Preparation and performance of amidoxime fiber adsorbents for recovery of uranium from seawater

Abstract

This paper reports on commercial acrylonitrile fibers of different shapes that were treated in a 1.5 or 3.0 wt.% NH{sub 2}OH methanolic solution at 80{degrees}C and then a 0.1 mol {center dot} L{sup {minus}1} NaOH aqueous solution at 30 or 80{degrees}C. The treatment was performed for various reaction periods. The intrinsic rate of adsorption of uranium from seawater using the amidoxime fibers became maximum at a certain reaction time for the NH{sub 2}OH treatment as well as the NaOH treatment and was in the range of 200-600 mg per kilogram of dry fiber per day for the first adsorption run. The adsorption rate of the optimized fibers was decreased by repeating the adsorption and desorption cycle, while that of the fibers whose NaOH treatment was not sufficient was nearly constant in spite of such repetition. The tensile strength of the adsorption fibers decreased with increasing NaOH treatment period.