Experimental and theoretical (MDS and FMO) study of 1-Benzylimidazole for mild steel in 0.1 N H2SO4 at normal and elevated temperatures: An efficient anti-pitting and anti-cracking agent

Abstract

1-Benzylimidazole (BI) was tested as an anti-pitting and anti-cracking agent for mild steel (MS) in 0.1 N sulphuric acid by experimental and theoretical techniques. Gravimetric, electrochemical impedance spectroscopy and potentiodynamic polarization techniques were used to find corrosion rate and percentage corrosion inhibition efficiency in the presence and absence of BI at three different temperatures. The molecular dynamics simulation and Frontier molecular orbital studies were carried out by using density functional theory. The surface study was performed by Langmuir and Frumkin adsorption isotherms, scanning electron microscopy, and metallurgical imaging techniques. Frequency calculation study was carried out on the geometry optimized structure of BI and corresponding theoretical IR spectra was obtained. Chemical reactivity parameters like global hardness, electronegativity, electrophilicity, nucleophilicity, electron releasing and accepting tendency, work function, back donation energy, proton affinity, metal inhibitor interaction, binding energies, etc., were calculated. Morphological study confirms the even and non-porous film on the MS supported by a decrease in Icorr and an increase in Rct with the concentration of BI. BI shows 93.31% inhibition efficiency at 1000 ppm for MS when exposed to 0.1 N H2SO4. BOD and COD of wastewater was found to be within the permissible limit.