光度法研究聚乙二醇-硫酸铵-邻苯三酚红体系中铋(Ⅲ), 铁(Ⅲ), 铜(Ⅱ), 镍(Ⅱ), 钴(Ⅱ), 铅(Ⅱ)的萃取分离

本文研究了在聚乙二醇(PEG)-硫酸铵[(NH_4)_2SO_4]-邻苯三酚红(PR)体系中Bi(Ⅲ),Fe(Ⅲ),Cu(Ⅱ),Ni(Ⅱ),Co(Ⅱ),Pb(Ⅱ)的萃取行为。实验结果表明,Bi(Ⅲ)在pH3.5～6.5及Fe(Ⅲ)在pH4.0～7.0范围内可以被PEG相几乎完全萃取,而Cu(Ⅱ),Co(Ⅱ)在pH1.0～7.0,Pb(Ⅱ)在pH2.0～7.0,Ni(Ⅱ)在pH1.0～4.5则不被萃取。从而实现了将Bi(Ⅲ)(pH3.5),Fe(Ⅲ)(pH5.0)与Cu(Ⅱ),Co(Ⅱ),Pb(Ⅱ),Ni(Ⅱ)混合离子的定量分离。同时探讨了PEG相的萃取机理。     

Co（Ⅱ）,Ni（Ⅱ）非有机溶剂液—液萃取行为的研究

In PEG-Eriochrome cyanine R-(NH4)2SO4 system the liquid-liquid extraction behaviour of Co(II) and Ni(II) without organic solvents was investigated. We found that Ni(II) was almost extracted by PEG phase while Co(II) was not extracted in the water solutions of NaAc-HAc (pH=5) and (NH4)2SO4. Thus Co(II) was quantitatively separated from mixed solutions of Ni(II) and Co(II) ions.     

Evaluation of Cyanex 923-coated magnetic particles for the extraction and separation of lanthanides and actinides from nuclear waste streams

In the magnetically assisted chemical separation (MACS) process, tiny ferromagnetic particles coated with solvent extractant are used to selectively separate radionuclides and hazardous metals from aqueous waste streams. The contaminant-loaded particles are then recovered from the waste solutions using a magnetic field. The contaminants attached to the magnetic particles are subsequently removed using a small volume of stripping agent. In the present study, Cyanex 923 (trialkylphosphine oxide) coated magnetic particles (cross-linked polyacrylamide and acrylic acid entrapping charcoal and iron oxide, 1:1:1, particle size=1–60 μm) are being evaluated for the possible application in the extraction and separation of lanthanides and actinides from nuclear waste streams. The uptake behaviour of Th(IV), U(VI), Am(III) and Eu(III) from nitric acid solutions was investigated by batch studies. The effects of sorption kinetics, extractant and nitric acid concentrations on the uptake behaviour of metal ions were systematically studied. The influence of fission products (Cs(I), Sr(II)) and interfering ions including Fe(III), Cr(VI), Mg(II), Mn(II), and Al(III) were investigated. The recycling capacity of the extractant-coated magnetic particles was also evaluated.     

AES and XPS investigations of the surface layers of porous silicon with Fe,Co, and Ni embedded pores

A Composite material of porous silicon with pore embedded d-metals por-Si(Me) can be used for fabricating memory cells. Por-Si layers have been produced by electrochemical etching of n-type silicon (100) according to the conventional process. Fe, Co, and Ni galvanic deposition in por-Si has been performed using aqueous solutions of corresponding sulfate salts. The Auger profiles of the obtained por-Si(Fe), por-Si(Co), por-Si(Ni) nanocomposites have shown that its surface layers (up to 40 nm thick) contained about 10% Fe and no more than 1% Co and Ni. These facts confirm data that Co and Ni, unlike Fe, penetrate deep into the silicon pores. The value of the magnetic moment for the nanocrystalline Ni atom incorporated into the por-Si(Ni) has been estimated based on the dependence of the relative intensity of the maxima for the 3s multiplet splitting of the X-ray phase spectra on the number of uncoupled d-electrons in systems with 3d metals. The obtained value ∼2.4 μB exceeds the atomic magnetic moment in bulk metallic Ni.     

