The Influence of a Fulvic Acid on the Adsorption of Europium and Strontium by Alumina and Quartz: Effects of pH and Ionic Strength

Nordén, Maria; Ephraim, James H.; Allard, Bert

doi:10.1524/ract.1994.65.4.265

Cited by 40 publications

(30 citation statements)

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“…These results corroborate data obtained by Righetto et al [12] in the case of Si02-Am(in)-HA system, by Fairhurst et al [13] for the Si02-Eu(III)-HA system, by Allard et al [27] in the case of Al203-Am(m)-HA/FA systems, and by Norden et al [28] for the Si02-Eu(III)-FA system.…”

Section: Americiumsupporting

confidence: 90%

Retention Properties of Humic Substances onto Amorphous Silica: Consequences for the Sorption of Cations

1997

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Silica / Humic substances / Actinides / Retention / Surface complexation model / Radwaste disposals SummaryThe Sorption of humic substances (Aldrich humic acids, fulvic acids from a granitic site) onto a amorphous silica has been investigated as well as their role on the sorption properties of tri-and hexavalent actinides (Am(III) and U(IV) respectively) onto this sorbent. Retention experiments have been performed (by batch procedures) in 0.1 M NaC104 electrolyte solutions in a pH ränge of 3-10 with humic and fulvic concentrations representative of those encountered in natural waters (1 -10 ppm). According to the oxidation State of the cation and the humic/ fulvic concentration, the actinide sorption behavior is enhanced or decreased compared to the system without humic substances and is related to the complexation strength of this cation towards the organic ligand. The complexation surface model (with no electrostatic term) has been applied in order to describe the mechanisms occurring at the oxide-water interface; apparent surface complexation constants have been determined for each species (cation, organic ligand) and surface reactions with the hydroxyl surface groups of silica surface are proposed.

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Section: Americiumsupporting

confidence: 90%

Retention Properties of Humic Substances onto Amorphous Silica: Consequences for the Sorption of Cations

1997

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“…It was noted that K d diminishes with increasing concentration of organic matter in subsurface water. These data are consistent with the results obtained by Norden et al (1994) and Ledin et al (1994).…”

Section: Sorption Of Radionuclides To Colloidal Particlessupporting

confidence: 93%

Effect of colloids on transfer of radionuclides by subsurface water

Malkovsky

Pék

2009

Geol. Ore Deposits

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The fluid transfer of radionuclides in the geologic medium is considered under conditions when radionuclides are contained in fluids not only as solutes but also as colloids. The effect of colloidal transport of radionuclides on the rate of spreading of radioactive contamination in an underground medium is estimated, with assessment of this effect in mathematical models describing the transport of radionuclides by subsurface water. For this purpose, the exchange of radionuclides between subsurface water, colloid, and an immobile solid phase is considered, taking into account the precipitation of colloidal particles on both the immobile solid phase and other colloidal particles and their recurrent mobilization into the liquid phase. It is noted that, in real colloidal transfer, the heterogeneity of the geologic medium and colloidal particles in subsurface water is of great importance. The known models of colloidal transfer of radionuclides are evaluated on the basis of the analysis performed.

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“…Taking the solubility and hydrolysis data of Stadler and Kim (13) for Am(III), the solubility limit for the given Cm(III) concentration in the absence of alumina will be exceeded around pH 7.5. Precipitation of Cm(OH) 3 is obviated by addition of the Cm(III) stock solution to the alumina sus-…”

Section: Resultsmentioning

confidence: 99%