The atmospheric particulate matter samples were collected in Shanghai, China. The X-ray absorption near-edge structure (XANES)
spectra of Cr, Mn, Cu and Zn were measured. The XANES spectroscopy was used as a fingerprint to compare with that of reference
materials to obtain speciation information. The oxidation state of these elements and main chemical components in the samples
were described using the method. The results show that in our samples the oxidation state of Cr is trivalent, Mn mainly exists
in the divalent state, Cu also exists in the divalent state, and Zn mainly exists in the zinc sulfate. For the XANES spectra
of samples with different particle size and from different sampling site, we did not find their obvious differences. When
we compared the XANES spectra of our samples with those of standard reference material SRM 1648, we found that they are similar
in regards to the determined elements. The elemental concentrations in the samples were determined by proton induced X-ray
emission (PIXE). The difference of elemental concentrations was observed in the different samples.
Authors:M. Bielewski, M. Eriksson, J. Himbert, M. Betti, F. Belloni, and G. Falkenberg
XANES has been recently used for the determination of oxidation states of actinides in environmental samples. To obtain reliable
results, however, a sufficiently long counting time at every probing energy and a large number of experimental points per
XANES spectrum are required, due to the complex mathematical model used to fit the measured spectrum. This makes micro-mapping
difficult, since the time required for data collection becomes unacceptably long. A simplified model for data collection and
evaluation is presented. Its effectiveness has been tested by measuring the distribution of Pu oxidation states in a “hot”
particle coming from a nuclear weapon test site.
Authors:Sumit Kumar, Aishwarya Kar, D. Bhattacharyya, and B. Tomar
LIII edge X-ray Absorption Fine Structure (XAFS) spectroscopic study of Eu(III) sorbed on γ-alumina from aqueous solutions of
different pH (values ranging from 6 to 8) has been carried out at XAFS beam line of Elettra Synchrotron facility, Italy, in
transmission mode. Extended X-ray Absorption Fine Structure spectra of reference compounds, namely, Eu2O3, Eu(OH)3 and Eu-aquo complex in solution, were also measured. The data were analyzed using the IFEFFIT suite of code. XAFS spectra
of the sorption samples is dominated by the Eu–O near neighbor co-ordination at distance 2.4 ± 0.1 Å. 8–9 oxygen atoms, coming
from both coordinating water molecule and oxygen atoms from alumina surface, surround the Eu(III) in the surface complex.
Next near neighbor atoms in all the sorption samples consist of Al at distance ~3.6 and 3.8 Å, which on comparison with literature
data indicates towards Eu(III) bidentate binding to apical oxygen of two different alumina octahedra on γ-alumina surface.
Two complimentary spectroscopic techniques, X-ray absorption and fluorescence spectroscopy have been conducted at spatial
scales of 1 to 25 μm on uranium contaminated soil sediments collected from two former nuclear materials processing facilities
of the DOE: Fernald, OH and Savannah River Site, SC. A method of imbedding particles in a non-reactive Si polymer was developed
such that individual particles could be examined before and after extraction with a wide range of chemicals typically used
in sequential extraction techniques and others proposed forex situ chemical intervention technologies. Using both the micro-X-ray fluorescence (XRF) and micro-X-ray Absorption Near Edge Structure
(XANES) techniques, both elemental and oxidation state distribution maps were generated on individual particles before and
following chemical extraction. XANES can determine the relative proportion of U(VI) and U(IV) in phases comprising individual
particles before and after extraction and showed that greater than 85% of the uranium existed as hexavalent U(VI). Fluorescence
spectra of contaminated particles containing mainly U(VI) revealed populations of uranyl hydroxide phases and demonstrated
the relative efficacy and specificity of each extraction method. Correlation of XAS and fluorescence data at micron scales
provides information of U oxidation state as well as chemical form in heterogeneous samples.
Authors:K. Akiyama, K. Sueki, H. Haba, K. Tsukada, M. Asai, T. Yaita, Y. Nagame, K. Kikuchi, M. Katada, and H. Nakahara
We have, previously, reported on the HPLC elution behavior of the Th, Pa, U, Np, and Am metallofullerenes and the UV/vis/NIR absorption spectra of the Th@C84 and U@C82 species. In this paper, the followings are reported: (1) Pu metallofullerenes were produced and their HPLC elution behavior was investigated using a radiotracer technique. The HPLC chromatogram of this metallofullerene was found to be almost the same as that of the Np and Am metallofullerenes. (2) The oxidation states of Th@C84 and U@C82 produced in macroscopic quantities were examined by XANES (X-ray absorption near edge structure) measurements. The oxidation state of the U atom in the C82 fullerene cage was estimated to be 3+ with the formal charge of the ionic molecule being U3+@C823-.
Authors:Edward Mausolf, Frederic Poineau, Janelle Droessler, and Kenneth Czerwinski
The reduction of ammonium pertechnetate by sodium borohydride in 0.1 M NaOH/glacial acetic acid has been studied. The reduction
products (solids and solutions) have been characterized by UV–Visible spectroscopy, Scanning Electron Microscopy/Energy-dispersive
X-ray emission spectroscopy (SEM/EDS), and X-ray absorption fine structure (XAFS) spectroscopy. UV–Visible spectra of the
solution, after reduction, exhibit bands at 350 and 500 nm that have been attributed to the formation of polymeric Tc(IV)
species. SEM/EDS on the solid (X-ray amorphous) indicates the absence of metallic Tc and the presence of oxygen. EXAFS measurements
further indicate that the precipitate exhibits a [Tc(μ-O)2Tc] core structure. XANES is consistent with the formation of Tc(III) and/or Tc(IV). Results infer that reduction of aqueous
Tc(VII) by borohydride in the presence of acetic acid does not produce metallic Tc, but a mixture of various oxidation states
of Tc near Tc(III) and Tc(IV).
Authors:J. Terry, B. Grzenia, D. Papagiannopoulou, J. Kyger, S. Jurisson, and J. D. Robertson
99mTc compounds play a very important role in modern medicine. These compounds are among the most widely used radiopharmaceuticals. Unfortunately, due to the necessity of working with small quantities of materials, the chemistry of these materials is not completely understood. Currently, the structure of the 99mTc-DTPA (a common renal imaging agent) is unknown. In this paper, we show that X-ray absorption spectroscopy (XAS) can be used to determine the structure of Tc ycompounds b comparing XAS results to those from X-ray diffraction (XRD). Specifically, XAS data and fits for TcCl62-, TcOCl4-, and TcNCl4- were found to be in excellent agreement with the known structures from XRD. Finally, we show the XAS spectrum from a 77 ng sample of 99Tc-DTPA. To our knowledge this is the first XAS spectrum taken from this material. The near-edge region (XANES) was visible after a single scan on this material. This clearly indicates that we will be able to determine the local atomic structure of this material.
Authors:M. Jablonski, K. Lawniczak-Jablonska, and M. T. Klepka
can apply other methods, such as X-ray absorption near edge structure (XANES) measurements [ 14 ], or thermogravimetric (TG) measurements, as well as the method based on balancing components estimated in the XRF. These methods can be used also for
Authors:Mi-Young Kim, Se Min Park, Jung-Hyun Park, Chae-Ho Shin, Won-Jin Moon, Nark-Eon Sung, and Gon Seo
the titania-incorporated into them. Ti K-edge XANES spectra of the platinum catalysts prepared by supporting platinum on the titania-incorporated silicas and then by treating them with hydrogen peroxide vary with the type of silicas used, as shown in