Molecular dynamic simulation and experimental investigation on the synergistic mechanism and synergistic effect of (1Z) N [2 (methylthio) phenyl] 2oxopropanehydrazonoyl chloride (S1) corrosion inhibitor on mild steel in acid medium1M HCl

Inhibitory activity of Schiff base namely: (1Z)-N-[2-(methylthio) phenyl]-2-oxopropane hydrazonoyl chloride (S1) against the corrosion of mild steel in HCl (1M) was investigated using mass loss, electrochemical impedance spectroscopy, potentiodynamic polarization, surface analysis (Scanning Electron Microscope coupled with Energy Dispersive X-Ray Analysis (SEM/EDX), X-Ray diffraction (XRD), Ultraviolet–visible spectroscopy (UV-VIS) and contact angle). The experimental results were showed thatschiff base (S1) has a good inhibitory effect on mild steel, and their effectiveness was increasedwith increasing inhibitor concentration and decreased with increasing temperature (from 25 °C to 55 °C). The maximum inhibition efficiency of 87% was obtainedwith2.5×10−3M solution S1 at 25 °C. From the contact angle results, it was found that the angle in the presence of S1 is 75°.This value was higher than in the case of the absence of the inhibitor. As for the results of the adsorption isotherms, they showed us that the highest correlation value of 99.997 has been found with the Langmuir isotherm. From all the experimental results, it was concluded that the S1 was adsorbed on the metal surface according to the Langmuir isotherm. Therefore, the corrosion reactions of mild steel were inhibited. In this study, it was also investigated the effect of the synergistic action between the S1 and the iodine anions on the corrosion inhibition of mild steel, experimentally by polarization and theoretically using MC simulation. The results revealed a strong inhibitory activity of 85% at 5×10−5 M. It was also found that there was a strong correspondence between the theoretical and experimental study.