Superhydrophilic Amidoxime-Modified Poly(vinyl alcohol) Fibers for Enhanced Uranium Extraction from Seawater

The efficient extraction of uranium from seawater is an important step in the sustainable development of nuclear energy. Polymer-based absorbents are considered to be ideal materials due to their high adsorption properties and industrialization feasibility. Their adsorption performance could be further improved by enlarging the specific surface area and enhancing hydrophilicity. Here, an amidoxime-modified poly(vinyl alcohol) fiber (PVA-<i>g</i>-PAO) with a high specific surface area and superhydrophilicity was prepared by a one-step grafting method. The hydrophilicity was conducive to the infiltration of ions into the adsorbent, and the pore structure constructed by grafting an adsorption functional layer on the surface of fibers increased the specific surface area. The adsorption capacity of PVA-<i>g</i>-PAO can be arrived at 11.3 mg/g in simulated seawater (uranium concentration: 330 ppb) with a high adsorption selectivity of uranium. Furthermore, more than 95% of uranium in a 5 ppm uranium solution can be adsorbed within 6 days, indicating the fast adsorption ability of PVA-<i>g</i>-PAO, which is further confirmed by the fast adsorption capacity in natural seawater (3.37 mg/g for 30 days). Such PVA-<i>g</i>-PAO gel fiber adsorbents with superhydrophilicity and high specific surface area are promising adsorbents for uranium extraction from natural seawater.