Experimental and theoretical investigation of 1-Hexyl-3-methylimidazolium iodide as a corrosion inhibitor for mild steel in HCl environment

Abstract

This study employed 1-Hexyl-3-methylimidazolium iodide to mitigate the corrosion of Q235 steel in a hydrochloric acid environment. The evaluation of corrosion inhibition effectiveness was comprehensively characterized by combining electrochemical experiments with surface morphology observation. The experimental results demonstrated the capability of the ionic liquid in establishing a film layer on the surface of Q235 steel, which effectively hindered the charge transfer process. Notably, the corrosion inhibition efficiency attained a value of 92.3% at a concentration of 1 mM corrosion inhibitor. Moreover, the process of the corrosion inhibitor adhering to the steel surface aligns with the Langmuir isotherm, demonstrating physicochemical adsorption behavior. The density functional theory (DFT) and molecular dynamics (MD) simulation were utilized for further exploration of the corrosion inhibition mechanism, and the results indicate the ionic liquid can be adsorbed onto the (110) surface of Fe in parallel through N atoms on the imidazole ring.