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

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.