Removal and Recovery of UO2(??) from Water Samples Using 2,2′‐Diamino‐4,4′‐bithiazole as a New Reagent for Solid Phase Extraction

A novel sensitive and simple method for rapid and selective extraction, preconcentration and determination of uranyl as its 2,2′‐diamino‐4,4′‐bithiazole (DABTZ) complex by using octadecylsilica columns and spectrophotometry is presented. Extraction efficiency and the influence of flow rates of sample solution and eluent, pH, amount of DABTZ, type and least amount of eluent for elution of uranyl complex from columns, break‐through volume and limit of detection were evaluated. Also the effects of various cationic and anionic interferences on percent recovery of uranyl were studied. Average extraction efficiency of ca. 90% was obtained by elution of the column with minimal amount of solvent in the presence of interferences. The average preconcentration factor, 136 and a detection limit 0.32 ng·mL^?1 were obtained. The method was applied to the recovery and determination of uranyl in different water samples.     

Solute activity coefficients in dilute aqueous electrolyte mixtures. III. The ternary system HClO4+UO2(ClO4)2+H2O at 25°C

Isopiestic vapor pressure comparison measurements were conducted with the three-component system HClO₄+UO₂(ClO₄)₂+H₂O in the concentration range between I=0.05 and 1.9m. Analysis of the mixture composition and concentration dependence of the osmotic coefficients with the Scatchard neutral-electrolyte and ion-component methods and with the Pitzer ioncomponent methods gave equally satisfactory results. Prediction of the observed osmotic coefficients by two-component approximations was satisfactory, and the data agreed well with values estimated with a model based on the osmolal fraction. A fair concordance was also found between predicted solute activity coefficients from simple models and values derived from complete treatments which included interaction terms.     

Cryoscopic Studies of the Uranyl Sulfate–Water, Uranyl Nitrate–Water, and Uranyl Nitrate–Nitric Acid–Water Systems

Freezing point lowerings of aqueous solutions of uranyl sulfate in the concentration range m 0.40 mol-kg^–1 and the activity and osmotic coefficients, which were calculated using the Pitzer equations for 2:2 electrolytes, are presented. Crystallization temperatures are reported for 0 to 13 molar nitric acid and 10–150 g uranium per liter uranyl nitrate–nitric acid–water solutions.     

正辛烷为稀释剂不对称N-甲基-N-辛基烷基酰胺萃取铀(Ⅵ)的研究(英)

The extraction of uranyl nitrate was studied with newly synthesized unsymmetrical alkylamides, Nmethyl-N-octyloctylamide (MOOA), N-methyl-N-octyldecanamide (MODA), and N-methyl-N-octyldodecanamide (MODOA), employing n-octane as diluent. The effect of the concentrations of nitric acid, sodium nitrate and extractants on the extraction was investigated and the extraction mechanism was suggested. The effect of temperature on the extraction was also studied and the related thermodynamic functions were calculated. The extracted species were characterized by FTIR spectrometry。     

A Highly Efficient Chelating Polymer for the Adsorption of Uranyl and Vanadyl Ions at Low Concentrations

A new polymer containing double amidoxime groups per repeating unit was synthesized to enhance the metal ion uptake capacity. The adsorption properties of this new polymeric adsorbent, amidoximated poly(N,N-dipropionitrile acrylamide), for U(VI), V(V), Cu(II), Co(II) and Ni(II) ions were investigated by batch and flow-through processes at very low concentration levels (ppb). The chelating polymer showed high adsorption capacity for uranyl as well as vanadyl ions. In selectivity studies from a mixture of metal ions in aqueous solutions, the adsorbent showed high selectivity for uranyl and vanadyl ions in the following order: U(VI) > V(V) Co(II) = Cu(II) Ni(II) as determined by calculating the distribution coefficients D, of corresponding ions. The adsorption of uranyl and vanadyl ions from natural seawater by the new adsorbent was also examined in flow through mode.     

