Evaluation of Eryngium maritimum Essential Oil as Environmentally Friendly Corrosion Inhibitor for Mild Steel in Hydrochloric Acid Solution

摘要

Essential oil of aerial parts of Eryngium maritimum L. (EM oil) was obtained by hydrodistillation andanalyzed by GC and GC/MS. After column chromatography (CC), 58 compounds accounting for 97.1% of the oil were identified. The essential oil was dominated by oxygenated sesquiterpenes (57.9 %).The main components were 4H-cadin-9-en-15-al (36.5 %), germacrene D (31.6 %), 4H-cadin-9-en- 15-ol (8.3 %) and 4H-muurol-9-en-15-al (6.5 %). The inhibition of the corrosion of mild steel in 1MHCl solution by EM oil and its CC-fractions have been studied using weight loss measurements.Inhibition was found to increase with increasing concentration of the essential oil to attain 97.91 % at 2mg/mL. The effect of temperature on the corrosion behavior of mild steel in 1M HCl without and withthe EM oil at 2 mg/mL was also studied. The inhibition was assumed to occur via adsorption of theinhibitor molecules on the mild steel surface according to the Langmuir adsorption isotherm. Thethermodynamic parameters for activation and adsorption processes were calculated and discussed. Theresults obtained showed that the EM oil could serve as an environmentally friendly inhibitor of thecorrosion of mild steel in HCl media.