ZIF-8 modified graphene oxide/sodium alginate 3D elastic spheres for uranium trapping in seawater

Abstract

Due to the popularization of nuclear energy and the application of nuclear technology, there is an increasing demand for uranium resources. Extraction of uranium from seawater has become a hot topic. To achieve uranium capture, a three-dimensional carbon structure material (GO/ZIF-8@SA) with ionic stress elastic expansion consisting of graphene oxide, ZIF-8 and sodium alginate was developed. Surface morphological characteristics and elemental composition evaluation were determined by using SEM. The doping concentration of the elements in the synthesized products was measured by EDS. XRD, FT-IR and XPS confirmed the successful doping of ZIF-8. In seawater spiked with uranium, GO/ZIF-8@SA showed not only an ultra-high adsorption capacity of 1897 mg·g−1 for U(VI), but also a high selectivity. Interestingly, the volume of GO/ZIF-8@SA can be elastically expanded with the adsorption of U(VI). The expanded microspheres can be directly captured from the seawater by the mesh sieve. GO/ZIF-8@SA solves the problem of balancing adsorption capacity and selectivity in a complex seawater environment, which gives it great potential for application in seawater uranium extraction.