Corrosion inhibition and adsorption behavior of 4-aminoantipyrine on mild steel in H2SO4

Abstract

Weight loss measurements and potentiodynamic polarization studies shows that 4-AAP acts as an inhibitor for corrosion of mild steel in 2M H2SO4 solution. The inhibition efficiency increases with the inhibitor concentration, but decreases with temperature. The inhibition of AAP is due to its adsorbance and blocking the active sites of the metal surface without affecting the corrosion mechanisms, AAP behaves mainly as anodic inhibitor. The Flory-Huggins isotherm and the kinetic model of El Awady et al., fits the experimental results well. In the paper, the thermodynamic of dissolution and adsorption are calculated and discussed.