scholarly journals An X-ray Absorption Near-Edge Structure (XANES) Study on the Oxidation State of Chromophores in Natural Kunzite Samples from Nuristan, Afghanistan

Minerals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 463
Author(s):  
Habib Ur Rehman ◽  
Gerhard Martens ◽  
Ying Lai Tsai ◽  
Chawalit Chankhantha ◽  
Pinit Kidkhunthod ◽  
...  
Keyword(s):  
Oxidation State ◽  
Inductively Coupled Plasma ◽  
Oxidation States ◽  
Transition Elements ◽  
Edge Structure ◽  
X Ray ◽  
Inductively Coupled ◽  
Valence States ◽  
Icp Ms ◽  
X Ray Absorption

Kunzite, the pink variety of spodumene is famous and desirable among gemstone lovers. Due to its tenebrescent properties, kunzite always remains a hot research candidate among physicists and mineralogists. The present work is continuing the effort towards value addition to kunzite by enhancing its color using different treatments. Before color enhancement, it is essential to identify the chromophores and their oxidation states. In this paper, the authors investigated the main impurities in natural kunzite from the Nuristan area in Afghanistan and their valence states. Some impurities in the LiAlSi2O6 spodumene structure were identified and quantified by using sensitive techniques, including Laser Ablation Inductively Coupled Plasma Mass Spectrometry (LA-ICP-MS), UV−VIS and X-ray absorption near-edge structure (XANES). LA-ICP-MS indicated many trace elements as impurities in kunzite, among which Fe and Mn are the main elements responsible for coloration. The oxidation states of these two transition elements were determined by the XANES technique. The study reveals that Mn is present in both Mn2+ and Mn3+ oxidation states, while Fe is present only in Fe3+ oxidation state.

Microstructure of TiC/Amorphous Hydrocarbon Nanocomposite Coatings

2000 ◽  
Vol 6 (S2) ◽  
pp. 440-441
Author(s):  
D. M. Cao ◽  
J. C. Jiang ◽  
B. Feng ◽  
W. J. Meng
Keyword(s):  
Inductively Coupled Plasma ◽  
High Hardness ◽  
Ceramic Surface ◽  
Edge Structure ◽  
X Ray ◽  
Inductively Coupled ◽  
Transmission Electron ◽  
Wide Range ◽  
Mechanical Components ◽  
X Ray Absorption

Application of an appropriate ceramic surface coating to mechanical components such as bearings and gears can provide longer life and increased performance reliability. Metal-containing hydrocarbon (Me-C:H) coatings possess high hardness, together with low friction and low wear rate. They have also been suggested to adhere better to metallic substrates. This combination of attractive mechanical/tribological properties makes Me-C:H coatings potentially useful for surface modification of a wide range of mechanical components.Using the technique of inductively coupled plasma (ICP) assisted vapor deposition[1], we have synthesized Ti-containing hydrocarbon (Ti-C:H) coatings with a wide range of Ti compositions[2]. Coating mechanical properties such as modulus and hardness have been measured by the technique of nanoindentation and correlated to Ti and hydrogen compositions[2,3].We have performed detailed microstructural examination of Ti-C:H coatings by transmission electron microscopy (TEM), Extended X-ray Absorption Fine Structure (EXAFS) spectroscopy, and X-ray Absorption Near Edge Structure (XANES) spectroscopy.

Oxygen Reduction Effect on T’-Pr2-xCexCuO4 Nanopowders in the Underdoped Regime Studied by X-Ray Absorption near Edge Structure

2018 ◽  
Vol 936 ◽  
pp. 93-97 ◽  
Author(s):  
Irfanita Resky ◽  
Putu Eka Dharma Putra ◽  
Triono Bambang ◽  
Saiyasombat Chatree ◽  
Kamonsuangkasem Krongthong ◽  
...  
Keyword(s):  
Oxidation State ◽  
Oxidation States ◽  
Edge Structure ◽  
X Ray ◽  
Reduction Annealing ◽  
Gas Atmosphere ◽  
Reduction Effect ◽  
Ar Gas ◽  
X Ray Absorption ◽  
Cu Ions

This research is aimed to examine oxidation state of Copper (Cu) in both as-synthesized and reduced T’-Pr2-xCexCuO4 (T’-PCCO) with x = 0, 0.10, and 0.15 using Cu K-edge x-ray absorption near edge structure (XANES). The T‘-PCCO nanopowders were successfully synthesized by the chemically dissolved method with HNO3 as a dissolving agent continued by calcination at 1000°C for 15 h. The reduced T’-PCCO nanopowders were obtained by reduction annealing process at 700°C for 5 h under Ar gas atmosphere. The analyses of XANES spectra show that oxidation states of the Cu ions in all of the T'-PCCO nanopowders have values between +1 and +2. This indicates the existence of electron doping in the CuO2 planes, even in the undoped T’-structure. It is found that the oxidation states of the Cu ions change after reduction annealing depending on the existence of apical oxygen in the T'-structure. Based on the XANES analyses, it is revealed that the change of oxidation state is influenced by the presence of both electron and hole carriers in the two-carrier model of T’-structure.

