An imidazole-based benzilic-dicationic ionic liquid performance in 1.0 M HCl solution to mitigate the mild steel degradation: Electrochemical noise/impedance investigation

Abstract

The corrosion prevention capability of an imidazole-based benzilic-dicationic ionic liquid labeled 1,4 -di [1′ –methylene- 3′- methyl imidazolium bromide]- benzene (DMIBr2) over mild steel in hydrochloric acid was investigated through experimental and theoretical studies. The excellent corrosion inhibitor ability of DMIBr2 was demonstrated using a new concept in noise resistance and spectral noise resistance interrelation to adequately eliminate the trend of electrochemical noise (EN) signals, which is in line with electrochemical impedance spectroscopy findings. EN also revealed that DMIBr2 mitigated both localized and general mild steel corrosion, as evidenced by SEM analysis. Potentiodynamic polarization suggested DMIBr2 can be described as a mixed-type corrosion inhibitor with cathodic control predominance in 1.0 M HCl. Langmuir adsorption isotherm was considered to interpret the DMIBr2 adsorption behavior on mild steel. Furthermore, according to quantum chemical calculations, the probable protonation process in the acid can affect the functionalities of different DMIBr2 components.