Effect of some organic surfactants on the electrochemical behaviour of carbon steel in formation water

The effect of adding some organic surfactants, cocamide diethanol amine as a nonionic surfactant (NS), cetrimonium chloride as a cationic surfactant (CS), and cocamidopropyl betaine as an amphoteric surfactant (AmS), on the electrochemical behaviour of carbon steel in formation water was investigated by using a potentiodynamic and impedance techniques. Results reported in this study show that the addition of these surfactants inhibits the corrosion of carbon steel and the extent of inhibition depends upon the type and concentration of the surfactant. The inhibition efficiency for three organic surfactants increase with the increase in the surfactants concentration but decrease with increasing temperature. The inhibition efficiency of each of AmS, NS, and CS reaches a maximum value around their critical micelle concentrations. The percentage of corrosion inhibition of these surfactants decreases in the order AmS > NS > CS. The inhibition occurs through adsorption of the organic surfactants on the metal surface without modifying the mechanism of corrosion process. The experimental data fit both of Flory-Huggins and kinetic-thermodynamic isotherm. (c) 2005 Elsevier B.V. All rights.