Study of Chemical State of Toxic Metals During the Life Cycle of Fly Ash Using X-Ray Absorption Near-Edge Structure

✍ Scribed by János Osán; Balázs Török; Szabina Török; Keith W. Jones

• Publisher: John Wiley and Sons
• Year: 1997
• Tongue: English
• Weight: 406 KB
• Volume: 26
• Category: Article
• ISSN: 0049-8246
• DOI: 10.1002/(sici)1097-4539(199701)26:1<37::aid-xrs189>3.0.co;2-g

✦ Synopsis

The non-destructive x-ray absorption near-edge structure (XANES) method was applied to the quantitative determination of chromium and arsenic species in coal Ñy ash. In order to study the chemical state changes caused by deposition and sedimentation of the particles, land Ðll 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 Ñuorescent mode. For achieving quantitative results on the ratio of closelying oxidation state forms, a non-linear Ðtting 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 Ñy ash and the chemical state remains the same after deposition and sedimentation. Arsenic is present as As(V) in Ñy ash and land Ðll samples, while the possible As(III) content of sediment samples is around 40% .