Nano-sized architectural design of multi-activity graphene oxide (GO) by chemical post-decoration for efficient...

The introduction of organic groups onto graphene oxide (GO) platelets can supply additional active sites for adsorption of uranium(VI) (U(VI)) to improve the adsorption capacity. However, as a result of the existence of stabilizing π-conjugation system, a facile and effective modification method remains a challenge. Therefore, a novel strategy is exploited by nano-sized architectural design of multi-activity GO through post-decoration with amidoxime functionalized diaminomaleonitrile (DM-AO). The post-modification of DM-AO successfully activated the inert sites in GO platelets. Meanwhile, the amidoxime group in DM-AO can improve the adsorption selectivity. Adsorption amount of U(VI) on the as prepared GO-DM-AO reached at 935 mg g^-1, which is increased by 209% increment compared with that of pristine GO at the same concentration. The adsorption efficiency of GO-DM-AO is greatly improved, and the time to reach the adsorption equilibrium is half of that of GO. Excitingly, the excellent removal efficiency could still maintained even after 5 cycles of adsorption-desorption. The outstanding adsorption amount, short adsorption equilibrium time, and excellent removal efficiency can provide a theoretical guidance for further immobilization of U(VI) from seawater.