Synthesis of magnetic ion-imprinted composites and selective separation and preconcentration of U(VI).

The U(VI) magnetic ion-imprinted composite (MIIC) with a uniform core-shell structure for the selective separation and preconcentration of U(VI) was prepared by copolymerization of a ternary complex of uranyl ions with 4-vinylpyridine (4-VP) and acrylamide in the presence of 2,2'-azobisisobutyronitrile. The sorption of U(VI) on the MIIC from aqueous solution was evaluated. The maximum sorption capacity of MIIC for U(VI) was 354.85 mg g(-1), which was much higher than that of the magnetic nonimprinted composite. The MIIC could be recovered by desorbing the U(VI)-loaded MIIC with 0.5 mol L(-1) HNO3, and the surface morphology of MIIC after five consecutive sorption/desorption cycles was significantly damaged. The competitive sorption experiments showed that the MIIC had a desirable selectivity for U(VI) over a range of competing metal ions. The MIIC may be a promising sorbent material for the selective separation and preconcentration of U(VI).