| Abstract
| - The feasibility of immobilizing radionuclides on mineral surfaces was examined in the absence and thepresence of phosphate anions, using trivalent lanthanide ions (Eu3+, Gd3+, and Dy3+) as chemical analoguesof trivalent actinide radionuclides. The amount of lanthanide ions (Ln3+) sorbed on boehmite (γ-AlOOH)surfaces dramatically increased in the presence of phosphate below pH 5. The structure of the sorbedlanthanide was determined by X-ray absorption spectroscopy, magnetic susceptibility measurements, andelectron paramagnetic resonance spectroscopy. We proved Dy3+ forms precipitates on boehmite surfacesin the presence of phosphate, and Gd3+ both in the presence and the absence of phosphate. In the presenceof phosphate, however, these rare-earth cations react to form ultrafine particles of LnPO4 surface precipitateson boehmite surfaces.
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