The calcium- and iron bound phosphate phase diagram

✍ Scribed by H. L. Golterman

• Book ID: 104613664
• Publisher: Springer
• Year: 1988
• Tongue: English
• Weight: 202 KB
• Volume: 159
• Category: Article
• ISSN: 1573-5141
• DOI: 10.1007/bf00014722

✦ Synopsis

A phase diagram for Ca-and Fe-bound phosphate has been calculated based on two criteria: a) the adsorption of ortho-phosphate onto iron hydroxide b) the solubility product of apatite as measured in two hard water rivers.

The phase diagram explains why ortho-phosphate (o-PO 4 ) in sediments, containing high concentrations of CaCO 3 (about 10-30%), is bound onto the iron hydroxide rather than onto the CaCO 3 . The concentration of the iron hydroxide has an effect on the equilibrium between the two phosphates, whilst the concentration of CaCO 3 has no effect whatsoever.