ISSN 2305-6894

Wood tar essential oil from Cedrus Atlantica of Morocco (Middle atlas) as a green corrosion inhibitor for mild steel in 1 M hydrochloric acid solution

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1 Laboratory of biotechnology, environment and quality, Department of Chemistry, Faculty of Sciences, University Ibn Tofail, B.P: 133 Kenitra,14000 Morocco
2 Forest Research Center B.P 763, Rabat Agdal, 10050, Morocco
3 Laboratory of Nanotechnology, Materials and Environment, Department of Chemistry, Faculty of Science, University Mohammed V, Av. Ibn Batouta, BP. 1014 Rabat, Morocco

Abstract: The present work is devoted to the study of Cedrus Atlantica wood tar essential oil as a green corrosion inhibitor to afford the protection of mild steel in 1 M HCl medium. In this context, the extracted compound was evaluated as corrosion inhibitor for mild steel in 1 M HCl in the temperature range of 298–333 K using electrochemical impedance spectroscopy and potentiodynamic polarization measurements in the presence of different concentrations. The chemical composition of the essential oil was characterized by 50 components, which accounted for 97.37% of the total oil. This analysis is characterized by five major compounds, β-Himachalene (24.25%), α-Himachalene (13.76%), methyl-1,4-cyclohexadiene (9.06%), trans-cadina-1(6),4-diene (7.65%), 6-camphenol (7.44%) and Sabinene hydrate (6.17%). Electrochemical impedance spectroscopy analysis shows an increase in polarization resistance due to the adsorbed inhibitor molecules on metal surface, and the inhibition efficiency was found to increase with essential oil concentration to attain 84% at 0.6 g/l. Potentiodynamic polarization studies showed that, the essential oil compounds, with an average efficiency of 87% at 0.6 g/l have fairly effective inhibiting properties on mild steel in hydrochloric acid, and the compound acted as mixed type inhibitor with predominant control of anodic reaction. The adsorption of inhibitor on the steel surface in 1 M HCl solution followed Langmuir’s isotherm, as well, the temperature effect on the inhibition process in 1 M HCl with the addition of essential oil was studied at a temperature range of 303–333 K, and the thermodynamic parameters (Ea, ΔH, ΔS) were determined and discussed to elaborate the corrosion mechanism. The corrosion inhibition effect was found to be dependent on the inhibitor concentration and temperature, and the experimental and theoretical results are in good agreement.

Keywords: wood tar, essential oil, Cedrus Atlantica, mild steel, electrochemical impedance spectroscopy, potentiodynamic polarization, hydrochloric acid, corrosion inhibition

Int. J. Corros. Scale Inhib., , 9, no. 1, 265-283 PDF (1 409 K)
doi: 10.17675/2305-6894-2020-9-1-17

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