title: Calcite-seeded crystallization of calcium phosphate for phosphorus recovery.
abstract: For phosphorus recovery from wastewater, the present paper aims at understanding the crystallization of calcium phosphate by using calcites (Juraperle and Coccolith) as seeds from hard water. Synthetic hard water with 60 mgCl(-1) carbonate and 10 mgPl(-1) phosphate was prepared and used in the batch experiments of calcite-seeded crystallization. The solution composition was measured throughout the batch crystallization process, and the corresponding saturation indices with respect to the minerals were calculated with PHREEQC Program. The surface of the calcite seeds was observed and measured with environmental scanning electron microscopy (ESEM), Fourier transform infrared (FTIR) and BET method. The studies show that both calcites are effective seeds for the crystallization of calcium phosphate from hard water; the used calcites are more efficient than the original ones because newly formed crystals with calcium phosphate have covered their surfaces. The studies show that the calcite seeds can be used for phosphorus recovery from hard waters.
authors.affiliation: Institute for Technical Chemistry-Section of Water and Geotechnology, Research Centre of Karlsruhe, D-76021 Karlsruhe, Germany. songyh@craes.org.cn
authors.forename: Yonghui
authors.initials: Y
authors.lastname: Song
authors.forename: Peter G
authors.initials: PG
authors.lastname: Weidler
authors.forename: Ute
authors.initials: U
authors.lastname: Berg
authors.forename: Rolf
authors.initials: R
authors.lastname: Nüesch
authors.forename: Dietfried
authors.initials: D
authors.lastname: Donnert
mesh_terms: D002119:Calcium Carbonate / Q000737:chemistry*; D002130:Calcium Phosphates / Q000737:chemistry*; D003247:Conservation of Natural Resources; D003460:Crystallization; D010758:Phosphorus / Q000737:chemistry / Q000302:isolation & purification*; D014865:Waste Disposal, Fluid; D014874:Water Pollutants, Chemical / Q000302:isolation & purification
chemical_list: D002130:Calcium Phosphates; D014874:Water Pollutants, Chemical; D010758:Phosphorus; C020243:calcium phosphate; D002119:Calcium Carbonate