title: Ultrasound-assisted synthesis of mesoporous zirconia-hydroxyapatite nanocomposites and their dual surface affinity for Cr3+/Cr2O7(2-) ions.
abstract: Zirconia-hydroxyapatite nanocomposites were prepared by sol-gel deposition of zirconium oxide from a zirconium alkoxide in the presence of apatite colloidal suspension under ultrasonication. The material porosity evolves from mainly microporous zirconia to mesoporous hydroxyapatite, with decreasing surface area and increasing pore volume. XRD studies indicate that the apatite phase is well-preserved within the composite materials. The homogeneous dispersion of apatite colloids within the zirconia network was supported by TEM observations and nitrogen sorption measurements. (31)P solid-state NMR studies suggest that partial dissolution of apatite may have occurred during the preparation, leading to the adsorption of phosphate species on zirconia particles. This is confirmed by XRD studies of nanocomposites after thermal treatment that demonstrate the preferred formation of tetragonal over monoclinic ZrO(2) in the presence of hydroxyapatite. In order to investigate the surface properties of these novel materials, the adsorption of Pb(2+), Cr(3+), and Cr(2)O(7)(2-) was evaluated. Metal cations were preferentially adsorbed on apatite-rich composites, whereas Cr(2)O(7)(2-) shows a good affinity for the zirconia-rich phases. Zirconia-apatite materials showed the most promising performance in terms of recyclability. These nanocomposites that combine microporosity, mesoporosity and dual sorption properties for these species appear as interesting materials for metal ion remediation and may also find applications as biomaterials.
authors: UPMC-P6, CNRS, Chimie de la Matière Condensée de Paris, Collège de France, 75005 Paris, France.
authors: Karima
authors: K
authors: Achelhi
authors: Sylvie
authors: S
authors: Masse
authors: Guillaume
authors: G
authors: Laurent
authors: Cécile
authors: C
authors: Roux
authors: Abdelaziz
authors: A
authors: Laghzizil
authors: Ahmed
authors: A
authors: Saoiabi
authors: Thibaud
authors: T
authors: Coradin
mesh_terms: D000327:Adsorption; D002857:Chromium / Q000737:chemistry* / Q000378:metabolism; D020099:Coated Materials, Biocompatible / Q000032:analysis / Q000138:chemical synthesis* / Q000378:metabolism; D003102:Colloids / Q000032:analysis / Q000138:chemical synthesis* / Q000378:metabolism; D017886:Durapatite / Q000737:chemistry* / Q000378:metabolism; D007477:Ions; D009682:Magnetic Resonance Spectroscopy; D046529:Microscopy, Electron, Transmission; D053761:Nanocomposites / Q000032:analysis / Q000737:chemistry* / Q000648:ultrastructure; D009584:Nitrogen / Q000737:chemistry; D010710:Phosphates / Q000737:chemistry; D016062:Porosity; D053838:Scattering, Small Angle; D013499:Surface Properties; D014465:Ultrasonics; D014961:X-Ray Diffraction; D015040:Zirconium / Q000737:chemistry* / Q000378:metabolism
chemical_list: D020099:Coated Materials, Biocompatible; D003102:Colloids; D007477:Ions; D010710:Phosphates; D002857:Chromium; D017886:Durapatite; D015040:Zirconium; D009584:Nitrogen; C028541:zirconium oxide