Electrochemical studies of Carum Carvi plant as corrosion inhibitor for mild steel in 1M HCl solution

The application of Carum Carvi's essential oil in a corrosion inhibitor for mild steel (MS) protection was investigated in 1 M HCl solution. Essential oil from Carum Carvi was obtained by Clevenger type water distillation. The major compounds in these essential oils was identified using gas chromatography-mass Spectrometry: Apiol dill ( 5,6%), Limonene (15,3%), Carvone (13,3 %) and p-Cymene (11,3%). The electrochemical impedance spectroscopy and potentiodynamic measurements were used at various concentrations and temperatures. The oil acted as an efficient inhibitor against the carbon steel corrosion in 1 M HCl, and its inhibition efficiency increased with the inhibitor concentration reaching a value of up to 88% at 3 g/L. Polarization studies showed that the oil was a mixed-type inhibitor. Adsorption of oil on the steel surface in 1 M HCl solution followed Langmuir's isotherm and the thermodynamic parameters were determined and discussed.