Bolaamphiphile-class surfactants as corrosion inhibitor model compounds against acid corrosion of mild steel

초록

As long as several years, an ever-growing focus has been placed on the study of corrosion inhibitors due to their useful role in reducing the dissolution of metals in different corrosive environments. In that sense, and with the aim of inhibiting the corrosion effects of HCl acid on mild steel (MS), two bolaamphiphile surfactants, which are 1,6-bis((1H-benzimidazol-2-thioyl)hexane (BITH), and 1,12-bis((1H-benzimidazol-2-thioyl)dodecane (BITD) have been examined by means of electrochemical techniques, Density Functional Theory (DFT), Molecular Dynamics (MD) simulations and Radial Distribution Function (RDF). The corrosion-inhibiting aspects of two compounds have also been examined with the use of scanning electron microscope (SEM) technique. The inhibitory performance of both compounds is improved by increasing the inhibitor concentration, getting the better one to 303 K, and an optimal concentration of 5 × 10−4 M. Findings are suggestive that both molecules adsorbed on the surface of MS and created hydrophobic films providing an effective barrier into the surface. The results of PDP tests strongly imply that the studied compounds are acting as mixed-type inhibitors. Their adsorption isotherms are Langmuir type, and primary mechanisms involve both physical and chemical adsorption. The computational study was performed in an attempt to identify factors most associated with anti-corrosive properties of tested compounds. © 2020 Elsevier B.V.

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