In the paper, investigation results of the uptake efficiency of radionuclides 60Co, 90Sr, and 137Cs dissolved in water onto iron oxides α-Fe2O3 and Fe3O4 are presented. It was found that sorption efficiency increased for higher pH values. Independent of the oxide nature, the uptake characteristics are the best toward 60Co and the worst toward 137Cs, forming the row as follows: 60Co > 90Sr > 137Cs. The highest sorption ability at pH 9 was found for magnetite Fe3O4, which was 93%, 73%, and 26% toward 60Co, 90Sr, and 137Cs, respectively, while the respective percentages for hematite α-Fe2O3 were 85%, 41%, and 18%. It was assumed that the main sorption mechanism was ion exchange. That may explain some decrease of the sorption efficiency in drinking water due to the interfering presence of magnesium and calcium cations. The obtained results indicated the feasibility of the tested sorbents and their merits, especially in terms of relatively high uptake coefficients, low costs, availability, and lack of toxicity.
Keywords: Fe3O4; cesium; cobalt; drinking water; radionuclides; sorption; strontium; α-Fe2O3.