Selective Sorption of Trace Amounts of Calcium and Strontium by Hydrous Oxides of Iron and Aluminum

摘要

Heated gibbsite, and freshly prepared Fe and Al gels selectively sorbed traces of Ca and Sr from solutions containing a large excess of NaNO. The fraction of the total Ca(Sr) sorbed depended principally on the suspe-sion pH, the amount of solid present, and only to a lesser extent on the NaNO and Ca concentrations. Significant Ca and Sr sorption occurred on the heated gibbsite, Fe and Ai gels, at pH's below their points of zero charge (8.25, 8.05 and 9.40, respectively), indicating specific adsorption. For the heated gibbsite and Fe gel, an empirical model based on the law of mass action fitted the data.