A newly synthesized quinoline derivative as corrosion inhibitor for mild steel in molar acid medium: Characterization (SEM/EDS), experimental and theoretical approach

The main objective of the article is the study of the corrosion inhibiting power of mild steel (MS) in one molar hydrochloric acid (1 M HCl) acid medium without and with the addition of quinoline derivative: 5-W4-Dimethylamino-benzylidene)-aminol -methyll-quinolin-8-ol (MABQ). Potentiodynamic polarization (PDP), AC impedance, and scanning electron microscopy with energy dispersive spectroscopy (SEM/EDS) technique were combined to investigate the corresponding inhibition performance. Density Functional Theory (DFT) and Molecular Dynamics Simulation (MD) were utilized to study the electronic properties and the interaction between inhibitor molecule and MS surface. Electrochemical impedance spectroscopy (EIS) studies revealed that MABQ augmented the polarization resistance while diminishing the double layer capacitance with increasing concentration due to the formation of a deterrent film on the MS with an efficiency of 95.8 % at 10(-3) M. In addition, the results of Potentiodynamic Polarization (PDP) demonstrate that this MABQ molecule acted as a mixed type inhibitor. The inhibitor tested is adsorbed on the surface of the steel according to the Langmuir isotherm model. The results obtained by DFT and the simulation of MD agree with the experimental results.

Automated summary

The study showed that the inhibitor MABQ effectively reduced the corrosion rate of mild steel in one molar hydrochloric acid by forming a deterrent film on the steel surface. Experimental results were in agreement with the DFT and MD simulation findings.