TY - JOUR
T1 - EXAFS and XANES studies of copper in a solidified fly ash
AU - Hsiao, M. C.
AU - Wang, H. Paul
AU - Yang, Y. W.
PY - 2001/6/15
Y1 - 2001/6/15
N2 - Speciation of copper in the fly ash solidification process has been studied by X-ray based spectroscopies in the present work. Fourier transformed EXAFS (extended X-ray absorption fine structural) spectra of the solidified fly ashes showed that the bond distance of Cu-O (first shell) was 1.96 Å with a coordination number (CN) of about 3.0. However, in the second shell of copper atoms, the bond distance of Cu-(O)-Cu was decreased by 0.12-0.22 Å during solidification, which might cause the stabilization of the CuO species in the solidified fly ash matrix. By the least-squares fits of the XANES (X-ray absorption near edge structural) spectra, fractions of the main copper species in the solidified fly ashes such as CuCl2(0.08-0.11), Cu2O (0.07-0.09), Cu(OH)2 (0.31-0.33), and CuO (0.49-0.52) were observed. Combined EXAFS and XANES observations suggested that chemical reactions such as hydroxylation of CuCl2 and oxidation of Cu2O and/or metallic Cu might involve in the solidification process, which also led to a significant reduction of the leachability of copper from the solidified fly ashes.
AB - Speciation of copper in the fly ash solidification process has been studied by X-ray based spectroscopies in the present work. Fourier transformed EXAFS (extended X-ray absorption fine structural) spectra of the solidified fly ashes showed that the bond distance of Cu-O (first shell) was 1.96 Å with a coordination number (CN) of about 3.0. However, in the second shell of copper atoms, the bond distance of Cu-(O)-Cu was decreased by 0.12-0.22 Å during solidification, which might cause the stabilization of the CuO species in the solidified fly ash matrix. By the least-squares fits of the XANES (X-ray absorption near edge structural) spectra, fractions of the main copper species in the solidified fly ashes such as CuCl2(0.08-0.11), Cu2O (0.07-0.09), Cu(OH)2 (0.31-0.33), and CuO (0.49-0.52) were observed. Combined EXAFS and XANES observations suggested that chemical reactions such as hydroxylation of CuCl2 and oxidation of Cu2O and/or metallic Cu might involve in the solidification process, which also led to a significant reduction of the leachability of copper from the solidified fly ashes.
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U2 - 10.1021/es001374v
DO - 10.1021/es001374v
M3 - Article
C2 - 11432559
AN - SCOPUS:0035874792
SN - 0013-936X
VL - 35
SP - 2532
EP - 2535
JO - Environmental Science & Technology
JF - Environmental Science & Technology
IS - 12
ER -