Etude phytochimique et évaluation de l'activité anti-corrosive de l’extrait de feuilles d'Olea europaea L. : Application à l’inhibition de l’acier en milieu NaCl 3%

Abstract

The aim of this work is to study the action of olive leaf extract (EFO) as a green inhibitor against corrosion of steel in pure and commercial NaCl medium (3%). The analysis of olive leaf powder by FTIR showed that extract contain large numbers of organic compounds. The results of the mass loss method and the technique of Tafel curves obtained show that EFO effectively inhibits the corrosion of steel and it can reach 71% for 10% of EFO. The EFO acts as a mixed type inhibitorwith an anodic predominance. The corrosion rate of steel in commercial NaCl is lower than in 3% pure NaCl. The KI has a synergistic effect and his presence reduces corrosion of steel. EFO forms a monolayer on the metal surface and its adsorption follows the Langmuir isotherm. The negative values of the free enthalpies confirm the spontaneity of the adsorption of the inhibitor molecules on the surface of the steel and the stability of the film formed. Keywords: Corrosion, Green inhibitor, Olive leaf extract, Mixed inhibitor, Adsorption, Langmuir isotherm.