| Abstract [eng] |
In this work the sorption kinetics of Cs(I), Pu(IV) and Am(III) radionuclides on synthetic and natural sorbents have been studied. The aim of the study was investigation of the radionuclide speciation distribution in the clay minerals during the long-term experiments (361 days). The investigation of 137Cs, 239,240Pu and 241Am radionuclide speciation in bottom sediments gives important information about their bioavailability and sorption behavior. The most important components, which are affecting sorption of radionuclides on the natural clay mineral surface, are iron oxides and organic. One of the available techniques for analysis of radionuclide speciation at the low environmental level (in clays and bottom sediments) is a sequential extraction. The obtained results show that for removal of Cs the best are titanium silicates. For the actinide removal it is better to use iron oxides. The obtained results show that Pu(IV) and Am(III) sorption kinetics on natural clay substances are controlled by diffusion in the inert layer of the solid phase (ID) control process. Data of Pu(IV) and Am(III) sorption on clay materials obtained during the long-term (361 days, 5-520000 min) experiment indicated that exchangeable and carbonate species of Am(III) were formed during the first 50 minutes. Pu(IV) was associated with amorphous oxides and natural organic matter. Iron oxides, organic compounds and clay minerals are responsible for strong bonding of Cs and Pu radionuclides to bottom sediments. Interaction of Am with bottom sediments is weaker and 241Am should be more mobile in the marine environment. |
