Anticorrosion performance of grape seed proanthocyanidins extract and Tween-80 for mild steel in hydrochloric acid medium

Grape seed proanthocyanidins extract (GSPE) is extracted from grape seeds, the waste of the grape consumption, based on a three-level three-factor response surface methodology (RSM). An eco-friendly corrosion inhibitor composed of GSPE and Tween-80 has been developed for mild steel in 1 M hydrochloric acid, whose inhibition performance is evaluated by using weight loss test, electrochemical investigations, and surface morphology analysis. The mixture of GSPE and Tween-80 mixture improves the corrosion inhibition of mild steel compared to individual inhibitors (i.e., 96.48% versus 77.68%/88.57%), reflecting a synergistic action between GSPE and Tween-80. Adsorption isotherm and kinetic parameters indicate that the adsorption follows Langmuir isotherm, and involves both physisorption and chemisorption. Potentiodynamic polarization (PDP) study shows that the GSPE–Tween-80 mixture acts as a mixed type inhibitor and mainly inhibits the anodic process. Surface morphology by scanning electron microscope (SEM), energy dispersive x-ray spectroscopy (EDX) and X-ray photoelectron spectroscopy (XPS) help to confirm the presence of the GSPE–Tween-80 mixture on the mild steel surface. Quantum chemical (QC) calculation and molecular dynamics (MD) simulations studies further supported the experimental results.