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1.
M. Aziz Sh. G. Beheir K. Shakir 《Journal of Radioanalytical and Nuclear Chemistry》1992,157(1):105-113
The extraction of uranium(VI) from an aqueous HNO3 phase into an organic phase consisting of a polyurethane foam immobilizing a solution of di(2-ethylhexyl)phosphoric acid (HDEHP) in o-dichlorobenzene has been investigated at varying concentrations of nitric acid and HDEHP. The mechanism of the extraction is discussed on the basis of the results obtained. The aggregation number of HDEHP immobilized on the foam was obtained from the analysis of data obtained for the extraction of cerium(III) from acidic perchlorate solutions of constant ionic strength. 相似文献
2.
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
3.
I. S. El-yamani M. Y. Farah E. N. Abd El-Messieh 《Journal of Radioanalytical and Nuclear Chemistry》1978,45(2):357-364
The distribution of Be(II) between aqueous sulphuric acid solutions and organic phases of di-(2-ethyl hexyl)-phosphoric acid
(HDEHP) has been described. The dependence of extraction on contact time, acidity, metal and extractant concentration, diluent
type and temperature was thoroughly investigated. The possible mechanism of the extraction is discussed on the basis of results
obtained. 相似文献
4.
Juan Luo Congzhi Wang Jianhui Lan Qunyan Wu Yuliang Zhao Zhifang Chai Changming Nie Weiqun Shi 《中国科学:化学(英文版)》2016,59(3):324-331
Separation of trivalent lanthanides (Ln(III)) and actinides (An(III)) is a key issue in the advanced spent nuclear fuel reprocessing. In the well-known trivalent actinide lanthanide separation by phosphorus reagent extraction from aqueous komplexes (TALSPEAK) process, the organophosphorus ligand HDEHP (di-(2-ethylhexyl) phosphoric acid) has been used as an efficient reagent for the partitioning of Ln(III) from An(III) with the combination of a holdback reagent in aqueous lactate buffer solution. In this work, the structural and electronic properties of Eu3+ and Am3+ complexes with HDEHP in nitric acid solution have been systematically explored by using scalar-relativistic density functional theory (DFT). It was found that HDEHP can coordinate with M(III) (M=Eu, Am) cations in the form of hydrogen-bonded dimers HL2- (L=DEHP), and the metal ions prefer to coordinate with the phosphoryl oxygen atom of the ligand. For all the extraction complexes, the metal-ligand bonds are mainly ionic in nature. Although Eu(III) complexes have higher interaction energies, the HL2- dimer shows comparable affinity for Eu(III) and Am(III) according to thermodynamic analysis, which may be attributed to the higher stabilities of Eu(III) nonahydrate. It is expected that this work could provide insightful information on the complexation of An(III) and Ln(III) with HDEHP at the molecular level. 相似文献
5.
A systematic investigation was carried out on the extraction of Sb(III) and (V) with HDEHP from various acidic, neutral and
alkaline solutions. Antimony(III) is best extracted from neutral or slightly acidic solutions, and the E values are nearly
the same in the forward and backward extractions. Antimony(V) extraction is high only from concentrated HCl and HClO4, and the E values are much larger in the backward direction. Extraction and separation of Sb(III) and (V) was studied as
a function of acidity, alkalinity, anion and water-miscible organic additives in the aqueous phase, as well as the diluent
used and HDEHP molarity. Separation factors obtained for Sb(III) and (V) were higher than when using isopropyl ether as solvent,
which was hitherto used for this purpose. 相似文献
6.
M. M. Charyulu D. G. Phal D. M. Noronha V. V. Ramakrishna V. Venugopal 《Journal of Radioanalytical and Nuclear Chemistry》2001,247(3):553-555
The extraction of Am(III) from nitric, hydrochloric, oxalic, phosphoric and hydrofluoric acids was studied using 0.4F di-2-ethyl hexyl phosphoric acid (HDEHP) containing 0.1M phosphorous pentoxide (P2O5) in dodecane/xylene. The extraction with pure 0.4F HDEHP was found to be negligible from all the media studied. However, the presence of a small amount of P2O5 in it increased the extraction substantially. The distribution ratios of Am(III) obtained for HDEHP - P2O5 mixture 3M nitric acid containing different concentrations of oxalic acid/phosphoric acid/hydrofluoric acid are in the order of 200-250. The same for 3M hydrochloric acid is very high (800). These distribution ratios are sufficiently high for the quantitative extraction of Am(III) from all the acid media studied. Different reagents such as ammonium oxalate, sodium oxalate, oxalic acid, hydrofluoric acid, sodium carbonate and potassium sulphate were explored for the back extraction of Am(III) from 0.4F HDEHP + 0.1M P2O5 in dodecane/xylene. Of these, 0.35M ammonium oxalate and 1M sodium carbonate were found to be most suitable. The back extraction of Am(III) was also attempted with water and 1M H2SO4, HNO3, HClO4 and HCl solutions after allowing the extracted organics to degrade on its own. It was found that more than 90% of Am could be back extracted with these acids. Using this method more than 90% of Am(III) was recovered from nitric acid solutions containing calcium and fluoride ions. 相似文献
7.
