PREPARATION OF FIBROUS ADSORBENTS CONTAINING AMIDOXIME GROUPS BY RADIATION-INDUCED GRAFTING AND APPLICATION TO URANIUM RECOVERY FROM SEA-WATER

Polypropylene fibers and polyethylene hollow fibers were used as trunk polymers and were irradiated by electron beams with a dose of 200 kGy under N2 atmosphere. Grafting of acrylonitrile to those irradiated fi bers was carried out at 40-degrees-C for different periods of time. Th e degree of grafting was determined as a function of time. The fibrous adsorbents containing amidoxime groups were prepared by the reaction of acrylonitrile-grafted polymers with 3% hydroxylamine in a methanol- water mixture (1 : 1). Distribution of copper ions complexed with amid oxime groups at various adsorption times was obtained by electron-prob e X-ray microanalysis. The amidoxime groups are homogeneously distribu ted in the cross section of fibrous adsorbents. The fibrous adsorbents based upon polypropylene fiber of 40 mum showed a remarkable kinetic behavior for Cu2+. Even after 15 min, the adsorption capacity was 2.32 mmol CU2+ per gram of fiber. Also, the functionalization with hydroxy lamine was carried out at different conditions to compare the adsorpti on characteristics of the resultant adsorbents. Despite having superfi cially different properties (elemental microanalysis, ion-exchange cap acities, adsorption capacity for UO22+), the polypropylene-based fibro us adsorbents showed similar adsorption properties for uranium from se a water. The adsorption tests proved the performance of the polypropyl ene-based fibrous adsorbents as a promising material for uranium recov ery from sea water. In addition, uranium uptake of fibrous adsorbents increased in proportion to the volume of sea water.