Corrosion inhibition of mild steel in hydrochloric acid solution by methylene blue dye

The corrosion inhibition of mild steel in hydrochloric acid solution by methylene blue dye (MB) was investigated by gravimetric techniques at 30 and 60 °C as well as thermometric technique. MB was shown to be an inhibitor in the acidic corrodent. Inhibition efficiency increased with MB concentration but decreased with rise in temperature, with maximum value of 94-95% obtained for 5.0 mM MB at 30 °C. Corrosion inhibition is attributed to the adsorption of MB on the mild steel surface via a physical adsorption mechanism. These results were further corroborated by kinetic and activation parameters for corrosion and adsorption processes evaluated from experimental data.