High Surfacial Positive Charge Density of Quaternary Ammonium Salt-Amidoxime Bifunctional Copolymers Promotes the Ultrafast Extraction of Uranium (Vi) from Seawater

Abstract

Uranium extraction from seawater is considered to be the most likely solution to future nuclear fuel shortages, but it faces some challenges. The development of adsorbent materials with high adsorption capacity and high adsorption rate is an urgent problem to be solved. In this work, three quaternary ammonium salt-amidoxime copolymers were synthesized by the one-step copolymerization method to improve the adsorption rate of the adsorbent materials, which can adsorb [UO2(CO3)3]4- ions directly. The zeta potential test shows that the copolymer surface carries a large number of positive charges. Based on the Coulomb attraction between positive and negative charges, the adsorbent has an ultra-fast adsorption rate of uranium (VI), and the adsorption equilibrium can be reached in 3 h. The results of adsorption experiments indicate that the adsorption rate showed an increasing and then decreasing trend with the change in quaternary ammonium salt content. Meanwhile, the adsorbent has good anti-fouling ability and cyclic stability, and the adsorption efficiency of uranium reaches 87% after 7 d adsorption in uranium-added seawater, which is a very potential material for uranium extraction from seawater.

Keywords: Uranium, Quaternary ammonium salt, seawater, ultrafast extraction