Corrosion Inhibition of Mild Steel in 0.5 M H₂SO₄ Using Ethanol Extract of Funtumia elastica

The adsorption and corrosion inhibitive effect of the ethanol extract of Funtumia elastica (FE) leaves on mild steel corrosion in 0.5 M H₂SO₄ was studied using gravimetric, potentiodynamic polarization and electrochemical impedance spectroscopic techniques. As well as Fourier transform infrared spectroscopy and computational methods. The gravimetric and electrochemical studies revealed that FE is an adsorption inhibitor. The potentiodynamic polarization result showed that the inhibitor is a mixed type corrosion inhibitor for mild steel in 0.5 M H₂SO₄, inhibiting both the cathodic and anodic partial reactions. Density functional theory calculations were performed to model the electronic structures of some selected extract constituents (conessine, and ascorbic acid) to confirm their inhibiting potential and established their individual contributions to the observed inhibiting effects.