scholarly journals The XPS study of physical and chemical forms of neptunium group on the surface of minerals

2010 ◽  
Vol 25 (1) ◽  
pp. 1-7 ◽  
Author(s):  
Anton Teterin ◽  
Alevtina Mikhailina ◽  
Konstantin Maslakov ◽  
Elena Zaharova ◽  
Yury Teterin
Keyword(s):  
Photoelectron Spectroscopy ◽  
Ionic Composition ◽  
Liquid Extraction ◽  
Sorption Behavior ◽  
Chemical Forms ◽  
X Ray ◽  
Oxygen Ions ◽  
Liquid Liquid Extraction ◽  
Xps Study ◽  
Physical And Chemical

The sorption behavior and the physical and chemical forms of neptunium on the surface of minerals of the two chlorate samples, biotite and kaolin, with different contents of Fe(II) was studied. The liquid-liquid extraction and the X-ray photoelectron spectroscopy were employed to identify the valence forms of neptunium. On the basis of the obtained data the quantitative elemental composition of the surface of the studied minerals, as well as the ionic composition of the formed neptunium complexes was determined. It was shown that the Np(IV) and Np(VI) containing compounds did not form, while the complexes Np(V)O+ -hydroxyl did form on the surface. The oxygen ions bonded with iron and oxygen belonging to water and/or of carboxyl were suggested to be present in the equatorial plane of the neptunyl group NpO+.

scholarly journals First online X‐ray fluorescence characterization of liquid‐liquid extraction in microfluidics

Nano Select ◽  
2021 ◽  
Author(s):  
Ange A. Maurice ◽  
Johannes Theisen ◽  
Varun Rai ◽  
Fabien Olivier ◽  
Asmae El Maangar ◽  
...  
Keyword(s):  
Liquid Extraction ◽  
X Ray ◽  
Liquid Liquid Extraction

DETERMINATION OF URANIUM IN FLOTATION CONCENTRATES AND IN LEACH LIQUORS BY X-RAY FLUORESCENCE

1959 ◽  
Vol 37 (1) ◽  
pp. 20-28 ◽  
Author(s):  
G. L. Smithson ◽  
R. L. Eager ◽  
A. B. VanCleave
Keyword(s):  
Direct Measurement ◽  
Pilot Plant ◽  
Internal Standard ◽  
Liquid Extraction ◽  
X Ray ◽  
Liquid Liquid Extraction ◽  
Northern Saskatchewan ◽  
Plant Operations ◽  
Time Required

X-Ray fluorescence has been applied to the analysis of flotation concentrates obtained from pegmatitic uranium ores occurring in Northern Saskatchewan. Approximate uranium analyses can be obtained by direct measurement on flotation concentrates but more accurate results are obtained by using an internal standard such as strontium or yttrium. The time required for an analysis, as compared to that of conventional chemical or fluorimetric methods, is considerably reduced and flotation pilot plant operations can therefore be more effectively controlled. The method has been extended to include the analysis of sulphate leach liquors obtained from the leaching of pegmatitic ores and their flotation concentrates. Organic phases obtained in liquid – liquid extraction studies can also be rapidly analyzed for uranium by X-ray fluorescence.

Surface Characterization of Carbon-Bearing Magnetite (CBM) and Carbon-Bearing Ni(II)-Ferrite (CBNF)

1994 ◽  
Vol 344 ◽  
Author(s):  
T. Sano ◽  
K. Akanuma ◽  
M. Tsuji ◽  
Y. Tamaura
Keyword(s):  
Photoelectron Spectroscopy ◽  
Spinel Structure ◽  
Surface Characterization ◽  
Carbon Deposition ◽  
X Ray Diffraction ◽  
Xps Spectra ◽  
X Ray ◽  
Oxygen Ions ◽  
Diffraction Patterns

