Separation of lanthanides(III) by inorganic nanofiltration membranes using a water soluble complexing agent.

J. Borrini (1, 2, 3) , G. Bernier (2) , S Pellet-Rostaing (3) , A. Favre-Reguillon (4, 1) , M. Lemaire (1)

1 ICBMS - Institut de Chimie et Biochimie Moléculaires et Supramoléculaires
2 CEA Marcoule
3 ICSM - UMR 5257 - Institut de Chimie Séparative de Marcoule
4 SIGMA - Laboratoire Signaux, Modèles et Apprentissage Statistique

First separation of Ln(III) using an inorganic nanofiltration membrane has been achieved. Ln(III) ions are strongly repelled by the ZrO2/TiO2 membrane. When diethylenetriaminepentaacetic acid (DTPA) is used as water soluble complexing agent, the complexes formed with Ln(III), surprisingly passes through the membrane. The stability constant of DTPA with Eu3+ is higher than the one with La3+. Thus [EuDTPA]2− complex is formed at lower pH than [LaDTPA]2− and so these two elements can be separated. With an equimolar mixture of Eu3+ and La3+, a La3+/Eu3+ separation factor of 2.5 is obtained at pH 1.9. Other polyaminocarboxylic acids have been used such as EDTA and HEDTA and similar phenomenon occur. The best La3+/Eu3+ separation factor has been obtained with HEDTA. In that case, the La3+/Eu3+ separation factor is 7.5 at pH 2.3. All these ligands have been also evaluated with a TiO2 nanofiltration membrane and results are comparable.

Mots clés: Inorganic membrane; Lanthanides(III); Separation; Polyaminocarboxylic acids

Domaines: Chimie organique

J. Borrini, G. Bernier, S Pellet-Rostaing, A. Favre-Reguillon, M. Lemaire. Separation of lanthanides(III) by inorganic nanofiltration membranes using a water soluble complexing agent.. Journal of Membrane Science, 2010, 348 (1-2), pp.41-46. ⟨10.1016/j.memsci.2009.10.034⟩. ⟨hal-01166237⟩