Ultra-high flexibility amidoximated ethylene acrylic acid copolymer film synthesized by the mixed melting method for uranium adsorption from simulated seawater

If U(VI) in seawater (unconventional uranium resource) can be extracted efficiently, it can provide important supplies and guarantees for the stable development of nuclear power. In this study, a mixing melting method without condensation agent was proposed to prepare ultra-high flexibility and different proportions DAMN modified EAA resin film (EAA-DAMN) through the condensation reaction between -COOH and -NH₂ and the uniform mixing of liquid EAA and DAMN. In addition, the dense film structure and -C[tbnd]N of EAA-DAMN were transformed into multiple pores structure and amidoxime groups of the amidoximated EAA (AO-EAA) by amidoxime reaction. The AO-EAA-3 showed the most excellent adsorption performance (q_e=146.40 mg g⁻¹) at pH = 5, which was 2.33 times that of EAA. Moreover, a hypothesis was proposed for the first time that -NH₂ in the material could combine with H⁺ ionized by water to form -NH₃⁺, and then adsorbed NO₃^- in the solution through electrostatic attraction, and O element from NO₃^- adsorbed on the surface and N-O from amidoxime groups of material as the adsorption active sites performed coordination with U(VI), thereby improving the adsorption performance of AO-EAA.