[en] Technetium (Tc) is one of the main components of nuclear wastes. On account of its radioactivity, its properties can be deduced from studies carried out with chemical analogous elements. The aim of this work is then to study the rhenium adsorption behavior on organic materials in order to specify the technetium ones (technetium is a chemical analog of rhenium) in natural medium. Experimental studies on the dissolution of rhenium oxides at different oxidation states have at first been conducted. The obtained results confirm that the expected Re solubility in the conditions of radioactive waste storage (ReO₄^- form) will be very high. Then have been studied the interactions between Re and some organic polymers. Chitosan, a natural polymer containing amine groups, poly-galacturonic acid and polystyrene-sulfonate which contain respectively -COOH and -SO₃H groups have been chosen. We have made the supposition that the non-specific adsorption of the ReO₄^- ions on chitosan occurs by the complexation with NH₃⁺ groups by electrostatic interaction. The code ECOSTAT has been used to model the adsorption mechanism of ReO₄^- on chitosan. The interface polymer-solution has been described by the electric double layer model and the Langmuir-Freundlich model. With this supposition, the calculation has allowed to obtain values in accordance with the experimental results. No interaction has been found between Re and the -COOH and -SO₃H groups. (O.M.)