The synergistic inhibitive effect of nitro aniline compounds and iodide ions on mild steel in 1M HCl: Experimental and theoretical approach

摘要

The effect of iodide ions on the inhibitive performance of ortho, meta and para nitro aniline in 1M HCl for mild steel has been studied using weight loss method (gravimetric) measurements at 303 and 333K. Results obtained show that the presence of the nitro aniline compounds in 1M HCl solution inhibits the corrosion process of mild steel. The inhibition efficiency of the nitro aniline compounds was found to increase with increase in concentration of these compounds and decrease with increase in temperature. Its adsorption was found to be physical, exothermic and spontaneous as confirmed by values of activation energy and free energy of adsorption (not up to -20 kJ mo~(-1) for free energy of adsorption and below 80 kJ mo~(-1) for activation energy) and also fitted the Langmuir adsorption model. Addition of iodide ions synergistically increased the inhibition efficiency of the nitro aniline compounds. Quantitative Structure Activity Relationship (QSAR) approach was used on a composite index of some quantum chemical parameters to characterize the inhibition performance of the studied molecules. The results showed that the Inhibition Efficiency was closely related to some of the quantum chemical parameters.