Polyamine and amidoxime groups modified bifunctional polyacrylonitrile-based ion exchange fibers for highly efficient extraction of U(VI) from real uranium mine water

It is of great significance to develop an adsorbent with high adsorption capacity and outstanding cyclic regeneration performance toward the extraction of U(VI). Herein, novel polyamine and amidoxime groups modified bifunctional polyacrylonitrile-based ion exchange fiber (PAN-P-A) has been successfully synthesized by hydrothermal method for highly efficient extraction of U(VI) from aqueous solution. The structure, morphology and property of fibers are characterized by Fourier transform infrared spectrum, scanning electron microscopy and thermogravimetric analysis techniques. Compared with raw polyacrylonitrile fiber, the thermal stability of PAN-P-A is enhanced. In addition, the results of batch experiments reveal that PAN-P-A possesses favorable adsorption capacity (200.1 mg g(-1) q(max) at pH = 5) to U(VI) in uranium-containing wastewater, attributed to the chelation between polyamine/amidoxime groups and uranium ions. More importantly, PAN-P-A exhibits higher removal efficiency (99.8%) and distribution coefficient (1779 mL g(-1)) to U(VI) than those of other coexisting ions in real uranium mine water. The adsorption capacity and desorption efficiency of PAN-P-A have a slight decrease after eight times cyclic regeneration experiment, indicating an excellent regeneration performance of PAN-P-A. Furthermore, the thermodynamic parameters demonstrate that the adsorption of PAN-P-A to U(VI) is a spontaneous and exothermic process. The adsorption process conforms to Langmuir isothermal model and pseudo-second-order kinetics model. The results indicate that PAN-P-A is a promising adsorbent to effectively extract U(VI) from real uranium mine water.