THE UPTAKE OF STRONTIUM BY CALCIUM-PHOSPHATE PHASE FORMED AT AN ELEVATED PH

The sorption of radioactive strontium by poorly crystalline hydroxyapa tite (HA) obtained by the transformation of amorphous calcium phosphat e (ACP) at initial pH 10.8, was investigated, Morphological analysis, performed by transmission electron microscopy, has demonstrated that t he solid phase consists of nanometer size ultra-micro particles connec ted into spherical aggregates. A maximum sorption capacity, determined as the asymptote of the sorption isotherm was Gamma = (3.8 +/- +/- 0. 3). 10(-2) mol Sr/mol P. Based on this result and the structural condi tions, a possible theoretical explanation for the incorporation of a s trontium ion into the apatite lattice has been proposed.