Corrosion inhibition performance of benzimidazole derivatives for protection of carbon steel in hydrochloric acid solution

Abstract

This paper presents a comprehensive study on the corrosion inhibition properties of new organic compounds, (1H-benzimidazol-2-yl)methanethiol (LF₁) and 1-dodecyl-2-((dodecylthio)methyl)-1H-benzimidazole (LF₂), have been examined for inhibiting of Carbon-Steel (C.S) in 1.0 M HCl. Numerous methods, such as potentiodynamic polarization, electrochemical impedance spectroscopy, scanning electron microscopy (SEM) and Energy Dispersive X-ray (EDX) analysis, atomic force microscopy (AFM), contact angle measurements, UV-visible spectroscopy, and theoretical calculations, were used to evaluate the effectiveness in preventing corrosion. The two benzimidazoles (LF₁ and LF₂)' inhibitory efficacy rose as their concentration increased, peaking at 88.2% and 95.4% respectively. The polarization graphs show a mixed behavior, with anodic predominance for LF₁ and cathodic predominance for LF₂. Thermodynamic investigations showed that the values of ΔG_ads were −40.0 kJ mol⁻¹ for LF₁ and −43.1 kJ mol⁻¹ for LF₂, highlighting their strong adsorption onto the metal surface. Their adsorption process was in line with the Langmuir isotherm. Density Functional Theory (DFT) and Molecular Dynamics (MD) modeling have been utilized to examine and clarify the relationship between the inhibitor and carbon steel (C.S).