Inhibitive and adsorption properties of leaves extr act of bitter leaf ( Vernonia amygdalina) as corrosion inhibitor of aluminium in 1.0M NaOH

摘要

This work examined the inhibitive and adsorption pr operties of leaves extract of bitter leaf (Vernonia amygdalina) as corrosion inhibitor of Al in 1M NaOH. Leaves ext ract of bitter leaf was characterized using Fourier transform infra-red (FT IR) spectroscopy to identify peaks of the functional groups. Weight loss, potential dyna mic polarization, Fourier transform infra-red and scann ing electron microscopic analyses were used for the corrosion inhibition study. The FT IR analysis of the bitter leaves extract revealed the presence of C=C-H, Ar-H (bending out of plane), C-H (bending in plane), stretched C-O, s tretched C=C, stretched C=N, stretched C=O, stretch ed C ≡ C, stretched C ≡ N, stretched C-H and stretched O-H functional group s. Adsorption of the extract on the Al surface was spontaneous and occurred according to the mechanism of physical adsorption. The optimal conditions for the corrosion inhibition of the Al in NaOH are concentr ation of the inhibitor of 1.0 g/l, temperature of 3 03 K and immersion time of 1hr. The optimum inhibition effic iency of the bitter leaves extract is 80.54 %. Leav es extract of bitter leaf is a mixed-type inhibitor of Al in NaOH medium.