Graphene fiber for radioactive iodine adsorption and the effect of silver functionalization

Iodine-129 is a primary concern in reprocessing plant due to its very long half-life of 1.6x10⁷ y as well as high mobility and volatile contaminant which bio accumulates concentrating in the thyroid gland affecting bio metabolism. For this reason, the Environmental Protection Agency (EPA) has implemented strict regulations on the release of ¹²⁹I from the reprocessing facilities, which require an effective capture efficiency in excess of 99% (decontamination factor > 167). Due to the large theoretical specific surface area (2630 m² g^-1) for a single layer graphene, in combination with its highly controllable defects and functional group concentration, interest has grown on the use of graphene as a sorbents material for gasses, though primarily for potential gas detectors. Besides this graphene-based nanomaterials such as graphene powders and aerogels that have high adsorption capacities for iodine (~50 mass%) This work presents the graphene fiber as potential sorbents for 129I in spent nuclear fuel reprocessing offgas and will investigate the sorption capacity of graphene fiber for I₂(g) in a saturated iodine environment. The fabrication process of graphene fiber is provided in addition to analysis of the sorption capacity and thermal stability of the iodine loaded samples. Silver(Ag) functionalized graphene fiber may also show good adsorption characteristics by the chemisorption of iodine whereas physisorption occurred in the graphene fiber. This functionalization may also enable the graphene fiber for the high temperature adsorption application.