Effect of Temperature on Inhibitive Action of Damsissa Extract on the Corrosion of Steel in Acidic Media

The inhibitive effect of damsissa (Ambrosia maritime, L.) plant extracts on the corrosion of steel in an aqueous solution of 1 M sulfuric acid (H₂SO₄) was investigated in the temperature range from 25°C to 40°C using potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) techniques. The stability of the inhibition efficiency of damsissa extracts with immersion time was examined by weight-loss measurements at 30°C and 60°C. Potentiodynamic polarization curves indicated that the damsissa extract behaves as a mixed-type inhibitor. EIS measurements showed that the dissolution process occurs under activation control. The corrosion rates of steel and the inhibition efficiencies of the extract obtained from impedance and polarization measurements were in good agreement. Inhibition was found to increase with an increasing concentration of the plant extract but decreases with increasing temperature. The results obtained show that the damsissa extract could serve as an effective inhibitor for the corrosion of steel in H₂SO₄ media. The inhibitive actions of damsissa extract are discussed on the basis of the adsorption of molecules on the electrode surface through the active centers. The theoretical fitting of different isotherms, Langmuir, Frumkin, Flory-Huggins, and the kinetic-thermodynamic model, were tested to clarify the nature of adsorption. The associated activation parameters were determined and discussed.