Abstract
Sustainable plant-based biomass has emerged as a significant resource for corrosion mitigation in metallic alloys. This study evaluated the efficiency of Swiss chard stems (SCS) and green pea peel (GPP) extracts in a 1 M HCl medium as low-cost and low-toxicity inhibitors for inhibiting aluminum corrosion. The inhibition performance of the inhibitors was assessed through a combination of techniques, including weight loss (WL) analysis, surface characterization of the metal samples via X-ray photoelectron spectroscopy (XPS) as well as atomic force microscopy (AFM), and electrochemical methods, including electrochemical impedance spectroscopy (EIS) as well as potentiodynamic polarization (PDP). WL indicated that the inhibition efficiency (% I.E.) increased in response to an increase in SCS and GPP extract concentrations, reaching up to 91.5% and 83.1%, respectively, at 250 ppm and 55 °C. Potentiodynamic polarization results confirmed that SCS and GPP extracts function as mixed-type inhibitors. Temperature-dependent studies allowed for the determination of thermodynamic activation parameters, while adsorption behavior was found to conform to the Langmuir isotherm more than the Henry isotherm. XPS along with AFM indicated that an inhibitory layer had formed over the surface of aluminum. Additionally, quantum chemical parameters facilitated a deeper insight into the mechanism of the inhibition. The analysis of the adsorption configuration of SCS and GPP extract molecules on the surface of aluminum specimens was conducted by molecular dynamics simulations. Finally, a comparative economics study was discussed.