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Article – Journal of Advanced Electrochemistry

Journal of Advanced Electrochemistry, Volume 2,Issue 3,2016 Pages 107-112

Kinetic and Thermodynamic Studies of Corrosion Inhibition of Mild Steel using Bridelia ferruginea Extract in Acidic Environment
G.A. Ijuo*, H.F. Chahul, I.S. Eneji

The kinetic and thermodynamic studies of the corrosion of mild steel in acidic medium using methanolic extracts of Bridelia ferruginea (BF) was carried out using gravimetric and electrochemical linear polarization techniques. It was found that the BF extract retarded the corrosion of mild steel in 1.0 M HCl solution. The inhibition efficiency increased with increase in extract concentration but decreased with increase in temperature and immersion time. The values of activation energy (Ea) obtained is suggestive of physical adsorption mechanism while the values of Gibbs free energy (ΔG°) obtained indicated a spontaneous adsorption of the extract components on the metal surface. Kinetic treatment of the data followed a pseudo first order reaction. The electrochemical linear polarization result suggests that the BF extract functioned as mixed-type inhibitor. The adsorption of BF extract onto the mild steel surface followed Langmuir and Fruendlich adsorption isotherm models. The micrographs obtained from optical microscopy revealed the presence of a good protective film upon adsorption of inhibitor molecules onto the MS surface, which was responsible for the inhibition of corrosion. Thus, it can be concluded that BF inhibitor system acted as a good inhibitor in hydrochloric acid.

Keywords: Mild Steel; Corrosion Inhibition; Adsorption; Bridelia ferruginea;