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1.
A simple solvent extraction procedure for the efficient separation of the radioactive tracers 95Nb and 182Ta from each other in a mixture using di-(2-ethylhexyl)phosphoric acid (HDEHP) as extractant is described. Tantalum was found to be quantitatively extracted from an aqueous madium, which is 1.6N in HCl and 10 ?2 M in oxalic acid, with a HDEHP solution of 0.1 M concentration. Extractabilities of both niobium and tantalum in mineral acids like HCl, H 2SO 4 and HNO 3 and in some organic acids like oxalic, citric, etc., in HDEHP under the experimental conditions were also studied. The reliability of the separation procedure was verified further by γ-ray spectrometry. 相似文献
2.
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 (P 2O 5) 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 P 2O 5 in it increased the extraction substantially. The distribution ratios of Am(III) obtained for HDEHP - P 2O 5 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 P 2O 5 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 H 2SO 4, HNO 3, HClO 4 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
3.
A partial separation of carrier-free 166Ho from milligram quantities of neutron-irradiated Dy 2O 3 targets was achieved from aqueous acidic solutions with HDEHP or TBP as the chromatographic stationary phase, and with electrophoresis using -HIBA as complexing agent. 相似文献
4.
Zusammenfassung Es werden zwei HPLC-Methoden vorgestellt, welche die Trennung von zwei-, drei- und vierbasigen Äther-Carbonsäuren in technischen Gemischen erlauben. Die Verfahren funktionieren mit den freien Säuren genause wie mit den Kalium- und Natriumsalzen und basieren auf den folgenden chromatographischen Systemen: (1) ein starker Anionenaustauscher mit einer mobilen Phase, die ein komplexbildendes Mittel enthält: Aminex A 14/Magnesiumacetat + Essigsäure und (2) ein Umkehrphasensystem: -Bondapak-C 18/H 2SO 4+Na 2SO 4. Die Trennzeiten betragen 45 bzw. 7 Minuten. Beide Methoden sind viel schneller und wahrscheinlich auch genauer als gas-chromatographische Verfahren, da keine Derivatisierung notwendig ist.
High-pressure liquid chromatography of ether-polycarboxylic acids Summary Two HPLC-methods are presented which permit the separation of two-, three-, and fourbasic ether-carboxylic acids in technical mixtures. The procedures work with the free acids as well as with the sodium and potassium salts and are based upon the following chromatographic systems: (1) A strong anion-exchanger with a mobile phase containing a complexing agent: Aminex A 14/magnesium acetate + acetic acid and (2) a reversed phase system: -Bondapak-C18/H2SO4+Na2SO4. The separation times are 45 and 7 minutes respectively. Both methods are much faster and probably more accurate than gas chromatographic procedures, because no derivatisation is necessary. 相似文献
5.
The extraction of Tm with HDEHP from H 2SO 4, HCl and HBr is inversely proportional to the third power of the hydrogen ion concentration while the extraction is small with HDEHP, LA-2 and TBP from binary mixtures of acids. The extraction of both Eu and Tm with HDEHP from KI solutions decreases in the presence of small concentrations of H 2SO 4. The decrease is sharper in case of Eu leading to high separation factors between Eu and Tm from KI?H 2SO 4 mixtures. 相似文献
7.
In order to measure 182Hf by accelerator mass spectrometry (AMS), a chemical procedure for separation of hafnium from tungsten has been developed by extraction chromatography. The extraction chromatographic behavior of hafnium and tungsten has been studied using tri- n-octylamine (TOA) as the stationary phase, HCl–H 2O 2 mixture and NH 3·H 2O as the mobile phase. The effects of H 2O 2 concentration, column loading and column dimensions are investigated. Hf and W with microgram amounts are successfully separated on a chromatographic column (Ø5 × 196 mm), on which Hf is hardly retained after completely eluted with 6 M HCl–1% H 2O 2 and W strongly adsorbed is then eluted with 3 M NH 3·H 2O. The decontamination factor for tungsten is 3.0 × 10 5 and the recovery of hafnium is better than 99% using a single column separation. 相似文献
8.