Stability of Ferromagnetism in Fe, Co, and Ni Metals under High Pressure with GGA and GGA+U

The stability of the ferromagnetic state in Fe, Co, and Ni metals under high pressure is investigated using generalized gradient approximation (GGA) and GGA+U within the density functional theory (DFT). It is found that the ferromagnetic state under pressure is very different for Fe, Co, and Ni metals, and is closely associated with the crystal structure. In the case of Fe, a ferromagnetic bcc ground state is obtained at ambient pressure and a nonmagnetic hcp ground state is found at pressure around 12 and 115 GPa for GGA and GGA+U, respectively. For Co, the phase transition from a ferromagnetic hcp to a nonmagnetic fcc is found around 107 GPa for GGA. In contrast to Fe and Co, a ferromagnetic fcc state in Ni is maintained even at 200 GPa. The calculated results suggest that the suppression of ferromagnetism in Fe, Co, and Ni is due to pressure-induced decrease of the density of state at the Fermi level.     

Migration of γ/α Phase Boundaries As the Initial Stage of the Inverse α → γ Transformation upon Slow Heating of Fe–32 at % Ni Metastable Alloy

Technical Physics - During quenching of Fe–Ni metastable alloys with the invar composition from the austenite region, precipitating Fe3Ni disperse particles are transformed into the...     

Evaluation of cerium doped tin oxide nanoparticles as a sensitive sensor for selective detection and extraction of cobalt

Chemo-sensor technology demands to design a single, preconcentrator based sensing system having higher sensitivity, sufficient selectivity and efficient removal of metal ions with simple operating and recognition methodology. Here we effectively deliberated Ce doped SnO₂ nanoparticles based sensing system which can be exploited for the recognition and extraction of Co(II) ions in a single step by strong interaction between Ce doped SnO₂ nanoparticles and Co(II). The sensing ability of Ce doped SnO₂ nanoparticles were deliberated for a selective removal of cobalt using inductively coupled plasma-optical emission spectrometry. The sensing ability of Ce doped SnO₂ is studied for various metal ions, such as Cd(II), Co(II), Cr(III), Cu(II), Fe(III), Ni(II) and Zn(II) but the designed sensor was most selective toward Co(II) which was 5000 time more sensitive to Co(II) rather than different interfering metal ions. In addition, the desorption study for regeneration of Ce doped SnO₂ nanoparticles was carried out. This novel approach provides a new route for simultaneous detection and removal of Co(II) in a single step and can be a time and cost alternative tool for environmental safety.     

Synthesis,Spectral Characterization,DNA Binding Studies and Antimicrobial Activity of Co(II), Ni(II), Zn(II), Fe(III) and VO(IV) Complexes with 4-Aminoantipyrine Schiff Base of Ortho-Vanillin

A series of transition metal complexes of Co(II), Ni(II), Zn(II), Fe(III) and VO(IV) have been synthesized involving the Schiff base, 2,3-dimethyl-1-phenyl-4-(2-hydroxy-3-methoxy benzylideneamino)-pyrazol-5-one(L), obtained by condensation of 4-aminoantipyrine with 3-methoxy salicylaldehyde. Structural features were obtained from their FT-IR, UV–vis, NMR, ESI Mass, elemental analysis, magnetic moments, molar conductivity and thermal analysis studies. The Schiff base acts as a monovalent bidentate ligand, coordinating through the azomethine nitrogen and phenolic oxygen atom. Based on elemental and spectral studies six coordinated geometry is assigned to Co(II), Ni(II), Fe(III) and VO(IV) complexes and four coordinated geometry is assigned to Zn(II) complex. The interaction of metal complexes with Calf thymus DNA were carried out by UV–VIS titrations, fluorescence spectroscopy and viscosity measurements. The binding constants (K_b) of the complexes were determined as 5?×?10⁵ M^?1 for Co(II) complex, 1.33?×?10⁴ M^?1 for Ni(II) complex, 3.33?×?10⁵ M^?1 for Zn(II) complex, 1.25?×?10⁵ M^?1 for Fe(III) complex and 8?×?10⁵ M^?1 for VO(IV) complex. Quenching studies of the complexes indicate that these complexes strongly bind to DNA. Viscosity measurements indicate the binding mode of complexes with CT DNA by intercalation through groove. The ligand and it’s metal complexes were screened for their antimicrobial activity against bacteria. The results showed the metal complexes to be biologically active, while the ligand to be inactive.     

