Theory and experimental investigations on the effect of the halogenated chain of new synthesis compounds based on benzimidazole derivatives on the inhibition corrosion of mild steel in acid media

• M. Bouziani Idrissi¹, H. Hailou¹, I. Filali¹, M. Rbaa², F. Benhiba^3,4, K. Nouneh⁵, E. El Kafsaoui¹, C. El Mahjoub⁵, A. El Midaoui¹, H. Oudda¹ and A. Zarrouk⁴

¹ Advanced Materials and Process Engineering Laboratory, Faculty of Science, Ibn Tofail University, P.O. Box 133, Kenitra, Morocco
² Laboratory of Organic Chemistry, Catalysis and Environment, Faculty of Sciences, Ibn Tofail University, PO Box 133, 14000, Kenitra, Morocco
³ Higher Institute of Nursing Professions and Health Techniques of Agadir, Annex Guelmim, Morocco
⁴ Laboratory of Materials, Nanotechnology and Environment, Faculty of Sciences, Mohammed V University in Rabat, Av. Ibn Battuta. P.O. Box 1014, Rabat, Morocco
⁵ Laboratory of Materials Physics & Subatomics, Faculty of Science, Ibn Tofail University, P.O. Box 133, Kenitra, Morocco

Abstract: In this study, the behavior of mild steel (MS) corrosion in hydrochloric acid (HCl) solutions in the presence of two new compounds, namely 2-(4-bromophenyl)-1-(2-chloroethyl)-1H-benzo¬[d]imidazole (24B12CBI) and 1-(2-chloroethyl)-2-(4-chlorophenyl)-1H-benzo[d]imidazole (12C24CBI), was investigated. To analyze the inhibitory effects of these substances, several analytical techniques such as electrochemical tests, scanning electron microscopy (SEM) combined with energy-dispersive X-ray (EDX) analysis, atomic force microscopy (AFM), and theoretical approaches (DFT and molecular dynamics) were used. The findings of the experiments showed that both 24B12CBI and 12C24CBI efficiently reduced MS corrosion in 1 M HCl, with a remarkable inhibition level of 90% at a concentration of 10^–3 M. The inhibitory mechanism was bifurcated, affecting both the anodic and cathodic processes. Electrochemical impedance spectroscopy (EIS) analysis revealed the presence of a singular loop in the diagrams, with an increase in loop size corresponding to higher inhibitor concentrations. This observation suggested the formation of a protective layer upon the metal surface. Furthermore, the 24B12CBI and 12C24CBI inhibitors exhibited minimal temperature dependence and the polarization resistance increased with time. SEM/EDX and AFM investigations confirmed the presence of a protective layer on the surface of the MS, lending credence to the electrochemical findings. Overall, the compounds 24B12CBI and 12C24CBI show significant potential as corrosion inhibitors (CIs) for MS in 1 M HCl solutions. These findings contribute to a deeper understanding of the inhibition mechanism and highlight the importance of these compounds for mitigating corrosion damage in acidic environments. Data of the theoretical approaches confirm experimental results.

Keywords: imidazole, MS, HCl, inhibition performance, SEM/AFM, DFT/Molecular dynamics

Int. J. Corros. Scale Inhib., 2023, 12, no. 4, 1535-1563
doi: 10.17675/2305-6894-2023-12-4-8

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