Green corrosion inhibitors for mild steel in H2SO^sub 4^ solution: Comparative study of flavonoids extracted from gongronema latifoliunm with crude the extract

The inhibitive properties of flavonoids extracted from Gongronema latifolium(FEGL) and crude ethanolic extracts from Gongronema latifolium (EEGL) on the corrosion of mild steel in H2SO^sub 4^ were studied using hydrogen evolution method at 30, 40, 50, and 60°C. The results revealed that the extracts act as good inhibitors for the corrosion of mild steel in 5.0 M H2SO^sub 4^ solution. The inhibition efficiencies were found to increase with increase in the extract concentration and decreased with increase in temperature. The order of efficiency was EEGL > FEGL. The experimental data fitted well into the Langmuir adsorption isotherm. Physical adsorption mechanism was proposed for the adsorption of the extracts on the mild steel surface from the data obtained for the activation energies of the inhibited and uninhibited systems.