Preparation of a Polypyrrole/Graphene Oxide Composite Electrode by Electrochemical Codeposition for Capacitor Deionization

Abstract

In this paper, a polypyrrole/graphene oxide (PPy/GO) composite electrode, applied to the capacitive deionization process for removing heavy metal ions, was prepared by one-step electrochemical codeposition. The PPy/GO composite electrode has a dense sheet structure, and PPy is spherical and uniformly distributed on the surface of GO sheets. The experimental results show that the PPy/GO composite electrode has a higher capacitance (186.67 F/g) and a lower charge transfer resistance (1.626 ω·cm2) than the PPy electrode. The adsorption capacity of the PPy/GO composite electrode is 41.51 mg/g, which is about 2.67 times (15.52 mg/g) that of the PPy electrode. After five adsorption/desorption treatments, the adsorption capacity was maintained at about 98.0%, and the regeneration rate was 94.7%. Therefore, the electrode has good cycle stability and regenerability. In addition, the adsorption capacity of different metal ions follows the order Ag+ < Cd2+ < Cu2+ < Pb2+