X-ray photoelectron studies of changes in the electronic structure upon phase transitions in Co–Ni and Co–Fe alloys

The changes in the electronic structure of Co–Ni and Co–Fe systems upon phase transitions are studied. X-ray photoelectron study of the valence-band spectra and the parameters of the multiplet splitting of Co, Ni and Fe 3s spectra is carried out at different temperatures. It is established that the ordering–separation phase transition in Co–Ni alloys takes place in the temperature range of 600–700°C. As opposed to Co–Ni alloys, in the Fe–Co alloy, ordering–separation–ordering phase transitions are observed. High-temperature ordering of the Fe₅₀Co₅₀ alloy is observed above 1200°C. The transition from ordering to separation is shown to lead to changes in the d electron spectra of the valence band and in the parameters of the multiplet splitting of the 3s spectra.     

A theoretical study of the structure and stability of borohydride on 3d transition metals

The adsorption of borohydride on 3d transition metals (Cr, Mn, Fe, Co, Ni and Cu) was studied using first principles calculations within spin-polarized density functional theory. Magnetic effect on the stability of borohydride is noted. Molecular adsorption is favorable on Co, Ni and Cu, which is characterized by the strong s–d_zz hybridization of the adsorbate-substrate states. Dissociated adsorption structure yielding one or two H adatom fragments on the surface is observed for Cr, Mn and Fe.     

Synthesis and Spectral Studies of Novel Co(II), Ni(II), Cu(II), Cd(II), and Fe(II) Metal Complexes with N-[5′-Amino-2,2′-bis(1,3,4-thiadiazole)-5-yl]-2-hydroxybenzaldehyde Imine (HL)

Co(II), Ni(II), Cu(II), Cd(II), and Fe(II) complexes with Schiff base derived from 2-amino-5-(2-amino-1,3,4-thiadiazolyl)-1,3,4-thiadiazole (1) and salicylaldehyde have been prepared. The ligand and its complexes have been characterized by IR, ¹H NMR spectra, elemental analyses, magnetic susceptibility, UV-Vis. and thermogravimetry–differential thermal analysis (TGA-DTA). The analytical data show 1:2 metal-to-ligand ratio for Co(II), Ni(II), Cd(II), and Fe(II) and 2:2 metal-to-ligand ratio for Cu(II) complexes. The suggested structures for the N-[5′-Amino-2,2′-bis(1,3,4-thiadiazole)-5-yl]-2-hydroxybenzaldehyde Imine (HL) complexes of Fe(II), Co(II), and Cd(II) are octahedral, for the Ni(II) complex is tetrahedral, and for the Cu(II) complex is square-planar     

Spectroscopic Properties of Co-Fe Hydrotalcites

The spectroscopic properties of hydrotalcite-like compounds, containing Co(II) and Fe(III) in the layers, have been studied. In these materials, depending on the experimental conditions during synthesis, Co(II) becomes partially oxidized to Co(III). Although the environment of the cations is close to octahedral in all cases, Mossbauer data indicate a more symmetric environment for Fe(III) ions in samples not submitted to hydrothermal treatment. The FT-IR spectra show some distortion of the carbonate anions in the interlayer space.     

