Electrochemical response and computational approach on surface-active ionic liquid (SAIL) in metal corrosion inhibition

Abstract

This exploration highlights the protective corrosion inhibition properties of imidazolium-based surface-active ionic liquid (SAIL): 1-dodecyl-3-methylimidazolium bromide (C12MImBr) on mild steel (MS) in acidic environment (1 M HCl). A systematic electrochemical study was performed employing the potentiodynamic polarization technique for measuring corrosion current and corrosion rate via Tafel plot which is well complemented by weight loss method covering the range of pre-micellar, at critical micelle concentration (CMC), and post-micellar concentration of C12MImBr. Findings exhibited the inhibition efficiency enhancement of about ~ 96% with increase in [C12MImBr]. Electrochemical impedance spectroscopy (EIS) calculations showed an amendment in the impedance parameters (Rt and Cdl) with [C12MImBr] which indicated a successive adsorption of the material resulting into a shielding layer formation on the MS. Scanning electron microscopic study gave the supporting visual confirmations of the MS surface morphology which inferred that the MS surface counterattack the corrosion process more in presence of C12MimBr than in its absence. Thermodynamic study inferred the corrosion process to be spontaneous and that it obeyed Langmuir isotherm. Finally, the impact of the inhibitor structure on the corrosion inhibition efficacy to give a hypothetical interpretation about inhibitor performance was elucidated by computational simulation approach.