Selective Adsorption of Uranium(VI) on U(VI) Ion-Imprinted Chitosan Composite Magnetic Microsphers

To find an effective method for uranium(VI) adsorption, uranium(VI) ion-imprinted chitosan composite magnetic microsphers (U(VI)-ICCMM) were synthesized using uranium(VI) as template, chitosan as functional monomer, epichlorohydrin and glutaraldehyde as crosslinking agents. Magnetic chitosan microsphers (MCM) were synthesized without U(VI) ion-imprinted as control. Experiments were conducted in a batch system. As compared with MCM, the adsorption capacity of U(VI)-ICCMM increased 8.6 mg·g^-1 in 30 minutes at pH 3.5 when the initial concentration of U(VI) was 100 mg·l^-1, and the percentage removal of U(VI) by U(VI)-ICCMM can reached 99.71% when the dosage of the adsorbent was 5.0 g·l^-1. Competitive adsorption of multi-ions studies indicated that U(VI)-ICCMM had a high single selectivity for U(VI). The order of metal ion affinity in the competitive conditions was U(VI) >; Cr(VI) >; Mn(II) >; Ca(II). The experimental results showed that U(VT) ICCMM was an effective adsorbent to adsorb U(VI), and it can be separated in a convenient way under a magnetic field, moreover, it could be reused in an easy way and the adsorption capacity of U(VI)-ICCMM didn´t decrease clearly even after six times regeneration.