title: Heavy metal immobilization in aqueous solution using calcium phosphate and calcium hydrogen phosphates.
abstract: This study examines the possibilities for removing heavy metal cations from water with calcium phosphate, calcium hydrogen phosphate, and calcium dihydrogen phosphate at 293 K. It was reported that immobilization of aqueous heavy metal cations, which is known to be one of the characteristic properties of calcium hydroxyapatite, proceeded favorably with these phosphates. Calcium phosphate, calcium hydrogen phosphate, and calcium dihydrogen phosphate could favorably remove Pb2+ from aqueous solution. Calcium hydrogen phosphate also removed aqueous Cu2+, Co2+, and Cd2+, whereas these cations were not immobilized by calcium phosphate and calcium dihydrogen phosphate. A contribution of the dissolution-precipitation mechanism to immobilization with these phosphates is suggested.
authors.affiliation: Department of Chemical Science and Technology, Faculty of Engineering, The University of Tokushima, Minamijosanjima, Tokushima 770-8506, Japan.
authors.forename: Shigeru
authors.initials: S
authors.lastname: Sugiyama
authors.forename: Takuya
authors.initials: T
authors.lastname: Ichii
authors.forename: Masayoshi
authors.initials: M
authors.lastname: Fujisawa
authors.forename: Katsuhiro
authors.initials: K
authors.lastname: Kawashiro
authors.forename: Tahei
authors.initials: T
authors.lastname: Tomida
authors.forename: Naoya
authors.initials: N
authors.lastname: Shigemoto
authors.forename: Hiromu
authors.initials: H
authors.lastname: Hayashi