Identification and analysis of green corrosion inhibitors in pomegranate peel extracts: a theoretical and experimental study

In this study, the corrosion efficacy of microwave-assisted Soxhlet extract of pomegranate (Punica granatum L.) peels as a corrosion inhibitor of mild steel S240 in a 3.5% NaCl solution was explored. The inhibition of corrosion was comprehensively evaluated using potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), and mass loss measurements. The results demonstrated that the extract achieved a maximum inhibition efficiency of 93.34% at a mass concentration of 800 ppm. The formation of a protective layer on the metal surface was provided through the use of EIS, scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDX). The molecular characterization of the adsorbed species was carried out by high-performance liquid chromatography (HPLC) in combination with electrospray ionization mass spectrometry (ESI-MS). To gain insights into the mechanism of action and the nature of the adsorption sites, the experimental findings were compared with theoretical predictions obtained through density functional theory (DFT) and Monte Carlo simulations.