Summary Pure silica gel (Pia Seed 5S-60-SIL) has been investigated as a cation-exchange stationary phase for ion chromatography of common monovalent and divalent cations (Li +, Na +, NH 4+, K +, Mg 2+, and Ca 2+) with conductimetric detection; dilute oxalic acid (0.05 m m oxalic acid, pH 4.1, to 1 m m oxalic acid, pH 3.0) was used as mobile phase. The Pia Seed 5S-60-SIL silica gel acted as a cation-exchange stationary phase for these cations when 0.2 m m oxalic acid at pH 3.6 was used as the mobile phase. Excellent simultaneous separation and highly sensitive indirect conductimetric detection of these cations were achieved in 20 min on a 150 mm × 4.6 mm i.d. Pia Seed 5S-60-SIL silica gel column with 0.2 m m oxalic acid containing 4 m m 18-crown-6 (1,4,7,10,13,16-hexaoxacycloctadecane), pH 3.7, as mobile phase (detection limits (signal-to-noise ratio, 3, injection volume, 20 L), were 0.15 m for Li +, 0.16 m for Na +, 0.21 m for NH 4+, 1.0 m for K +, 0.17 m for Mg 2+, and 0.25 m for Ca 2+). The proposed IC–CD method was successfully applied to the separation and detection of major cations (Na +, NH 4+, K +, Mg 2+, and Ca 2+) in rain and river water samples. 相似文献
9.
In this paper, we have investigated the formation of the third-phase in tertiary amine (N235)-PtCl 6 2? -HCl system and the microscopic phase structural evolution of platinum-loaded organic phases before and after the occurrence of the third-phase. The third-phase is characterized by various spectroscopic techniques, and the small angle X-ray scattering (SAXS) experiments demonstrate the appearance of nano-aggregates, i.e., water-in-oil reversed micelles, in the third phase. The experimental results indicate that (1) formation of the third phase is related to the aggregation behaviors of nano-reversed micelles in which a super-concentrated hydrochloric acid formed with the H + to H 2O molar ratio being much higher than that of the conventional 37 wt% saturated hydrochloric acid. (2) The occurrence of the super-concentrated HCl results in a great amount of H + and Cl ? ions enriched and confined within the nano-water pools of W/O reversed micelles in third phase. Therefore, the coordination behaviors of platinum complex ions in that super-concentrated hydrochloric acid are very different from their corresponding behaviors in bulk aqueous solutions. It is possible that H + ions participate in the formation of such complexes as H m PtCl 6 z+ in the super-concentrated hydrochloric acid. (3) The relative contents of various H m PtCl 6 z+ complexes are different corresponding to the H + ion concentrations in confined nano-water pools. The association ability of the acidified tertiary amine N235 molecules (R 3NH +) with various H m PtCl 6 z+ complexes plays an important role in affecting the platinum extraction behaviors. 相似文献
10.
The surface region of sulfate aerosols (supercooled aqueous concentrated sulfuric acid solutions) is the likely site of a number of important heterogeneous reactions in various locations in the atmosphere, but the surface region ionic composition is not known. As a first step in exploring this issue, the first acid ionization reaction for sulfuric acid, H 2SO 4 + H 2O HSO 4– + H 3O +, is studied via electronic structure calculations at the Hartree–Fock level on an H 2SO 4 molecule embedded in the surface region of a cluster containing 33 water molecules. An initial H 2SO 4 configuration is selected which could produce H 3O + readily available for heterogeneous reactions, but which involves reduced solvation and is consistent with no dangling OH bonds for H 2SO 4. It is found that at 0 K and with zero-point energy included, the proton transfer is endothermic by 3.4 kcal/mol. This result is discussed in the context of reactions on sulfate aerosol surfaces and, further, more complex calculations.Contribution to the Jacopo Tomasi Honorary Issue 相似文献
11.
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)UO 2X 2·2TBP (o)+2H
(aq)
+
where HX denotes HDEHP and the HDEHP loaded on the foam is trimerized. 相似文献
12.
The reaction of N-nitro- O-(4-nitrophenyl)hydroxylamine ( 1) with conc. H 2SO 4 affords 4-nitropyrocatechol and that with conc. sulfonic acids (RSO 3H where R = Me, CF 3) affords 2-hydroxy-5-nitrophenyl-R-sulfonates in yields of 80?C85%. These reactions are assumed to proceed through an intermediate (phenoxy)oxodiazonium ion [NO 2C 6H 4O-N=N=O] +, which eliminates the N 2O molecule to form the aryloxenium ion [NO 2C 6H 4O] +. The latter reacts with acid anions at the ortho-carbon atom of the phenyl ring. The thermodynamical parameters of the elementary reactions resulting in the formation of the (phenoxy)oxodiazonium ion [NO 2C 6H 4O-N=N=O] + and aryloxenium ion [NO 2C 6H 4O] + were calculated in the B3LYP/6?311+G(d) study of the combined molecular system (nitrohydroxylamine 1 + [H 3SO 4] +). The reaction of nitrohydroxylamine 1 with aqueous solutions of strong acids (??70% H 2SO 4, CF 3SO 3H) affords mainly 4-nitrophenol. It appears that the mechanism of this reaction does not involve the formation of the aryloxenium ion. 相似文献
13.
