Corrosion Inhibition of Mild Steel in 1 M H2SO4 by Polyvinyl Pyrrolidone and Synergistic Iodide Additives

The corrosion inhibition of mild steel in 1M H2SO4 by polyvinyl pyrrolidone (PVP) and the synergistic effect of iodide ions were investigated using weight loss and hydrogen evolution methods in the temperature range of 30 – 60 o C. The corrosion rates of mild steel decreased with the increasing concentration of PVP, while the inhibition efficiency (%I) increased. The inhibition efficiency of PVP decreased with rise in temperature, suggesting a physical adsorption mechanism, which was found to follow Freundlich and Temkin adsorption isotherms. The inhibition mechanism was further collaborated by the values of kinetics/thermodynamic parameters obtained from the experimental data. The inhibiting action of PVP was considerably enhanced in the presence of iodide ions and values of the synergism parameter (S1) obtained point to synergistic interactions between PVP and iodide ions.