Tobacco Plant Extracts as Save Corrosion Inhibitor for Carbon Steel in Hydrochloric Acid Solutions

The inhibitive action of the aqueous extract of tobacco towards the corrosion of C-steel in HCl solution was investigated. The inhibition efficiency was measured using weight loss, potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and electrochemical frequency modulation (EFM) techniques. The surface morphology of carbon steel was also studied. It was found that the addition of the extract reduces the corrosion rate of C-steel and hence increases the inhibition efficiency. The inhibitive effect of the tested extract was discussed in view of adsorption of its components on the steel surface. The adsorption of the extract components on the C-steel surface follows Langmuir adsorption isotherm. The thermodynamic functions of dissolution and adsorption processes were calculated and discussed. The inhibition efficiency increases as the temperature is increased. The presence of extract decreases the activation energy of the corrosion process.