Synergistic effect of nizoral and iodide ions on the corrosion inhibition of mild steel in sulphuric acid solution

The corrosion rates in the presence of nizoral (NZR), an antifungal drug, as mild steel corrosion inhibitor in 0.1 M H₂SO₄ was measured by the weight loss method in the temperature range from 30 - 50 °C. Results obtained revealed that NZR acts as an inhibitor for mild steel in sulphuric acid solution. Inhibition efficiency increased with increase in concentration of the inhibitor but decreased with increase in temperature. The addition of KI increased the inhibition of NZR to a considerable extent. The experimental results suggest that the presence of iodide ions in the solution stabilized the adsorption of Nizoral molecules on the mild steel surface thereby improving the inhibition efficiency of Nizoral. The adsorption characteristics of the inhibitor were approximated by Langmuir adsorption isotherm and kinetic/thermodynamic adsorption model of El-Awady et al. Mechanism of physical adsorption is proposed from the activation and thermodynamic parameters calculated.