3-Mercaptopropionic Acid as corrosion inhibitor on carbon steel in environmental appropriate for the oil field condition

Abstract

The inhibition effect of 3-mercaptopropanoic acid (MPA) on the corrosion behaviour of carbon steel in C02-saturated NaCI solution at particular pH level and temperature appropriate for the oil mining conditions was studied by means of potenliodynamic curves (Tafel) and electrochemical impedance spectroscopy (EIS). The effects of temperature and pH controlled by acetic buffer on the corrosion behaviour of carbon steel in media was studied in the temperature range from 300 to 360K and in the pH range from 3.0 to 5.0. Results obtained reveal that MPA is very good inhibitors. The inhibition efficiency increases with the increase of inhibitor concentration and reached 90% at 0.25 mM for the MPA studied. Potentiodynamic polarization studies clearly reveal that MPA acts essentially as anodic inhibitor. The experimental impedance data were analyzed according to a proposed equivalent circuit model for the electrode/electrolyte interface, its show that the mechanism of MPA inhibition through the formation of protective film was physically adsorpted on the carbon steel surface, which is in line with Langmuir adsorption isotherm.