Examination of the main chemical components of essential oil of Syzygium aromaticum as a corrosion inhibitor on the mild steel in 0.5 M HCl medium

The study delves into the versatile applications of essential oils, natural aromatic compounds derived from plants through hydro-distillation or cold extraction, across industries such as cosmetics, fragrances, food processing, traditional medicine, and agriculture. Notably, these plant-derived compounds have gained prominence as corrosion inhibitors for metals and alloys in acidic environments. The research focuses on evaluating the inhibitory capacity of Suzygium aromaticuim on regular steel submerged in an acidic medium, employing various concentrations of essential oil (1.5 g/L to 6 g/L). The inhibitory effectiveness was evaluated using electrochemical techniques, including potentiodynamic polarization curves and electrochemical impedance spectroscopy. Electrochemical measurements and optical microscope analyses were used to examine the effect of cloves' essential oils on the corrosion resistance of mild steel in a 0.5 M HCl media. NMR and IR spectroscopy were used to learn about the two isolated chemicals (eugenol and β-caryophyllene). The corrosion-inhibiting properties of β-caryophyllene at 2 g/L in an acidic media were studied. Density functional theory (DFT) computations and molecular dynamics simulations were used to isolate the essential oil component of cloves responsible for the corrosion inhibition of mild steel. Inhibition effectiveness peaked at 94 % at 4 g/L, leading the researchers to infer that the natural substance is a mixed-type inhibitor. Optical microscope analysis confirmed the protection offered at the optimum concentration, while β-caryophyllene demonstrated noteworthy inhibitor efficiency, especially when compared to Eugenol. DFT analysis further supported the corrosion inhibition potential of β-caryophyllene in aggressive solutions. © 2023 Elsevier B.V.