Ocimum basilicum Extract as a Potential Green Inhibitor for Corrosion of Mild Steel in 0.5M H2SO4 Solution

Abstract

The objective of the study is to determine the effect of extract of Ocimum basilicum on corrosion of mild steel in aqueous 0.5M H₂SO₄. The systematic study was done by using weight loss method, potentiodynamics polarization technique and electrochemical impedance spectroscopy. The corrosion inhibition is found to occur on mild steel in presence of the extract and the inhibition efficiency of the extract increases with increase in concentration. Polarization measurement indicates that Ocimum basilicum acts as a mixed-type inhibitor and the inhibition efficiency decreases with rise in temperature. The corrosion inhibition on mild steel is found to occur due to the adsorption of inhibitor molecules on metal surface, which obeys Langmuir adsorption isotherm. The increasing values of activation energies (E_a) in presence of the extract indicate the retardation in rate of corrosion on metal surface. Scanning electron microscopic study confirmed the inhibition of corrosion on metal surface.