Knowledge of the chemical speciation of arsenic and selenium in coal fly ash is essential in the evaluation of the environmental behavior of fly ash disposed in a landfill in a natural environment. In this study, a series of high-As coal fly ash from stoker boilers were collected to determine the chemical forms of arsenic and selenium. The ash surface chemical characteristics and the speciation of arsenic and selenium were characterized by X-ray photoelectron spectroscopy and X-ray-induced Auger electron spectroscopy. The results indicate that the surface enrichment ratio for selenium (63.3–309.5) is higher than that of arsenic (1.2–21.2). The Wagner chemical-state plot of arsenic indicates that As is mainly present as As(V) bonded to oxygen ligands, that is, the [AsO4]3– anion; Se is found predominantly as elemental Se (62.0–83.3%), followed by selenite (16.7–38%). The extreme enrichment of both arsenic and selenium arsenic is controlled by iron oxides in the coal fly ash.

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Published in ACS Omega, v. 3, issue 12, p. 17637-17645.

© 2018 American Chemical Society

This is an open access article published under an ACS AuthorChoice License, which permits copying and redistribution of the article or any adaptations for non-commercial purposes.

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The Supporting Information is available free of charge on the ACS Publications website at DOI: 10.1021/acsomega.8b02929.

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