Electrospun PAN-Based Carbon Nanofibers for Aqueous Boron Recovery.

Designed for the recovery of aqueous boron, a critical element with various industrial applications, the use of carbon fibers as an effective adsorbent for boron in aqueous solutions was explored, and the changes in carbon fibers were investigated during repeated boron adsorption and desorption. In this research, prepared PAN fibers by electrospinning were carbonized into nitrogen-doped carbon fibers. The resulting fiber mats undergo boron adsorption in boric acid solution and subsequent regeneration in HCl solution, and these processes repeat multiple times to assess the reusability of carbon fibers. SEM analysis confirmed the successful electrospinning of PAN fibers and their carbonized ones, while EDS and XPS analyses determined the presence of doped nitrogen on the graphene-like surface and the consequential effective boron adsorption. Then ICP-OES showed that the boron adsorption was completed within ~ 1 h to an equilibrium capacity even at room temperature, and the capacity increased with the regeneration of fibers, also confirmed by SEM and BET analyses in that the specific surface area increased along with the physical breakage and shattering of fibers during regeneration. In conclusion, the carbon fibers proposed in this study are applicable for aqueous boron recovery with their operative reusability. [ABSTRACT FROM AUTHOR]