Graphene-polypyrrole nanocomposite as a highly efficient and low cost electrically switched ion exchanger for removing ClO₄^- from wastewater

Perchlorate (ClO₄^-) contamination is a widespread concern affecting water utilities. In the present study, functionalized graphene sheets were employed as the scaffold to synthesize a novel graphene-polypyrrole (Ppy) nanocomposite, which served as an excellent electrically switched ion exchanger for perchlorate removal. Scanning electron microscopy and electrochemical measurements showed that the 3D nanostructured graphene-Ppy nanocomposite exhibited a significantly improved uptake capacity for ClO ₄^- compared with Ppy film alone. X-ray photoelectron spectroscopy confirmed the uptake and release process of ClO₄ ^- in graphene-Ppy nanocomposite. In addition, the presence of graphene substrate resulted in high stability of graphene-Ppy nanocomposite during potential cycling. The present work provides a promising method for large scale water treatment.