The extraction behavior of Zr(IV), Ce(III), Th(IV) and U(VI) from aqueous solutions containing Arsenazo-I with the organic solvents tridodecylamine (TDA), 1-[thenoyl-(2)]-3-3-3-trifluoroacetone (HTTA), di(2-ethylhexyl) phosphoric acid (HDEHP) and tricaprylmethylammonium chloride (TCMA) in xylene has been investigated. Effect of hydrogen ion concentration in the aqueous phase, Arsenazo-I concentration, as well as the effect of solvent concentration on the extraction was studied. Some alternatives for separation of the elements studied were recommended enabling the spectrophotometric determination of these elements using Arsenazo-I without interference. 相似文献
8.
The cloud point extraction behaviors of lanthanoids(III) (Ln(III) = La(III), Eu(III) and Lu(III)) with and without di(2-ethylhexyl)phosphoric acid (HDEHP) using Triton X-100 were investigated. It was suggested that the extraction of Ln(III) into the surfactant-rich phase without added chelating agent was caused by the impurities contained in Triton X-100. The extraction percentage more than 91% for all Ln(III) metals was obtained using 3.0 × 10−5 mol dm−3 HDEHP and 2.0% (v/v) Triton X-100. From the equilibrium analysis, it was clarified that Ln(III) was extracted as Ln(DEHP)3 into the surfactant-rich phase. The extraction constant of Ln(III) with HDEHP and 2.0% (v/v) Triton X-100 were also obtained. 相似文献
9.
Systematic studies were carried out on the extraction of U(VI), Th(IV) and Ce(III) with HDEHP from pure hydrochloric and sulfuric acid solutions as well as from their binary mixtures. The influence of water-miscible alcohols and acetone on the extraction of these elements was also investigated. Results were discussed and procedures for the separation of the concerned elements have been recommended. A suggested extraction mechanism is presented in the light of the obtained results. 相似文献
10.
《Journal of Inorganic and Nuclear Chemistry》1980,42(3):415-420
The distribution of vanadium(IV) between sulphuric acid solutions and solutions of bis-(2-ethyl hexyl)-phosphoric acid (abbreviated as HDEHP or H2A2) in benzene and kerosene has been investigated as a function of the extractable metal ion, sulphate, acetate, nitrate and extractant concentrations, temperature and the nature of the diluents. The distribution coefficient has been found to increase with increasing concentration of the extractant, acetate, nitrate and temperature and with decreasing acidity and sulphate concentration. From the temperature dependence data, the apparent enthalphy change for the extraction reaction has been calculated to be ΔH = 4.74 kcal/mole. The molecular weight and the phosphorus-vanadium atom ratio of the solid complex have been found to be 2000 and 2:1 respectively. The mechanism of the extraction is discussed. 相似文献
11.
The IR and electronic absorption spectra of di-2-ethylhexyl hydrogen phosphate (HDEHP) extracts of vanadium(V) and sulfuric acid and of vanadium(V) solutions in sulfuric acid were studied. The composition of the extractable complex was determined, and the equation of vanadium(V) extraction with HDEHP was suggested. The equilibrium constant of vanadium(V) extraction from concentrated sulfuric acid solutions was found. 相似文献
12.
Investigation of aggregation in solvent extraction of lanthanides by acidic extractants (organo-phosphorus and naphthenic acid) 总被引:2,自引:0,他引:2
Three acidic extractants (Ⅰ) di(2-ethylhexyl) phosphoric acid (HDEHP),(Ⅱ) 2-ethylhexyl phos-phonic acid mono-2-ethylhexyl ester (KEHPEHE) and (Ⅲ) naphthenic acid were employed in preparing the samples for the characterization of the coordination structure of lanthanlde-extractant complexes and the physicochemical nature of aggregates formed in the organic diluent of the solvent extraction systems.Photo correlation spectroscopy (PCS) re-suits on the aggregates formed by the partially saponified HDEHP in n -heptane showed that the hydrodynamic radius of the aggregates was comparable to the molecular dimensions of HDEHP.The addition of 2-octanol into the diluent,by which the mixed solvent was formed,increased the dimensions of the corresponding aggregates.Aggregates formed from the ianthamde ions and HDEHP in the organic phase of the extraction systems were found very unstable.In the case of naphthenic acid,PCS data showed the formation of w/o microemulsion from the saponified naphthenic acid in the mix 相似文献
13.
