Use of radionuclide-microscopic diagnostics for revealing differences in textural organization and sorption behavior of synthetic and natural calcium carbonate

The dynamics of sorption of microamounts of Sr²⁺ ions spiked with ⁹⁰Sr + ⁹⁰Y from neutral aqueous solutions at 22 ± 2°C on various samples of calcium carbonate (artificially prepared calcite and aragonite, limestone from Novyi Afon cave, skeleton of dendritic madrepore coral from the northeastern part of the Indian Ocean) was studied using radionuclide-microscopic diagnostics. It was shown by X-ray phase analysis that the limestone sample is calcite with an impurity of quartz, and the coral sample is pure aragonite. In all the cases, the radionuclide sorption was characterized by the presence of two steps: fast, complete in 15–30 min, and slow, lasting for more than 20 days. Owing to the more perfect texture, the natural materials under similar conditions sorbed ⁹⁰Sr to an appreciably lesser extent than did the artificial materials. The data obtained showed that, using radionuclide-microscopic diagnostics, it is possible to reliably reveal differences in the sorption behavior of artificial and natural samples of calcium carbonate.