Abstract:The corrosion of mild steel in H2SO4 and its inhibition by penicillin G have been studied using gasometric and thermometric methods of monitoring corrosion. Penicillin G inhibits the corrosion of mild steel by adsorbtion on the surface of mild steel through the mechanism of physical adsorption. Inhibition efficiency of penicillin G decreases with temperature. Values of activation energy calculated for the inhibited corrosion of mild steel were higher than values obtained for the blank. Values of heat of adsorption (enthalpy of adsorption) and free energy of adsorption were negative. Therefore, we concluded that penicillin G retards the corrosion of mild steel and that the adsorption of penicillin G on mild steel is spontaneous and exothermic.

Key Word: Corrosion of mild steel, inhibition, penicillin G