Comparison of binding abilities of fulvic and humic acids extracted from recent marine sediments with UO22+

Munier-Lamy, Colette; Adrian, P.; Berthelin, J.; Rouiller, J.

doi:10.1016/0146-6380(86)90109-9

Cited by 39 publications

(14 citation statements)

References 41 publications

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“…1. Under the considered conditions, U(VI) occurs in form of various hydroxo species, mainly ( 5 + dominating for U(VI) concentrations above 0.4 µmol/L, i.e., also for the reference samples. HA can in principle react with all the positively charged hydroxo species, whereas the neutral species UO 2 (OH) 2 (aq) has a very low affinity to the negatively charged binding sites of HA at pH 7.…”

Section: Complexation Model For Neutral Ph Conditionsmentioning

confidence: 99%

“…2). Comparing lifetime and peak maxima of this species with those obtained for further reference samples containing various U(VI) hydroxo species [28], the long-living fluorescence species can be ascribed to the (UO 2 ) 3 (OH) 5 + complex which dominates the U(VI) speciation in the reference system. This assignment is supported by literature data of Moulin et al [29], who reported a fluorescence lifetime of 23 ± 3 µs and peak maxima at 479, 496, 514, 535, 556, and 584 nm for the (UO 2 ) 3 (OH) 5 + complex.…”

Section: U(vi) Fluorescence In Absence Of Humic Acidmentioning

confidence: 99%

“…The first step in data processing was to calculate [(UO 2 ) 3 (OH) 5 + ] free for each sample. For that, the fluo- rescence spectra of series 1 and 2 measured at 10.03 µs and 10.53 µs, respectively, were isolated from the data sets and each integrated over the recorded wavelength range.…”

Section: U(vi) Fluorescence In Presence Of Humic Acidmentioning

confidence: 99%

“…Thermodynamic complexation data for the interaction of U(VI) with HA (e.g., [1][2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17]) have been determined applying different methods and complexation models. These studies *Author for correspondence (E-mail: S.Sachs@fz-rossendorf.de).…”

Section: Introductionmentioning

confidence: 99%

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Uranium(VI) complexation by humic acid under neutral pH conditions studied by laser-induced fluorescence spectroscopy

Sachs¹,

Brendler²,

Geipel³

2007

Radiochimica Acta

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The complexation of U(VI) with Aldrich humic acid (HA) was studied at pH 7 under exclusion of CO 2 . Using two independent laser-induced spectroscopic methods, timeresolved laser-induced fluorescence spectroscopy (TRLFS) and TRLFS with ultrafast pulses (fs-TRLFS), the formation of the ternary U(VI) mono hydroxo humate complex UO 2 (OH)HA(I) by reaction of UO 2 OH + with HA was studied. Assuming that all proton exchanging functional groups of the HA are able to contribute to the complex formation, a mean stability constant of 6.58 ± 0.24 was derived for UO 2 (OH)HA(I). Alternatively, the analytical data were evaluated based on the metal ion charge neutralization model resulting in a complexation constant of 6.95 ± 0.10 and a loading capacity of 0.76 ± 0.28. An overall complexation constant of log β 0.1 M = 14.89 ± 0.54 was calculated for the total reaction of U(VI) with HA starting from the non-hydrolyzed UO 2 2+ ion. This value agrees very well with literature data. Taking into account the UO 2 (OH)HA(I) complex, the speciation of U(VI) in presence of HA was recalculated. It was found, that the formation of UO 2 (OH)HA(I) can significantly influence the U(VI) distribution in the environmentally relevant pH region. As a consequence, the mobility of U(VI) in natural aquifer systems could be enhanced.

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Section: Complexation Model For Neutral Ph Conditionsmentioning

confidence: 99%

Section: U(vi) Fluorescence In Absence Of Humic Acidmentioning

confidence: 99%

Section: U(vi) Fluorescence In Presence Of Humic Acidmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Uranium(VI) complexation by humic acid under neutral pH conditions studied by laser-induced fluorescence spectroscopy

Sachs¹,

Brendler²,

Geipel³

2007

Radiochimica Acta

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“…Therefore the complexation has been rather extensively studied [7][8][9][10][11][12][13][14][15][16]. The nature of the uranium-humic acid complexes was characterized using a number of methods including ion exchange [9,11,[13][14][15][16], dialysis [8], ultrafiltration [8,15], solvent extraction [10], chelating resin [12] and laser spectroscopy [12,15], yielding several stability constants of the complexes. Very little direct information on the charge of the complexes was obtained [15] and virtually no data on their electrophoretic mobilities exist.…”

Section: Introductionmentioning

confidence: 99%

Effect of Humic Acid on the Electrophoretic Mobility of Uranium (VI) in Aqueous Solutions

1999

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Electrophoresis of hexavalent uranium in aqueous solutions containing humic acid (HA) Gohy-573 was studied with the aim to characterize the uranium-humic acid (U-HA) complexes formed. Electrophoretic mobility of uranium towards cathode and anode was determined using a free-liquid electrophoresis, as a function of pH and concentration of humic acid and uranium. Experiments with solutions of 1 X 10~4 mol/1 uranium in absence of humic acid indicated hydrolysis of uranium at pH 3-5. Similar hydrolysis, probably accompanied by the formation of pseudocolloids, was also found for 1 X 10 6 mol/1 uranium. Addition of humic acid in 5.6 X 10~6, 3 X10 5 or 1 X 10 4 mol/1 concentration to 5 X 10" 7 -2 X 10 4 mol/1 solution of uranium at pH 4.0 caused decrease in uranium mobility towards cathode and increase in its mobility towards anode, due to the formation of neutral and/or negatively charged U-HA complexes. The changes were more pronounced at higher ratio [HA]/[U] concentrations. Abundances of U-HA complexes and their mean mobilities towards anode were calculated from the results obtained. It was found that the mobilities decrease with the increasing [U]/HA] ratio due to saturation of negative charge of the humic acid with positively charged uranium species, mainly UO! + .

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Interaction of Uranyl with Humic and Fulvic Acids at High Ionic Strength

Labonne-Wall

Choppin

López

et al. 1999

Actinide Speciation in High Ionic Strength Media

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Comparison of binding abilities of fulvic and humic acids extracted from recent marine sediments with UO22+

Cited by 39 publications

References 41 publications

Uranium(VI) complexation by humic acid under neutral pH conditions studied by laser-induced fluorescence spectroscopy

Uranium(VI) complexation by humic acid under neutral pH conditions studied by laser-induced fluorescence spectroscopy

Effect of Humic Acid on the Electrophoretic Mobility of Uranium (VI) in Aqueous Solutions

Interaction of Uranyl with Humic and Fulvic Acids at High Ionic Strength

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