Inhibitive Performance of Musa acuminata Fruit Peel Extract on the Corrosion of Mild Steel in Sulphuric Acid Medium Dr. Gunavathy N.1,*, Dr. Murugavel S. C.2 1Department of Chemistry, Nirmala College for Women, Coimbatore, India 2Department of Chemistry, PSG College of Technology, Coimbatore, India *Corresponding Author E-mail: gunavathykrishnaprakash@yahoo.co.in
Online published on 28 August, 2014. Abstract The corrosion inhibition behaviour of the extract of Musa acuminata fruit peel [MAN(P)] in 1N H2SO4 on mild steel was studied using conventional weight loss method, electrochemical polarization, electrochemical impedance spectroscopy (EIS) and scanning electron microscope (SEM). The weight loss results revealed that the extract of Musa acuminata fruit peel is an excellent corrosion inhibitor. The addition of MAN (P) extract to the acid decreased the corrosion rate and consequently the inhibition efficiency increased with concentration. The polarization curves indicated that the MAN (P) acts as a mixed type inhibitor. Electrochemical impedance spectroscopy studies showed the change in charge transfer capacitance with the change in concentration of the fruit peel extract. This is attributed to the adsorption of active nutrients present in the fruit peel on the surface of mild steel leading to the formation of a protective layer. The adsorption of MAN (P) extract on the mild steel surface has been found to obey Temkin adsorption model. The SEM study showed that the inhibited metal surface was smoother than the uninhibited surface indicating the reduction in corrosion rate to a very low value in the presence of the inhibitor. This may be due to adsorption of inhibitor molecules on the surface as a protective layer and preventing the acid attack. A mechanism of physical adsorption of the phytochemical components of the peel extract on the surface of the metal is proposed for the inhibition action. Top Keywords Mild steel, fruit peel extract, weight loss, electrochemical polarization, EIS, SEM. Top |