Except for conditions of low acidity and low ratios of di(2-ethylhexyl)phosphoric acid (HDEHP) to U(VI) the data obtained for the distribution of U(VI) between sulfuric acid solutions and polyurethane foams loaded with solutions of HDEHP in nitrobenzene could be analyzed by the equation: log (4.36 D u)=log K+1.43 log (C d–4C u)/(C H) 1.4+log f u where the polymerization number of HDEHP is about 2.8, D u is the distribution ratio, and f u=[UO
2
2+
] (aq)/[UO 2] (aq) indicating that the extraction proceeds via the formation of a 14 UO 2:HDEHP complex. At both low acidity and HDEHP/U(VI) ratio a UO 2-HDEHP polymer is formed. 相似文献
14.
Bench-Scale studies on the partitioning and recovery of minoractinides from the actual and synthetic sulphate-bearing high level waste (SBHLW) solutions have been carried out by giving two contacts with 30% TBP to deplete uranium content followed by four contacts with 0.2M CMPO+1.2M TBP in dodecane. The acidity of the SBHLW solutions was about 0.3M. In the case of actual SBHLW, the final raffinate contained about 0.4% -activity originally present in the HLW, whereas with synthetic SBHLW the -activity was reduced to the background level. 144Ce is extracted almost quantitative in the CMPO phase, 106Ru about 12% and 137Cs is practically not extracted at all. The extraction chromatographic column studies with synthetic SBHLW (aftertwo TBP contacts) has shown that large volume of waste solutions could be passed through the column without break-through of actinide metal ions. Using 0.04M HNO 3>99% Am(III) and rare earths could be eluted/stripped. Similarly >99% Pu(IV) and U(VI) could be eluted.stripped using 0.01M oxalic acid and 0.25M sodium carbonate, respectively. In the presence of 0.16M SO
4
2–
(in the SBHLW) the complex ions AmSO
4
+
, UO 2SO 4, PuSO
4
2+
and Pu(SO 4) 2 were formed in the aqueous phase but the species extracted into the organic phase (CMPO+TBP) were only the nitrato complexes Am(NO 3) 3·3CMPO, UO 2(NO 3) 2·2CMPO and Pu(NO 3) 4·2CMPO. A scheme for the recovery of minor actinides from SBHLW solution with two contacts of 30% TBP followed by either solvent extraction or extraction chromatographic techniques has been proposed. 相似文献
15.
A single-column ion chromatography (SCIC) for the simultaneous determination of alkali, alkaline earth and transition metal
elements in UO 2, ThO 2 powders and sintered (Th, U) O 2 pellet is described in this paper. Metrosep cation 1-2 analytical column containing poly butadiene-maleic acid (PBDMA) coated
silica has been applied to the ion chromatographic separation of 12 cations (copper, lithium, sodium, ammonium, nickel, potassium,
zinc, cobalt, manganese, magnesium, calcium and strontium) using an isocratic elution with tartaric acid and oxalic acid as
mobile phase with non-suppressed conductivity detection. Mobile phase composition was optimized to 1 mM tartaric acid and
0.75 mM oxalic acid for the baseline separation of 12 cations. The calibration plots were linear in the range of 0.05–40 mg L −1 with regression coefficients better than 0.998. The relative standard deviations (RSDs) of the retention time, peak area
and peak height were less than 1, 2.8 and 3.0%, respectively. The recoveries of the spiked samples for the cations were 94–110%.
The method developed was validated by comparison with certified standards of UO 2 and ThO 2 powders. 相似文献
16.
Extraction behavior of zirconium and hafnium tracers, 95Zr and 175,181Hf, in HF, HCl, HNO 3 and H 2SO 4 media with the liquid anion exchanger TOA has been studied. Under optimum conditions, TOA was found to be very effective for quantitative extraction of the individual elements at their trace scale concentrations, but due to higher extractibility and almost identical chemical behavior of the radiotracers towards TOA, the reagent was not so effective for mutual separation of the elements when they were present as congeneric pairs in the aqueous solutions. Extents of extraction of the elements at different stages were measured by -ray spectrometry. 相似文献
17.
