Computational, SEM/EDX and experimental insights on the adsorption process of novel Schiff base molecules on mild steel/1 M HCl interface

• SAP1, SAP2, and SAP3 performance towards the corrosion inhibition for mild steel in 1 M HCl using weight loss, EIS and PP measurements revealed excellent results. • The inhibition efficiency showed a slight decrease with the rise of temperature. • The surface characterization SEM/EDX justified the adsorption of SAP molecules on mild steel surface. • Quantum chemical calculations and Monte Carlo simulation confirmed the experimentally obtained results. Controlling corrosion of metals and their alloys in acidic environments has recently received increasing scientific attention. Therefore, our study investigated three newly synthesized Schiff base (imine) derivatives, namely (3Z,3‘Z)-4,4'-(ethane-1,2-diyldiimino)bispent-3-en-2-one (SAP1), (4'E)-4,4'-(pyridine-2,6-diyldinitrilo)dipentan-2-one (SAP2), and (4'E)-4,4'-(benzene-1,3-diyldinitrilo)dipentan-2-one (SAP3) to understand their adsorption on mild steel (MS) surface effects in 1 M HCl solution using electrochemical and theoretical methods. The obtained results show that the three inhibitors have good protective effects. Electrochemical techniques show that the presence of these compounds significantly increases the polarization resistance and influences both the anodic and cathodic reactions. This means that these inhibitors have mixed properties. The stability of these molecules at higher temperatures, from 298 K up to 328 K, was examined by polarization potentiodynamic measurements. This study revealed that these compounds resist temperature by adsorbing on the MS surface to form a protective barrier. Scanning electron microscopy with Energy Dispersive X-ray Analysis (SEM-EDX) was also implemented to understand the adsorption phenomenon. In addition, density functional theory (DFT) and Monte Carlo simulation (MC) were performed to confirm the experimental results.