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1.
This study was carried out to investigate the characteristics of an oxidative-dissolution of fission products (FP) when uranium (U) is dissolved in a Na2CO3–H2O2 carbonate solution. Simulated FP-oxides which contained 12 components were added to the solution to examine their dissolution behaviors. It was found that H2O2 was an effective oxidant to minimize the dissolution of FP. For the 0.5 M Na2CO3–0.5 M H2O2 solution, such elements as Re, Te, Cs, and MoO2 were dissolved with yields of 98 ± 2%, 98 ± 2%, 93 ± 2%, and 26 ± 3%, respectively, for 2 h. Among these components, Re, Te, and Cs were completely dissolved within 10–20 min without regard to the concentrations of Na2CO3, and H2O2 due to their high solubility in the carbonate solution with and without H2O2. However, MoO2 was very slowly dissolved and its yield was 29 ± 3% for 4 h. The pH of the dissolved solution revealed the greatest influence on the dissolution yields of the FP, exhibiting the most effective pH condition in the range of 10–12 in order to create a considerable suppression of the co-dissolution of FP during the oxidative-dissolution of U.  相似文献   

2.
A feasibility and basic study to find a possibility to develop such a process for recovering U alone from spent fuel by using the methods of an oxidative leaching and a precipitation of U in high alkaline carbonate media was newly suggested with the characteristics of a highly enhanced proliferation-resistance and more environmental friendliness. This study has focused on the examination of an oxidative leaching of uranium from SIMFUEL powders contained 16 elements (U, Ce, Gd, La, Nd, Pr, Sm, Eu, Y, Mo, Pd, Ru, Zr, Ba, Sr, and Te) using a Na2CO3 solution with hydrogen peroxide. U3O8 was dissolved more rapidly than UO2 in a carbonate solution. However, in the presence of H2O2, we can find out that the leaching rates of the reduced SIMFUEL powder are faster than the oxidized SIMFUEL powder. In carbonate solutions with hydrogen peroxide, uranium oxides were dissolved in the form of uranyl peroxo-carbonato complexes. UO2(O2) x (CO3) y 2−2x−2y , where x/y has 1/2, 2/1.  相似文献   

3.
A novel binuclear Cobalt(II) complex with N-(2-propionic acid)-salicyloyl hydrazone (C10H10N2O4, H3L) was prepared and characterized. The crystal structure of [Co(C10H9N2O4)2] · 3H2O was determined by X-ray single-crystal diffractometry. The Co2+ ion is six-coordinated by the carboxyl and acyl O atoms and azomethine N atoms of two tridentate N-(2-propionicacid)-salicyloyl hydrazone ligands, which form two stable five-numbered rings sharing one side in the keto form. The coordination environment around the Co2+ ion might be described as a distorted octahedron. Abundant hydrogen bonds of the types O-H…N and O-H…O between the water molecules and ligands not only form the three-dimensional network, but also provide an extrastability for the crystal. The complex was studied for the interaction with calf thymus DNA by electronic absorption titration and emission titration. The results show that the complex is bound to calf thymus DNA mainly by intercalation. The article is published in the original.  相似文献   

4.
In recent years, more and more attention has been paid in the research of heterojunction catalysts, due to their better catalytic ability than that of single component catalysts. Up to now, many kinds of heterojunction catalysts have been reported, such as Bi2O3/Bi2WO6, WO3/BiVO4, SnO2/TiO2, CdS/TiO2, Ta3N5/Pt/IrO2 and so on, among which the heterojunction catalyst composed of g-C3N4 and TiO2 has been studied tremendously recently, due to the high activity, high thermal and chemical stability, and well matched energy structure of them. Up to now, many methods have been explored for the synthesis of g-C3N4/TiO2 heterojunction catalysts, such as ball milling of g-C3N4 and TiO2, hydrothermal growth of TiO2 on g-C3N4 and so on. In this review, the recent researches on the synthesis of g-C3N4/TiO2 catalysts were summarized. Moreover, the applications of g-C3N4/TiO2 catalysts in the field of photocatalysis were detailedly introduced.  相似文献   

5.
Single crystal X-ray diffraction study of glycine phosphite C2H5NO2·H3PO3 was performed (monoclinic, space group P21/c, a = 7.401(3) Å, b = 8.465(3) Å, c = 9.737(3) Å; β = 100.73(5)°, Z = 4). It has been found that one of hydrogen atoms is located at the centre of symmetry forming two strong hydrogen bonds to yield H4P2O 6 ?2 dimers, while another hydrogen atom is statistically disordered over two positions and organizes the dimers into an infinite corrugated chain. The ordering of this hydrogen atom position and/or displacement of the other one from the centre of symmetry will lead to the loss of symmetry centre and lowering of the point group symmetry from C2h to piezo-active group C2 or C s .  相似文献   