Synthesis and Crystal Structure of Bis(nitrate)bis(dipiperidin-1-yl-methanone)uranyl(II)

1 INTRODUCTION The extraction chemistry of uranium is a veryimportant research field, and the new high extrac-tants of uranium have being studied for several deca-des[1, . Our interest is studying the behaviors of new 2]extractants and their st…     

Thermal Responsive Ion Selectivity of Uranyl Peroxide Nanocages: An Inorganic Mimic of K+ Ion Channels

An actinyl peroxide cage cluster, Li_48+mK₁₂(OH)_m[UO₂(O₂)(OH)]₆₀ (H₂O)_n (m≈20 and n≈310; U₆₀), discriminates precisely between Na⁺ and K⁺ ions when heated to certain temperatures, a most essential feature for K⁺ selective filters. The U₆₀ clusters demonstrate several other features in common with K⁺ ion channels, including passive transport of K⁺ ions, a high flux rate, and the dehydration of U₆₀ and K⁺ ions. These qualities make U₆₀ (a pure inorganic cluster) a promising ion channel mimic in an aqueous environment. Laser light scattering (LLS) and isothermal titration calorimetry (ITC) studies revealed that the tailorable ion selectivity of U₆₀ clusters is a result of the thermal responsiveness of the U₆₀ hydration shells.     

N、N′-二乙基-N、N′-二苯基脲的萃取性能和二硝酸二(N、N′-二乙基-N、N′-二苯基脲)合铀酰(Ⅱ)配合物的合成、结构研究

The extraction behavior of N,N′-diethyl-N,N′-dibenzenyl-urea (DEDBU) to Uranium(Ⅵ) and Thorium(Ⅳ) from nitric acid solution was studied by using xylene as diluent. The effects of aqueous HNO₃ concentration and ex-tractant concentration on the extraction distribution ratio of U(Ⅵ) and Th(Ⅳ) were studied, and the results show that the extraction behavior of the extractant to U(Ⅵ) is similar to tributyl phosphate (TBP), the solvation numbers for DEDBU and TBP are two, respectively. Under the experiment condition, the extractant does not show the extraction behavior to Th(Ⅳ), this result exhibits that the extractant has good application to separate U(Ⅵ) and Th(Ⅳ). The crystal structure of the complex UO₂(NO₃)₂[CH₂(CH₂)₂CONC₈H₁₇]₂ was determined by single crystal X-ray diffraction. Crystal data: C₂₄H₄₆N₄O₁₀U, triclinic, space group , a = 8.662(2)?, b= 10.07(2)?, c= 10.895(3)?, α = 103.77(2)°, β = 92.01(2)°, γ = 96.23(2)°, V= 915.7(4)?³, M_r = 934.78, Z= 1, D_c= 1.695 g·cm^-3, F(000) = 462, μ = 4.495mm-1, R= 0.0250, wR= 0.0591, observed reflec-tions 3566 (I>2σ(I)).The central uranyl ions is coordinated by six oxygen atoms, two of them are from the carbonyl groups of N,N′-diethyl-N,N′-dibenzenyl-urea molecules, and the other four are from two nitrate groups.     

Separation of Isotopes of Lithium and Uranium by Electromigration Using Cation-Exchange Membranes

Isotope separation by chromatographic electromigration has been studied for lithium (⁶Li and ⁷Li) and uranium (²³⁵U and ²³⁸U), using cation-exchange membranes as migration media. The membranes were pulled back against the direction of the movement of isotopic cations in a countercurrent manner. In both cases of the elements the lighter isotope, ⁶Li or ²³⁵U, was concentrated at the frontal part of a migration zone; at the extreme front the ⁶Li atom % increased to 16.8% from the original value of 7.5% after 386 cm migration, and the ²³⁵ U atom % rose to 0.743% from the original value of 0.723% after 200 cm migration. Isotope separation coefficients were experimentally determined: ε = (3.7 ± 0.4) μ 10^?3 for lithium isotopes, and two slightly different values ε = (4.9 ± 1.0) μ 10^?5 and (5.4 ± 1.1) μ 10^?5 for uranium isotopes. The steep isotope accumulation was observed in a narrow boundary region. A mathematical expression for the isotope accumulation curve was derived, and the slope of the curve was assessed for each experimental result.     

Polarized Laser Raman Spectra of the Crystal Cs3UO2F3

Abstract

Polarized Raman spectra of Cs₃UO₂F₅ in which the UO₂F₅ ^3? ion is in its statistical position have made it possible to assign definitely the Raman fundamental vibration modes as follows : v₁(A′¹) = 784, v₂(A′¹) = 423, v₈(E′²) = 325, v₈(E′²) = 219 and v₁₀(E″¹) = 259 cm^?1.