Novel bismuth-based electrospinning materials for highly efficient capture of radioiodine

Radioiodine is one of the main fission products in the nuclear industry. Due to its strong volatility and radiotoxicity, it must be filtered and purified before being released into the environment. In this work, we reported three novel bismuth-based iodine sorption materials coated with Bi and/or Bi2O3 on the surface of electrospinning carbon nanofibers (HT-Bi2O3-ESCNF, HT-Bi-Bi2O3-ESCNF and HT-Bi-ESCNF). These materials were obtained by adding a hydrothermal step on the basis of electrospinning, pre-oxidation and carbonization process. The benefit of hydrothermal load was that active sites appeared on the outer surface of the fiber, making the contact with iodine gas more convenient and effective, and was no longer restricted by the concentration of Bi3+ in the solution like before. Finally, iodine capture tests were also conducted on these three sorbents and the property changes were investigated before and after iodine exposure. The results showed that the coating on the surface of the fiber did greatly improve the iodine capture capacity, and elemental bismuth had a greater effective atomic utilization rate of iodine than bismuth oxide, whose sorption capacity reached a record high of 732 mg/g among all the bismuth-based sorbents. The capture mechanism was thoroughly elucidated by a combination of PXRD, SEM, TEM, BET, XPS, Raman spectra and TGA characterizations.