An unparalleled wet spinning polyacrylonitrile/polyamidoxime fibers for multi-concentration U(VI) adsorption and elution

In the treatment of wastewater containing uranium, the adsorption capacity, reusability, and industrial application of materials have traditionally been the primary areas of attention. In this work, the mixed solutions of unmodified polyacrylonitrile and polyacrylonitrile modified by hydroxylamine hydrochloride were innovatively wet spun to obtain polyacrylonitrile/polyamidoxime (PAN/PAO) fibers. The fibers had been successfully mass-produced to meet industrial demand and had a maximum adsorption capacity of 100.2 mg·g−1. The pseudo-second-order kinetic, intraparticle diffusion, liquid film diffusion, and Langmuir models can well explain the kinetics and thermodynamic process of adsorption. Furthermore, a variety of eluents such as nitric acid and tartaric acid had an excellent elution effect on PAN/PAO fibers. And the U elution rate could still reach >90 % after six adsorption-elution cycles. The PAN/PAO fibers exhibited a high removal rate of U(VI) in the presence of other coexisting cations, with a value of 95.5 %. In addition, the waste liquid produced by a fuel component factory with 270 μg·L−1 could be reduced to below 10 μg·L−1 using PAN/PAO fibers at a flow rate of 10 L·h−1 for 80 h at all times. This work presents a novel strategy for treating low-concentration wastewater containing uranium.