Abstract
The effect of extract of cannabis plant on the corrosion of copper in aqueous 0.5M sulphuric acid was investigated by electrochemical impedance spectroscopy (EIS), potentiodynamic polarization, weight loss and optical micrograph techniques. EIS and polarization measurements showed that the dissolution process of copper occurs under diffusion control. Potentiodynamic polarization curves indicated that the plant extract behaves as cathodic-type inhibitor. The corrosion rates of copper and the inhibition efficiencies of the extract were calculated. The results obtained show that the extract solution of the plant could serve as an effective inhibitor for the corrosion of copper in sulphuric acid media. Theoretical fitting of different isotherms, Langmuir, Flory-Huggins, and the kinetic-thermodynamic model, were tested to clarify the nature of adsorption.