Application of green active bio-molecules from the aquatic extract of Mint leaves for steel corrosion control in hydrochloric acid (1M) solution: Surface, electrochemical, and theoretical explorations

Abstract

Due to environmental awarenesses and strict restrictions, industries are forced to bring their processes closer to the considered eco-friendly standards. Without a doubt, corrosion is the most obvious problem in industries and inhibitors are among the most applicable materials for metals' corrosion retardation. For this reason, extensive studies have been conducted in the field of green corrosion inhibitors in recent years. The present work concentrated on the evaluation of the bio-molecules from Mint leaves extract on the steel corrosion mitigation in HCl solution. The Mint extract (ME) structures were investigated by FTIR, UV-Vis, and Raman spectroscopies. It was shown by a polarization experiment that Mint extract at 800 ppm caused the current density (icorr) reduction from 1.03 mA/cm2 (for the blank sample) to 0.11 mA/cm2 which was aided by a mixed inhibition (cathodic – anodic) mechanism. The EIS results illustrated that at the optimum condition around 91 % inhibition degree was reached after introducing 800 ppm Mint extract. The weight loss investigations, however, affirmed that a 92 % efficiency was achievable at 25 °C, which was mitigated to 89 % at 55 °C. Eventually, the thermodynamic and adsorption isotherm records represented that Mint extract molecules mono-layer was constructed by utilizing the exothermic interactions. Via the MD and DFT simulations, the interfacial interactions and corrosion inhibitors' adsorption mechanism over the steel surface was exhibited.