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1.
P. Spacu Florica Popea und Constana Tohaneanu 《Fresenius' Journal of Analytical Chemistry》1965,214(5):338-341
Zusammenfassung Die Pufferlösungen CH2ClCOOH + CH2ClCOONa (I), CH2BrCOOH + CH2BrCOONa (II) und CH2JCOOH + CH2JCOONa (III) wurden als Reagentien für die Uranbestimmung vorgeschlagen.Das Beersche Gesetz wird für den Konzentrationsbereich von 0,11903 bis 2,85684 mg/ml Uran mit 0,1 m Reagenslösungen befolgt. Y3+, Ce3+ und Th4+ sind ohne Einfluß.Für den Konzentrationsbereich von 0,11903–3,80912 mg/ml Uran werden 1 m Reagenslösungen angewendet. Bei Verwendung von (I) oder (II) stören Y3+, Ce3+ und Th4+ nicht. Wird (III) benutzt, muß man zur Vermeidung der Störung durch Thorium, Uran mit Essigester extrahieren.
Summary The buffer solutions CH2ClCOOH + CH2ClCOONa (I), CH2BrCOOH + CH2BrCOONa (II) and CH2ICOOH + CH2ICOONa (III) are shown to provide new reagents for the spectrophotometric determination of uranium.The method can be used for the direct determination of 0.11903 to 2.85684 mg of uranium with. 0.1 M reagents, when Y3+ or Ce3+ or Th4+ are present. With 1 M concentrations, 0.11903 to 3.80912 mg of uranium can be directly determined in presence of Y3+ and Ce3+; with (I) or (II), thorium has no effect on the absorbance, too; with. (III) uranium must be previously extracted into ethyl acetate.相似文献
2.
《Analytical letters》2012,45(8):1635-1644
ABSTRACT The stepwise formation constants of Ce3+, Th4+ and UO2 2+ complexes with four azo compounds based on I-phenyl-2, 3-dimethylpyrazoline-5-one nucleus namely; 4-phenylazo- (2-hydroxy, 5-x) 1-pheny1-2, 3-dimethy1-pyrazoline-5-one, where x= H (1), OH (II), COOH (III) and NH2 (IV) have been determined potentiometrically at different temperatures and ionic strengths in 30% (v/v) ethanol-water solutions, then the thermodynamic parameters are calculated. Negatives values of both ∠H and ∠G are obtained indicating the exothermic and spontaneous nature of complexation reactions, whereas positive values of ∠S show that entropy consideration favour complex formation. The study at different ionic strengths shows that an increase in the latter causes a decrese in the pK values. The azo compounds are also tested as new reagents for the spectrophotometric determination of Ce3+, Th4+ and UO2 2+ ions in synthetic and natural solutions by extensive investigation of the optimum conditions favoring the formation of colored complexes. 相似文献
3.
The electronic absorption spectra of C. I. Acid Red 186 are studied in solution of different pH. The pK values of the acid-base equilibria set are determined and commented upon. The complexes of UO++2, Ce3+ and Th4+ ions are investigated by some spectroscopic techniques and potentiometric titration. The formation of 1:1, 1:2 and 1:2 complexes (M:L) with UO2++, Ce3+ and Th4+ respectively is confirmed and their conditional stability constants are determined. The solid complexes are prepared and analysed for their metal content, their ir spectra are disussed in comparison to that of the ligand to establish the bonding between the ligand and metal ions. 相似文献
4.
《Analytical letters》2012,45(3):141-152
Abstract The complex formed between molybdenum(VI) and benzoylacetanilide in the pH range 0.6 and 1.9 has been extracted into methyl isobutyl ketone and the absorbance has been measured at 410 mμ. Quantities of 0.15 to 2.10 mg of molybdenum have been determined with a standard deviation of 0.6%. The color is stable up to 2 hours. The presence of Co2+, Ni2+, Zn2+, Mn2+, Be2+, Al3+, Cr3+, Ce4+, Th4+ or UO2+ 2 up to 100 μg causes no interference. Ordinarily, Fe3+ interferes with the determination, but when masked with 1 ml of 0.5% solution of ascorbic acid the tolerance limit is 10 mg. Thus, molybdenum can be determined in steel when present in amounts as low as 0.26%. 相似文献
5.
