Impact of Aaronsohnia pubescens Essential Oil to Prevent Against the Corrosion of Mild Steel in 1.0 M HCl: Experimental and Computational Modeling Studies

The essential oil obtained from the aerial parts of Aaronsohnia pubescens plant (AP oil) was extracted by hydrodistillation, and then, its composition was analyzed by gas chromatography (GC) and GC-mass spectrometry (GC/MS). The corrosion inhibition and adsorption performance of the AP oil on the corrosion mild steel in 1 M hydrochloric acid was evaluated by weight loss analysis, electrochemical methods both stationary [Potentiodynamic polarization (PDP)] and transient [Electrochemical impedance spectroscopy (EIS)]. The weight loss outcomes indicate that AP oil shows a worthy inhibitory efficiency of 83.22% reached at 1.5 g L−1 and 343 K. The charge transfer process mainly controls the results of EIS measurements; PDP measurements showed that the studied AP oil performs as a mixed-type inhibitor. Furthermore, the adsorption on the steel is made according to the Langmuir model. The computational chemistry calculations by density functional theory, the electrostatic potential surface and Metropolis Monte Carlo methods were performed to acquire a greater understanding of adsorption mechanism for each compound among the third major compounds of AP oil on the Fe (110) surface. The finding results exhibited that the E-anethole will be considered as the best inhibitor against mild steel corrosion.