Posted by Developing a green and safe reversible iodine capture material is key for nuclear waste treatment. A readily obtainable β-CD-based polymer network (CDPN) that can reversibly capture iodine was reported. This white CDPN material is able to capture both gaseous iodine and liquid iodine, with a good iodine uptake capacity of 2.73 g/g. The I2 can be easily released from I2@CDPN by soaking it in methanol, achieving nearly complete release within 1 min. The CDPN powder exhibits good recyclability in its iodine capture performance.
Another study verified the effectiveness of superabsorbent polymer (SAP) and α-cyclodextrin as treatment agents to separate radioactive iodine from waste liquids [2]. Sodium iodide (Na125I) was added to purified water and artificial urine to prepare simulated waste liquids containing iodine equivalent to the urine of patients treated with radioactive iodine. The as-prepared simulated waste liquid was poured into a container with superabsorbent polymer and left for 90 d. The residual iodine rate in the simulated waste liquid was estimated by measuring 125I radioactivity. When the water was sufficiently dried, residual iodine rates on day 15 were 0.102 and 0.884 in the simulated waste liquids comprising purified water and artificial urine, respectively. The simulated waste liquid comprising purified water with 5% α-cyclodextrin absorbed by 1 g of superabsorbent polymer had a residual rate of 0.980. Moreover, the residual rate of simulated waste liquid comprising artificial urine with 2% α-cyclodextrin absorbed by 1 g of SAP was 0.949.
The idea of trapping iodine from nuclear waste by using cyclodextrin polymer is not a novelty. Szente et al. published promising results with cyclodextrin-epichlorohydrin polymer 25 years ago [3].
[1] Jin Wang, Leilei Shen, Lingli Cai, Haiyan Li, Xiaoqin Yang, Yuhan Zhang, Ziyi Zhang, Hua Zhang, Fan Yu, Yanqing Wang, Zhaoxia Li (2024) Recyclable β-CD-crosslinked porous polymer networks for iodine capture. Journal of Molecular Structure 1318(Part 2), 139427.
https://doi.org/10.1016/j.molstruc.2024.139427
[2] Hirota, Masahiro, Higaki, Shogo, Ishida, Yoshiyuki, Nakata, Daisuke, Terao, Keiji, Ito, Shigeki (2024) Feasibility of Treatment Agents in Radioactive Iodine Separation from Waste Liquids. Health Physics 127(3):365-372. | https://doi.org/10.1097/HP.0000000000001780, https://journals.lww.com/health-physics/abstract/2024/09000/feasibility_of_treatment_agents_in_radioactive.1.aspx
[3] Lajos Szente, Éva Fenyvesi, József Szejtli (1999) Entrapment of Iodine with Cyclodextrins: Potential Application of Cyclodextrins in Nuclear Waste Management. Environ. Sci. Technol. 1999, 33, 24, 4495–4498. https://doi.org/10.1021/es981287r