Enrichment of uranium in seawater by glycine cross-linked graphene oxide membrane

Abstract

Extraction of uranium from seawater can satisfy the request for uranium in the field of sustainable nuclear power generation. However, direct extraction of uranium from seawater with traditional methods encounters many difficulties with reduced efficiency because of the extremely low uranium concentration. Based on the hydration diameter difference between uranium and the main coexisting ions (K+, Na+, Ca2+ and Mg2+), membrane separation technology is thought as an effective way to enrich uranium in seawater. Here, a new type of glycine (Gly) cross-linked graphene oxide (GO-Gly) membrane was fabricated, whose interlayer spacing (d) is very stable with uniform channel size satisfied the requirement for uranium enrichment. The respectively single ion rejection properties of uranium and the main coexisting ions in seawater revealed that ∼ 100% of uranium was rejected by the GO-Gly membrane. In addition, the excellent uranium rejection property of this membrane can be maintained in continuously filtrating the simulated seawater, only uranium ion was obviously enriched but the concentrations of the main coexisting ions kept nearly constant. The distinct rejection and enrichment properties of uranium ions by GO-Gly membrane made it an ideal candidate for uranium enrichment in seawater.