Polyamidoxime nanofiber membranes with hierarchical pores for enhanced uranium extraction from seawater

Herein, we have successfully fabricated hierarchically porous polyamidoxime nanofibers (PAO-PNF) for capturing uranium from seawater via the combinations of electrospinning and non-solvent induced phase separation. The hierarchical structures of PAO-PNF greatly enhanced specific surface areas and hydrophilicity, which greatly reduces the mass transfer resistance inside the fibers and increases adsorption sites. In addition, the hierarchical structures could achieve more sufficient amidoximation reactions, resulting in higher grafting densities of amidoxime groups. The hierarchical structures can effectively improve the adsorption capacity, which is increased by 78.9% compared with non-porous PAO nanofibers. In addition, the PAO-PNF can regenerate and reuse more than six adsorption-desorption cycles, which have great potential in the fields of uranium extraction.