Advanced Amidoximated Polyethylene Nanofibrous Membranes for Practical Uranium Extraction from Seawater

As the key material of the adsorption method used for practical uranium extraction from seawater, the adsorbent should have a high uranium adsorption capacity and long service life. Polyethylene nanofibrous membranes (PENFMs) using a one-step grafting strategy to prepare scalable membrane adsorbents are reported with supreme uranium uptake capacity and long service life. A series of amidoximated polyethylene nanofibrous membrane (called amidoximated membrane or AM) adsorbent materials with different degrees of grafting (DGs) are modified by one-step radiation-induced graft polymerization (RIGP) of acrylonitrile (AN) and acrylic acid (AA) and an amidoximation reaction. The AM adsorbents prepared from the PENFM show outstanding hydrophilicity, good adsorption capacity, and excellent affinity for uranium. The highest uranium uptake capacity of AM adsorbents is 115.32 mg/g in simulated seawater for 24 h and 6.03 mg/g in natural seawater for 10 weeks. The AM adsorbents are reusable for more than 10 cycles of continuous adsorption–desorption–regeneration tests, showing the long service life. In addition, the AM adsorbent adsorption results in natural seawater indicate that only prolonging time to pursue high adsorption capacity is not conducive to the acquisition of benefits. The AM adsorbents have broad potential application in the industrialization of uranium extraction from seawater by choosing the best adsorption efficiency to achieve high adsorption amount.