AbstractOxygen-deficient magnetite (ODM; Fe3O4-δ, δ>0) synthesized by reduction of magnetite with H2 at 300°C decomposed CO2 to carbon with an efficiency of nearly 100% at 300°C. In this reaction, two oxygen ions of the CO2 were incorporated into the spinel structure of ODM and carbon was deposited on the surface of ODM with zero valence to form visible particles. The particles of carbon separated from ODM were studied by Raman, energy-dispersive X-ray and wave-dispersive X-ray spectroscopies. The carbon which had been deposited on the ODM was found to be a mixture of graphite and amorphous carbon in at least two levels of crystallization. X-ray photoelectron spectroscopy and X-ray diffraction patterns of the carbon-bearing magnetite (CBM) showed no indication of carbide (Fe3C) or metallic iron (α-Fe) phase formation. In the C 1s XPS spectra of the CBM, no peaks were observed which could be assigned to CO2 or CO. X-ray diffractometry, chemical analysis and TG-MS measurement showed that the carbon-bearing Ni(II)-ferrite (CBNF) (Ni(II)/Fetotal = 0.15) synthesized by the carbon deposition reaction from CO2 with the H2-reduced Ni(II)-ferrite was represented by (Ni0.28Fe2.72O4.00)1-δ (Ni2+06.9Fe2+2.31O3.00)δCτ (δ= 0.27, τ= 0.17). The carbon of the CBNF gave the CIOlayer-like oxide containing some Ni2+ ions.

scholarly journals Highly Efficient, Tripodal Ion-Pair Receptors for Switching Selectivity between Acetates and Sulfates Using Solid–Liquid and Liquid–Liquid Extractions

2020 ◽  
Vol 21 (24) ◽  
pp. 9465
Author(s):  
Marta Zaleskaya ◽  
Łukasz Dobrzycki ◽  
Jan Romański
Keyword(s):  
Binding Sites ◽  
Liquid Extraction ◽  
Ion Pair ◽  
Anion Binding ◽  
Binding Modes ◽  
Anion Receptor ◽  
X Ray ◽  
Liquid Liquid Extraction ◽  
Solid Liquid Extraction ◽  
Solid Liquid

A tripodal, squaramide-based ion-pair receptor 1 was synthesized in a modular fashion, and 1H NMR and UV-vis studies revealed its ability to interact more efficiently with anions with the assistance of cations. The reference tripodal anion receptor 2, lacking a crown ether unit, was found to lose the enhancement in anion binding induced by presence of cations. Besides the ability to bind anions in enhanced manner by the “single armed” ion-pair receptor 3, the lack of multiple and prearranged binding sites resulted in its much lower affinity towards anions than in the case of tripodal receptors. Unlike with receptors 2 or 3, the high affinity of 1 towards salts opens up the possibility of extracting extremely hydrophilic sulfate anions from aqueous to organic phase. The disparity in receptor 1 binding modes towards monovalent anions and divalent sulfates assures its selectivity towards sulfates over other lipophilic salts upon liquid–liquid extraction (LLE) and enables the Hofmeister bias to be overcome. By changing the extraction conditions from LLE to SLE (solid–liquid extraction), a switch of selectivity from sulfates to acetates was achieved. X-ray measurements support the ability of anion binding by cooperation of the arms of receptor 1 together with simultaneous binding of cations.

scholarly journals X-ray Photoelectron Spectroscopy(XPS) Study of Fracture Mechanism in Sintered Si3N4.

2000 ◽  
Vol 108 (1253) ◽  
pp. 61-64 ◽  
Author(s):  
Masahiro OZAWA ◽  
Yoichiro FURUKAWA ◽  
Mitsushige OGAWA ◽  
Kei ISOZAKI
Keyword(s):  
Photoelectron Spectroscopy ◽  
Fracture Mechanism ◽  
X Ray ◽  
Xps Study

Xps Study of the Nitridation Process of A Polytitanocarbosilane into Si-Ti-N-O Ceramics

1992 ◽  
Vol 271 ◽  
Author(s):  
G. Granozzi ◽  
A. Glisenti ◽  
R. Bertoncello ◽  
G. D. Soraru
Keyword(s):  
Titanium Nitride ◽  
Firing Temperature ◽  
Photoelectron Spectroscopy ◽  
Transformation Process ◽  
Nitrogen Enrichment ◽  
X Ray ◽  
Nitridation Process ◽  
Nitride Ceramics ◽  
Xps Study

ABSTRACTThe nitridation process of a polytitanocarbosilane, leading to the formation of a Si-Ti-N-O ceramics, has been investigated mainly by means of X-ray photoelectron spectroscopy (XPS). Ti2p spectra collected on samples fired at various stages of the transformation process clearly shown that Ti-N bonds of TiOxNy mixed units start to form at 500 °C. By increasing the firing temperature, the Ti2p peak shifts toward values typical of titanium nitride ceramics, so indicating the progressive nitrogen enrichment of the mixed units up to the formation of a TiN phase.

