Corrosion inhibition of Pomelo peel extract on 304SS: experimental and theoretical studies

The electrochemical corrosion inhibition performance of Pomelo peel extract (PPE) on 304 stainless steel (304SS) in a 1 M hydrochloric acid solution at various temperatures was comprehensively evaluated, alongside its influence on the surface composition and corrosion morphology of 304SS. The results show that PPE contains 15 active ingredients, including citric acid, naringenin, and 3-hydroxyflavone. PPE demonstrates exceptional corrosion inhibition performance for 304SS, achieving a corrosion inhibition efficiency (η) of 94.3% as determined by potentiodynamic polarization tests under optimized conditions of 1.0 g/l PPE at 298 K. The adsorption behavior of the active components on the 304SS surface conforms to the Langmuir isotherm model, with interfacial protection afforded by the formation of a monomolecular layer composed of functional groups, such as C=C, C=O, C=O+, C–N, and C–N+. The surface contact angle of 304SS increases from 73.3° to 92.6°, significantly enhancing its hydrophobicity. Density functional theory and molecular dynamics simulations were employed to elucidate the detailed adsorption mechanism of the active compounds on the 304SS surface. This research confirms that PPE serves as an environmentally friendly corrosion inhibitor for stainless steel, exhibiting significant engineering value due to its highly efficient protective performance and sustainability advantages in acidic media.