title: Selective lanthanides sequestration based on a self-assembled organosilica.
abstract: In this paper, we investigate the cation-exchange properties of a self-assembled hybrid material towards trivalent ions, lanthanides (La(3+), Eu(3+), Gd(3+), Yb(3+)) and Fe(3+). The bis-zwitterionic lamellar material was prepared by sol-gel process from only 3-aminopropyltriethoxysilane (APTES), succinic anhydride, and ethylenediamine. In ethanol heated under reflux, the exchange ethylenediammonium versus Ln(3+) proved to be complete by complexometry measurements and elemental analyses, one Cl(-) ion per one Ln(III) remaining as expected for charge balance. In aqueous solution at 20 degrees C, the material was found to be selective towards lanthanide in spite of the similarity of their ionic radii. The cation uptake depends on the nature of the salt, the difference between two lanthanides reaching up to 20 % in some cases. Finally, ion-exchange reaction with FeCl(3) was chosen as a probe to get more information on the material after incorporation of trivalent ions. Based on Mössbauer spectroscopic investigations on the resulting material in conjunction with the XRD analysis of materials containing trivalent ions, a structural model was proposed to describe the incorporation of trivalent ions by exchange reaction within the original zwitterionic material.
authors.affiliation: Institut de chimie séparative de Marcoule, UMR 5257, ICSM Site de Marcoule, BP 17171, 30207 Bagnols sur Cèze Cedex, France.
authors.forename: Eric
authors.initials: E
authors.lastname: Besson
authors.forename: Ahmad
authors.initials: A
authors.lastname: Mehdi
authors.forename: Arie
authors.initials: A
authors.lastname: Van der Lee
authors.forename: Hervé
authors.initials: H
authors.lastname: Chollet
authors.forename: Catherine
authors.initials: C
authors.lastname: Reyé
authors.forename: Roger
authors.initials: R
authors.lastname: Guilard
authors.forename: Robert J P
authors.initials: RJ
authors.lastname: Corriu