Ginger extract as green corrosion inhibitor for 304 stainless steel in HCl solution: experimental and theoretical calculations

Abstract

In this study, Ginger extract (GE) was prepared using an ultrasound-assisted method and utilized as a green corrosion inhibitor for 304 stainless steel (304SS) in a 1 M HCl solution. Rich active ingredients, including zingerone, gingerdione, quercetin, and aspartic acid, were identified in GE, featuring functional groups such as -COOH, C = O, and C = C. Electrochemical results show that GE functions as a mixed-type corrosion inhibitor capable of controlling both anodic and cathodic reactions, exhibiting a “geometric coverage” corrosion inhibition mechanism. The corrosion inhibition efficiencies of GE at the optimal concentration of 3.0 g/L are approximately 96.4%, 90.1%, and 85.8% at 25, 35, and 45 ℃, respectively. Macroscopic adsorption studies reveal that the active components within GE are adsorbed onto the 304SS surface in a mixed manner, with physical adsorption slightly dominating, consistent with the Langmuir isotherm. X-ray photoelectron spectroscopy (XPS), field-emission scanning electron microscopy (FE-SEM), and surface contact angle tests confirm the presence of an adsorption film on the 304SS surface, which significantly reduces surface hydrophilicity and inhibits the corrosion of 304SS. Density functional theory (DFT) and molecular dynamics (MD) simulations further validate the electron-donating and electron-accepting behaviors of the active constituents within GE and their parallel orientation adsorption on the 304SS surface. GE demonstrates promising potential for its application as a regenerative corrosion inhibitor for 304SS in HCl pickling solutions.