Inhibitive Action of New Synthesized Cationic Surfactant with Free Hydroxyl Group on the C1018 Steel Corrosion: Experimental and Theoretical Investigations

Resumo

A new cationic surfactant namely, N-(2-(2-hydroxyethoxy)ethyl)-N,N-dimethylhexadecan-1-ammonium bromide (HEDHB) was prepared and its performance as a corrosion inhibitor for carbon steel in 1.0 M HCl solution was monitored by four techniques (weight loss, potentiodynamic polarization, electrochemical frequency modulation (EFM) and electrochemical impedance spectroscopy (EIS)). The temperature influence on the corrosion rate has been assessed throughout gravimetric technique. The corrosion thermodynamic and the inhibitor adsorption processes were inspected and assessed. The weight loss results confirmed that, the inhibition efficiency of the synthesized HEDHB inhibitor directly proportionally to inhibitor concentration and the temperature. Langmuir’s adsorption isotherm was the best fitted isotherm, which describes the ability of the molecule to adsorb on the steel surface. Tafel polarization reveals that the HEDHB inhibitor suppress both the anodic and cathodic reactions and thus, classified as a mixed-type inhibitor. The morphology of the treated surface with HEDHB inhibitor was monitored by two techniques (Scanning Electron Microscope (SEM) and Atomic Force Microscopy (AFM)). A quantum chemical study has been utilized to investigate the influence of molecular structure of the synthesized HEDHB inhibitor on corrosion inhibition efficiency.