scholarly journals Seleno-l-Methionine Is the Predominant Organic Form of Selenium in Cupriavidus metallidurans CH34 Exposed to Selenite or Selenate

2006 ◽  
Vol 72 (9) ◽  
pp. 6414-6416 ◽  
Author(s):  
Laure Avoscan ◽  
Richard Collins ◽  
Marie Carriere ◽  
Barbara Gouget ◽  
Jacques Cov�s
Keyword(s):  
Inductively Coupled Plasma ◽  
High Performance ◽  
Organic Form ◽  
Edge Structure ◽  
Cupriavidus Metallidurans Ch34 ◽  
X Ray ◽  
Inductively Coupled ◽  
Cupriavidus Metallidurans ◽  
Plasma Mass Spectrometry ◽  
X Ray Absorption

ABSTRACT The accumulated organic form of selenium previously detected by X-ray absorption near-edge structure (XANES) analyses in Cupriavidus metallidurans CH34 exposed to selenite or selenate was identified as seleno-l-methionine by coupling high-performance liquid chromatography to inductively coupled plasma-mass spectrometry.

scholarly journals A compact furnace for in situ X-ray absorption spectroscopy: design, fabrication and study of cationic oxidation states in Pr6O11 and NiO

2021 ◽  
Vol 28 (2) ◽  
pp. 455-460
Author(s):  
Suchinda Sattayaporn ◽  
Somboonsup Rodporn ◽  
Pinit Kidkhunthod ◽  
Narong Chanlek ◽  
Chutarat Yonchai ◽  
...  
Keyword(s):  
Oxidation State ◽  
Absorption Spectroscopy ◽  
Heating Temperature ◽  
Reduction Process ◽  
Oxidation States ◽  
Quartz Tube ◽  
Edge Structure ◽  
X Ray ◽  
X Ray Absorption

A well designed compact furnace has been designed for in situ X-ray absorption spectroscopy (XAS). It enables various heat ramps from 300 K to 1473 K. The furnace consists of heaters, a quartz tube, a circulated refrigerator and a power controller. It can generate ohmic heating via an induction process with tantalum filaments. The maximum heating rate exceeds 20 K min−1. A quartz tube with gas feedthroughs allows the mixing of gases and adjustment of the flow rate. The use of this compact furnace allows in situ XAS investigations to be carried out in transmission or fluorescence modes under controlled temperature and atmosphere. Moreover, the furnace is compact, light and well compatible to XAS. The furnace was used to study cationic oxidation states in Pr6O11 and NiO compounds under elevated temperature and reduced atmosphere using the in situ X-ray absorption near-edge structure (XANES) technique at beamline 5.2 SUT-NANOTEC-SLRI of the Synchrotron Light Research Institute, Thailand. At room temperature, Pr6O11 contains a mixture of Pr3+ and Pr4+ cations, resulting in an average oxidation state of +3.67. In situ XANES spectra of Pr (L 3-edge) show that the oxidation state of Pr4+ cations was totally reduced to +3.00 at 1273 K under H2 atmosphere. Considering NiO, Ni2+ species were present under ambient conditions. At 573 K, the reduction process of Ni2+ occurred. The Ni0/Ni2+ ratio increased linearly with respect to the heating temperature. Finally, the reduction process of Ni2+ was completely finished at 770 K.

Using XANES to Monitor the Oxidation State of Cobalt Complexes

2007 ◽  
Vol 60 (3) ◽  
pp. 180 ◽  
Author(s):  
Matthew D. Hall ◽  
Clare K. Underwood ◽  
Timothy W. Failes ◽  
Garry J. Foran ◽  
Trevor W. Hambley
Keyword(s):  
Oxidation State ◽  
Cobalt Complexes ◽  
Reducing Agents ◽  
Oxidation States ◽  
Xanes Spectroscopy ◽  
Edge Structure ◽  
X Ray ◽  
X Ray Absorption

X-Ray absorption near-edge structure (XANES) spectroscopy was used to monitor the oxidation state of cobalt following treatment of CoIII complexes with reducing agents such as ascorbate and cysteine. It was established that the XANES spectra of mixtures of CoII and CoIII complexes can be used to calculate proportions of the two oxidation states by monitoring the height of the Co K-edge. The relationships developed were used to estimate proportions of each complex in solutions of CoIII complexes treated with reducing agents.

scholarly journals Homogeneous Incorporation of Gallium into Layered Double Hydroxide Lattice for Potential Radiodiagnostics: Proof-of-Concept

Nanomaterials ◽  
2020 ◽  
Vol 11 (1) ◽  
pp. 44
Author(s):  
Do-Gak Jeung ◽  
Tae-Hyun Kim ◽  
Jae-Min Oh
Keyword(s):  
Electron Microscopy ◽  
Layered Double Hydroxide ◽  
Inductively Coupled Plasma ◽  
Hydrothermal Reaction ◽  
Edge Structure ◽  
X Ray ◽  
Inductively Coupled ◽  
Diffraction Patterns ◽  
Double Hydroxide ◽  
X Ray Absorption

