Millimeter-sized Bi2S3@polyacrylonitrile hybrid beads for highly efficient iodine capture

Abstract

Iodine (I₂) capture and storage is very important in many industrial practices. Herein, we demonstrate strong iodine (I₂) adsorption using millimeter-sized spherical bismuth sulfide@polyacrylonitrile (Bi₂S₃@PAN) hybrid beads. Our findings showed that the iodine capture capacity of Bi₂S₃@PAN was 986 mg g⁻¹, which could reach approximately 4.0-fold that of commercial silver-exchanged zeolite (AgZ). Besides maintaining the crystallinity of the embedded Bi₂S₃ powder in the polyacrylonitrile matrix, the hybrid beads exhibited high capacity and a fast I₂ absorption rate. Through characterization, we revealed that the adsorption of iodine on Bi₂S₃@PAN was mainly chemical adsorption (the formation of thermodynamically stable BiI₃). Overall, the merits of the cost-effective process, capability of achieving scale-up of preparation, and the good performance in iodine capture suggest that Bi₂S₃@PAN may be considered as a promising candidate for the removal of radioactive iodine from reprocessing plant off-gas streams.