Eco-friendly Pistacia lentiscus leaves extract corrosion inhibitor for C38 steel in 1 M HCl

Abstract

The inhibition effect of the alcoholic plant extract Pistacia lentiscus L. on the corrosion of C38 steel in 1 M hydrochloric acid solution was studied by weight loss measurement, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM). The results obtained by gravimetric show that the corrosion rate decreases with increasing inhibitor concentration. The cathodic and anodic polarization curves show that Pistacia lentiscus L. is a mixed type inhibitor. The electrochemical impedance spectroscopy results show that the charge transfer resistance in the presence of the inhibitor increases. The effectiveness of corrosion inhibition increases with the concentration of the plant extract. At a concentration of 2 g/L of the inhibitor, the inhibitory efficiency reaches a percentage of 91%. Thus, this inhibiting effect is mainly due to the adsorption of the molecules present in the extract on the surface of the steel. The adsorption of this plant extract on the surface of the C38 steel obeys the Langmuir adsorption isotherm. Morphological analysis performed by scanning electron microscopy (SEM) showed a smoother steel surface in the presence of the extract than without the inhibitor. The results revealed that Pistacia lentiscus L. extract could be used as an excellent corrosion inhibitor for C38 steel in 1 M hydrochloric acid medium.