EXTRACTS OF MINT AND TEA AS GREEN CORROSION INHIBITORS FOR MILD STEEL IN HYDROCHLORIC ACID SOLUTION

Abstract

The corrosion inhibition of mild steel in 1.0 M hydrochloric acid by the extracts of Stems of Mint (SM), Leaves Mint (LM), Caffeine (CE), and Tea extract (TEX) has been studied as cheap and eco-friendly inhibitors using weight loss, electrochemical impedance spectroscopy, and potentiodynamic polarization techniques. Efficiency was found to increase with increasing concentrations of the extracts. The effect of temperature on the corrosion behavior of mild steel in 1.0 M HCl on addition of extracts was also studied. The inhibition is assumed to occur via adsorption of the inhibitor molecules on the metal surface. The adsorption of the molecules of the extract on the mild steel surface obeyed the Langmuir adsorption isotherm. The results obtained showed that the extracts of Mint (stems, leaves) and Tea (Caffeine, TEX) are mixed type inhibitors and could serve as an effective inhibitor of the corrosion of mild steel in 1.0 M hydrochloric acid media.