Mild steel protection in acidic media using Mucuna pruriens seed extract

• C.O. Akalezi¹, C.E. Ogukwe¹, E.A. Ejele² and E.E. Oguzie¹

¹ Electrochemical and Material Science Unit (EMRU), Department of Chemistry, School of Sciences, Federal University of Technology Owerri, PMB 1526 Owerri, Nigeria
² Department of Chemistry; School of Physical Sciences, Federal University of Technology Owerri, PMB 1526 Owerri, Nigeria

Abstract: The inhibition of corrosion of mild steel in 1 molar hydrochloric acid solution (1 M HCl) by Mucuna pruriens seed extract (MPSE) was investigated by weight-loss and electrochemical techniques. A significant decrease in the corrosion rate of mild steel was observed in the presence of the investigated additive and the inhibition efficiency was found to depend on the concentration of the MPSE. The potentiodynamic polarization data indicated that this additive was of mixed type, but the anodic effect was more pronounced. Nyquist plots showed that on increasing the MPSE concentration, the charge transfer resistance increased and double layer capacitance decreased. The thermodynamic parameters of adsorption revealed a strong interaction between the MPSE constituents and the corroding metal surface. MPSE lowered the corrosion reaction by blocking the mild steel surface through chemical adsorption. The mechanism of inhibition was discussed in the light of the chemical structure of the four major components of MPSE.

Keywords: Mucuna pruriens, mild steel, corrosion inhibition, hydrochloric acid

Int. J. Corros. Scale Inhib., 2016, 5, no. 2, 132–146 PDF (392 K)
doi: 10.17675/2305-6894-2016-5-2-3

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