Comparison of binding abilities of fulvic and humic acids extracted from recent marine sediments with UO2 |
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Authors: | C Munier-Lamy Ph Adrian J Berthelin J Rouiller |
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Abstract: | Potentiometric titrations were used to measure conditional stability constants of UO22+-fulvic acid and UO22+-humic acid complexes. Both 2:1 and 1:1 COO-:UO22+ binding were observed. With decreasing metal concentration (2.5·10−4-6.25·10−5 M) increasing amounts of UO22+ were in the form of 1:1 humate complexes and 2:1 fulvate complexes. Despite the high nitrogen content and the low acidic OH group content, the successive stability constant values were similar to those determined for divalent cations associated with fulvic and humic compounds isolated from soils. Stability constant values increase simultaneously with increasing ionization of the humic (or fulvic) acid polyelectrolytes and with decreasing metal concentration. |
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Keywords: | marine sediments humic compounds acidity constants dissociation binding abilities UO22+ |
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