Electrochemically triggered iodide-vacancy BiOI film for selective extraction of iodide ion from aqueous solutions

The effective extraction and regeneration of radioactive iodide remains an urgent concern for safe nuclear energy utilization. Herein, we developed a novel electrochemically triggered iodide-vacancy BiOI film, which exhibited excellent I- ion extraction capacity of 328.3 mg.g(-1). Especially, due to the ion vacancy trap effect, the film showed high selectivity towards I- ions in the existence of a large number of competitive anions. Additionally, the electrochemically switched ion extraction (ESIE) process with this iodide-vacancy BiOI film possessed fast extraction kinetics and high stability. More importantly, the trapped I(- )ions were easily desorbed from the film without the secondary pollution during the ESIE process and meanwhile, the iodide-vacancy BiOI film was able to be completely regenerated. It is expected that such an iodide-vacancy BiO film with ESIE could become a promising process for the selective extraction of I- ions from the radioactive water.