been identified. Evaluation of alternative extractants is, therefore, desirable which can overcome at least some of these problems. Extensive studies have been carried out on the evaluation of N,N-dialkyl amides as extractants in the back-end of the nuclear fuel cycle for addressing the issues related to the reprocessing of U and Th based spent fuels. Under advanced fuel cycle scenario, efforts are also being made by countries with a developed nuclear technological base to provide safe nuclear power to other countries and to minimize proliferation concerns worldwide. This paper presents an overview of studies carried out in our laboratory on different aspects of reprocessing of U and Th based spent fuels employing N,N-dialkyl amides as extractants. 相似文献
6.
A. Sobkowska 《Journal of Radioanalytical and Nuclear Chemistry》1983,78(1):43-51
The results of a study on the polarographic behaviour of TBP and its influence on the determination of uranyl ions is presented. The half-wave potential of the adsorption wave of TBP depends on the concentration of TBP, type of supporting elec trolyte and its concentration. In the presence of TBP the polarographic wave of U(VI) ion is changed. Below 7·10?5 M TBP the polarographic wave of U(VI) is not affected, between 7·10?5 and 2·10?4 M TBP the shape, height and half-wave potential of U(VI) waves are changed and above 2·10?4 M, up to saturated solution of TBP, the waves of U(VI) do, not change further. The bes supporting electrolytes for the determination of U(VI) are KNO3 or NaClO4 in concentrations of 0.1 to 0.5 M, pH 1–2 and TBP concentrations from 3·10?4 to 1.2·10?3 M. 相似文献
7.
Owen S. Jeong B. C. Poole P. S. Macaskie L. E. 《Applied biochemistry and biotechnology》1992,(1):693-707
Tributyl phosphate (TBP), a plasticizer and solvent, is used in nuclear fuel reprocessing, generating TBP wastes laden with
residual uranium. ACitrobacter sp. accumulated heavy metals via a phosphohydrolase(s) that precipitated metals with inorganic phosphate liberated from an
organic phosphate “donor” molecule (TBP). Mutant analysis suggested that TBP hydrolysis was not attributable to a previously
documented acid phosphatase (monoesterase). Purified monoesterase had little activity against phospho di- and triesters, had
no requirement for Mg2+ or Mn2+, and was EDTA-resistant. Conversely, TBP cleavage by immobilized cells was enhanced by Mg2+, and ininhibited by Mn2+ and EDTA. A separate phosphotri/diesterase was implicated. 相似文献
8.
K. Chandran Tarun Kumar Sahoo P. Muralidaran V. Ganesan T. G. Srinivasan 《Journal of Thermal Analysis and Calorimetry》2012,110(2):879-890
Thermal decomposition of neat TBP, acid-solvates (TBP·1.1HNO3, TBP·2.4HNO3) (prepared by equilibrating neat TBP with 8 and 15.6?M nitric acid) with and without the presence of additives such as uranyl nitrate, sodium nitrate and sodium nitrite, mixtures of neat TBP and nitric acid of different acidities, 1.1?M TBP solutions in diluents such as n-dodecane (n-DD), n-octane and isooctane has been studied using an adiabatic calorimeter. Enthalpy change and the activation energy for the decomposition reaction derived from the calorimetric data wherever possible are reported in this article. Neat TBP was found to be stable up to 255?°C, whereas the acid-solvates TBP·1.1HNO3 and TBP·2.4HNO3 decomposed at 120 and 111?°C, respectively, with a decomposition enthalpy of ?495.8?±?10.9 and ?1115.5?±?8.2?kJ?mol?1 of TBP. Activation energy and pre exponential factor derived from the calorimetric data for the decomposition of these acid-solvates were found be 108.8?±?3.7, 103.5?±?1.4?kJ?mol?1 of TBP and 6.1?×?1010 and 5.6?×?109?S?1, respectively. The thermochemical parameters such as, the onset temperature, enthalpy of decomposition, activation energy and the pre-exponential factor were found to strongly depend on acid-solvate stoichiometry. Heat capacity (C p ), of neat TBP and the acid-solvates (TBP·1.1HNO3 and TBP·2.4HNO3) were measured at constant pressure using heat flux type differential scanning calorimeter (DSC) in the temperature range 32?C67?°C. The values obtained at 32?°C for neat TBP, acid-solvates TBP·1.1HNO3 and TBP·2.4HNO3 are 1.8, 1.76 and 1.63?J?g?1?K?1, respectively. C p of neat TBP, 1.82?J?g?1?K?1, was also measured at 27?°C using ??hot disk?? method and was found to agree well with the values obtained by DSC method. 相似文献
9.
