The paper reports the adsorption of strontium(II) and americium(III) from aqueous solutions onto calcium alginate (CaA), barium alginate (BaA) and strontium alginate (SrA) beads. Adsorption process was studied in batch experiments as a function of the initial pH of the solution and the contact time. All sorbents were examined by the termogravimetric analysis (TG). Laboratory obtained spherical beads of CaA, BaA and SrA seem to be good metal sorbents from liquid radioactive wastes. A contact time of about 4 h and neutral pH of the initial aqueous solution have been proposed to be optimum conditions for Sr-85 and Am-241 removal from the contaminated solutions using alginate sorbents. Laboratory obtained beads of CaA, BaA and SrA are characterized by the decontamination factor (DF) equal to 85% for Sr(II) and 90% for Am(III).

Two new sorbents for americium(III) removal from an aqueous environment were studied: Volclay bentonite and red clay – both modified by a cationic surfactant (hexadecyltrimethylammonium bromide) and phosphate ions. Sorption of Am(III) was investigated using the batch method. It was concluded that the kinetics of Am(III) sorption on both sorbents can be evaluated based on the pseudo-second-order rate equation. The following two-parameter equations – Langmuir-Freundlich, Temkin, and Dubinin- Radushkevich isotherms – were examined for their ability to model equilibrium sorption data. It was shown that bentonite and red clay modified by phosphate ions exhibited better sorption properties toward Am(III) ions than sodium forms of the adsorbents. This was probably a result of the complexation of Am(III) ions by PO₄^3- ions immobilized on the adsorbent surface in the form of ionic pairs with surfactant cations. Changes in Am(III) sorption with pH were modeled based on the molar fractions of the particular complexes in the aqueous phase, and it was concluded that Am(CO₃)₃³- and Am(OH)₃ species had a predominant influence on the overall sorption process.