Mimosa Tannin As Green Corrosion Inhibitor For Mild Steel In Concentrated Hydrochloric Acid Heavy Pickling Solution

摘要

Plant essential oils and herbal extracts were studied and successfully applied as effective inhibitors for different metals in various corrosive media. In this research, Mimosa tannin is studied as a potential corrosion inhibitor for mild steel corrosion in concentrated (30%) hydrochloric acid solution as a strong pickling solution for highly rusted and greasy steel parts. Electrochemical methods employed involve Tafel polarization and electrochemical impedance spectroscopy (EIS) methods. Weight loss measurements are performed as a standard basis for comparison. Results showed that even in such a strong corrosive medium, mimosa tannin as a cost effective natural product exhibits good inhibitory effect. Also a mechanism based on the adopted molecular structure of mimosa tannin and interactions of the tannin atoms with iron metal orbitals is proposed. The adsorption mechanism of the tannin molecules on the metal surface is found to be of Temkin type. Based on these results, Mimosa tannin can be used as an environmentally friendly green inhibitor for short time acid pickling applications for removal of rust from highly rusted and greasy parts.