Electrochemical preparation of graphene from waste battery-electrodes directed to organic dyes removal in aqueous solution

In this research, we present a new method for preparation of graphene from waste zinc carbon battery (ZCB) electrodes using electrochemically exfoliation via a intercalating of sulfate ions into the graphitic layers at different D.C. voltages and optimized conditions (i.e., electrolyte medium and applied voltage). The synthesized graphene was characterized by X-ray diffraction (XRD), Raman spectroscopy and Scanning/Transmission electron microcopy (SEM/TEM). The synthesized graphene has been used as the adsorbents for efficient removal of methylene blue (MB) as a cationic dye from aqueous solutions to test their qualities. Results shown that the equilibrium adsorption capacity (qe) of prepared graphene samples are from 92.32 mg.g-1 to 99.73 mg.g-1 which are extremly higher than that of the pristine waste graphite electrode (5.03 mg.g-1) or powdered  waste electrode graphite (40.05 mg.g-1). These obtaned results indicated that the graphene can be produced from waste graphite electrodes by electrochemical method, which can be considered as an eco-friendly method not only for production of quality graphene but also for reuse of waste graphite electrodes.