Experimental and theoretical evaluation of the adsorption process of some polyphenols and their corrosion inhibitory properties on mild steel in acidic media

Abstract

Polyphenols are now widely acknowledged as safe and biodegradable corrosion inhibitors due to their cost-effectiveness. As a result, this research examines how well polyphenols extracted from Artemisia Herba alba (AHA) prevent mild steel corrosion in a 1 M HCl solution. Inhibitory performance is determined using electrochemical impedance spectroscopy (EIS), potentiodynamic polarization, and weight loss tests. The shape and chemical content of the mild steel sample surface are evaluated by atomic force microscopy (AFM), scanning electron microscopy (SEM), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) after contact with AHA secondary metabolites in the acidic solution. According to the results of polarization curves, AHA extract works as a mixed-type inhibitor. For all AHA concentrations tested, the Nyquist plots show a semi-circular capacitive loop. On metal surfaces, the Langmuir isotherm regulates inhibitor adsorption. The effectiveness of inhibition is proportional to the extract concentration, reaching 92.9% at 900 ppm. On metal surfaces, the Langmuir isotherm governs inhibitor adsorption. The effectiveness of inhibition is proportional to the extract concentration, reaching 92.9% at 900 ppm. These findings are supported by metal surface experiments, which show that the deposited inhibitor molecules successfully prevent HCl attacks at steel grain boundaries. Finally, quantum chemistry simulations show that dicaffeoylquinic acids, which were found to be the most prevalent AHA extract components, are effective corrosion inhibitors.