Trivalent gallium ion was successfully incorporated into chemically well-defined MgAl-layered double hydroxide (LDH) frameworks through postsynthetic hydrothermal treatment. Quantitative analysis with inductively coupled plasma-mass spectroscopy exhibited that Ga3+ was first incorporated into LDH through partial dissolution-precipitation at the edge of LDH particle and homogeneously distributed throughout the particle by substitution of Ga3+ for Al3+ in LDH frame works. The powder X-ray diffraction patterns showed that the Ga3+ incorporation did not affect the crystal structure without evolution of unexpected impurities. The morphology and surface property of LDH evaluated by scanning electron microscopy and light scattering showed the preservation of physicochemical properties throughout 24 h of hydrothermal reaction. The distribution of incorporated Ga3+ was visualized with energy dispersive spectroscopy-assisted transmission electron microscopy, suggesting the homogeneous location of Ga3+ in an LDH particle. The X-ray absorption near-edge structure and extended X-ray absorption fine structure suggested that the Ga moiety was immobilized in LDH from 0.5 h and readily crystallized upon reaction time.

scholarly journals Characterising the chemistry of micropores in a sodic soil with strong texture-contrast using synchrotron X-ray techniques and LA-ICP-MS

Soil Research ◽  
2012 ◽  
Vol 50 (5) ◽  
pp. 424 ◽  
Author(s):  
Laurence Jassogne ◽  
Ganga Hettiarachchi ◽  
Ann McNeill ◽  
David Chittleborough
Keyword(s):  
Inductively Coupled Plasma ◽  
Reduced Form ◽  
Edge Structure ◽  
Thin Sections ◽  
X Ray ◽  
Distribution Maps ◽  
Xafs Spectroscopy ◽  
Icp Ms ◽  
Texture Contrast ◽  
X Ray Absorption

Soils with strong texture-contrast between A and B horizons dominate the agricultural zones of the west and south of Australia. The B horizon is often sodic and of much finer texture than the A (or E) horizon above, and can have a bulk density as high as 2 g cm–3. When dry, these B horizons may severely impede the root growth of annual cereal crops. The objective of this study was to characterise the mineralogy and chemistry of fine pores at the interface of an E and a sodic B horizon of an Alfisol (Sodosol). Micro-X-ray fluorescence spectroscopy (μ-XRF) was used to locate the distribution of calcium (Ca), manganese (Mn), iron (Fe), zinc (Zn), and copper (Cu), and μ-X-ray absorption near edge structure (μ-XANES) spectroscopy or μ-X-ray absorption fine structure (μ-XAFS) spectroscopy to investigate speciation of Fe, Mn, Zn, and Cu around a pore. Both natural aggregates and thin sections were employed but measurements from thin sections were more useful because of the smaller thickness of the sample. The distribution maps showed that Ca was present in the pores but the other elements were not. Copper, Mn, and Zn were concentrated around the micropore. Manganese was always well correlated with Fe. Manganese was found in reduced form, i.e. Mn(II), and associated with phosphates, whereas Fe was in oxidised form and mostly associated with oxides. Zinc was mostly associated with carbonates (CO3), sulfates (SO4), and silicates (SiO4). The results were then compared with measurements by laser ablation inductively coupled plasma-mass spectrometry (LA-ICP-MS). Only some of the observations made by μ-XRF were confirmed by LA-ICP-MS, most probably because of the superior detection limits of synchrotron-based μ-XRF.

Discrepancy in the quantitative oxidation-state analysis of Eu species in sulfide phosphors by K-, L1- and L3-edge XANES spectrometry: choice of absorption edge and measurement mode

2018 ◽  
Vol 33 (4) ◽  
pp. 585-592 ◽  
Author(s):  
Takashi Yamamoto ◽  
Akira Yukumoto
Keyword(s):  
Quantitative Analysis ◽  
Oxidation State ◽  
Absorption Edge ◽  
Oxidation States ◽  
Xanes Spectroscopy ◽  
Edge Structure ◽  
X Ray ◽  
Measurement Mode ◽  
Constituent Elements ◽  
X Ray Absorption

A quantitative analysis of the oxidation state of europium (Eu) in phosphor samples was performed using X-ray absorption near-edge structure (XANES) spectroscopy to investigate the influence of the constituent elements, absorption edge and measurement mode on the evaluated oxidation states.

scholarly journals Probing the variability in oxidation states of magnetite nanoparticles by single-particle spectroscopy

2018 ◽  
Vol 6 (4) ◽  
pp. 875-882 ◽  
Author(s):  
A. Fraile Rodríguez ◽  
C. Moya ◽  
M. Escoda-Torroella ◽  
A. Romero ◽  
A. Labarta ◽  
...  
Keyword(s):  
Oxidation State ◽  
Absorption Spectroscopy ◽  
Magnetite Nanoparticles ◽  
Single Particle ◽  
Cation Distribution ◽  
Oxidation States ◽  
Magnetic Response ◽  
X Ray ◽  
Single Particle Spectroscopy ◽  
X Ray Absorption

Single-particle X-ray absorption spectroscopy reveals that the oxidation state and cation distribution of individual magnetite nanoparticles may be largely heterogeneous even when the macroscopic structural and magnetic response of the ensembles is uniform.

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