title: Interdependence of Anion and Cation Exchanges in Calcium Hydroxyapatite: Pb(2+) and Cl(-).
abstract: The ion exchange of Pb(2+) and Cl(-) into calcium hydroxyapatite from aqueous solutions is studied at 293 K. Although the exchange of Cl(-) into CaHAp and PbHAp was not observed, in the presence of both Pb(2+) and Cl(-) in aqueous solution the exchange of both Pb(2+) and Cl(-) into CaHAp occurred, and, at least at intermediate concentrations of HCl, a proportionality between the sorbed quantities of these two ions was observed. The dissolution of CaHAp is shown to be dependent upon the pH, while the quantity of Pb(2+) exchanged into the solid is not a function of the proton content; consequently, the exchange is not primarily a dissolution-precipitation process. Copyright 1999 Academic Press.
authors.affiliation: Faculty of Engineering, The University of Tokushima, Minamijosanjima, Tokushima, 770-8506, Japan
authors.initials: S
authors.lastname: Sugiyama
authors.initials: N
authors.lastname: Fukuda
authors.initials: H
authors.lastname: Matsumoto
authors.initials: H
authors.lastname: Hayashi
authors.initials: N
authors.lastname: Shigemoto
authors.initials: Y
authors.lastname: Hiraga
authors.initials: JB
authors.lastname: Moffat