Active ion-exchangeable Bi2O(OH)2SO4 synthesized by ball milling for effective iodine enrichment: Insight into the pathway

Effective capture of radioactive iodine and iodine enrichment from dilute source are highly desirable but still remain as significant challenges. Based on mechanochemical activation of Bi oxide (Bi2O3) toward iodine incorporation by forming BiOI, we report a new approach to functionalize Bi2O3 with several anion groups just by simply co-milling with Bi sulfate. Several analytical methods were used to characterize the reaction products and its high efficiency for iodine enrichment inside. Compared with activation just for α-Bi2O3 itself, formation of Bi2O(OH)2SO4 was confirmed to allow a tremendous increase in adsorption capacity up to 335.57 mg/g towards iodine with the product, due to effect by ion-exchange with three anion groups (SO42−, CO32−, OH−) to form BiOI with a stable structure of Bi-O layer, demonstrating obvious advantages as a newly developed typical anionic adsorbent. Iodine can be recovered by heating BiOI to give back Bi2O3 for recycling. As a cost-effective and environmental-friendly process to produce an efficient material for iodine enrichment, this research may open a promising way to effectively remove radioactive iodine and recover iodine resources.