XPS STUDY OF DOPING MECHANISM IN HEAVILY DOPED PbWO4:M3+(M = La, Nd, Gd) CRYSTALS

2007 ◽  
Vol 14 (04) ◽  
pp. 725-728
Author(s):  
XIQI FENG ◽  
WEIFENG LI ◽  
WENLIANG ZHU
Keyword(s):  
Photoelectron Spectroscopy ◽  
Rare Earth Ions ◽  
High Concentration ◽  
Lead Tungstate ◽  
X Ray ◽  
Optoelectronic Application ◽  
Trivalent Rare Earth ◽  
Heavily Doped ◽  
Doping Mechanism ◽  
Xps Study

Lead tungstate ( PbWO 4) (PWO) crystals doped with high concentration trivalent rare earth ions have demonstrated to be a promising Cherenkov radiator material and also a potential material for optoelectronic application. In this paper, the doping mechanisms of the trivalent ions ( La 3+, Nd 3+, and Gd 3+) in the PWO host were studied using X-ray photoelectron spectroscopy (XPS), and the results were consistent with those of computer simulation. It was found that when heavily doped, La 3+ may substitute for the W sites as well as the Pb sites for self-compensation by forming La dimers or small aggregates. However, the doping mechanism of heavily doped PWO: Nd 3+ and PWO: Gd 3+ might be different from that of heavily doped PWO: La 3+ crystals.

Synthesis and Extraction Behaviour of Calix[4]arenes Partially Substituted at the Wide Rim by Carbamoylmethylphosphine Oxide (CMPO) Functions

2003 ◽  
Vol 56 (11) ◽  
pp. 1113 ◽  
Author(s):  
Françoise Arnaud-Neu ◽  
Silvia Barboso ◽  
Volker Böhmer ◽  
Frédéric Brisach ◽  
Laetitia Delmau ◽  
...  
Keyword(s):  
Single Crystal ◽  
Liquid Extraction ◽  
Hydrogen Atoms ◽  
Cone Conformation ◽  
X Ray ◽  
Liquid Liquid Extraction ◽  
Extraction Behaviour ◽  
Extraction Properties

Tetraethers of calix[4]arenes fixed in the cone conformation and substituted at their wide rim by one to three CMPO residues and hydrogen atoms or t-butyl moieties in the remaining position(s) were synthesized. Liquid/liquid extraction studies of selected lanthanides and actinides were undertaken with these calix[4]arenes, including also a linear trimer, in order to obtain a better understanding for the extraction properties of the corresponding calix[4]arene substituted by four CMPO functions. The structure of the 1,3-di-CMPO derivative was confirmed by single crystal X-ray analysis.

scholarly journals A microfluidic study of synergic liquid–liquid extraction of rare earth elements

2020 ◽  
Vol 22 (10) ◽  
pp. 5449-5462 ◽  
Author(s):  
Asmae El Maangar ◽  
Johannes Theisen ◽  
Christophe Penisson ◽  
Thomas Zemb ◽  
Jean-Christophe P. Gabriel
Keyword(s):  
Rare Earth ◽  
Rare Earth Elements ◽  
Microfluidic Device ◽  
Complex Mixture ◽  
Liquid Extraction ◽  
Free Energies ◽  
X Ray ◽  
Free Energies Of Transfer ◽  
Liquid Liquid Extraction

A membrane based liquid–liquid extraction microfluidic device coupled with X-ray fluorescence enables the first quantification of free energies of transfer dependence for a complex mixture of rare earth elements and iron using synergic extractants.

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