The asymmetric unit of the title salt [systematic name: bis(4‐(2,3‐dichlorophenyl)‐1‐{4‐[(2‐oxo‐1,2,3,4‐tetrahydroquinolin‐7‐yl)oxy]butyl}piperazin‐1‐ium) oxalate–oxalic acid (1/1)], 2C 23H 28Cl 2N 3O 2+·C 2O 42−·C 2H 2O 4, consists of one protonated aripiprazole unit (HArip +), half an oxalate dianion and half an oxalic acid molecule, the latter two lying on inversion centres. The conformation of the HArip + cation differs from that in other reported salts and resembles more the conformation of neutral Arip units in reported polymorphs and solvates. The intermolecular interaction linking HArip + cations is also similar to those in reported Arip compounds crystallizing in the space group P, with head‐to‐head N—H...O hydrogen bonds generating centrosymmetric dimers, which are further organized into planar ribbons parallel to (01). The oxalate anions and oxalic acid molecules form hydrogen‐bonded chains running along [010], which `pierce' the planar ribbons, interacting with them through a number of stronger N—H...O and weaker C—H...O hydrogen bonds, forming a three‐dimensional network. 相似文献
18.
A method of ion-pair chromatography was developed on a reversed-phase silica-based monolithic column for the fast and simultaneous determination of trifluoromethanesulfonate (CF3SO3
−) and p-toluenesulfonate (C7H7SO3
−). The analysis was performed using a mobile phase of tetrabutylammonium hydroxide + citric acid + acetonitrile on the Chromolith Speed ROD RP-18e column with direct conductivity detection. The effects of the eluent, column temperature and flow rate on the retention of the anions were investigated. The experimental phenomenon was discussed according to hydrophobic interaction and ion-exchange mechanism in the separation. The optimized chromatographic conditions were selected. The optimized eluent for the separation consisted of 0.2 mmol L−1 tetrabutylammonium hydroxide + 0.10 mmol L−1 citric acid + 9% acetonitrile (pH 5.5). The flow rate was set at 6.0 mL min−1. The column temperature was 25 °C. Under the optimal conditions, the better separation of CF3SO3
− and C7H7SO3
− was achieved without any interference by other anions (Cl−, Br−, I−, NO3
−, SO4
2−, ClO3
−, BF4
− and PF6
−). The detection limit (S/N = 3) was 0.28 and 0.71 mg L−1 for CF3SO3
− and C7H7SO3
−, respectively. The method has been applied to the determination of CF3SO3
− and C7H7SO3
− in ionic liquids. The spiked recoveries of CF3SO3
− and C7H7SO3
− were 101.1 and 100.2%, respectively. 相似文献
19.
Summary The extraction of molybdenum and tungsten thiocyanates and dithiocarbamates, as well as the extraction with HDEHP, -benzoinoxime and N-benzoyl-N-phenyl-hydroxylamine in 1–10 mol/l HCl, H 2SO 4, HF, HF-HCl, and HNO 3 medium was studied with the aim to compare the extraction efficiencies of different extractants. The optimum extraction conditions for separation of these two elements are given. New perceptions were obtained for the extraction from hydrofluoric acid medium, especially for the extraction of dithiocarbamates.
Extraktion von Molybdän und Wolfram mit verschiedenen Reagensmitteln
Herrn Prof. Dr. Rolf Neeb zum 60. Geburtstag gewidmet 相似文献
20.
Solvent extraction of Cu(II) by 4-(5-nonyl)pyridine (NPy) in benzene from mineral acid solutions containing thiosulfate ions has been studied at room temperature (23±2°C). Mineral acid solutions alone constitute an aqueous phase from which Cu(II) is not extracted. Addition of small amounts of thiosulfate ions augments the extraction to an extent that quantitative recovery is possible. Stoichiometric studies reveal the involvement of ion-pair type complexes (NPy·H) 2·Cu(S 2O 3) 2 which are responsible for extraction. Stability constants lg K ex for this complex are 7.2±0.2; 9.1±0.2 and 9.5±0.2 for HCl, HNO 3 and H 2SO 4, respectively. The presence of 0.01 mol/l of some complexing ions like ascorbate, acetate, citrate, oxalate, tartrate or iodide does not affect the extraction, thus allowing the recovery of the metal from diverse matrices. Under optimal conditions (0.1M NPy in benzene-0.1M HNO 3 or H 2SO 4+0.01M S 2O 3 ?2 or 0.5M HCl+0.05 M S 2O 3 ?2 ) a clean separation from some elements, e.g. Cs(I). Co(II), Fe(III), Eu(III), Ce(III), Se(IV) and Cr(VI) can be achieved. 相似文献
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