Corrosion Inhibition of Carbon Steel Pipelines by Some New Amphoteric and Di-cationic Surfactants in Acidic Solution by Chemical and Electrochemical Methods

The inhibition effect of new synthesized amphoteric and di-cationic surfactants, namely: 4-((((1-dode-cylpyridin-1-ium bromide)-4-yl) methylene) amino) benzoate sodium (I) and 1-dodecyl-4-(((1-dodecylpyridin-1-ium-4yl)imino) methyl) pyridin-1-ium bromide (II), respectively, on the corrosion of carbon steel in 1 M HCl have been investigated using electrochemical impedance spectroscopy, Tafel polarization and weight loss measurements. The inhibition efficiencies obtained from all methods employed are in good agreement with each other. Tafel polarization studies showed that the surfactants are mixed type inhibitors. The adsorption of two compounds onto the surface of carbon steel in 1 MHCl obeys the Langmuir isotherm. Adsorption thermodynamic parameters reveal that the adsorption of inhibitors is a mixture of physical and chemical adsorption.