The inhibition of 3H-2- Methyl-1,2,4- Triazepino[2,3-a] Benzimidazole-4(5h)-one (MTB) on corrosion of mild steel in 1 M HCl solutions; Theatrical and experimental study

Abstract

The inhibitive action of a new Benzimidazole derivation, 3H-2-Methyl-1,2,4-Triazepino [2,3-a] Benzimidazole-4 (5h)-one (MTB), for the corrosion of mild steel in one molar hydrochloric acid solution was investigated. Corrosion tests has been conducted using weight loss measurement electrochemical method and scanning electron microscopy associated with energy dispersion spectrometer (SEM/EDS). The results showed increasing inhibition efficiency with increasing the inhibitor concentration and reach to 98% at 1×10-2 M. The thermal studies indicated that the newly synthesized MTB inhibited the corrosion of mild steel by its adsorbing on the specimen surface via both physisorption and chemisorption mechanism. The adsorption process of MTB on the mild steel surface obeys Langmuir adsorption isotherm and act as mix-type inhibitor. The analysis of surface morphology confirmed the thermal results by showing the MTB molecules on the mild steel surface. Various DFT parameter like HOMO and LUMO energy, gab energy (∆E), electronegativity (χ), softness (�, global hardness (η) were derived for MTB molecules and correlated with experimental results. Keywords: Surface morphology, Thermal study, Corrosion, Inhibitor, Polarization, Mild Steel, Isotherm, Benzimidazole, Quantum chemical, DFT Calculation.