Description
This work aims to investigate the possible use of the palm kernel cake powder (Elaeis guineensis Jacq.) as corrosion
inhibitor for ASTM 1020 carbon steel in acidic media (0.5 mol L−1 HCl). The investigation was carried out using electro‑
chemical impedance spectroscopy (EIS), polarization curves, gravimetric technique and scanning vibrating electrode tech‑
nique (SVET). Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) were employed as
chemical and surface characterization techniques, respectively. The results of the EIS and gravimetric tests showed that the
substance acts as an efective corrosion inhibitor and inhibition efciency (IE) increases according with the increase of the
corrosion inhibitor concentration in the aggressive medium. The highest IE of 87% was obtained for the highest corrosion
inhibitor concentration used (1.77 g/L). The polarization curves revealed a mixed inhibitor. The adsorption of the studied
inhibitor on carbon steel surface obeyed Langmuir isotherm. The SVET measurements did not reveal anodic or cathodic
activities in the substrate surface in the presence of the inhibitor, revealing that the corrosion inhibitor was able to block both
reactions. FTIR analyses identifed in the powder the presence of hydroxyl group, aromatic rings, nitrogen and oxygen in such
groups as amines and oleaginous acid, which can be responsible for the inhibitory properties of the whole material. SEM
analyses showed that the corrosion process was retarded when the inhibitor was added to electrolyte. The results indicate
that the powder of palm kernel cake is promising for use as corrosion inhibition purpose for carbon steel in acidic media.