Cr、Mn、Co、Ni掺杂对Al13Fe4相稳定性和力学性能影响的第一性原理研

采用基于密度泛函理论的第一性原理计算方法,系统地研究了不同掺杂浓度下过渡族元素Cr、Mn、Co、Ni在Al13Fe4相中的占位情况、结构稳定性和机械性能. 计算得到所有的Al13(Fe24-xMx) (M=Cr、Mn、Co、Ni;X=1,2,4)相都具有良好的热力学稳定性和机械稳定性. 相同掺杂浓度化合物的形成焓按如下顺序减小：Al78(Fe24-xCrx) > Al78(Fe24-xMnx) > Al13Fe4 > Al78(Fe24-xNix) > Al78(Fe24-xCox).形成焓的降低增加了Al13Fe4相成核驱动力,Co和Ni有利于促进Al-Fe合金中Al13Fe4相形核,细化Al13Fe4相. 过渡族元素可以改善金属间化合物的脆性,增强塑性变形能力. 并且随着掺杂浓度的增加,过渡族元素的加入对脆性的改善呈先增大后减小的趋势.     

metamagnetic behavior of linear chain pyridine compounds: Co(Pyridine)2Cl2, Fe(Pyridine)2Cl2, Fe(Pyridine)2(NCS)2 and Ni(Pyridine)2Cl2

Magnetic phase transitions in the pyridine (pyr) compounds Co(pyr)₂Cl₂, Fe(pyr)₂Cl₂, Fe(pyr)₂(NCS)₂ and Ni(pyr)₂Cl₂ have been observed at applied magnetic fields of ～0.7, 0.7, 1.1 and 2.7 kG respectively. These low field phase transitions are observed in the Fe and Ni compounds at T = 4.2 K, and in the Co compound at T < 3K, and are consistent with metamagnetic behavior. Magnetic saturation is not achieved in any of these compounds for fields of 60 kG, reflecting high anisotropy.     

金属-糖胺配合物的合成,光谱表征及催化酯类水解的动力学研究

合成了4种新的糖胺 金属配合物,分别为[Ni(HL) (H2 O) 2 ]2 Cl2 ·CH3OH·2H2 O ,[Cu(HL) ]2 Cl2 ·CH3CH2 OH·3H2 O ,[Zn(HL) ]2 Cl2 ·H2 O ,[Co(HL) (H2 O) (OH) ]2 Cl2 ·CH3OH·2H2 O (HLN ,N′ 二βD 葡萄糖基乙二胺) ,并用元素分析、红外、紫外、核磁共振氢谱对其结构进行了表征。结果表明,Ni(Ⅱ) ,Co(Ⅲ)配合物为八面体构型,而Cu(Ⅱ) ,Zn(Ⅱ)配合物为四面体构型。最后研究了其对对硝基苯吡啶甲酸酯(PNPP)催化水解的催化速率常数。     

Giant negative magnetization in a layered organic magnet

Bimetallic oxalates are a class of layered organic magnets with transition metals M(II) and M'(III) coupled by oxalate molecules in an open honeycomb structure. Energy, structure, and symmetry considerations are used to construct a reduced Hamiltonian, including exchange and spin-orbit interactions, that explains the giant negative magnetization in some of the ferrimagnetic Fe(II)Fe(III) compounds. We also provide new predictions for the spin-wave gap, the effects of uniaxial strain, and the optical flipping of the negative magnetization in Fe(II)Fe(III) bimetallic oxalates.     

Electronic and magnetic properties of Fe-, Co-, and Ni-decorated BC3: A first-principles study

The electronic and magnetic properties of Fe-, Co-, and Ni-decorated two dimensional (2D) BC₃ are systematically investigated by first-principles calculations. We find that the Fe, Co, and Ni atoms can be strongly adsorbed on the hollow sites of 2D BC₃. Fe and Co adatoms are more stable when adsorbed on the hollow sites of the carbon rings in the 2D BC₃, while the hollow sites of boron-carbon rings in the 2D BC₃ are the most stable sites for the adsorption of Ni adatoms. These proposed metal–BC₃ complexes exhibit interesting electronic and magnetic behaviors. In particular, the Fe–BC₃ and Co–BC₃ complexes are metals with magnetic ground states , while the Ni–BC₃ complex behaves as a nonmagnetic semiconductor with a direct bandgap. Furthermore, our magnetic analysis reveals that induced magnetism in the Fe–BC₃ and Co–BC₃ complexes arises from their local magnetic moments. Functionalization of 2D BC₃ through these metal–adatom adsorption appears to be a promising way to extend its applications.     

