PHOSPHATE ADSORPTION AND DESORPTION BY GOETHITES DIFFERING IN CRYSTAL MORPHOLOGY

Investigates the phosphate adsorption and desorption properties of 31 synthetic goethites differing widely in specific surface area, crystal morphology, and AlOOH 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 suggesting that the common crystal faces have similar P-sorbing capacities. The amount of phosphate nonextractable by 0.1 M KOH, and the amount not extracted by dissolving one layer of one-unit-cell thickness with an acid (HCl-H2SO4) treatment, are related to crystal morphology: samples consisting of thin, multidomainic laths retain more P than those having thick, monodomainic crystals. -from Authors