Abstract. The cornstarch: poly(vinyl alcohol) (PVA) fi lms characterized by the alternating ratio of starch: PVA (100:0, 80:20, 60:40, 40:60, 20:80, and 0:100) and containing 30% of glycerol were prepared by solution casting. The fi lms were irradiated with an absorbed dose of 25 kGy with gamma rays in a vacuum and with fast electrons in the air. The fi lms characterized by a high content of starch appeared stiff, while the fi lms characterized by a high content of PVA were highly fl exible. The tensile strength and fl exibility, as well as swelling and hydrophilicity, increased with the increase in the PVA content in the fi lms. However, the tensile strength and wetting angle values achieved a minimum at an intermediate composition. It was found that irradiation enables to reduce hydrophilicity of the fi lms accompanied by a decrease in their fl exibility. No general conclusion concerning the effect of irradiation on tensile strength and swelling behavior can be derived. An increase in the homogeneity of the fi lms and an increase in the compatibility of their components was found by scanning electron microscopy (SEM). Strong interactions of the starch and the PVA components were discovered by diffuse refl ectance spectroscopy. Degradation was found to be the prevailing process occurring in the fi lms under the infl uence of irradiation. The possible accompanying crosslinking is discussed in terms of the gel content in the samples. Creation of various oxidation products in the fi lms characterized by the modifi ed composition was observed under the infl uence of irradiation carried out in the air. Basing on the obtained results it can be supposed that the selected starch-PVA compositions might appear useful as packagings of the products predicted for radiation decontamination.

Solvent extraction of uranium from acidic and alkaline post-leaching liquors that were obtained by leaching of Polish ores is reported in this paper. The stripping of uranium from organic to aqueous phase was also studied. The synergistic mixture of 2-diethylhexylphosphoric acid (D2EHPA) and tri-n-butylphosphate (0.2 M:0.2 M) was found as a good extracting agent for uranium. Recovery of uranium was reached even 98 %. The effect of such parameters like uranium concentration and concentration of reagents used in the experiments was evaluated in advance by using a model uranium solutions.

Abstract. The main objective of the present study was an assessment of the possibility of uranium recovery from domestic resources in Poland. In the fi rst stage uranium was leached from the ground uranium ore by using acidic (sulfuric acid or hydrochloric acid) or alkaline (carbonate) solutions. The leaching effi ciencies of uranium were dependent on the type of ore and it reached 81% for Dictyonemic shales and almost 100% for sandstones. The novel leaching routes, with the application of the helical membrane contactor equipped with rotating part were tested. The obtained postleaching solutions were concentrated and purifi ed using solvent extraction or ion exchange chromatography. New methods of solvent extraction, as well as hybrid processes for separation and purifi cation of the product, were studied. Extraction with the use of membrane capillary contactors that has many advantages above conventional methods was also proposed as an alternative purifi cation method. The fi nal product U 3 O 8 could be obtained by the precipitation of 'yellow cake', followed by calcination step. The results of precipitation of ammonium diuranate and uranium peroxide from diluted uranium solution were presented.

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