Phosphate Adsorption and Desorption by Goethites Differing in Crystal Morphology
- J. Torrent ,
- V. Barrón and
- U. Schwertmann
Goethite is an important component influencing phosphate adsorption in many soils and sediments. Little is known, however, about the relationships between crystalline properties and phosphate adsorption and desorption by this mineral. In this study we investigated the phosphate adsorption and desorption properties of 31 synthetic goethites differing widely in specific surface area, crystal morphology, and AIOOH mole fraction. The amount of phosphate adsorbed per unit surface area at pH 6 and an equilibrium concentration of 6 mg P L−1 was similar for all goethites (x̄ = 2.51, SD = 0.17 µmol P m−2), suggesting that the common crystal faces have similar P-sorbing capacities. This condition is compatible with the existence of only (110) faces; in fact, according to transmission electron microscope (
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