The feasibility of uranium extraction from seawater remains a challenge and relies on the development of an advanced adsorbent with high selectivity and loading capacity for the uranyl ion in seawater. Solid phase extraction based on polyolefin fibrous adsorbent with amidoxime (AO) functional group is considered to be the most commercially promising approach for uranium extraction from seawater due to its enough mechanical strength, high capacity and recyclability. In our study, several amidoxime-based fibrous adsorbents, such as UHMWPE, HDPE and PP, were prepared by radiation-induced graft copolymerization of acrylonitrile (AN) and acrylic acid (AA) and subsequent amidoximation reaction. Dependence of degree of grafting (DG) on absorbed dose, concentration and ratio of monomers, solvent, polymerization inhibitor, reaction temperature and time was investigated in order to optimize grafting process. The grafted fibers and fibrous adsorbents were characterized and tested by FT-IR, SEM, TEM, XRD and TGA. Mechanical and adsorption properties of the fibrous adsorbents were evaluated by single-filament strength test and adsorption test. High absorbed dose and monomer concentration are beneficial to the radiation grafting of monomer onto UHMWPE fiber. Dimethylformamide is a good solvent for grafting of AN on UHMWPE fiber. The copolymerization of monomers is effectively inhibited by mohr’s salt. Characteristic absorption peaks of nitrile and carboxyl groups appearing in FT-IR spectra indicate the grafting of AN and AA on the fibers. After amidoximation of the grafted fibers, nitrile group was converted to amidoxime group. The fibrous adsorbents were tested to evaluate their adsorption of uranyl ions in artificial seawater in laboratory as well as in ocean.<br/><br/>Figure.1 FT-IR spectra of (a) the non-grafted fibers, (b) the grafted fibers, and (c) the amidoxime-based fibrous adsorbents.<br/><br/>

Synthesis and properties of amidoxime-based fibrous adsorbents for extraction of uranium from seawater by radiation-induced graft polymerization

249th National Meeting (2015)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.