A. M. El-Kot 《Journal of Radioanalytical and Nuclear Chemistry》1993,170(1):207-214
The extraction of Na3+, Eu3+ and Tm3+ by di-(2-ethylhexyl)phosphoric acid, HDEHP has been studied from various aqueous acidic solutions. The extraction of these elements is inversely proportional to the third power of the hydrogen ion concentration. Antagonistic effects were observed when the extraction was studied by mixtures of HDEHP and tributyl phosphate, TBP, or trioctylphosphine oxide, TOPO. The presence of water-miscible alcohols and acetone generally increases the extraction of these three elements from HCl solutions. Reaction mechanisms have been suggested and discussed in the light of the data obtained. 相似文献
14.
L. G. Golubyatnikova R. A. Khisamutdinov A. N. Lobov Yu. I. Murinov 《Russian Journal of Inorganic Chemistry》2013,58(4):491-498
Extraction of gold(III) with (RS)-1-(4-chlorophenyl)-4,4-dimethyl-3-(1H-1,2,4-triazol-1-ylmethyl)-pentan-3-ol from 3 M hydrochloric acid solutions (with chloroform as a diluent) has been studied. Optimal extraction conditions have been found. The reagent has been shown to extract efficiently metal ion from solutions containing 3 M hydrochloric acid due to formation of coordination bond between gold(III) and the N4 atom of the triazole ring. The coordination mechanism of gold(III) extraction has been proposed on the basis of the data obtained. Concentration constants of extraction have been calculated, and the thermodynamic parameters of extraction have been determined. 相似文献
15.
The liquid-liquid extraction of rare-earth elements (REE) by 0.75 M di-(2-ethylhexyl) phosphoric acid (HDEHP) in cyclohexane from perchloric acid (1–12M) has been investigated. At moderate perchloric acid molarities (1–6 M), the distribution coefficient, E, has an inverse third-power dependency upon the acid concentration in the aqueous phase. However, at higher perchloric acid concentrations, the slope of the resulting curve is about +18, which means a change in the extraction mechanism. In 12 M perchloric acid medium, REE are quantitatively and selectively extracted from apatite minerals, in the organic phase. In order to strip out all the lanthanides, back-extractions were carried out with 9 M hydrochloric acid solutions. 相似文献
16.
Four composite materials with di-(2-ethylhexyl) phosphoric acid (HDEHP) as an extraction agent and PAN as a binding polymer
were studied in this work. The intended use of these materials is in extraction chromatography. They were prepared by various
methods and contained different amounts of HDEHP. The properties were compared by studying europium uptake from nitric acid
solutions. Materials prepared by direct incorporation of extraction agent into PAN polymer during beads production and with
up to 40% (w/w) of HDEHP are suitable for analytical separations. Materials with high capacity can be prepared by impregnation
of ready-made PAN beads. 相似文献
17.
Zusammenfassung Die extraktionschromatographische Abtrennung von Uran(IV) aus salpetersauren Lösungen wird beschrieben. Kolonnen mit Di-(2-äthylhexyl)-phosphorsäure (HDEHP) in Xylol als stationärer Phase wurden verwendet. Bei alleiniger Anwesenheit von Uran(IV) und Uran(VI) genügte es, mit Salpetersäure/0,1-m Hydrazin zu eluieren. Aus Lösungen komplexerer Zusammensetzung, die neben Uran(IV) und Uran(VI) auch noch längerlebige Spaltprodukte (144Ce,106Ru,95Nb und137Cs), Plutonium (III) und Korrosionsprodukte von Stahl [Fe(III), Co(II), Ni(II) und Cr(III)] enthielten, wurde das Uran(IV) auf zwei Arten abgetrennt. Bei der ersten Variante wurde es durch 5%iges HDEHP in Xylol an der Kolonne festgehalten und alle Begleitionen mit 2-n Salpetersäure/0,1-m Hydrazin entfernt. Bei der zweiten Variante konnte neben dem Uran (IV) auch das Uran(VI) in einer gesonderten Fraktion aufgefangen werden. Als stationäre Phase wurde 30%iges HDEHP, als Elutionsmittel 11,7-n Salpetersäure/0,1-m Hydrazin verwendet. Bei beiden Varianten konnte das Uran(IV) mit einem Gemisch aus 15% Schwefelsäure/5% Phosphorsäure von der Kolonne eluiert werden. Bei der ersten Variante konnte das Uran(IV) auch mit 11,7-n Salpetersäure/0,1-m Hydrazin eluiert werden, wenn es nach der Trennung in salpetersaurer Lösung vorliegen sollte. Die Stabilität der Kolonnen und des Uran(IV), der Einfluß der HDEHP-Konzentration in Xylol und der Salpetersäurekonzentration sowie das Verhalten einiger Ionen bei den Trennbedingungen werden besprochen.
