Upcycling Black Olive Kernel Extract into a Green Corrosion Inhibitor for Tinplate in Simulated Olive Brine Solution

This study explores the potential of black olive kernel extract (BOKE) as a green corrosion inhibitor for tinplate in a simulated black olive brine solution (SBOB). To assess the corrosion behavior, various electrochemical techniques were employed, including open circuit potential (OCP) measurements, potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), and weight loss analysis. In addition, surface characterization was carried out using scanning electron microscopy (SEM), Fourier‐transform infrared spectroscopy attenuated total reflectance(FTIR‐ATR), and liquid chromatography‐mass spectrometry (LC‐MS) to identify the functional groups and chemical compounds present on the tinplate surface after exposure to the corrosive environment. The results clearly show that adding BOKE extract to the SBOB solution significantly reduces the corrosion rate of tinplate. Electrochemical analyses indicate that the extract acts as a mixed‐type inhibitor and its effectiveness increases with concentration. At the highest tested concentration of 400 mg/L, BOKE achieved an impressive inhibition efficiency of 96.54%. The corrosion protection provided by the tested inhibitor is mainly attributed to the formation of an adsorbed protective layer on the tinplate surface. SEM‐EDX analysis confirmed the presence of this layer. Moreover, FTIR‐ATR and LC‐MS analyses identified its primary constituents as coumaric acid, esculin hydrate, cinnamic acid, folic acid, and 4‐methoxybenzoic acid.