Sorption properties of nanostructured potassium aluminosilicate

Abstract

The ability of synthetic nanostructured potassium aluminosilicate (PAS) KAlSi₃O₈·1.5H₂O with the specific surface area of 105 ± 5 m² g⁻¹ to take up cesium ions was studied. The maximal sorption capacity of PAS in sorption of Cs⁺ ions from cesium carbonate solutions containing no other salts is ∼3.7 mmol g⁻¹. In Cs⁺ sorption from solutions containing no other salts, the sorption capacity is the lowest at pH 1; it increases with pH, reaching a maximum at pH 10.8. The effect of salt background (various concentrations and ratios of KCl and NaCl) on the sorption properties of PAS was examined. The sorption capacity decreases to the greatest extent (to 0.25 mmol g⁻¹) in solutions containing the K+ and Na+ ions simultaneously at concentrations of 68 and 517 mM, respectively. The dependence of the cesium sorption on the concentration of nitrates (NaNO₃, KNO₃, NH₄NO₃) and the kinetics of the cesium sorption from aqueous NaNO₃ solution were studied with the ¹³⁷Cs tracer. The highest distribution coefficients (up to 12000 mL g⁻¹) are observed in ¹³⁷Cs sorption from NaNO₃ solutions. The degree of the ¹³⁷Cs sorption reaches a maximum (92 ± 4%) in sorption from 0.01 M NaNO₃ solutions at the sorption time of 4 h.