The earth’s seawater contains over 4.5 billion metric tons of dissolved uranium, which is approximately 1000 times larger than the amount of uranium in terrestrial ores. Nuclear plants utilize uranium for their fuel and the average lifetime of nuclear plants is ~60 years. Thus, a steady source of uranium is needed to sustain the nuclear fuel feeds. Recovery of uranium from seawater is considered as an attractive solution to supply nuclear fuel feeds in future. However, the presence of a variety of competing metal ions and the low concentration of uranium (~3 ppb) in seawater make the extraction of uranium from seawater challenging. The goal of this work is to design, synthesize, and functionalize novel adsorbent fibers that can recover uranium from the slightly alkaline (pH 8.0 – 8.3) seawater. At first, the fibers are prepared using two different grafting processes. In the first process, radiation-induced graft polymerization (RIGP) is used where fibers are prepared by irradiating and treating polyethylene (PE) with different bulk ratios of vinyl benzyl chloride (VBC) and methacrylic acid (MAA) or itaconic acid. The second process involves graft polymerization of glycidyl methacrylate (GMA) to a halide-functionalized fiber using atom-transfer radical polymerization technique. The degree of grafting is controlled by varying reaction time. Chemical modifications of these fibers prepared via two separate processes are performed where novel ligands are incorporated into fibers. These ligands contain imidedioxime, which is known to be a good uranium-philic functionality. Also, the core structures of these ligands containing two binding sites facilitate the formation of chelates with uranyl ion under seawater conditions. Once synthesized, these ligands are incorporated into fibers employing azide alkyne cycloaddition reaction. These imidedioxime-containing functionalized fibers show moderate to high uranium adsorption capacities. Various parameters that affect the uranium adsorption capacity will be discussed in this presentation.<br/><br/>Acknowledgement: This work was sponsored by the US Department of Energy, Office of Nuclear Energy, under contract DE-AC05-00OR22725 with Oak Ridge National Laboratory, managed by UT-Battelle, LLC.

Fiber functionalization via novel ligand for uranium recovery from seawater

249th National Meeting (2015)

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