Author/Authors :
Benali, O. Univesrity Dr Moulay Tahar - Faculty of Sciences and Technology - Department of Biology, Algeria , Benmehdi, H. University of Bechar - Department of Engineering Procedures, Algeria , Hasnaoui, O. Univesrity Dr Moulay Tahar - Faculty of Sciences and Technology - Department of Biology, Algeria , Selles, C. University of Tlemcen - Laboratory of LASNABIO, Department of Chemistry, Algeria , Salghi, R. Université Ibn Zohr - ENSA - Equipe de Génie de l’Environnement et de Biotechnologie, Morocco
Abstract :
The corrosion and inhibition behaviors of mild steel in sulfuric acid + 5% EtOH in the presence of tannin extract of Chamaerops humilis plant (LF-Ch) and potassium iodide (KI) have been studied using the electrochemical methods. It was found that the inhibition efficiency increased with LF-Ch extract concentration. The addition of potassium iodide to LF-Ch extract in solution increased the inhibition efficiency of this latter. A synergistic effect was observed between KI and extract with optimum of concentration of 100 mg /L LF-Ch extract + 0.025% potassium iodide. Adsorption of extract alone or in combination with potassium iodide on the metal surface obeyed the Langmuir adsorption isotherm and thermodynamic calculations revealed that the adsorption of inhibitor were of chemical nature. That suggest the presence of iodide ions in solution increases the surface coverage. The adsorption of LF-Ch extract on the mild steel in aggressive medium leads to the formation of a protective film which grows in thickness and effectiveness with increasing exposure time
Keywords :
Mild steel , corrosion test , electromechanical techniques , adsorption , synergistic effect
