Determination of the oxidation state of cerium in rocks by Ce LIII-edge X-ray absorption near-edge structure spectroscopy

2002 ◽  
Vol 468 (2) ◽  
pp. 345-354 ◽  
Author(s):  
Yoshio Takahashi ◽  
Hiroshi Sakami ◽  
Masaharu Nomura
Keyword(s):  
Oxidation State ◽  
Edge Structure ◽  
X Ray ◽  
X Ray Absorption

Direct determination of oxidation state of gold deposits in metal-reducing bacterium Shewanella algae using X-ray absorption near-edge structure spectroscopy (XANES)

2007 ◽  
Vol 103 (6) ◽  
pp. 568-571 ◽  
Author(s):  
Yasuhiro Konishi ◽  
Takeshi Tsukiyama ◽  
Norizoh Saitoh ◽  
Toshiyuki Nomura ◽  
Shinsuke Nagamine ◽  
...  
Keyword(s):  
Oxidation State ◽  
Direct Determination ◽  
Gold Deposits ◽  
Edge Structure ◽  
X Ray ◽  
Shewanella Algae ◽  
X Ray Absorption

EELS and Xanes Analysis of Plutonium and Cerium Edges From Titanate Ceramics for Fissile Materials Disposal

1999 ◽  
Vol 5 (S2) ◽  
pp. 768-769
Author(s):  
J.A. Fortner ◽  
E.C. Buck ◽  
A.J. Kropf ◽  
A.J. Bakel ◽  
M.C. Hash ◽  
...  
Keyword(s):  
Oxidation State ◽  
Electron Loss ◽  
Edge Structure ◽  
X Ray ◽  
Titanate Ceramics ◽  
X Ray Absorption ◽  
Photon Source ◽  
Titanate Ceramic ◽  
Exafs Spectra

We report x-ray absorption near edge structure (XANES) and extended x-ray fine structure analysis (EXAFS) spectra from the plutonium Llll and cerium Lm edges in prototype titanate ceramic hosts for disposal of surplus fissile materials. These spectra were obtained using the MRCAT beamline at the Advanced Photon Source (APS). The XANES and EXAFS results are compared with electron loss spectra (EELS) determination of oxidation state from the plutonium MlV,V and cerium MlV,V edges [1,2]. The titanate ceramics studied are based upon the hafniumpyrochlore and zirconolite mineral structures and will serve as an immobilization host, containing as much as 10 weight % fissile plutonium, and 20 weight % (natural or depleted) uranium. Similar formulations were composed using cerium as a “surrogate” element, replacing both plutonium and uranium in the ceramic matrix. We find the plutonium to be present almost entirely as Pu (IV), while the cerium is clearly in a mixed III-IV oxidation state in the surrogate ceramic.

In situ determination of the nickel oxidation state in La2NiO4+δ and La4Ni3O10−δ using X-ray absorption near-edge structure

2011 ◽  
Vol 21 (46) ◽  
pp. 18592 ◽  
Author(s):  
Russell J. Woolley ◽  
Benoit N. Illy ◽  
Mary P. Ryan ◽  
Stephen J. Skinner
Keyword(s):  
Oxidation State ◽  
Edge Structure ◽  
X Ray ◽  
Nickel Oxidation ◽  
X Ray Absorption

Determination of the oxidation state of radiogenic Pb in natural zircon using X-ray absorption near-edge structure

2010 ◽  
Vol 37 (4) ◽  
pp. 249-254 ◽  
Author(s):  
Kazuya Tanaka ◽  
Yoshio Takahashi ◽  
Kenji Horie ◽  
Hiroshi Shimizu ◽  
Takashi Murakami
Keyword(s):  
Oxidation State ◽  
Edge Structure ◽  
X Ray ◽  
Natural Zircon ◽  
X Ray Absorption

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.

X-ray absorption spectroscopy studies for the determination of adsorption binding modes of selenium oxoanions onto iron and manganese based nanomaterials

2012 ◽  
Vol 1480 ◽  
Author(s):  
Christina M. Gonzalez ◽  
Jason G. Parsons ◽  
Jeffrey Hernandez ◽  
Jorge L. Gardea-Torresdey
Keyword(s):  
Absorption Spectroscopy ◽  
Binding Modes ◽  
Edge Structure ◽  
X Ray ◽  
Microwave Assisted ◽  
Spectroscopy Studies ◽  
X Ray Absorption ◽  
Binding Mechanisms ◽  
Iron And Manganese

ABSTRACTIncreasing concentrations of selenium oxoanions in the environment are placing many animals at risk for reproduction failure and deformities. The understanding of binding mechanisms of selenium oxoanions to iron and manganese based oxide minerals could lead to enhanced understanding of selenium mobility in the environment. In this study, the binding mechanisms of selenium oxoanions, selenite and selenate, to non microwave-assisted and microwave-assisted synthetic Fe3O4, Mn3O4, and MnFe2O4 nanomaterials were investigated through the use of X-ray absorption spectroscopy. The X-ray absorption near-edge structure (XANES) spectroscopy studies revealed the oxidation state of selenite and selenate remains the same after binding occurs to all nanomaterials in pH 2, 4, or 6 environments. The binding modes of selenite and selenate were determined to be bidentate binuclear through use of Extended x-ray absorption fine structure (EXAFS) and were independent of nanomaterials, synthetic technique, and pH.

Using X-ray absorption near edge structure (XANES) spectroscopy to determine selenium oxidation states in animal mineral supplements and feeds

2004 ◽  
Vol 84 (2) ◽  
pp. 171-175 ◽  
Author(s):  
C. R. Christensen ◽  
J. N. Cutler ◽  
D. A. Christensen
Keyword(s):  
Oxidation State ◽  
Animal Feed ◽  
Xanes Spectroscopy ◽  
Elemental Selenium ◽  
Selenium Speciation ◽  
Edge Structure ◽  
X Ray ◽  
Mineral Supplements ◽  
Animal Feeds ◽  
X Ray Absorption

Synchrotron-based X-ray absorption near edge structure (XANES) spectroscopy is a relatively new technique within the life sciences. XANES has been utilized to identify the location, oxidation state and spatial distribution of heavy metal elements in plants , neurons, blood and DNA, but has not been widely used in the animal sciences. Selenium content in animal feeds is monitored, as both selenium deficiencies and toxicities are associated with physiological disorders. Selenium is available as an animal feed in both inorganic and organic states. The bioavailability of selenium species has been tested in numerous animal trials; however, a simple, non-destructive test for selenium speciation is not available. The objective of this study was to determine whether XANES spectroscopy could be used to determine the selenium oxidation state found in various commercial animal feed products. A comparison of absorption spectra indicated that the animal mineral supplements contained an organoselenium or selenite. The processed animal feeds had a spectral profile similar to that of elemental selenium. Further experiments are necessary to determine the implication of selenium speciation on animal physiology. Key words: Selenium speciation, mineral supplements, ruminants, non-ruminants, synchrotron, XANES, X-ray

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