Biosorption of Strontium Ions by Magnetically Modified Yeast Cells

The sorption of Sr²⁺ ions from aqueous solutions on magnetically modified fodder yeast (Kluyveromyces fragilis) cells and their subsequent desorption were studied. The Sr²⁺ sorption increased with increasing pH and reached a plateau between pH 4.0 and 7.0. The changes of temperature slightly influenced the sorption process. The sorption values were 19.5 mg g^?1 and 53.5 mg g^?1 for 10 mg L^?1 and 40 mg L^?1 Sr²⁺ solutions respectively after 20 min incubation at a pH higher than 4. The Langmuir isotherm was successfully used to fit experimental data; the maximum adsorption capacity was 140.8 mg g^?1 under optimal conditions. The adsorbed Sr²⁺ ions can be desorbed with nitric acid (0.1 mol L^?1).