Investigating the effectiveness of an aromatic derivative with a calix[4]arene structure as a corrosion inhibitor for extra-mild steel in acidic medium (1 M HCl)

Corrosion is a natural phenomenon that poses a major challenge for many materials, especially metals, due to its adverse effects on their durability and performance. This study investigates the effectiveness of an organic substance derived from calix[4]arene, specifically: 1 2 ,3 2 ,5 2 ,7 2 -tetrakis(benzyloxy)-1 5 ,3 5 ,5 5 ,7 5 -tetra- tert -butyl-1,5(1,3),3,7(1,4)-tetrabenzenacyclooctaphane (Calix-L2), as a corrosion inhibitor for extra-mild steel (EMS) in a 1 M hydrochloric acid (HCl) solution. A variety of experimental techniques were employed, including weight loss (WL) measurements to evaluate corrosion reduction, along with electrochemical methods such as electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization (PDP). The results indicate that increasing the concentration of Calix-L2 enhances its corrosion inhibition performance, with the highest recorded inhibition efficiency reaching 93 %. Electrochemical PDP analysis reveals that Calix-L2 acts as a mixed-type inhibitor. Adsorption of Calix-L2 on the steel surface follows the Langmuir adsorption isotherm. Surface characterization using scanning electron microscopy (SEM), energy-dispersive X-ray spectroscopy (EDS) confirms the formation of a protective coating on the steel surface. Additionally, theoretical studies using quantum chemical simulations and molecular modeling support the experimental findings, this confirms the adsorption of Calix-L2 onto the EMS surface and supports its effectiveness as a corrosion inhibitor.