NEW INSIGHTS INTO THE ADSORPTION OF CARBON DIOXIDE CORROSION INHIBITORS ON MILD STEEL

摘要

This paper presents a study of the influence of various chemical inhibitors on the corrosion rate of mild steel in brine electrolyte under carbon dioxide conditions. The performances as corrosion inhibitors were fitted to a Temkin adsorption isotherm, and various constants of adsorption (i.e., adsorption equilibrium constants and molecular interaction constants) have been obtained. The inhibitor adsorption mechanism has been discussed in terms of thermodynamics (i.e., ΔH, ΔG and ΔS) and this revealed that some compounds chemisorb onto the steel electrode. In addition, molecular modelling was undertaken using PCSPARTAN~® Plus and HyperChem~® Professional, and the various molecular parameters have been correlated with the thermodynamic adsorption properties of the inhibitors. A four-parameter fit for both negative and positive charged molecules is discussed.