共查询到20条相似文献,搜索用时 15 毫秒
1.
A. G. Belous O. Z. Yanchevskii A. V. Kramarenko 《Russian Journal of Applied Chemistry》2006,79(3):345-350
Rounded nanosize particles of Co3O4 and NiO were prepared by precipitation with ammonium carbonate from cobalt and nickel nitrate solutions. Cobalt and nickel oxides and their precursors were characterized by thermal and X-ray phase analyses, electron microscopy, and IR spectroscopy. 相似文献
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Summary It is shown by ion-exchange studies that the presence of a non-aqueous solvent will aid the formation of anionic chloro complexes of cobalt at lower hydrochloric acid concentrations, the effect being in the order acetone > ethyl alcohol > methyl alcohol. This effect has been made use of in the anion exchange separation of cobalt and nickel using an acetone-hydrochloric acid mixture as eluant.
One of us (J. S.) thanks the Council of Scientific and Industrial Research (India) for the award of a Junior Research Fellowship. 相似文献
Zusammenfassung Die Bildung anionischer Chlorokomplexe des Kobalts bei niederen Salzsäurekonzentrationen wird durch die Gegenwart organischer Lösungsmittel begünstigt, deren Wirkung in der Reihenfolge Aceton > Äthanol > Methanol abnimmt. Da Nickel kein ähnliches Verhalten zeigt, kann eine Trennung von Kobalt und Nickel mit Hilfe eines Anionenaustauschers durchgeführt werden, wobei ein Aceton-Salzsäuregemisch als Eluierungsmittel dient.
One of us (J. S.) thanks the Council of Scientific and Industrial Research (India) for the award of a Junior Research Fellowship. 相似文献
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N. N. Prokopchuk V. A. Kopilevich L. V. Voitenko 《Russian Journal of Applied Chemistry》2008,81(3):386-391
The possibility of the heterogeneous synthesis of crystalline nickel(II) cobalt(II) aqua ammine orthophosphates with a specified ratio of cations was studied. The substances were studied by IR spectroscopy, X-ray phase analysis, and thermal analysis. Owing to a wide color spectrum, they show promise as pigments for ceramic industry. 相似文献
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Super-microporous hexagonal niobium phosphate synthesized using neutral surfactant (S0I0 mechanism) and cubic structure with cationic surfactant (S+X-I+); the hexagonal niobium phosphate possesses an excellent anion exchange capacity (6.3 mmol g-1) and high product selectivity towards 4-naphthaquinone (88.6%) in the oxidation of 1-naphthol in presence of aqueous H2O2. 相似文献
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Reactions of 1,1'-bis(dipheny1phosphino)cobaltocene with Co(PMe(3))(4), Ni(PMe(3))(4), Fe(PMe(3))(4), Ni(COD)(2), FeMe(2)(PMe(3))(4) or NiMe(2)(PMe(3))(3) afford a series of novel dinuclear complexes [((Me(3)P)[lower bond 1 start]Co(η(5)-C(5)H(4)[upper bond 1 start]PPh(2)))((Me(3)P)M[upper bond 1 end](η(5)-C(5)H(4)P[lower bond 1 end]Ph(2)))] (M = Co(1), Ni(2) and Fe(3)) [Co(η(5)-C(5)H(4)[upper bond 1 start]PPh(2))(2)Ni[upper bond 1 end](COD)](4), [Co(η(5)-C(5)H(4)[upper bond 1 start]PPh(2))(2)Ni[upper bond 1 end](PMe(3))(2)] (5) and [((Me(3)P)[lower bond 1 start]Co(Me)(η(5)-C(5)H(4)[upper bond 1 start]PPh(2)))((Me(3)P)Fe[upper bond 1 end](Me)(η(5)-C(5)H(4)P[lower bond 1 end]Ph(2)))] (6). Reactions of 1,1'-bis(dipheny1phosphino)ferrocene with Ni(PMe(3))(4), NiMe(2)(PMe(3))(3), or Co(PMe(3))(4) gives rise to complexes [Fe(η(5)-C(5)H(4)[upper bond 1 start]PPh(2))(2)M[upper bond 1 end](PMe(3))(2)] (M = Ni (7), Co (8)). The complexes 1-8 were spectroscopically investigated and studied by X-ray single crystal diffraction. The possible reaction mechanisms and structural characteristics are discussed. Density functional theory (DFT) calculations strongly support the deductions. 相似文献
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Powders of the solid solutions In1-xCrxPO4 (0 < or = x < or = 1), In1-xCrx(PO3)3 (0 < or = x < or = 1), (In1-xCrx)4(P2O7)3 (0 < or = x < or = 0.7), and In1-xMnx(PO3)3 (0 < or = x < or = 0.8) have been synthesized by solid-state reactions. Depending on the dopant concentration, these materials show striking variations in color [In1-xCrxPO4, light pink to green-brown; (In1-xCrx)4(P2O7)3, light pink to red-brown; In1-xCrx(PO3)3, pale green to green; In1-xMnx(PO3)3, light blue to purple). Powder reflectance spectra of the solid solutions were measured in the UV/vis/NIR region (5500-35000 cm(-1)). Observed d-d electronic transition energies and results of calculations within the framework of the angular overlap model (AOM) for the low-symmetry chromophores [M(III)O6] (M = Cr, Mn) are in good agreement. In the case of the mixed In/Cr phosphates, the observed color changes can be related to second-sphere ligand-field effects. Clear evidence for differences in the pi-bonding of oxygen toward Cr(3+) (d(3) ion) and In(3+) (d(10) ion) are observed. For In1-xMnx(PO3)3, the variation in color is attributed to a slightly increasing elongation of the [Mn(III)O6] chromophore with increasing dopant concentration. 相似文献
