Figure 7: XAS results from soil samples.
From: Mobile uranium(IV)-bearing colloids in a mining-impacted wetland
Uranium LIII-edge data recorded for soil samples at 5–10 (light blue), 10–15 (deep blue), 15–20 (light yellow) and 20–25 cm (deep yellow) at spot A and those at 5–10 (light purple), 15–20 (deep purple), 20–25 (light grey) and 35–40 cm (black) at spot B compared with monomeric U(IV) (green) and U(VI)-acetate (red) model compounds. (a) XANES data of spot A showing that U(IV) is the predominant valence state in soil samples; (b) unfiltered k3-weighted EXAFS data of spot A; (c) magnitude and imaginary part of the Fourier transform (FT) of spot A; (d) XANES data of spot B showing that U(IV) predominates in the soil samples; (e) unfiltered k3-weighted EXAFS data of spot B; (f) magnitude and imaginary part of the FT of spot B. Experimental and calculated curves (see Supplementary Table S3 for fitting parameters) are displayed as solid and dashed lines, respectively. The vertical-dashed lines labelled ‘U(IV)’ and ‘U(VI)’ in a and d show the energy of the U(IV) and U(VI) white lines, respectively. The vertical lines labelled ‘1’, ‘5’ and ‘5’ at the top left-hand corner of a and d, b and e, c and f represent the scale of y axis.
