Protecting Mild Steel from Acid Corrosion Using Extract from Ocimum gratissimum Leaves

Abstract

The anti-corrosion properties of the ethanol extract of Ocimum gratissimum (OG) leaves on the corrosion of mild steel in both 1 M HCl and 0.5 M H2SO4 was studied using gravimetric, electrochemical, Fourier transform Infrared spectroscopy and scanning electron microscopy methods of corrosion monitoring. The gravimetric results revealed that the inhibitor maintained good inhibition efficiency even at 120 hours of immersion. The electrochemical results showed that OG extract functioned as a mixed type corrosion inhibitor for mild steel in both 1 M HCl and 0.5 M H2SO4, inhibiting both the anodic and cathodic partial reactions via adsorption of the extract constituents on the metal/solution interface. Fourier Transform Infrared Spectroscopy and surface examination results confirmed the adsorption of the extract, organic constituents on the mild steel surface. The results showed that OG ethanol extract functioned as a good corrosion inhibitor for mild steel in both 1 M HCl and 0.5 M H2SO4 solutions.