title: Surface reactivity of hydroxyapatite nanocoatings deposited on iron oxide magnetic spheres toward toxic metals.
abstract: OBJECTIVE
  Hydroxyapatite and magnetite are two environmentally-friendly mineral phases that have fruitful properties for remediation process. The formation of magnetic core@sorbent shell nanostructures should provide efficient materials for toxic metal removal from aqueous media. However the nanoscale confinement of hydroxyapatite may influence its reactivity.
  
  
  METHODS
  Fe3O4@Hydroxyapatite nanocomposites were prepared by surface-controlled precipitation of hydroxyapatite layers from 10 nm to 150 nm in thickness on iron oxide spheres. The surface reactivity of the core-shell particles toward selected inorganic ions of environmental relevance (Pb(II), Y(III), Eu(III), Sb(III)) was studied by batch sorption experiments, X-ray diffraction and electron microscopy.
  
  
  RESULTS
  The reactivity of the hydroxyapatite coating varied from partial cation exchange to dissolution/transformation of the shell. The nature and extent of the reactions depended significantly on the hydroxyapatite layer structure but was not significantly influenced by the magnetic core. These novel nanocomposites should be useful for environmental applications.
authors.affiliation: UPMC Univ Paris 06, CNRS, Chimie de la Matière Condensée de Paris, Collège de France, 11 place Marcelin Berthelot, F-75005 Paris, France; Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, People's Republic of China. Electronic address: hhyanghh@gmail.com.
authors.forename: Huihui
authors.initials: H
authors.lastname: Yang
authors.affiliation: UPMC Univ Paris 06, CNRS, Chimie de la Matière Condensée de Paris, Collège de France, 11 place Marcelin Berthelot, F-75005 Paris, France. Electronic address: sylvie.masse@upmc.fr.
authors.forename: Sylvie
authors.initials: S
authors.lastname: Masse
authors.affiliation: Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, People's Republic of China. Electronic address: stavrosatic@gmail.com.
authors.forename: Hao
authors.initials: H
authors.lastname: Zhang
authors.affiliation: UPMC Univ Paris 06, CNRS, Chimie de la Matière Condensée de Paris, Collège de France, 11 place Marcelin Berthelot, F-75005 Paris, France. Electronic address: christophehelary@hotmail.com.
authors.forename: Christophe
authors.initials: C
authors.lastname: Hélary
authors.affiliation: Key Laboratory of Cryogenics, Technical Institute of Physics and Chemistry, Chinese Academy of Sciences, Beijing 100190, People's Republic of China. Electronic address: laifengli@mail.ipc.ac.cn.
authors.forename: Laifeng
authors.initials: L
authors.lastname: Li
authors.affiliation: UPMC Univ Paris 06, CNRS, Chimie de la Matière Condensée de Paris, Collège de France, 11 place Marcelin Berthelot, F-75005 Paris, France. Electronic address: thibaud.coradin@upmc.fr.
authors.forename: Thibaud
authors.initials: T
authors.lastname: Coradin
keywords: Hydroxyapatite; Iron oxide; Magnetic recovery; Nanocomposites; Remediation