The non-destructive x-ray absorption near-edge structure (XANES) method was applied to the quantitative determination of chromium and arsenic species in coal fly ash. In order to study the chemical state changes caused by deposition and sedimentation of the particles, land fill and river sediment samples obtained in the neighborhood of power plants were also investigated. The measurements were carried out at the X26 beam line of the BNL National Synchrotron Light Source (USA) in fluorescent mode. For achieving quantitative results on the ratio of close-lying oxidation state forms, a non-linear fitting model was developed to process the XANES spectra obtained. The features of the spectra such as the white line, the multiple scattering resonance peak and the absorption edge were modelled with analytical functions. The results obtained show that chromium is present mostly (>95%) as Cr(III) in fly ash and the chemical state remains the same after deposition and sedimentation. Arsenic is present as As(V) in fly ash and land fill samples, while the possible As(III) content of sediment samples is around 40%.
|Number of pages||8|
|Publication status||Published - Jan 1 1997|
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