Facile preparation of Ce enhanced vinyl-functionalized silica aerogel-like monoliths for selective separation of radioactive thorium from monazite

Thorium (Th) is an associated ore of rare earth metals that is radioactive and harmful to the environment, but it is also a potential nuclear fuel replacement for uranium. The separation of Th from rare earth elements (REEs) is of great importance in environmental governance and clean-energy development. In this work, a monolithic cerium (Ce) doped silica aerogel-like with flexibility was synthesized using a low consumption and rapid technique, and it was used in a continuous solid-phase extraction as an adsorbent for the selective separation of Th/REEs. The batch adsorption experiments showed that the adsorption efficiency of Th(IV) can be up to 96% when abnormally high levels of metal ions (20 ppm) exist. Under the same conditions, the adsorption efficiency of REEs is at a near-zero level, which demonstrates the great selective separation of Th/REEs for the aerogel-like. The results also indicated that Th(IV) could desorb from the adsorbent in weak acidic media, which is friendly to the environment. Therefore, the material has application prospects for the separation of Th/REEs and removal of radioactive contamination from the environment. Keywords: Silica aerogel-like monoliths, Selective adsorption, Rare earth, Thorium, Monazite