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Martin Cabañas B Leclercq S Barboux P Fédoroff M Lefèvre G 《Journal of colloid and interface science》2011,360(2):695-700
The corrosion of the metal parts in the primary circuit of pressurized water reactors leads to the release of colloidal particles (NiFe(2)O(4), CoFe(2)O(4), NiO, Ni...) and ionic species (Co, Ni, Cr...). Particles can interact with ionic species in the primary medium, contributing to their transport and to their deposition onto surfaces outside the neutron flux generating radioactive contamination. Sorption and zetametry experiments at 25 °C were performed on the Ni(2+)/CoFe(2)O(4) and Co(2+)/NiFe(2)O(4) systems in order to determine the behaviour of corrosion products in the fluid of the primary circuit. Sorption appears as surface complexation starting from pH 6 and is followed by precipitation of hydroxide above pH 7.5. Complexation and solubility constants were obtained from the modelling of sorption curves. The two oxide systems present a very similar sorption behaviour, but some differences, due to their different isoelectric points, could be observed on zetametric measurements. 相似文献
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《Radiation Physics and Chemistry》2008,77(8):968-973
Radiation removal of Co2+ and Ni2+ ions from aqueous solutions containing Me2+ and various scavengers for OH radicals has been studied. In nondeaerated solutions containing HCOOK as OH radical scavenger, two mechanisms of removal were found: reduction leading to the insoluble colloidal metals and precipitation causing predominant formation of carbonate. The processes taking place are mainly affected by the concentration of formate scavenger and depend on the type of metal ions in solution.In the presence of aliphatic alcohols as OH radical scavengers at pH in the interval 6–8, the radiation treatment leads to the metallic product. The efficiency of reduction depends on the rate constant for the reaction of Me+ intermediate with corresponding alcohol radical. 相似文献
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Density functional theory (DFT) calculations of geometry optimization at the B3LYP/6-31+G(d) level have been made for the tri-tert-butoxysilanethiolato anion, i.e. (tBuO)3SiS− [coded A], and its O- and S-protonated derivatives: (tBuO)3SiSH (B), (tBuO+H)(tBuO)2SiS− (C), (tBuO)3SiSH2+ (D) and (tBuO+H)(tBuO)2SiSH (E). Energy balances for the protonation of silanethiol B in vacuum and the aqueous phase (using the polarized continuum IPCM model) were considered. Based on theoretical calculations, it was found that protonation on the oxygen atom causes Si–S bond shortening, while protonation on the sulfur atoms results in elongation of the bond. Changeability of the Si–S and Si–O bond lengths was analyzed in terms of the natural bond orbital (NBO) method. Principal electronic delocalizations caused by anomeric effects of the sulfur and oxygen lone pairs interaction with the anti-bonding Si–O orbitals were confirmed by the correlation between the shortening of the Si–S bond length and the elongation of the Si–O bond within the structures of the species A–E. 相似文献
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Iwona Gęca Mateusz Ochab Mieczyslaw Korolczuk 《International journal of environmental analytical chemistry》2016,96(13):1264-1275
For the first time, a solid lead electrode (PbE) was exploited for adsorptive stripping voltammetric determination of Ni(II) and Co(II) in the presence of nioxime as a complexing agent. The calibration graphs for Ni(II) and Co(II) were linear from 0.059 to 0.59 µg L?1 and from 0.029 to 0.29 µg L?1 (accumulation time 120 s), respectively. The analytical parameters such as the detection limit and separation of analytical signals obtained at the solid lead electrode were comparable with those obtained using a lead film electrode while better in comparison to those reported before for the bismuth film or solid bismuth electrodes. Co(II) could be determined in the presence of a large excess of Ni(II) and Zn(II). The proposed electrode was applied to determine Co(II) and Ni(II) traces in certified reference material and a natural water sample with satisfactory results. 相似文献
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Ho TA Argyris D Cole DR Striolo A 《Langmuir : the ACS journal of surfaces and colloids》2012,28(2):1256-1266
