Green corrosion inhibition of mild steel in acidic media using Datura stramonium seed extract: A study for sustainable engineering applications

Abstract

This study investigates the corrosion inhibition potential of Datura stramonium seed extracts on mild steel in 1.0 mol·L⁻¹ HCl and 0.5 mol·L⁻¹ H₂SO₄, utilizing both ethanolic and aqueous extracts as eco-friendly inhibitors. Electrochemical techniques, thermodynamic studies, and quantum chemical calculations were employed to evaluate the adsorption mechanism and inhibitory action at the metal/electrolyte interface. Maximum inhibition efficiencies of 93.1% in HCl and 97.7% in H₂SO₄ were achieved with the ethanolic extract at a concentration of 0.2 g·L⁻¹, while the aqueous extract demonstrated 93.8% inhibition in HCl and 96.6% in H₂SO₄. Polarization curves indicated mixed-type inhibition with a slight anodic bias. The thermodynamic analysis of two extracts in both environments indicated that the K_ads increased and that the ΔG_ads were close to −40 kJ·mol⁻¹, suggesting that the adsorption followed the Langmuir isotherm, indicating a combination of physical and chemical adsorption. SEM/EDX analysis confirmed the formation of a protective layer, while quantum chemical studies further validated strong adsorption, evidenced by a low ΔE of 2.396 eV and an adsorption energy of −878 kcal·mol⁻¹ (1 kcal·mol⁻¹ = 4.18 kJ·mol⁻¹). These results demonstrate that Datura stramonium extracts are promising inhibitors, particularly in sulfuric acid, for industrial applications. Reason: Improved clarity, vocabulary, and technical accuracy while maintaining the original meaning.