Influence of humic acid size on actinide complexation
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Jean-Marc Monsallier
Abstract
The complexation of Am(III) and Eu(III) with humic acid of different molecular sizes was measured and the data for the ≥300kD and ≥10kD sized HA at pcH 4.0 and 6.0 was analyzed by the Charge Neutralization Model (CNM) and the Polyelectrolyte Model (PM). For the PM, solvent extraction was used to obtain the stability constants of 241Am at tracer concentration. For the CNM, ultrafiltration was used to determine the loading capacity and the stability constants for Eu(III) at macro concentrations. There was a difference of 1-2 orders of magnitude in the stability constants from the two models. The 5D0–7F0 excitation spectra of Eu(III) as a function of loading of HA was found to have a shift in wavenumbers of the peak maximum, indicating that the coordination environment of Eu(III) varied with pH, presumably due to variation in the number of functional groups of the humate bound to the metal ion.
© 2003 Oldenbourg Wissenschaftsverlag GmbH
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Artikel in diesem Heft
- Thermochromatographic studies of berkelium chlorides: BkCl3 and BkCl4
- Thermodynamics of extraction of Am(III) and Eu(III) from different anionic media with Tri-n-octyl phosphine oxide
- Influence of humic acid size on actinide complexation
- The role of oxidants in Pu-Th separation studies employing di(2-ethylhexyl)isobutyramide (D2EHIBA) as extractant
- Synthesis and properties of neptunium(VI,V) and plutonium(VI) pertechnetates
- Speciation of polonium released from molten lead bismuth
- Extraction separation of No-carrier-added astatine from bismuth target
- Enhanced extraction and separation of trivalent lanthanoids with 3-phenyl-4-(4-fluorobenzoyl)-5-isoxazolone and dicyclohexano-18-crown-6
- Thermodynamic modeling of metal–ligand interactions in high ionic strength NaCl solutions: the Ni2+-oxalate system
- Influence of surface charge of an Fe-oxide and an organic matter dominated soil on iodide and pertechnetate sorption
- Concentration distributions of radionuclides in sediments along the Romanian sector of the Danube River and the Black Sea coast
