Adsorption of phosphate and tartrate on hydroxy-aluminum-oxalate precipitates

Abstract

Sorption of phosphate in the presence of low molecular mass organic ligands on hydroxy-Al-organics coprecipitates may be the rule and not the exception in rhizospheric soils. We studied the competitive sorption of phosphate and tartrate on hydroxy-Al-oxalate precipitates obtained by coprecipitating Al and oxalate at pH 7.0 and initial oxalate/Al molar ratios of 0, 0.1, 0.2, and 0.5. The noncrystalline precipitates showed different chemical and physicochemical properties. Oxalate was not homogeneously distributed throughout the solids, and the greater its content in the samples, the higher the surface area, reactivity, and solubility of the solids. Oxalate was released from each complex mainl..