PORTUGALIAE ELECTROCHIMICA ACTA Corrosion Inhibition of 1,4-di (1-vinyl-3-methylimidazolium) Benzene Dibromide on Mild Steel in HCl Solution

Abstract The inhibition and the effect of temperature and concentration of 1,4-di(1-vinyl-3-methylimidazolium) benzene dibromide (VMIBB) on the corrosion of mild steel in 1.0 M HCl solution was investigated by electrochemical polarization and weight loss experiments at temperatures ranging from 303 to 343 K. The studied inhibitor concentrations ranged between 1.0x10 -6 M and 1.0x10 -2 M. The percentage inhibition increased with the increase of the inhibitor's concentration. The percentage inhibition has reached about 93 % at the concentration of 1x10 -2 M and 303 K. On the other hand, the percentage inhibition decreased with the increase of temperature. Using the Langmuir adsorption isotherm, the thermodynamic parameters for the adsorption of this inhibitor on the metal surface were calculated. 1,4-di(1-vinyl-3-methylimidazolium) benzene dibromide was found to be a potential corrosion inhibitor, since it contained not only nitrogen, but also three aromatic systems, double bond, and it is a large molecule which has a big surface with high malar surface coverage. Keywords: Corrosion, inhibitor, 1,4-di(1-vinyl-3-methylimidazolium) benzene dibromide, Langmuir adsorption isotherm. Introduction In many civil services and industries, corrosion of metals constitutes a serious economic problem. Corrosion leads to an increase in running costs, a decrease in plant efficiency, and affects the product quality. In order to protect the metal from corrosion, inhibitors are used especially when the metal is in contact with aggressive solutions, such as during acid pickling. Prior to coating by electroplating, galvanizing, or painting techniques, the metal has to go through a treatment which requires the removal of scale and salts from steel surfaces, tanks, and pipelines. In order to prevent an extensive dissolution of the underlying metal, the acid must be treated by the addition of organic inhibitors which wil