All-atom molecular dynamics simulations were conducted to study the dynamics of aqueous electrolyte solutions confined in slit-shaped silica nanopores of various degrees of protonation. Five degrees of protonation were prepared by randomly removing surface hydrogen atoms from fully protonated crystalline silica surfaces. Aqueous electrolyte solutions containing NaCl or CsCl salt were simulated at ambient conditions. In all cases, the ionic concentration was 1 M. The results were quantified in terms of atomic density distributions within the pores, and the self-diffusion coefficient along the direction parallel to the pore surface. We found evidence for ion-specific properties that depend on ion-surface, water-ion, and only in some cases ion-ion correlations. The degree of protonation strongly affects the structure, distribution, and the dynamic behavior of confined water and electrolytes. Cl(-) ions adsorb on the surface at large degrees of protonation, and their behavior does not depend significantly on the cation type (either Na(+) or Cs(+) ions are present in the systems considered). The cations show significant ion-specific behavior. Na(+) ions occupy different positions within the pore as the degree of protonation changes, while Cs(+) ions mainly remain near the pore center at all conditions considered. For a given degree of protonation, the planar self-diffusion coefficient of Cs(+) is always greater than that of Na(+) ions. The results are useful for better understanding transport under confinement, including brine behavior in the subsurface, with important applications such as environmental remediation. 相似文献
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M. V. Novozhilova E. A. Smirnova M. P. Karushev A. M. Timonov V. V. Malev O. V. Levin 《Russian Journal of Electrochemistry》2016,52(12):1183-1190
The article presents the results of studies of new nanosize catalysts of electrochemical oxygen reduction reaction (ORR) obtained using the method of thermal decomposition of polymer complexes of nickel and cobalt with tetradentate (N2O2) Schiff bases. The catalysts are characterized using the methods of thermogravimetry, electrochemical quartz microgravimetry, scanning electron microscopy with X-ray microanalysis, XPS. The ORR process on electrodes modified by the above catalysts was studied using the voltammetry and rotating disk electrode techniques. The obtained catalysts manifested high specific activity per initial polymer mass (more than 600 mA/mg). 相似文献
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On the basis of studying the isotope exchange of oxygen and the position of the Fermi level in the system MiO–LixNi1–xO, an explanation is proposed for the compensation effect in the reaction of CO oxidation on nickel oxide and its solid solutions.
NiO–LixNi1–xO CO .相似文献
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P. Grange H. Charcosset P. Gallezot P. Turlier J. Vialle 《Journal of solid state chemistry》1974,11(1):26-32
The antiferromagnetism of NiOZnO solid solutions is not always correlated to a rhombohedral distortion of the cubic cell. This confirms the previous results on the NiOCuO system. An anomaly in the reducibility by hydrogen is found in a narrow range of temperature near the Ne´el point of these solids, even though the disappearance of the antiferromagnetism does not result in any detectable structural transformation. 相似文献
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Abstract Polymerizable amphiphilic organophosphorous compounds were synthesized and their self-aggregation behavior was investigated.
The studied molecules contain a hydrophilic phosphorus end group, an alkyl chain spacer with a variable length from 3 to 11
CH2 groups and a polymerizable methacrylic group at the other chain end. Thus, the molecules represent a class of polymerizable
surfactants. Two different reaction methods were used; either unsaturated alcohols or bromine-containing alcohols were applied
as starting compounds for the preparation of the organophosphorous surfactants. The self-aggregation and micelle formation
of the prepared compounds were investigated in aqueous solution by dynamic light scattering measurements. The critical micelle
concentration of the P-containing amphiphiles was in all cases smaller than 0.040 mol/l and strongly dependent on the polarity
of the phorphorous head group and the chain length of the spacer.
Graphical abstract
The synthesis of organophosphorous amphiphiles as surface active monomers for the modification of metal oxide surfaces is
presented. The spacer between the phosphorous head group and the methacrylate group was varied with regard to their length
and composition. The self-aggregation behavior of these methacrylate-functionalized phosphates and phosphonates surfactants
was investigated. 相似文献
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