Inhibition of zinc corrosion by glycerol stearate in 1.0M hydrochloric acid medium with experimental, theoretical, and electrochemical techniques

Abstract

Glycerol Stearate (GS) was investigated as a corrosion inhibitor via weight loss on zinc (Zn) metal inside 1.0M hydrochloric acids (HCl). Different electrochemical techniques such as potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS) and characterization methods were used in the study. Weight loss measurements and inhibition efficiency (IE) were used to calculate the amount of weight loss and to scrutinize the effect of inhibition concentration on the metal in HCl, and it demonstrated that weight loss decreased as the inhibition concentration increased, and percentage inhibition efficiency increased with increasing inhibition concentration. The Corrosion rate () was calculated, and it was observed that it decreased with the increasing inhibition concentration but increased with an increase in temperature. The compound of inhibitor effectively prevented corrosion by becoming adsorbed to the metal surface and was confirmed by Fourier transform infrared spectroscopy (FTIR). Free Gibbs energy (FGE) demonstrated a spontaneous corrosion process at the metal surface of zinc and the scanning electron microscope (SEM) was used to investigate the surface morphology of the protective layer and confirmed that the adsorption of glycerol stearate was via physisorption adsorption. The adsorption of glycerol stearate on the metal surface was found to follow the Langmuir adsorption isotherm model.