Preparation of an extractant-impregnated porous membrane for the high-speed separation of a metal ion

Asai, Shiho; Watanabe, Kazuo; Sugo, Takanobu*; Saito, Kyoichi*

The analysis of radioactive species in radioactive wastes is essential to the safe and economical disposal of such wastes. Among radioactive species, alpha- and beta-emitting nuclides should be purified prior to various radiometric determinations. To overcome the disadvantages of the conventional separation techniques, we have proposed functional porous hollow-fiber membranes that achieve a high speed operation assisted by convective flow. Stable immobilization in aqueous media is ensured by the hydrophobic interaction between the hydrophobic moiety of the extractant and octadecyl part of octadecylamino group. In this study, HDEHP, which shows the selectivity for rare earth elements, such as yttrium, was immobilized onto the porous membrane. The amount of immobilized HDEHP increased with increasing molar conversion. This can be explained by the fact that an increase in the CNH group allows the polymer brush to extend itself due to electrostatic repulsion originating from the amino part of the CNH group.