Study of the inhibition effect of a new cationic surfactant on mild steel corrosion in a 1 M HCl solution

Abstract

6-(2,3-dioxoindolin-1-yl)-N,N,N-trimethylhexan-1-ammonium bromide 3, a cationic surfactant, was synthesized and characterized by different spectroscopic techniques (nuclear magnetic resonance and High-resolution mass spectrometry (1H NMR, 13C NMR, and HRMS)). The effect of the cationic surfactant on the corrosion of mild steel in a 1 M HCl solution at temperatures between 298°K and 328°K has been assessed using the weight loss method and various electrochemical techniques (potentiodynamic polarization and electrochemical impedance spectroscopy (EIS)). The results of this study showed that the synthesized surfactant is an efficient corrosion inhibitor for mild steel in 1 M HCl. The inhibition efficiency reached 92.98% after 6 h of immersion at 298 K using a concentration of 1 mM. Both kinetic and thermodynamic parameters of the corrosion and inhibition process were investigated. As surfactant concentration increases, the corrosion inhibition efficiency (IE%) increases. Besides, it was found that the cationic surfactant adsorption on the surface of the mild steel followed the Langmuir isotherm. Also, electrochemical impedance spectroscopy (EIS) and potentiodynamic polarization measurements showed that the inhibitor was considered as a mixed inhibitor with an anodic dominant character.