Corrosion Inhibition of Mild Steel in HCl Solution Using MPO: Experimental and Theoretical Insights

Corrosion is a pervasive challenge in various industrial applications, particularly in acidic environments. This comprehensive study delves into the effectiveness of 2-methyl-4-propyl-1,3-oxathiane (MPO) as a corrosion inhibitor for mild steel exposed to hydrochloric acid (HCl) solutions. The investigation employs weight loss techniques to assess the inhibitor's performance over varying durations (ranging from 1 to 48 hours) and concentrations (0.1 to 1 mM). At a concentration of 0.5 mM, the inhibitor demonstrates impressive inhibitory efficiency, ranging from 87.6% at 303 K to 92.9% at 333 K during a 5-hour exposure period. Additionally, the impact of temperature on the corrosion inhibition process is examined at temperatures of 303, 313, 323, and 333 K, showing substantial inhibition efficiencies. Quantum chemical calculations using Density Functional Theory (DFT) methods elucidate the molecular interactions between MPO and the metal surface. Notably, the analysis of EHOMO (Highest Occupied Molecular Orbital Energy), ELUMO (Lowest Unoccupied Molecular Orbital Energy), Egap (Energy Gap), total hardness (η), electronegativity (χ), and electron fraction transition atom (ΔN) reveals valuable insights into MPO's corrosion inhibition capabilities. The outcomes underscore MPO's potential as an effective corrosion inhibitor for mild steel in HCl environments, laying the groundwork for more efficient corrosion prevention strategies in industrial settings.