Metal oxidation prevention of low carbon steel in acidic medium: synthesis, electrochemical, and theoretical studies of a novel di-cationic pyridinium surfactant

Abstract

Low carbon steels are widely used industrially, especially in the automotive and construction sectors. The corrosion rates of these metals in acidic environments are generally very fast and it is of particular importance to prevent metal corrosion in this environment. For this reason, in this study, di-cationic surfactant containing two pyridinium nitrogen with corrosion inhibitory potential, named 1-dodecyl-2-(11-(pyridin-1-ium-1-yl)undecanamido)pyridin-1-ium di-bromide (DPUP), was synthesized. The structure of this compound was elucidated by spectroscopic methods (FT-IR and NMR) and electrochemical measurement methods (potentiodynamic polarization and electrochemical impedance spectroscopy) were preferred to determine the corrosion inhibition activities at different concentrations (2, 10 and 50 ppm) at room temperature (25°C). The lowest corrosion rate and the highest corrosion inhibition efficiency were obtained at an inhibitor concentration of 50 ppm. In order to understand whether this new compound was adsorbed on the metal surface, and thereby making the surface hydrophobic, contact angle measurement was performed using the drop method. Adsorption isotherm studies were performed to determine the predominant type of adsorption (physical or chemical) of the compound adsorbed on the steel surface and it was found to be in accordance with Langmuir. In addition, SEM + EDX analysis was performed on the metal surfaces to visually support that the metal is protected against corrosion and theoretical calculations were carried out using Density Functional Theory (DFT) method. © 2025, Russian Association of Corrosion Engineers. All rights reserved.