Experimental study on uranium extraction from seawater: 1- Surface improvement of polypropylene and polyethylene micro hollow fibers via the functional groups grafting by the electron beam irradiation

For the prevention of energy crisis after finishing the uranium earth sources, the study on the alternative sources is necessary and unavoidable. Seawater contains uranium about 1000 times more than that of the earth which is one of the most important sources. In the present work, at first, the free radicals were created on the polyethylene and polypropylene micro hollow fibers at very low temperatures via preirradiation electron beams by Rodotron accelerator and then, the acrylonitrile and methacrylic acid immediately were grafted on these fibers. To investigate the solvent and concentration effects, the grafting solutions were prepared with the different concentrations by DMSO and DMF solvents, and then, the radiated micro hollow fibers were immersed into them. The best grafting percentage was 90% corresponding to the polypropylene micro hollow fibers in the grafting solution with 60 to 40 for the monomer to solvent volume ratio. The nitrile groups were converted to the amidoxime groups by the hydroxylamine 10% within 72 hours at 80℃ By using the gravimetric method, the amidoximation degree was 80%. The grafting and amidoximation steps, and the surface morphology of fibers were characterized by FTIR spectroscopy and scanning electron microscopy respectively.