Amino acid structure analog as a corrosion inhibitor of carbon steel in 0.5 M H2SO4: Electrochemical, synergistic effect and theoretical studies

Abstract

Abstract In this study, a novel corrosion inhibitor named diethyl(4-methylphenyl)-N-(phenyl) aminomethylphosphonate (AP) has been exploited versus corrosion of carbon steel (CS) in 0.5 M H2SO4. The effect of AP inhibitor on CS corrosion was studied employing potentiodynamic polarization (PDP) curves and electrochemical impedance spectroscopy (EIS) measurements at 298 K. The results showed that AP acted as a mixed inhibitor with predominantly anodic, whose inhibition action was improved by increasing its concentration. The inhibition performance (I.E) was improved by the introduction of halide ion (KI) in the process. The synergistic effect between AP and KI was evaluated by estimating the synergism parameter. The adsorption of AP compound onto carbon steel surface obeyed to Langmuir's adsorption isotherm. Quantum calculations were conducted by employing the Density Functional Theory (DFT). The interaction between the inhibitor and the surface Fe (1 0 0) was assessed by molecular dynamics simulation (MDs).