J. A. Daoud N. Abdel Rahman H. F. Aly 《Journal of Radioanalytical and Nuclear Chemistry》1997,221(1-2):41-44
The kinetics of extraction of U(IV) by TBP in kerosene was investigated using a stirred Lewis cell. The effect of the different parameters affecting the extraction rate as well as temperature were separately investigated. The rate equation deduced from the experimental results show that the extraction of U(IV) is first order dependent on TBP concentration while it is of zero order with respect to U(IV), H+, NO
3
–
and HNO3 concentrations. The data obtained show that the extraction process is governed by chemical reactions taking place at teh interface. 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.
P. K. Mohapatra V. K. Manchanda 《Journal of Radioanalytical and Nuclear Chemistry》1999,240(1):159-164
The role of temperature on the distribution of Am3+ and UO2
2+ was investigated in the extraction systems involving TBP and DOSO as the neutral oxodonors and picrate as the organophilic
counter anion. The inner-sphere water molecules and their substitution by the oxodonor molecules appeared to influence the
extraction constants of these metal ions. The conditional extraction constants for Am3+ were found to be larger (about 3 order of magnitude) than those for UO2
2+. From the thermodynamics data it appeared that both TBP as well as DOSO bind Am3+ ion through outer-sphere coordination. In presence of 1M NaCl, though the interaction with TBP remains unaltered DOSO tend
to form an inner-sphere complex. On the other hand, UO2
2+ forms inner-sphere complexes with DOSO and outer-sphere complex with TBP in the absence of salt. In the presence of 1M NaCl,
both TBP and DOSO form inner-sphere complexes. The effect of ionic strength on metal ion extraction was also investigated.
For Part I see Ref. 9. 相似文献
12.
The separation of iron from cobalt, copper and nickel by reversed-phase foam chromatography was investigated. The distribution of Fe, Co and Cu in TBP-HCl and TBP(polyurethane foam)-HCl systems was measured. Iron can be separated from the three other metals on polyether-type polyurethane foam columns loaded with TBP. The break-through curve of iron on TBP (polyurethane foam) columns was measured. The column was found suitable for the separation of 58Co and 59Fe isotopes. 相似文献
13.
The extraction of the pertechnetate anion has been investigated in the systems tributylphosphate (TBP)—solvent (carbon tetrachloride,
n-heptane, chloroform)—metal salt (uranyl nitrate and chloride, thorium nitrate)—ammonium salt. In the absence of a metal,
the solvates HTeO4. iTBP (i=4) are extracted, while in the presence of uranium and thorium, the distribution of technetium corresponds to the
formation of the mixed complexes: UO2(NO3)(TeO4)·2TBP, UO2Cl(TcO4)·2TBP and Th(NO3)3 (TcO1)·2TBP. The effective constants of the reactions H++TcO
4
−
+i(TBP)org←(HTcO1·iTBP)org, and (MLn·2TBP)org+TcO
4
−
←(MLn−1TcO4·2TBP)org+L were established in the above systems. The extraction of pertechnetate ion is more effective when it is coordinated to
a cation solvated by TBP than the extraction in the form of pertechnetate acid solvated by TBP. 相似文献
14.
