Sustainable corrosion inhibition of carbon steel in 3.5% NaCl using Moringa oleifera leaf extract

Abstract

Corrosion is an unavoidable process in metals, but it can be effectively managed through various techniques. One such approach involves the use of environmentally friendly corrosion inhibitors, commonly referred to as green corrosion inhibitors. Moringa oleifera (MO) leaves are renowned for their high concentration of antioxidant compounds; however, their applications have primarily been limited to water purification and food ingredients. Addressing this gap, research was conducted to explore the potential of Moringa leaf extract as a green corrosion inhibitor for X70 steel. The study employed varying concentrations of the leaf extract (0.04, 0.08, 0.1 and 0.2 g∙L–1) to identify the optimal performance under 3.5% NaCl conditions. The effectiveness of the MO leaf extract in reducing the corrosion rate was evaluated using Tafel polarisation and electrochemical impedance spectroscopy (EIS) tests. The results demonstrated a significant reduction in the corrosion rate, with the highest inhibition efficiency reaching 83% in the NaCl medium. scanning electron microscopy (SEM) analysis further confirmed the formation of a protective layer on the steel surface, consistent with findings from gravimetric and electrochemical studies. These results highlight the potential of Moringa leaf extract as a sustainable and effective corrosion inhibitor.