Synthesis of bifunctional copolymeric nanofibers with selective extracting U(VI) from the solution and antibacterial property

Abstract

Facing the problem of future nuclear fuel shortage, developing high-performance adsorbent materials is key. In this work, the amidoxime group/imidazole functionalized ionic liquid copolymer fibers containing bromide salts, and fluoroborate salts (namely P(AO/VEIMBr)8 and P(AO/VEIMBF4)6) were prepared by a one-pot method and free radical polymerization, hydroxyl amination reaction and electrostatic spinning, and characterized by SEM, FT-IR, and 1 H NMR. The influence of solid-liquid ratio, ionic strength, and adsorption time on the adsorption performance was investigated by batch adsorption experiments. In the meanwhile, the adsorption kinetics and thermodynamic processes of U(VI) on the copolymer fibers was also studied. Adsorption mechanism of U (VI) on polymer fibers was explored by XPS spectroscopic analysis combined with DFT method. Finally, the antimicrobial properties of the copolymer fibers were tested. The experimental results showed that the polymer nanofibers synthesized for U(VI) has a fast adsorption, high adsorption capacity at ionic strength close to seawater, and excellent reusability. The adsorption process conformed to the pseudo-second-order kinetic model and Langmuir model, which indicated that chemical adsorption and monolayer adsorption are dominant for adsorption U(VI) on the polymer nanofibers, and exhibits the highest Uranium adsorption capacity (76.92 mg/g and 81.96 mg/g at pH=8.1+0.1, respectively). XPS result showed the amine nitrogen and oxime oxygen in the amidoxime functional group were coordinated with uranyl(VI) ions. The antibacterial experiments showed that the copolymer fibers have antimicrobial properties and the antibacterial rate is over 90 %. Therefore, the nanofibers may be a promising material for extracting uranium from the weak alkaline wastewater or seawater.