Adsorption of uranium, as UO2
2+, and thorium, as Th4+, has been studied using a modified fly ash bed. Effects of pH and various ions like La3+, Fe3+, Ce4+, SiO3
2- etc., have been examined. Synthetic mixtures of UO2
2+ and Th4+ in different concentrations were passed through the bed and eluted separately with various selective reagents viz. ammonium carbonate, sodium carbonate and acetic acid-sodium hydroxide buffer. Separations of these elements at ppm level are shown to be very effective. The separation of uranium and thorium in the presence of lanthanides in monazite sand has been studied successfully. In the analysis of monazite sand, the oxalate precipitation has been avoided. The method is simple and of very low cost. The modified fly ash bed can also be used to remove uranium from contaminated water. 相似文献
6.
Stability constants for La3+, Ce3+, UO2
2+, and Th4+ metal ion complexes with rhodanine azosulfonamide derivatives have been determined potentiometrically in 0.1 M KCl in a 30% (v/v) ethanol–water mixture. The order of the stability constants of the complexes found was to La3+ < Ce
2+ < UO
2
2+ < Th
4+. The influence of substituents on the stability of the complexes was examined on the basis of electron-repelling property of the substituent. The effect of temperature on the stability constants was studied and the Gibbs energy, the enthalpy, and entropy of complexation thermodynamic parameters were derived and are discussed. The stoichiometries of these complexes were determined conductometrically and the results indicated the formation of 1:1 and 1:2 (metal:ligand) complexes. 相似文献
7.
Gurcharan Singh Manku 《Mikrochimica acta》1972,60(6):811-817
Summary 3-Nitroso-4-hydroxycoumarin is suggested as a new reagent for the spectrophotometric determination of 125 g to 0.50 mg Th(IV) in 3: 1 dioxan: water medium as 1: 1 complex having orange red colour with absorption maximum at 419 nm, at pH 4.5–6.0. For the estimation of9.6 ppm Th(IV) 100-folds acetate, citrate, tartrate; 50 ppm UO2
2+, 75 ppm Ce3+, La3+, Gd3+; 4.5 ppm Ce4+; 25 ppm Tm3+, Zr4+; and 100 ppm Ti4+, V5+, MoO4
2– and WO4
2– do not interfere.
Zusammenfassung 3-Nitroso-4-hydroxycoumarin wird als neues Reagens für die spektrophotometrische Bestimmung von 125 g bis 0,50 mg Th(IV) in Dioxan: Wasser = 3: 1 als 1: 1-Komplex mit orange-roter Farbe mit einem Absorptionsmaximum bei 419 nm bei pH 4,5–6,0 empfohlen. Bei einem Einsatz von 9,6 ppm Th(IV) stört die hundertfache Menge Acetat, Citrat, Tartrat nicht. Auch 50 ppm UO2 2+, 75 ppm Ce3+, La3+, Gd3+, 4,5 ppm Ce4+, 25 ppm Tm3+, Zr4+, 100 ppm Ti4+, V5+, MoO4 2– bzw. WO4 2– stören nicht.相似文献
8.
Guo Zhijun Wu Wangsuo Shao Dadong Tan Minyu 《Journal of Radioanalytical and Nuclear Chemistry》2003,258(1):199-203
Two open-chain crown ethers 2,2'-(ethylenedioxy)bis[(8-quinolyloxymethyl)benzene], (L1), and 2,2'-(ethylenedioxy)bis[(8-quinaldyloxymethyl)benzene], (L2) have been prepared and characterized by using elemental analysis, IR spectra, 1H NMR spectra and positive-ion FAB mass spectra. The extraction of UO2
2+ and Th4+ by both open-chain crown ethers, L1 and L2 in chloroform as a diluent was studied at 25 °C. Extraction distribution ratios (D) of UO2
2+ and Th4+ were investigated as a function of pH, lithium picrate concentration, and extractant concentration. Based on the expertimental results, it was found that 1 : 1 complexes were formed involving either UO2
2+ or Th4+ with L1, and Th4+ with L2. The extractability of L1 for Th4+ is significantly higher than that for UO2
2+, the extractabilities of L1 and L2 for Th4+ being almost identical. L1 and L2 used here are not feasible for industry because of their relatively low extractabilities for Th4+ at pH<2.0 and for UO2
2+ at the extraction conditions used in this work. 相似文献
9.
