MODELING OF AN ADSORPTION UNIT PACKED WITH AMIDOXIME FIBER BALLS FOR THE RECOVERY OF URANIUM FROM SEAWATER

Amidoxime fiber adsorbents are prepared by treating commercial poly(acrylonitrile) fibers with NH2OH in methanol and then with an aqueous NaOH solution. The rate of adsorption of uranium from seawater is 0.1-0.3 (g of U/kg of dry fiber)/day. The fiber is placed in 2-cm-diameter spherical shells of plastic net, and these fibrous balls are packed in a column. Seawater is assumed to flow through the packed bed by the kinetic force of the ocean current. The permeation velocity of liquid in each ball is evaluated with a small electrode that detects the electrochemical limiting current. When the permeation velocity is slow, most uranyl ions are adsorbed only in the peripheral part of the ball. A model of the packed bed adsorption unit is proposed, and a numerical calculation gives optimum values of design parameters.