Corrosion inhibition and synergistic effect of ionic liquids and iodide ions on the corrosion of C-steel in formation water associated with crude oil

Abstract

AbstractThe inhibition effect of some of three different ionic liquids namely, IL-4, IL-8, and IL-10 on the corrosion behavior of C-steel immersed in 10% formation water (FW) solutions was examined at various concentrations and temperatures. Gravimetric measurements were complemented by surface investigation for some corroded C-steel samples using a scanning electron microscope (SCE). The inhibition efficiency, IE %, was found to increase with increasing the inhibitor concentration depending on its type while the rise in the solution temperature reduces the IE %. At optimum concentration of 500 the IE % reaches 52.21%, 45.83%, and 43.98%, successively, with IL10, IL8, and IL4. The presence of 0.02 M KI mixed with 500 ppm enhances the IE % to reach a maximum value of 90.5%, 85.6%, and 77.9%, successively, with IL10, IL8, and IL4. The existence of KI is considered an effective co-inhibitor that introduces a synergistic effect and stimulates the synergism. The inhibition mechanism was discussed through an adsorption process that follows the Langmuir model. The thermodynamic data suggests the existence of physisorption besides chemisorption processes on the surface of the C-steel surface.