6.
7.
Single crystals of Li(H3O)[UO2(C2O4)2(H2O)] · H2O (I) have been synthesized and studied by X-ray diffraction. Compound I crystallizes in the monoclinic crystal system with the unit cell parameters: a = 7.1682(10) Å, b = 29.639(6) Å, c = 6.6770(12) Å, β= 112.3(7)°, space group P 21/c, Z = 4, R = 4.36%. Structure I contains discrete mononuclear groups [UO2(C2O4)2(H2O)]2? ascribed to the crystal-chemical group AB 2 01 M1 (A = UO2 2+, B01 =C2O 4 2? , M1 = H2O), which are “cross-linked” by the lithium ions into infinite layers {Li(UO2)(C2O4)2(H2O)2}? perpendicular to [010]. The hydroxonium ions are located between adjacent uranium-containing layers. A hydrogen bond system involving water molecules, oxalate ions, and hydroxonium combines the anionic layers into a three-dimensional framework.  相似文献   

8.
The title compound, cobalt 4′,7-diethoxylisoflavone-3′-sulfonate([Co(H2O)6](X)2⋅8H2O, X = C19H17O4SO3) was synthesized and its structure was determined by single-crystal X-ray diffraction analysis. It crystallizes in the triclinic space group P-1 with cell parameters a = 9.026(3) Å, b = 16.431(5) Å, c = 18.195(6) Å, α = 72.289(4), β = 87.498(4), γ = 82.775(5), V = 2550.1(13) Å−3, Dc = 1.419 Mg m−3, and Z = 2. The results show that the title compound consists of one cobalt cation, six coordinated water molecules, eight lattice water molecules, and two 4′,7-diethoxylisoflavone-3′-sulfonate anions, C19H17O4SO3. Two anions have different conformations. Twelve H atoms of six coordinated water molecules, as donors, form hydrogen bonds with four oxygen atoms of sulfo-groups of two anions and eight oxygen atoms of eight lattice water molecules. In addition, π < eqid1 > ⋅ < eqid2 > π stacking interactions exist in the crystal structure, which together with hydrogen bonds lead to supramolecular formation with a three-dimensional network.  相似文献   

9.
The crystal structure of complex [Mg(H2O)6][VO(edta)] · 3.5H2O (I) was determined by X-ray diffraction study. The crystals are monoclinic, a = 6.779 Å, b = 13.373(6) Å, c = 25.054 Å, β = 96.55°, Z = 4, space group P21. The unit cell contains two independent [VO(edta)]2? anions, two independent [Mg(H2O)6]2+ cations, and seven crystal-water molecules. The coordination polyhedron of each vanadium atom is formed by five donor atoms of the edta ligand (2N + 3O) (V(1)-N(1), 2.278 Å; V(1)-N(2), 2.149 Å; V(2)-N(3), 2.301 Å; V(2)-N(4), 2.165 Å; V-O(acet), 2.00 ± 0.02 Å) and the oxygen atom of the oxo group (V-O, 1.60 ± 0.01 Å). The edta ligands and the vanadium atom form three glycinate rings: two R-type rings and one G-type ring (one acetate branch remains free), as well as an E-type ring with an asymmetric gauche configuration. The [Mg(H2O)6] cations are slightly distorted octahedra (Mg-O, 2.013–2.132 Å, the OMgO angles are 86.6°–94.2°). The H2O molecules form a bifurcate system of H-bonds. The crystals of compound I belong to OD-type structures with an incomplete ordering of layers.  相似文献   

10.
The system hydrogen peroxide–hexafluoroacetone sesquihydrate effectively oxidizes adamantane in the presence of VO(acac)2 to afford 64% of adamantan-1-ol in tert-butyl alcohol or 76% of adamantan-2-one in a mixture of acetic acid with pyridine.  相似文献   

11.
Single crystals of Mg pivalate hydrate, Mg(H2O)6(Piv)2 · 3H2O (HPiv = (CH3)3CCOOH) are synthesized and their structure is determined by X-ray diffraction method. The crystals are rhombic: a = 10.917(2) Å, b = 12.625(2) Å, c = 31.394(8) Å, Z = 8, space group Pbca, R 1 = 0.0525. The Mg atom has octahedral surrounding of the O atoms of water molecules (Mg-O 2.044–2.137 Å). The cationic chains of [Mg(H2O)6] 2+ lie in the voids of doubled network anionic layers of [(H2O)3(Piv)2] ∞∞ 2? . Inside the layer, the pivalate anions alternate with water molecules in the xy plane, being bonded to them by hydrogen bonds. The cationic chains and the anionic layers are united into layered packs by hydrogen bonds between coordinated water molecules and pivalate anions and between coordinated and crystal hydrate water molecules.  相似文献   

