An investigation of benzimidazole derivative as corrosion inhibitor for mild steel in different concentration HCl solutions

The influences of a benzimidazole derivative, namely 1,8-bis (1-chlorobenzyl-benzimidazolyl) -octane (CBO) on the corrosion behaviour of mild steel in different concentration HCl solutions were studied by weight loss, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) measurements and SEM observations. The results showed that CBO acted as an excellent and a mixed-type inhibitor via strongly chemical adsorption onto mild steel surface to suppress simultaneously both anodic and cathodic processes according to the Langmuir adsorption isotherm. Inhibition efficiencies increased with increasing concentration of inhibitor and HCl. An inhibition mechanism was proposed in terms of strongly adsorption of inhibitor molecules on mild steel surface.

Research highlights
► The inhibitive action of 1,8-bis (1-chlorobenzyl-benzimidazolyl)-octane for mild steel in different concentration HCl solution was studied by weight loss, electrochemical methods and SEM. The following principle conclusions can be deduced:
► The corrosion of mild steel in HCl medium is effectively reduced by the addition of CBO.
► The compound acts as a mixed-type inhibitor and obeys Langmuir adsorption isotherm.
► Cl− plays an interconnecting bridge role between steel surface and cationic inhibitor.
► The inhibitor has excellent inhibiting properties in HCl solution.