Inhibition Effect of Reed Leaves Extract on Steel in Hydrochloric Acid and Sulphuric Acid Solutions

The corrosion inhibition of mild steel in 1.0 M HCl and 0.5 M H2SO4 by the reed leaves extract (RLE) has been studied using weight loss methods and potentiodynamic polarization techniques. The results show that the inhibition efficiency increases with the increase of RLE concentration in both acids, and the higher inhibition efficiency is obtained in 0.5 M H2SO4 solutions. The effect of temperature, immersion time and acid concentration on the corrosion behavior of mild steel in 1M HCl and 0.5 M H2SO4 with addition of extract was also studied. The adsorption of RLE molecules on the steel surface obeys Langmuir adsorption isotherm in both acids, and occurs spontaneously. The activation energy as well as other thermodynamic parameters (Ea, ∆H, and ∆S) for the inhibition process was calculated. These thermodynamic parameters show strong interaction between inhibitor and mild steel surface.