Inhibitory Effect of Fennel Fruit Essential Oil and Its Main Component Anethole of Corrosion on Steel Plates in 1 M HCL

Abstract

Corrosion worldwide causes large losses of metal, which is why various ways are being sought to slow it down. The aim of this study was to investigate the inhibitory effect of fennel fruit essential oil (Foeniculum vulgare Mill.) and its main component anethole. The inhibitory effect of three different concentrations of the fennel essential oil and anethole (1.0 mL/L, 1.5 mL/L, and 2.5 mL/L) in a solution of 1 M HCl at 298 K for 6 h on a sheet of low-carbon steel was investigated. The inhibitory effect was established using gravimetric methods evaluating weight loss, corrosion rate, and inhibition efficiency, as well as electrochemical methods. In gravimetric studies, the inhibition effect of the inhibitors fennel essential oil and isolate anethole at a concentration of 2.0 mL/L was 70.85% and 45.86%, respectively. The anodic polarization curve data at 298 K demonstrate that the anethole and fennel essential oil adsorption on the metal surface creates a barrier that hinders hydrogen ions’ access and prevents them from being reduced on the steel surface’s cathode sites. Fennel essential oil acting as a mixed type-inhibitor can replace synthetic organic substances and could become an alternative to be used as environmental corrosion inhibitors.