Uranium removal from seawater by means of polyamide 6 fibers directly grafted with diallyl oxalate through a single-step, solvent-free irradiation process
Travis C. Dietz, Claire E. Tomaszewski, Zois Tsinas, Dianne L. Poster, Aaron Barkatt, Mohammad Adel-Hadadi, Fred B. Bateman, Lonnie T. Cumberland, Erich Schneider, Karen Gaskell, Jay LaVerne, Mohamad Al-Sheikhly
To test the effectiveness of oxalate-based polymeric adsorbents in the recovery of uranium from seawater, diallyl oxalate (DAOx) was grafted onto polyamide 6 fabrics by exposing the fabric, immersed in pure liquid DAOx or in a surfactant stabilized dispersion of DAOx in water, to electron beam or γ radiation. After the fabrics were dried and weighed to determine the degree of grafting (DoG), the presence of oxalate in the fabrics was verified using XPS. Zeta potential measurements showed the fabric surfaces to be negatively charged. The fabrics were tested by rotating them for 7 days in a rotary agitator with actual seawater spiked with 0.2 or 1.0 mg·L−1 uranium. The fraction of uranium in the solution which was removed due to uptake on the fabrics was found to rise with increasing DoG at both uranium concentrations. EDS measurements were used to map the distribution of adsorbed uranium on the polymeric fibers.