Thermodynamics Study of Inhibitory Action of Lignin Extract from Gmelina arborea on the Corrosion of Mild Steel in Dilute Hydrochloric Acid

Inhibitive effect of Lignin extract from Gmelina arborea bark on the corrosion of mild steel in 1M Hydrochloric Acid solution was studied by weight loss method with various periods of contact and temperature. The study revealed that the percentage inhibition efficiency increased with increase in inhibitor concentration. The temperature studies reflect that the adsorption of inhibitor on metal surface takes place via physisorption and through a spontaneous process. The inhibition at the metal surface was confirmed by X- ray diffraction examination