Effect of humic acids and iron hydroxides deposited on the surface of clay minerals on the 137Cs immobilization

Abstract

The effect exerted on the relationships of 137Cs sorption by humic acids and iron hydroxides deposited on the surface of clay minerals, montmorillonite and kaolinite, differing in the exchange capacity, was studied. The presence of humic acids and Fe(OH)3 deposited on the mineral surface leads to an increase in the 137Cs sorption in a wide pH range (pH 4–9), suggesting the participation of functional groups of humic acids and ferrinol groups of iron(III) hydroxide in binding of the metal ions. The Na+, K+, and Ca2+ ions, on the contrary, with an increase in their concentration in aqueous solution decrease the immobilization of cesium radionuclides and favor their migration in the environment.