Herrn o. Univ.-Prof. Dr.Hans Nowotny zum 60. Geburtstag gewidmet. 相似文献
Separation of uranium(VI) by extraction chromatography from the solutions resulting from nuclear technology
Summary The extraction-chromatographic separation of uranium(VI) from nitric acid solutions is described. Columns were employed containing di-(2-ethylhexyl)-phosphoric acid (HDEHP) in xylene as stationary phase. If only uranium(IV) and uranium(VI) are present, it is sufficient to elute with nitric acid/0.1M hydrazine. From solutions of more complex composition, which in addition to uranium(IV) and uranium(VI) also contain longer-lived fission products (144Ce,106Ru,95Nb and137Cs), plutonium(III) and corrosion products of steel [Fe(III), Co(II), Ni(II) and Cr(III)], the uranium(IV) was separated by two varieties. In the first variant it was retained on the column by 5% HDEHP in xylene and all accompanying ions were removed with 2N nitric acid/0.1M hydrazine. In the second variant, in addition to the uranium(IV), the uranium(VI) also was captured in a separate fraction. 30% HDEHP was employed as stationary phase, while the elution agent was 11.7N nitric acid/0.1M hydrazine. In both variants, the uranium(IV) could be eluted from the column by a mixture of 15% sulfuric acid/5% phosphoric acid. In the first variant, the uranium(IV) could also be eluted by means of 11.7N nitric acid/0.1M hydrazine in case it was planned to have it present after the separation in nitric acid solution. The stability of the columns and of the uranium(IV) and the influence of the HDEHP concentration in xylene and the nitric acid concentration as well as the behavior of several ions under the separation conditions are discussed.
Herrn o. Univ.-Prof. Dr.Hans Nowotny zum 60. Geburtstag gewidmet. 相似文献
18.
M. Watanabe R. Tatsugae K. Shirahashi Y. Morita M. Kubota 《Journal of Radioanalytical and Nuclear Chemistry》2001,250(2):377-379
The back-extraction of uranium(VI) from di(2-ethylhexyl)phosphoric acid (HDEHP) and diisodecylphosphoric acid (DIDPA) was studied by using hydrazine carbonate as back-extractant. U(VI) was back-extracted from n-dodecane solutions of 0.5M HDEHP - 0.2M TBP and 0.5M DIDPA - 0.1M TBP by hydrazine carbonate. The distribution ratios were decreased with an increase of hydrazine carbonate concentration. The back-extraction equilibria were expressed by slope analysis in consideration of neutralization between the extractant (DIDPA, HDEHP) and hydrazine carbonate, which occurred quantitatively during the back-extraction. 相似文献
19.
Xian-Bo Sun Hui-Fang Du Zhu-Xian Yang Zu-Ming Zhou 《Journal of Radioanalytical and Nuclear Chemistry》2000,245(2):421-424
The kinetics of solvent extraction of U(VI) with di(2-ethylhexyl) phosphoric acid (HDEHP) using a microporous hydrophobic hollow fiber membrane extractor has been investigated. The effects of U(VI) and hydrogen ion concentrations in aqueous phase, HDEHP concentration in organic phase, flow velocities of aqueous and organic phase and temperature on extraction rate of U(VI) were examined. The experimental results suggest that the extraction rate of U(VI) is controlled by diffusion. 相似文献
20.
K. Shakir M. Aziz Sh. G. Beheir 《Journal of Radioanalytical and Nuclear Chemistry》1991,147(2):309-319
The extraction of cerium(III) from weakly acidic chloride solutions by HDEHP-nitrobenzene-loaded polyurethane foams could be analyzed quantitatively in terms of the equation: log(9.056 Dc)=log Kc+2.14 log (Cd?6Cc)+3 pH+log fc where Dc is the distribution ratio of cerium(III) between the foam and aqueous phases, Cd and Cc are the total HDEHP and Ce(III) concentrations on the foam, respectively, log fc=[Ce3+](sq)/[ΣCe(III)](aq), and Kc is the equilibrium constant of the equation: Ce (aq) 3+ +2.14(HX)2.8(o) ? ? CeX6·H3(o)+3H (aq) + . Values of Kc under the different extraction conditions tested are given. 相似文献