Analysis of Fig Leaf Extract as Steel Eco-friendly Corrosion Inhibitor in Acidic Medium: Electrochemical, Gravimetric, Spectroscopic, and Surface Studies

The trend upwards using green, safe, and environmentally friendly corrosion inhibitors has led to many studies being conducted on plant extracts and presenting them as an ideal alternative candidate. Here, Fig leaf extract (FLE) was prepared quickly at a low temperature (313K) to preserve the main chemical composition and distilled water as the solvent of extraction. This green inhibitor was employed to prevent steel corrosion in hydrochloric acid 1 M. The inhibitory efficacy, adsorption, and action mechanism of this prepared inhibitor were assessed using potentiodynamic polarization, electrochemical impedance spectroscopy, and gravimetric measurements. Thermodynamic analysis and adsorption isotherms have been, also, applied to elucidate the adsorption mechanism. The obtained results have shown that FLE is of a mixed type, follows the Langmuir isotherm and his inhibitory efficiency reached a maximum of 94%. The formation of an inhibitor film chemically adsorbed was confirmed by the analysis of corrosion process activation parameters, and also by a rise in inhibition efficiency as temperature was increased. These findings were validated by FTIR and FTIR second derivative spectra. Steel surface morphology was investigated using SEM techniques and XRD analysis. A satisfactory corrosion inhibitory effect on acid steel was brought by fig leaf extract, which is in line with the desire for the use of environmentally friendly, non-toxic products.