A proposed structure of an aluminum-prosphate species of importance in wastewater treatment.

Abstract

Abstract A laboratory study was conducted to determine the nature of the hydroxy-aluminum phosphate species present in wastewater treatment processes employing aluminum salts for the removal of phosphorus. At pH 5.0 the aluminum to phosphate molar ratio for optimum phosphorus removal was 1.44. Although several species may be formed, the chemical formula determined for the principal complex proposed by the authors is Al13 (OH)30 (H2PO4)9 · 18H2O. A postulated structure for this precipitate is presented.