Study of Blend of Extracts from Bitter Leaf (Vernonia Amygdalina) Leaves and Banana (Musa Acuminata) Stem as Corrosion Inhibitor of Mild steel in Acidic Medium

Abstract

This study investigates the effect of concentration of different ratio of the leaves extracts Bitter leaf (Vernonia amygdalina) and Banana stem (Musa Acuminata) on corrosion of mild steel in acidic medium using weight loss method at different temperatures (303 K to 323 K) to determine the inhibitory potentials of the extracts. The FTIR and SEM were used to determine the functional groups and morphology of the mild steel respectively during the experiment. The results showed that the inhibition efficiency (IE) increased with an increase in the concentration of the inhibitor (0.1 g/l to 0.5 g/l) but decreased with an increase in temperature (303 K to 323 K) for all the ratios of bitter leaf and banana stem extracts used. The results also showed that the inhibition efficiency increases with an increase in the concentration and shows maximum inhibition efficiency of (80.85%) at optimum concentration (0.5 g/L) The Energy Dispersive X-ray Spectroscopy (EDS) spectra of the mild steel showed that the composition of Carbon and Oxygen increased by 4% and 24.31%, respectively. The increase might probably be attributed to the presence of (CH2) in CH2OH group. The presence of cavities and pits in the Scanning Electronic Microscope (SEM) images of mild steel showed the damages on the mild steel by corrosion medium. The corrosion rate of mild steel in 1M HCl decreased with an increase in the concentration of the extracts for the different concentrations of extracts used, 100% bitter leaf extract (BLE) has the highest corrosion inhibitory efficiency; this was closely followed by 1:4 blends of bitter leaf extract (BLE) and banana extract (BNE). 100 % BNE extract has the lowest inhibitory efficiency for the different ratios of extracts concentration used. Bitter leaves extracts have better inhibitory efficiency than Banana stem extracts.