12.
Tetra-n-butyl ammonium bromide (TBAB) semi-clathrate (sc) hydrates of gas are of prime importance in the secondary refrigeration domain and in the separation of gas molecules by molecular size. However, there is a scarcity of dissociation enthalpies under pressure of pure gases and gases mixtures for such systems. In addition, the phase equilibrium of TBAB sc hydrates of several pure gases is not well defined yet as a function of the TBAB concentration and as a function of the pressure. In this paper, dissociation enthalpies and the phase equilibrium of TBAB sc hydrates of gas have been investigated by differential scanning calorimetry (DSC) under pressure. Pure gases such as N2 and CO2 and gases mixtures such as N2 +  CO2 and CH4 +  CO2 were studied. To our knowledge, we present the first phase diagram of TBAB sc hydrates of N2 for different pressures of gas in the TBAB concentration range from 0.170 to 0.350 wt. Enthalpies of dissociation of TBAB sc hydrates of pure gases and gases mixtures were determined as a function of the presssure for a compound with a congruent melting point whose hydration number corresponds to 26.  相似文献   

13.
A new neptunium(V) complex [(NpO2)2(CH3COO)2(H2O)] ? 2H2O was synthesized and its crystal structure was determined. The unit cell parameters are: a = 24.007(10) Å, b = 6.779(3) Å, c = 8.076(3) Å, space group Pnma, Z = 4, V = 1314.2(9) Å3, R = 0.049, wR(F2) = 0.105. The crystal structure of the compound is composed of neutral [(NpO2)2(CH3COO)2(H2O)] layers and molecules of the water of crystallization. Each of the crystallographically independent neptunoyl ions performs a bidentate function thus forming a composite system of cation-cation bonds.  相似文献   

14.
In-flight spheroidization of alumina powders in Ar–H2 (H2–7.6%, vol/vol) and Ar–N2 (N2–13.0%, vol/vol) RF induction plasmas was investigated numerically and experimentally. The mathematical model for the plasma flows incorporates the k– turbulence model, and that for particles is the Particle-Source-in-Cell (PSI-Cell) model. Experimental results demonstrate that spheroidized alumina particles are produced in both Ar–H2 and Ar–N2 RF plasmas, with different particle size distributions and crystal phases. Agreement between the predicted and measured particle size distributions is satisfactory under high particle feed rate conditions, while the results obtained for the Ar–H2 plasma are better than those for the Ar–N2 plasma. The discrepancy occurring in low feed rate conditions suggests that particle evaporation is an important factor affecting the plasma–particle heat transfer.  相似文献   

15.
Single crystals of Cs[(UO2)2(C2O4)2(OH)] · H2O were synthesized and structurally studied using X-ray diffraction. The compound crystallizes in monoclinic space group P21/m, Z = 2, with the unit cell parameters a = 5.5032(4) Å, b = 13.5577(8) Å, c = 9.5859(8) Å, β = 97.012(3)°, V = 709.86(9) Å3, R = 0.0444. The main building units of crystals are [(UO2)2(C2O4)2(OH)]? layers of the A2K 2 02 M2 (A = UO 2 2+ , K02 = C2O 4 2? , and M2 = OH?) crystal-chemical family. Uranium-containing layers are linked into a three-dimensional framework via electrostatic interactions with outer-sphere cations and hydrogen bonds with water molecules.  相似文献   

16.
Single crystals of Ba3[UO2(C2O4)2(NCS)]2 · 9H2O are synthesized and studied by X-ray diffraction. The crystals are orthorhombic, space group Fddd, Z = 16, and the unit cell parameters are a = 16.253(3) Å, b = 22.245(3) Å, c = 39.031(6) Å. The main crystal structural units are mononuclear complex groups [UO2(C2O4)2NCS]3? of the crystal-chemical family (AB 2 01 M1 (A = UO 2 2+ , B01 = C2O 4 2? , M1 = NCS?) of the uranyl complexes linked into a three-dimensional framework by electrostatic interactions and hydrogen bonds involving oxalate ions and water molecules.  相似文献   