L. Y. Zhu W. H. Duan J. M. Xu Y. J. Zhu 《Journal of Radioanalytical and Nuclear Chemistry》2011,287(2):443-448
A novel method that spent nuclear fuel is converted into nitrates with N2O4, and then nitrates are extracted with TBP in supercritical CO2 (SC-CO2), has been developed for reprocessing of spent nuclear fuel, which has a potential prospect because of its potential to decrease
generation of the secondary liquid waste. In this paper, conversion of Nd2O3 with N2O4 into its nitrate under various conditions and extraction of the conversion product with TBP in SC-CO2 were investigated. When temperature was 60–120 °C, the molar ratio of H2O to Nd2O3 was from 1 to 6, and molar ratio of N2O4 to Nd2O3 was above 8, complete conversion of Nd2O3 into its nitrate was achieved. The conversion product was characterized by thermal analysis (TG-DTA), X-ray diffraction (XRD),
Fourier transformed infrared spectroscopy (FT-IR) and Raman spectroscopy. Quantitative extraction of the conversion product
with TBP in supercritical CO2 was also achieved under experimental conditions. 相似文献
15.
Hydrogen bonding between water and tributyl phosphate (TBP) in TBP? CCl4? H2O system has been studied by 1H NMR. A new model and an empirical equation have been established on the basis of Li's model and the parameters of hydrogen bond between water and TBP are determined by nonlinear optimization method. In TBP? CCl4? H2O system change of 1H chemical shift of water can be satisfactorily explained by the new model and the empirical equation in the whole concentration range. When the concentration of water in the organic phase is very low, the main existing forms of water are H2O · TBP and H2O · 2TBP. When the concentration of water reaches saturation, the main existing form is associated water, but there are still about 20% of water existing in the forms of H2O · TBP and H2O · 2TBP. 相似文献
16.
Pravati Swain C. Mallika R. Srinivasan U. Kamachi Mudali R. Natarajan 《Journal of Radioanalytical and Nuclear Chemistry》2013,298(2):781-796
The chemistry of the noble metal fission product, ruthenium is very complex due to the existence of many oxidation states in addition to forming a large number of co-ordination complexes. In the PUREX process for the separation of U and Pu from the spent nuclear fuels from fast breeder reactors, owing to the high volatile nature of RuO4 problems arise not only during the extraction stages but also in the treatment of high active liquid waste and subsequent vitrification. As this volatile RuO4 can deposit in cooler parts, there is an increase in the radiation field due to the presence of 106Ru. The problem is very acute in the reprocessing of fast reactor fuels due to the increased concentration of ruthenium in the spent fuel. In nitric acid medium Ru can exist in various nitroso nitrate complexes and nitroso complexes are more stable than nitrates. The nitrates are non-extractable by the solvent TBP; however, they are extractable to a higher degree by DBP (the primary degradation product of TBP). The extractability of Ru nitrates into the solvent is inhibited by high acid content, temperature and prolonged hold-up time. Nevertheless, these factors promote the volatilization of Ru as RuO4. The volatilization is enhanced by the addition of phosphate ions, but is suppressed by phosphite or hypophosphite ions. Thus, it would be advantageous if ruthenium is removed so that not only the purity of the product (Pu) is improved, but also the problem related to volatilisation can be resolved. High molecular weight amines (tertiary amines) capable of forming co-ordinate bonds are reported to be ideal extractants for Ru. Gas phase separation is an effective method for the recovery of Ru from catalysts, lead button and from other platinum group metals. Separation and pre-concentration of noble metals can be accomplished from non-metals by simple sorbents like coconut shell activated carbon to complicated chelating resins, aromatic polymers and zeolites. In the electro-oxidation of active Ru from nitroso salts, Pd was found to interfere and removal of Pd prior to oxidation of Ru is recommended. Redox catalysts such as Ag2+ and Ce4+ are found to play a prominent role in the electro-oxidation of Ru. Though, various methods and extractants are reported in the literature for the separation of Ru, R&D is being pursued for the removal of Ru during aqueous reprocessing of spent fuels using extractants and methods which are conducive to plant conditions. Hence, an exhaustive survey of literature was made and the different methods reported for the removal of Ru with emphasis towards reprocessing applications are discussed in this report as a review. Attempts made by the authors in separating Ru from simulated waste solution are also included in this review. 相似文献
17.
