Efficient uranium adsorbent prepared by grafting amidoxime groups on dopamine modified graphene oxide

In this study, a novel amidoxime functionalized graphene oxide adsorbent (GO-D-AO), based on the reaction of dopamine modified graphene oxide with acrylamide diacetonitrile and on the reaction of amidoximation, was successfully designed and prepared to effectively adsorb U(VI) ions. GO-D-AO was characterized by SEM , FT-IR, XRD and XPS techniques, and then applied as the adsorbent for the U(VI) adsorption. The GO-D-AO contained more amidoximation groups after the amidoximation modification due to the use of acrylamide diacetonitrile modifier. A series of adsorption experiments were carried out to investigate the influence factors in the adsorption process , including the pH values, contact time, temperature and initial concentration of U(VI) solution. The U(VI) maximum adsorption capacity of GO-D-AO was 1823.6 mg·g -1 , which was significantly higher than that of GO because of the excellent chelating ability of amidoxime group with U(VI) ions. And the U(VI) adsorption process of GO-D-AO fitted well with the Langmuir model and the pseudo-second-order kinetic model , indicating the adsorption process was monolayer and chemical adsorption .