O. E. Sherif Y. M. Issa M. E. M. Hassouna S. M. Abass 《Monatshefte für Chemie / Chemical Monthly》1993,124(6-7):627-635
Summary Solid complexes of 3-acetyl-1,5-diaryl and 3-cyano-1,5-diaryl formazans were prepared and characterized by elemental analysis, IR, NMR, TGA and DTA analyses. Based on these studies, the suggested general formula for the complexes is [M(HL)
m
(OH–)
n
or (NO
3
–
or Cl–)
x
·(H2O)
y
or (C2H5OH orDMSO)
z
, where HL=formazanM=Ce3+, Th4+, and UO
2
2+
,m=1–2,n=0–3,x=0–3,y=0–4 andz=0–3. The metal ions are expected to have coordination numbers 6–8.
Strukturuntersuchungen an 3-Acetyl-1,5-diaryl- und 3-Cyan-1,5-diaryl-formazan-Chelaten mit Cer(III), Thorium(IV) und Uran(VI)
Zusammenfassung Die hergestellten Chelate wurden mittels Elementaranalyse, IR, NMR, TGA und DTA charakterisiert. Darauf basierend wird die generelle Formel [M(HL) m (OH–) n bzw. (NO 3 – oder Cl–) x ·(H2O) y oder (C2H5OH bzw.DMSO) z ] vorgeschlagen, wobei HL=Formazan,M=Ce3+, Th4+ oder UO 2 2+ ,m=1–2,n=0–3,x=0–3,y=0–4 undz=0–3. Die Metallionen haben Koordinationszahlen von 6–8.相似文献
10.
The stepwise metal-ligand stability constants of ARS chelates with Al3+, Ce1+ and Th4+ have been determined by using Bjerrum-Calvin technique. Various computational methods were used to determine the stability constants. The thermodynamic stability constants were also calculated by determining the stepwise stability constants at various ionic strengths and then by extrapolating to zero ionic strength. The order of stability constants was found to be: Th>Al>Ce. 相似文献
11.
《液相色谱法及相关技术杂志》2012,35(7):1253-1264
Abstract The adsorption behaviour of 47 metal ions has been studied in aqueous HCl systems using stannic ersenate layers. The effect of solvent pH on Rf alongwith the complexation effect of HCl has been investigated. On the basis of Rf values the KSP of some metel arsenates have been predicted. HCl has been utilized to resolve some binary and ternary mixtures such as Be2+ - Mg2+, Zr4+ - La3+, Th4+ - Ce4+, Th4+ - UO2+ 2, Cr3+ - Mo6+ or W6+, Sb3+ - Bi3+ - Cd2+ and Ag+ - Cu2+ - Cd2+. 相似文献
12.
One new single crystal [Th(NO3)2(H2O)6](CB6)(NO3)2·2H2O was prepared using Th(NO3)4·4H2O and cucurbit[6]uril (CB6) as reagents in HNO3 aqueous solution by slow evaporation. The coordination number of Th4+ is ten. Th4+ is coordinated with six monodentate water molecules and two symmetric bidentate chelating nitrate ions, while other two nitrate ions act as the counterion anions. CB6 is a second-sphere ligand which is hydrogen bonded to the water molecules of [Th(NO3)2(H2O)6]2+. Besides, there are also two free water molecules in the crystal system. 相似文献
13.
F. H. El-Sweify R. Shabana N. Abdel-Rahman H. F. Aly 《Journal of Radioanalytical and Nuclear Chemistry》1985,91(1):91-97
The distribution of UO
2
2+
, Ce3+ and Am3+ between Chelex-100 and 0.2 and 5.0M ammonium thiocyanate solutions of different hydrogen ion concentrations has been investigated. The results obtained are compared with parallel experimental results using the anion exchanger Dowex-1×4 and the cation excharger Dowex-50×8. It is found that Chelex-100 can act as anion exchanger at pH<2 and as cation and chelate exchanger at higher pH. A main feature of the distribution results of UO
2
2+
, Am3+ and Ce3+ with Chelex-100 is the very high distribution coefficient for the three cations at pH higher than 3.5 from aqueous solutions containing 0.2 or 5.0M ammonium thiocyanate. 相似文献
14.