Gary S. Groenewold Jani C. Ingram James E. Delmore Anthony D. Appelhans 《Journal of the American Society for Mass Spectrometry》1995,6(3):165-174
The static secondary ionization mass spectrometry (SIMS) spectrum of tri-n-butyl phosphate (TBP) on a variety of basalt and quartz samples is affected by the chemical composition of the mineral surface. When TBP is adsorbed on Fe(II)-bearing surfaces, the compound undergoes concomitant H? abstraction and reduction, followed by the elimination of two C4H8 molecules to form an ion at m/z 137+. When TBP is adsorbed to quartz or other nonreducing surfaces, it merely undergoes protonation and elimination of three C4H8 molecules to form H4PO 4 + . When TBP is adsorbed to Fe(III)-bearing surfaces, it undergoes H? abstraction and elimination of two C4H8 molecules, to form an ion at m/z 153+. These conclusions are supported by model studies that employed FeO, Fe203, TBP, and tributyl phosphite. The results show that the SIMS spectrum is very sensitive to the mode of TBP adsorption on the mineral surface. 相似文献
18.
K. Henning und H. Specker 《Fresenius' Journal of Analytical Chemistry》1968,241(2):81-90
Zusammenfassung Das Verteilungsverhalten der Halogenide und Halogenometallate von Gallium, Indium und Thallium mit den drei Solventien (S) Tributylphosphat (TBP), Cyclohexanon (Cyclo) und Isobutylmethylketon (IBMK) wurde untersucht. Die extrahierten Verbindungen wurden nach der Geradenmethode nach Asmus, der logarithmischen Methode nach McKay, der Methode der kontinuierlichen Variation, durch Analyse der beiden Phasen und durch konduktometrische Extraktionstitration nachgewiesen. Identifiziert wurden folgende Verbindungen: [GaCl4]–·2 S, Ga-(SCN) 3·3 TBP, [Ga(SCN)4]–·2 TBP, [InCl4]–·2 TBP, [InBr4]–·2TBP, [InBr4]·x Cyclo, [InBr4]–·x IBMK, [InJ4]–·2 S, In(SCN)3·3 TBP, [In(SCN)4]–·2 TBP, TlCl3·1 TBP, [TlCl4]–·2 S, TlBr3·1 TBP, [Tl-Br4] –·2 S, TlJ3·x TBP und [TlJ4]–·xS. Wegen der nicht eindeutig definierten Oxydationsstufe von Thalliumjodiden ergaben sich bei den Versuchen experimentelle Schwierigkeiten. Daher wurde in diesem System zusätzlich das radioaktive Isotop 204Thallium verwendet.
Herrn Professor Dr. E. Asmus zum 60. Geburtstag gewidmet.