On turbulent chemical explosions into dilute aluminum particle clouds

We use a hybrid two-phase numerical methodology to investigate the flow-field subsequent to the detonation of a spherical charge of TNT with an ambient distribution of a dilute cloud of aluminum particles. Rayleigh–Taylor instability ensues on the contact surface that separates the inner detonation products and the outer shock-compressed air due to interphase interaction, which grows in time and results in a mixing layer where the detonation products afterburn with the air. At early times, the ambient particles are completely engulfed into the detonation products, where they pick up heat and ignite, pick up momentum and disperse. Subsequently, as they disperse radially outwards, they interact with the temporally growing Rayleigh–Taylor structures, and the vortex rings around the hydrodynamic structures results in the clustering of the particles by also introducing local transverse dispersion. Then the particles leave the mixing layer and quench, yet preserve their hydrodynamic ‘footprint’ even until much later; due to this clustering, preferential heating and combustion of particles is observed. With a higher initial mass loading in the ambient cloud, larger clusters are observed due to stronger/larger hydrodynamic structures in the mixing layer – a direct consequence of more particles available to perturb the contact surface initially. With a larger particle size in the initial cloud, clustering is not observed, but when the initial cloud is wider, fewer and degenerate clusters are observed. We identify five different phases in the dispersion of the particles: (1) engulfment phase; (2) hydrodynamic instability-interaction phase; (3) first vortex-free dispersion phase; (4) reshock phase; and (5) second vortex-free dispersion phase. Finally, a theoretical Buoyancy-Drag model is used to predict the growth pattern of the ‘bubbles’ and is in agreement with the simulation results. Overall, this study has provided some useful insights on the post-detonation explosive dispersal of dilute aluminum particle clouds.     

Sensitive analysis of metal cations in positive ion mode electrospray ionization mass spectrometry using commercial chelating agents and cationic ion-pairing reagents

Metals play a very important role in many scientific and environmental fields, and thus their detection and analysis is of great necessity. A simple and very sensitive method has been developed herein for the detection of metals in positive ion mode ESI-MS. Metal ions are positively charged, and as such they can potentially be detected in positive ion mode ESI-MS; however, their small mass-to-charge (m/z) ratio makes them fall in the low-mass region of the mass spectrum, which has the largest background noise. Therefore, their detection can become extremely difficult. A better and well-known way to detect metals by ESI-MS is by chelating them with complexation agents. In this study eleven different metals, Fe(II), Fe(III), Mg(II), Cu(II), Ru(III), Co(II), Ca(II), Ni(II), Mn(II), Sn(II), and Ag(I), were paired with two commercially available chelating agents: ethylenediaminetetraacetic acid (EDTA) and ethylenediaminedisuccinic acid (EDDS). Since negative ion mode ESI-MS has many disadvantages compared to positive ion mode ESI-MS, it would be very beneficial if these negatively charged complex ions could be detected in the positive mode. Such a method is described in this paper and it is shown to achieve much lower sensitivities. Each of the negatively charged metal complexes is paired with six cationic ion-pairing reagents. The new positively charged ternary complexes are then analyzed by ESI-MS in the positive single ion monitoring (SIM) and single reaction monitoring (SRM) modes. The results clearly revealed that the presence of the cationic reagents significantly improved the sensitivity for these analytes, often by several orders of magnitude. This novel method developed herein for the detection of metals improved the limits of detection (LODs) significantly when compared to negative ion mode ESI-MS and shows great potential in future trace studies of these and many other species.