17.
Single crystals of CuCl · C6H4N3(OC3H5)(I) are synthesized by ac electrochemical method from Cu(II) chloride and 1-allyloxybenzotriazole in ethanol solution and their unit cell parameters are determined: space group P21/a a=11.583(4) , b=11.443(7) , c=8.620(4) , =108.77(3)°, V=1082(2) 3, R(F)=0.0366, R w (F)=0.0396 for 1095 reflections. In the structure of -complex I, inorganic fragment Cu2Cl2 forms centrocymmetric parallelogram. A molecule of 1-allyloxybenzotriazole acts as a bridge, which is bonded to the Cu atoms of two inorganic dimers through the C=C bond of the allyl group and to the N atom of a triazole ring. Owing to this bridging function, the ligand molecules form zigzag organometallic layers. The trigonal-pyramidal coordination sphere of a metal atom includes two Cl atoms and the C=C group. The structural motif of complex I significantly differs from that of the previously studied 2CuCl · C6H4N3(OC3H5) and resembles the motif of a bromide analog Cu2Br2 · [C6H4N3(OC3H5)]2.__________Translated from Koordinatsionnaya Khimiya, Vol. 31, No. 5, 2005, pp. 364–369.Original Russian Text Copyright © 2005 by Goreshnik, Myskiv.  相似文献   

18.
The non-isothermal kinetics of dehydration of AlPO4·2H2O was studied in dynamic air atmosphere by TG–DTG–DTA at different heating rates. The result implies an important theoretical support for preparing AlPO4. The AlPO4·2H2O decomposes in two step reactions occurring in the range of 80–150 °C. The activation energy of the second dehydration reaction of AlPO4·2H2O as calculated by Kissinger method was found to be 69.68 kJ mol−1, while the Avrami exponent value was 1.49. The results confirmed the elimination of water of crystallization, which related with the crystal growth mechanism. The thermodynamic functions (ΔH*, ΔG* and ΔS*) of the dehydration reaction are calculated by the activated complex theory. These values in the dehydration step showed that it is directly related to the introduction of heat and is non-spontaneous process.  相似文献   

19.
A lanthanum metal–organic framework, [La(BTC)(H2O)(DMF)] (H3BTC = 1, 3, 5-benzenetricarboxylic acid), was synthesized under mild hydrothermal conditions. The synthesized [La(BTC)(H2O)(DMF)] was characterized by scanning electron microscopy in combination with energy dispersive X-ray spectroscopy (SEM/EDS), transmission electron microscopy (TEM), X-ray diffraction (XRD), and fourier transform infrared spectroscopy (FT-IR). Its electrochemical properties and electrocatalytic activity towards H2O2 reduction in acidic media were studied by cyclic voltammetry (CV) and amperometric current–time response. The [La(BTC)(H2O)(DMF)] modified electrode shows good electrochemical behavior and performs well electrocatalytic activity towards hydrogen peroxide (H2O2) reduction at ca. ?0.7 V. The modified electrode displays a linear range from 5 μM to 2.67 mM and a limit of detection of 0.73 μM to H2O2. The [La(BTC)(H2O)(DMF)] modified electrode also possesses good selectivity and stability. Thus, [La(BTC)(H2O)(DMF)] will be a promising material for non-enzymatic H2O2 sensor.  相似文献   

20.
The crystal structure of tripotassium trisaccharinate dihydrate, K3(C7H4NO3S)3·2H2O, is triclic, space group\(P \bar 1, Z = 2\). It consists of three crystallographically independent potassium and saccharinato ions as well as two structurally different water molecules. Potassium coordination polyhedra are irregular, with K1 and K3 six-coordinated and the third one K2 seven-coordinated. The K?O distances range from 2.652(9) to 3.100(2) Å(mean: 2.790 Å) whereas the K?N distance is 3.025(3) Å. The water molecules W2 is disordered over three positions with occupancies of approximately 0.6, 0.2 and 0.2. The hydrogen atom (H1W1) of the ordered water molecule (O1W) is hydrogen bonded to the sulfonyl oxygen atom (O11) (R(O...O)=2.976(3) Å), whereas the other hydrogen atom (H2W1) is bifurcated to the carbonyl oxygen atom (O13) (R(O...O)=2.851(3) Å) and the disordered water molecules (O23W) (R(O...O)=3.067(12) Å). The carbonyl oxygens (O13, O23 and O33) and one of the disordered water molecules (O22W) are involved in C?H...O hydrogen bonds (R(C?H...O)=3.027(4)–3.304(9) Å). Structural characteristics of the studied compound are compared with the analogous trisodium trisaccharinate dihydrate and dipotassium sodium trisaccharinate monohydrate. Infrared and Raman spectra of the title compound have been analyzed in relation to the structure, and compared with the spectra of trisodium trisaccharinate dihydrate.  相似文献   

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