Facilely synthesized zinc hydroxide nanoparticles by electro-dissolution of zinc sacrificial anodes were investigated for the adsorption of thorium (Th4+), uranium (U4+) and cerium (Ce4+) from aqueous solution. Various operating parameters such as effect of pH, current density, temperature, electrode configuration, and electrode spacing on the adsorption efficiency of Th4+, U4+ and Ce4+ were studied. The results showed that the maximum removal efficiency was achieved for Th4+, U4+ and Ce4+ with zinc as anode and stainless steel as cathode at a current density of 0.2 A/dm2 and pH of 7.0. First- and second-order rate equations were applied to study the adsorption kinetics. The adsorption process follows second order kinetics model with good correlation. The Langmuir, Freundlich adsorption models were applied to describe the equilibrium isotherms and the isotherm constants were determined. The experimental adsorption data were fitted to the Langmuir adsorption model. Thermodynamic parameters such as free energy (ΔG°), enthalpy (ΔH°), and entropy changes (ΔS°) for the adsorption of Th4+, U4+ and Ce4+ were computed to predict the nature of adsorption process. Temperature studies showed that the adsorption was endothermic and spontaneous in nature. 相似文献
15.
S. L. Stefan 《Monatshefte für Chemie / Chemical Monthly》1994,125(8-9):859-867
Summary Stability constants of complexes of aryl-bis-(5-hydroxy-3-methyl-1-phenyl-4-pyrazolyl) methane [ArBPyM] derivatives with thorium(IV) ions were determined by the potentiometric method at 30°C and an ionic strength of 0.1 mol·dm–3 (KNO3) in 75% (v/v) dioxane-water. The evaluation of the titration data indicated that four kinds of complexes ([ThL]2+, [ThLOH]+, [ThL
2], and [ThL(OH)2]2–) were formed. The formation constants for all [ThL]2+ and [ThL
2] complexes have been calculated to compare these values with those previously reported [1, 2] with Ln3+ and UO
2
2+
metal ions [2, 3]. The probable ligand-bonding sites of the complexes are proposed. In addition, the applicability of theHammett equation for the correlation of the stability constants of [Th(IV)-ArBPyM] complexes are discussed.
Stabilitätskonstanten von Thorium(IV)-Komplexen mit Aryl-bis-(5-hydroxy-3-methyl-1-phenyl-4-pyrazolyl)-methan-Liganden
Zusammenfassung Stabilitätskonstanten von Komplexen von Aryl-bis-(5-hydroxy-3-methyl-1-phenyl-4-pyrazolyl)-methan — Derivaten [ArBPyM] mit Thorium(IV) — Ionen wurden bei 30°C und einer Ionenstärke von 0.1 mol-dm–3 (KNO3) in 75% (v/v) Dioxan-Wasser potentiometrisch bestimmt. Die Auswertung der Titrationskurven zeigte, daß vier verschiedene Komplexe vorlagen ([ThL]2+, [ThLOH]+, [ThL 2] und [ThL(OH)2]2+). Die Bildungskonstanten aller [ThL]2+- und [ThL 2]-Komplexe wurden berechnet, um sie mit den früher für Ln3+- und UO 2 2+ -Ionen publizierten zu vergleichen. Potentielle Bindungsstellen der Komplexe für Liganden werden vorgeschlagen. Zusätzlich wird die Anwendbarkeit derHammet-Beziehung auf die Korrelation der Stabilitätskonstanten von [Th(IV)-ArBPyM] — Komplexen diskutiert.相似文献
16.
The extraction of UO
2
2+
, Am3+, and Th4+ by 1-phenyl-3-methyl-4-benzylpyrazolone with crown ethers was studies using 0.1M (NaClO4) aqueous phase and toluene. The crown ethers were 12C4, 15C5, 18C6, DB18C6 and DCH18C6. The synergic equilibrium constant did not show correlation between the cationic radii and the ether cavity size nor did the values follow a simple order of ether basicity. The ether basicity, steric effects, and the number of ether oxygens bound to the cation are the combined factors which seemingly determine the pattern of M(PMBP)n—CE interaction. 相似文献
17.
Milan Marhol 《Fresenius' Journal of Analytical Chemistry》1967,231(4):265-272
Summary Uranium or thorium separations from a number of various ions were studied by means of cation exchangers containing phosphorus in their functional group. These ion exchangers adsorb selectively only UO2
2+ or Th4+ ions from the mixture studied in a medium of >0.4 N nitric or hydrochloric acid. Several di- and trivalent cations are not sorbed under these conditions. In the absence of UO2
2+ and Th4+ ions, Me2+ may be more easily separated quantitatively from Me3+ in 0.2 N nitric or hydrochloric acid than with cation exchangers containing the -SO3H group.
