Evaluation of Corrosion Mitigation Properties of 3-1H-Benzo[d]Imidazol-2-yl-Quinolin-2-ol on the Mild Steel in HCl and H2SO4

Abstract

In the present study, the 3-1H-benzo [d] imidazole-2-yl-quinolin-2-ol (BIMQ) was used as a corrosion inhibitor and its mitigation performance against the corrosion of mild steel (MS) in 1 M HCl and H2SO4 solution was examined through gravimetric weight loss, potentiodynamic polarization (PDP), and electrochemical impedance studies (EIS). The surface morphology was examined using scanning electron microscopy (SEM), and UV-visible (UV-Vis) spectroscopic studies were carried out to study the electron transfer. Theoretical studies have been implemented using quantum chemical calculations and molecular dynamics simulation. Weight loss studies revealed that the corrosion rates decreased with increasing concentration of BIMQ. Polarization results confirmed that the presence of BIMQ suppressed the metal dissolution and hydrogen evolution at the anodic and cathodic regions in both acidic media. The inhibitor showed 86.0 and 94.2% inhibition efficiency at a 50 ppm concentration of BIMQ. EIS results indicated that the BIMQ reduces the speed of corrosion reaction of MS in 1 M HCl and H2SO4. Inhibitor adsorption isotherm data revealed that the inhibition process obeys Langmuir isotherm. The UV-Vis absorption spectrum confirmed the electron transfer, and SEM studies showed that the corrosion of MS surface is significantly reduced in the presence of BIMQ. Quantum chemical calculations revealed that the investigated molecule has a widespread electron density and active sites over the entire molecular structure. Molecular dynamics simulation indicated that the molecule stands parallel to the iron surface in close contact to the iron surface.