An electroactive ion exchange hybrid film with collaboratively-driven ability for electrochemically-mediated selective extraction of chloride ions

The development of selective separation materials with large capacity and high selectivity has always been a research hotspot in the field of water remediation. In this study, an electroactive ion exchange hybrid film of bismuth oxychloride/chloride ion-imprinted polypyrrole (BiOCl/PPy-Cl) with core-shell nanosheet structure was successfully fabricated by a chemical oxidation method for selective extraction of chloride ions. Herein, the BiOCl/PPy-Cl hybrid film possessed superior conductivity due to the incorporation of the conductive polymer. Furthermore, the hybrid film could more quickly and effectively extract Cl- compared with BiOCl and PPy-Cl, and its uptake capacity reached as high as 80.81 mg.g(-1) at the optimal potential of 0.6 V. Meanwhile, based on the screening effect brought by the outer PPy-Cl shell, the hybrid film displayed prominent selectivity toward Cl- even in the presence of other competing species. In addition, the hybrid film maintained steady adsorption capacity in 10 cycles as well as under different acid-base environments. The outstanding Cl- uptake performance of the hybrid film was primarily ascribed to the open interlayer structure of BiOCl and the collaboratively-driven force generated by the reversible electrochemical redox of BiOCl and PPy. It is expected that the obtained BiOCl/PPy-Cl hybrid film could be a promising alternative for the extraction of Cl- from wastewater.