Electrodeposited iodide ions imprinted polypyrrole@bismuth oxyiodide film for an electrochemically switched renewable extractor towards iodide ions

[Display omitted] Effective extraction and regeneration of radioactive iodide is one of urgent concerns for the safe utilization of nuclear energy. As a novel environmentally benign ion separation technique, electrochemically switched ion extraction (ESIE) process can be applied for effective capture and recovery of iodide ions (I−). Herein, a novel kelp seaweed-like core/shell I− imprinted polypyrrole@bismuth oxyiodide (PPy/I−@BiOI) composite film is successfully prepared for the selective I− capture in the ESIE system. It is found that the I− can be easily trapped in the PPy/I−@BiOI film after I− is in situ desorbed from the film by an electrochemical reduction process since it offers particular electroactive binding sites for I− extraction. The I− imprinted PPy/I−@BiOI film displays an extraction capacity as high as 325.2 mg·g−1 for I− with favorable stability. In particular, the extraction and desorption of I− is achieved by adjusting the redox potential and the pristine PPy/I−@BiOI film can be regenerated and reused for multiple times without decrease in extraction capacity. It is expected that such a PPy/I−@BiOI film would be useful as an electrochemically switched renewable extractor that could capture and regenerate I− from radioactive water.