Mild Steel Corrosion Inhibition by Eremomastax polysperma Leaf Extract in Acidic Medium
Okon U. Abakedi *
Department of Chemistry, University of Uyo, P.M.B.1017, Uyo, Nigeria
James E. Asuquo
Department of Chemistry, University of Uyo, P.M.B.1017, Uyo, Nigeria
*Author to whom correspondence should be addressed.
Abstract
The inhibition of mild steel corrosion in 1 M H2SO4 solution by Eremomastax polysperma leaf extract has been studied using weight loss and hydrogen evolution techniques. The results obtained show that Eremomastax polysperma leaf extract is a good inhibitor of mild steel corrosion in H2SO4 solution. The inhibition efficiency increased with increase in extract concentration but decreased with increase in temperature. Physical adsorption has been proposed for the adsorption of the leaf extract on mild steel surface. Thermodynamic parameters reveal that the corrosion inhibition process in the presence of the extract was endothermic and occurred spontaneously. The adsorption of Eremomastax polysperma leaf extract on mild steel surface best fitted the Langmuir adsorption isotherm.
Keywords: Corrosion inhibition, Eremomastax polysperma, mild steel, physisorption, weight loss, hydrogen evolution, Langmuir isotherm