Biosorption of Uranium, Am-241 and Cs-137 by Rice Husk - 15437

New techniques involving the treatment of radioactive waste which combine simplicity and low cost have directed attention to biosorption. The biosorption term is used to describe the removal of metals, nonmetals and/or radionuclides by a material from a biological source, regardless of its metabolic activity. Among the potential biomass, agricultural residues have very attractive features, as they allow for the removal of radionuclides present in the waste using a low cost biosorbent. The aim of this study was to evaluate the capacity of rice husk to remove uranium, Am-241 and Cs-137 in real radioactive liquid organic waste. This work was divided into two stages: i) Preparation and physical characterization of the rice husk and ii) Batch biosorption experiments. The parameters evaluated for physical characterization of biomass were morphological characteristics of rice husk, real and apparent density and surface area. The adopted contact times were 30 min, 1, 2 and 4 hours and the concentrations tested ranged between 10% and 100%. The results were evaluated by maximum experimental sorption capacity and isotherm and kinetics ternary models. The maximum capacity of the biosprtion for the rice husk with approximate values was of 0.5 mg/g of U (total), 14 x10 -6 mg/g of Am-241 and 20 x10 -9 mg/g of Cs-137. These results suggest that biosorption with rice husk can be applied in the treatment of radioactive liquid organic waste.