Evaluating the efficacy of synthesized quinoline derivatives as Corrosion inhibitors for mild steel in acidic environments: An analysis using electrochemical, computational, and surface techniques

•Q and QN act as effective inhibitor for steel acidic corrosion.•Adsorption on the surface is analyzed by XPS, AFM, SEM/EDS and CA techniques.•Theoretical data provide in-depth understanding of the experimental results. Two quinoline derivatives such as 5-(ethoxymethyl)-2-methylquinoline-8-ol,and 5-((2-aminoethoxy)methyl)-2-methylquinoline-8-ol symbolized by (Q) and (QN), respectively were studied in HCl (1.0 M) by experimental, and computational approaches to inhibit the corroding of the mild steel (M-S). Q and QN were found to delay the corrosion of the mild steel in the research environment. Q and QN displayed mixed inhibiting properties, decreasing the rate of anodic and cathodic corrosion reactions. The Q and QN molecules developed a film on the surface of the material in HCl (1.0 M), which is consistent with the impedance measurements. Coverage data of the surface adsorption has fitted into the Langmuir adsorption isotherm. SEM/EDS, AFM, contact angle, and XPS analysis also indicated that the adsorbent film of Q and QN protects the steel from ions of acid. In addition, a molecular dynamics simulation was performed to optimize the inhibitor molecule equilibrium configurations at the Fe surface. From the experimental results, the sequence of the effectiveness of the studied inhibitors was validated through theoretical calculations.