Wie danken Herrn Priv.-Doz. Dr. H. Nickel für die freundliche Unterstützung bei den in der KFA Jülich durchgeführten radioaktiven Messungen. 相似文献
Extracted compounds of gallium, indium and thallium in distribution systems with tributyl phosphate, cyclohexanone and isobutylmethylketone
The behaviour of distribution of the halides and halogenometallates of gallium, indium and thallium with the three solvents (S) tributylphosphate (TBP), cyclohexanone (Cyclo) and isobutylmethylketone (IBMK) are investigated. The extracted compounds are detected with the straight-line method of Asmus, the logarithmic method of McKay, the method of continuous variation, by analysis of the two phases, and with the conductometric extraction-titration. The following compounds were identified: [GaCl4]–·2S, Ga(SCN)3·3TBP, [Ga(SCN)4]–·2TBP, [InCl4]–·2TBP, [InBr4]–·2TBP, [InBr4]·x Cyclo, [InBr4]–·x IBMK, [InJ4]– ·2S, In(SCN)3·3TBP, [In(SCN)4]–·2TBP, TlCl3·1TBP, [TlCl4]–·2S, TlBr3 ·1TBP, [TlBr4]–·2S, TlJ3·x TBP and [TlJ4]–·x S. The not unequivocally defined stage of oxidation of thallium iodides resulted in experimental difficulties. Thus, in this system the radioactive isotope 204thallium was additionally used.
Herrn Professor Dr. E. Asmus zum 60. Geburtstag gewidmet.
Wie danken Herrn Priv.-Doz. Dr. H. Nickel für die freundliche Unterstützung bei den in der KFA Jülich durchgeführten radioaktiven Messungen. 相似文献
19.
N. K. De Vries H. M. Buck 《Phosphorus, sulfur, and silicon and the related elements》2013,188(3-4):267-279
Abstract A MNDO and 300-MHz 1H NMR study of some trigonal-bipyramidal (TBP) five-coördinated phosphorus (Pv) compounds is reported. It is shown by the MNDO calculations that, in the oxaphosphole Pv TBP compounds 5a-c, the electron distribution in the axial bonds of the TBP is affected by the electronegativity of the substituent at C4 of the oxaphosphole ring. With increasing electronegativity of the substituent at C4, the electron density on the axial exocyclic oxygen atom O1 decreases whereas the electron density on the axial endocyclic atom O1 increases. This is supported by a 1H NMR conformational analysis of the C1[sbnd]C2 bond of the oxaphosphole Pv TBP compounds 6–11. The gauche(-) rotamer fraction (O1 and O1 trans situated) of these compounds, which is correlated to the electron density on O1, is reduced to 30% as compared to the absolute axial g?rotamer fraction (59%) of the dioxaphosphole Pv TBP compound 13, most likely because of the presence of the carbonyl group at C4 of the oxaphosphole ring. So, both the 1H NMR and MNDO study show that electron withdrawing substituents on the oxaphosphole ring of Pv TBP compounds reverse the electron transfer in the axial P[sbnd]O bonds of the TBP (as compared to dioxaphosphole compounds), from exocyclic O1 towards endocyclic O1. 相似文献
20.
Kamil Vavřinec Mareš Ferdinand Šebesta 《Journal of Radioanalytical and Nuclear Chemistry》2014,302(1):341-345
Three production routes of the preparation of a solid extractant based on tributylphosphate (TBP) embedded in the polyacrylonitrile matrix (PAN) have been studied. The method of direct PAN coagulation with TBP was found to be not viable due to the significant TBP solubility in the coagulation bath. The most suitable PAN-TBP solid extractant was prepared by the well-known impregnation method of ready-made neat PAN beads. The kinetics of uranium extraction from 3 mol L?1 HNO3, the effect of nitrate and nitric acids concentrations on the value of weight distribution coefficients D g as well as the uranium “extraction isotherm” were determined for this material. Uranium extraction was rather fast, approximately 1 h was sufficient for the equilibrium achievement. Capacity for the uranium uptake, measured in batch experiments on PAN-TBP for 0.048 mol L?1 of uranium in 3 mol L?1 nitric acid, was found to be q = 0.363 mmol g?1 (58 % of the theoretical capacity). It was concluded that PAN-TBP material behaves like TBP in liquid–liquid extraction. Extraction capacity determined in column experiments was lower (by about 23 %) than expected from the “extraction isotherm” due to the TBP leaching out of the column. The thus prepared material is therefore not very suitable for multicycle extraction and stripping and can be used once, particularly for the analytical purposes. 相似文献