Corrosion Inhibition Potential of Vernonia Armgdalina Leaves Extract on Mild Steel in H2so4 Solution

This study explores the use of Vernonia amygdalina (commonly known as bitter leaf) extract as a sustainable and eco-friendly corrosion inhibitor for mild steel in a 1.0 M acidic medium. The plant, abundant across Africa, contains phytochemical compounds that contribute to its strong corrosion-inhibiting properties. Electrochemical measurements, Atomic Absorption Spectroscopy (AAS), and Scanning Electron Microscopy (SEM) were employed to evaluate its effectiveness. Results from SEM and Atomic Force Microscopy (AFM) confirmed the formation of a protective film on the steel surface, reducing metal dissolution. The inhibition efficiency increased with higher extract concentration and temperature, demonstrating strong adsorption behavior. Thermodynamic analysis revealed that the corrosion inhibition process is feasible, endothermic, and involves the physical adsorption of phytochemicals onto the metal surface. The calculated activation energies for inhibited and uninhibited systems (7.913–28.178 kJ/mol) further support the inhibitor’s stability and performance. Negative ∆Gₐdₛ values indicate spontaneous adsorption, while negative ∆Sₐdₛ and positive ∆Hₐdₛ values suggest a non-spontaneous yet endothermic process. Overall, Vernonia amygdalina extract presents a promising, low-cost, and environmentally friendly alternative to synthetic corrosion inhibitors for industrial applications, offering effective protection of mild steel in acidic environments.