Abstract

The effective removal of nuclear waste from fission has attracted significant attention, with numerous porous sorbents reported in recent decades. The practical application of current sorbents is often hindered by limited removal efficiency and low production scalability. Here, we developed activated carbon fibers (ACFs) as an ultrafast and effective iodine capture material using a scalable method. The engineered ACFs possess and extraordinary micro/mesoporous structure with a surface area exceeding 2900 m2 g−1 while maintaining mechanical and thermal stability. The resulting fibers demonstrate a superior iodine capture capacity of 3.10 g g−1 and a capture rate of 2.76 g g−1 h−1. To further augment these properties, a novel oxygen-doping strategy was implemented. This approach dramatically improves performance, achieving 51% higher capacity (4.68 g g−1) and 76% faster rate (4.86 g g−1 h−1). Notably, exfoliation reactions of iodine within carbon layers that induced structural changes were discovered. Our work underlines the promise of ACFs for nuclear waste management.

A joint research team, led by Professors Han Gi Chae and Seung Geol Lee from the Department of Materials Science and Engineering at UNIST has unveiled a novel, ultra-porous carbon fiber capable of quickly capturing

radioactive iodine gases—a critical challenge in nuclear waste treatment and environmental safety. This scalable material demonstrates exceptional adsorption capacity and speed, with potential applications in nuclear facilities and emergency response.

The engineered carbon fibers feature an extraordinary surface area exceeding 2,980 m² per gram, thanks to a manufacturing process that creates diverse pore sizes and incorporates oxygen doping. This structure enables the fibers to adsorb up to 4.68 grams of iodine per gram—over 1.5 times higher than conventional materials—and reach saturation within approximately 100 minutes. The oxygen doping enhances the chemical interaction with iodine, further boosting performance by 51% in capacity and 76% in adsorption rate. Additionally, the fibers maintain over 90% of their initial capacity after multiple reuse cycles, supporting cost-effective, large-scale deployment.

The fabrication process is straightforward and cost-efficient, avoiding complex shaping steps typical of other materials like metal-organic frameworks (MOFs), making mass production feasible.

Professor Han Gi Chae explains, “Our findings reveal the dynamic structural changes during iodine adsorption, providing new insights into how porous carbon materials interact with hazardous gases. This advancement could revolutionize safety measures in nuclear waste management and environmental remediation.”

This innovative material offers a practical, scalable solution for rapid iodine removal, essential for nuclear safety and environmental protection. Its ease of production and reusability pave the way for widespread application in nuclear facilities, accident response systems, and pollutant treatment.

The findings of this research have been published in Chemical Engineering Journal on April 1, 2026. The study has been supported by the Ministry of Trade, Industry and Energy (MOTIE), the Korea Planning & Evaluation Institute of Industrial Technology (KEIT), and the Ministry of Science and ICT (MSIT).

Journal Reference

Changbeom Jeon, Hyejin Lee, Ga-Hyeun Lee, et al., "Simple oxygen doping strategy for highly porous carbon fibers enabling ultrafast and efficient iodine capture," Chem. Eng. J., (2026).