Di-imine Schiff base inhibitor for carbon steel corrosion in 1 M HCl: Electrochemical, surface and theoretical investigations

Abstract

Many strategies for an efficient inhibitor preparing were proposed for metals protection against corrosion in last decades. Herein, the adsorption and inhibitory effect of aromatic di-imine Schiff base inhibitor (Ar-Sb) namely (N1-(2-(((E)− 4-(dimethylamino)benzylidene)amino)ethyl)-N2-(2-((2-((2(Z)− 4-dimethylamino)ben- zylidene)amino) ethyl) amino) ethyl) amino) ethyl)ethane-1,2-diamine) on carbon steel (CS) in 1 M HCl solution was investigated experimentally and theoretically. The electrochemical measurements (EMs) such as electrochemical impedance spectroscopy (EIS), Potentiodynamic polarization (PDP) and cyclic voltammetry (CV) techniques exhibited the anticorrosion performance of Ar-Sb. Also, the adsorption of Ar-Sb on CS surface at different temperatures and immersion times was studied using PDP and EIS which indicated formation of a protective film layer of Ar-Sb responsible for CS corrosion mitigation. Ar-Sb inhibitor provided 95.79% inhibition efficiency at 5 × 10−4 M which reflected blocking of CS active sites through the adsorption process which was studied using various adsorption isotherms. CS surface morphology was studied using scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and atomic force microscope (AFM) reflecting the inhibition role of Ar-Sb in CS protection. The data obtained from PDP suggested that Ar-Sb inhibitor acted as mixed-type inhibitor. Also, quantum calculations such as density functional theory (DFT) and Monte Carlo (MCs) verified the inhibitive performance of Ar-Sb for CS surface with the experimental results.