Zusammenfassung Die quantitative Trennung von UO2 2+ oder Th4+ von einer Reihe anderer Ionen wurde mit Hilfe phosphorhaltiger Kationenaustauscher untersucht. Diese Ionenaustauscher sorbieren selektiv nur UO2 2+ oder Th4+-Ionen aus einem Medium von >0,4 N HNO3 oder HCl. Eine Reihe verschiedener zwei- und dreiwertiger Kationen wird unter diesen Bedingungen nicht sortiert. Bei Abwesenheit von UO2 2+- und Th4+-Ionen kann man Me2+ in 0,2 N HNO3- oder HCl-Lösung quantitativ von Me3+ trennen, und zwar leichter als mit -SO3H-haltigen Austauschern.相似文献
18.
Summary o-Phenylenedioxydiacetic acid has been found to be a selective reagent for the estimation of zirconium. As little as 2.1 mg of zirconium can be easily estimated. The composition of the precipitate varies somewhat and therefore, direct weighing is not possible. This difficulty is overcome by igniting as oxide. Be2+, Ca2+, Ba2+, Zn2+, Hg2+, Al3+, Ce3+, Ti4+, Th4+, UO2+, Mn2+, Fe3+, Co2+, and Ni2+, ions do not interfere. Although V2O2
4+ and Cr3+ ions are not precipitated in neutral or slightly acidic solutions they contaminate the zirconium precipitate, at about 0.30 N HCl concentration. The amount of contamination is so small that it is removed by double precipitation. This method gives satisfactory results even in the presence of small amounts of SO4
2–ions. 相似文献
19.
Complexation of U(VI), Ce(III) and Nd(III) with acetohydroxamic acid in perchlorate aqueous solution
Dong-Yong Chung Eun-Kyoung Choi Eil-Hee Lee Kwang-Wook Kim 《Journal of Radioanalytical and Nuclear Chemistry》2011,289(2):315-319
Complexes of UO2
2+, Ce3+ and Nd3+ (M) with acetohydroxamic acid (AHA or L) in an aqueous solution have been investigated by the pH-spectral titration method
at 25 °C in an aqueous medium of 1.0 M NaClO4 ionic strength. Cerium(III) and neodymium(III) form [ML]2+, [ML2]+, [ML3] complexes with acetohydroxamic acid, while in case of UO2
2+ form [UO2L]+, [UO2L2] complexes with acetohydroxamic acid. Data processing with SQUAD program calculates the best values for the stability constants
from pH-spectrophotometric titration data. The protonation constant obtained was pK1 = 9.15 ± 0.04 at 25 °C. The stability constants for acetohydroxamic acid with UO2
2+, Ce3+ and Nd3+ were β1 = 7.22 ± 0.011, β2 = 14.89 ± 0.018 for UO2
2+ and β1 = 5.05 ± 0.062, β2 = 10.60 ± 0.076, β3 = 16.23 ± 0.088 for Ce3+ and β1 = 5.90 ± 0.028, β2 = 12.22 ± 0.038, β3 = 18.58 ± 0.042 for Nd3+, respectively. 相似文献
20.
Yusov A. B. Fedoseev A. M. Astafurova L. N. 《Russian Journal of Coordination Chemistry》2002,28(4):264-271
The interaction of Np(VI), Pu(VI), Np(V), Np(IV), Pu(IV), Nd(III), and Am(III) with Al(III) in solutions at pH 0–4 was studied by the spectrophotometric method. It was shown that, in the range of pH 3–4, the hydrolyzed forms of neptunyl and plutonyl react with the hydrolyzed forms of aluminium. In the case of Pu(VI), the mixed hydroxoaqua complexes (H2O)3PuO2(-OH)2Al(OH)(H2O)3
2+ or (H2O)4PuO2OAl(OH)(H2O)4
2+ are formed at the first stage of hydrolysis. Np(VI) also forms similar hydroxoaqua complexes with Al(III). The formation of the mixed hydroxoaqua complexes was also observed when Np(IV) or Pu(IV) was simultaneously hydrolyzed with Al(III) at pH 1.5–2.5. The Np(IV) complex with Al(III) has, most likely, the formula (H2O)
n
(OH)Np(-OH)2Al(OH)(H2O)3
3+. At pH from 2 to 4.1 (when aluminium hydroxide precipitates), the Np(V) or Nd(III) ions exist in solutions with or without Al(III) in similar forms. When pH is increased to 5–5.5, these ions are almost not captured by the aluminium hydroxide precipitate. 相似文献