Ketoprofen as an innovative corrosion inhibitor for mild steel in acid: Experimental insights using advanced analytical techniques

This study introduces the innovative use of ketoprofen (KP), a pharmaceutical compound, as a green corrosion inhibitor for mild steel (MS), investigated through a synergistic combination of electrochemical, spectroscopic, and quantum chemical techniques. The research examined the effectiveness of KP as an inhibitor for MS corrosion in 0.5 M HCl solution. Electrochemical measurements, including potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS), revealed that KP is highly effective in MS corrosion inhibition with inhibition efficiencies exceeding 98% at the optimal concentration of 17 × 10 -4 M. Besides, atomic absorption spectroscopy (AAS) supports the results through a remarkable decline in the dissolution of Fe 2+ ions in treated solutions. KP is a mixed-type inhibitor that adsorbs onto the metal surface, as revealed by modeling the Langmuir adsorption isotherm (ΔG ° ads = -33.38 kJ∙mol -1 ). This indicates a spontaneous adsorption process involving physisorption and chemisorption. In addition, quantum chemical calculations highlight KP’s strong adsorption potential and efficient electronic properties. Findings justify KP’s efficacy and potential as an eco-friendly corrosion inhibitor against acidic environments.