Moroccan, Mauritania, and senegalese gum Arabic variants as green corrosion inhibitors for mild steel in HCl: Weight loss, electrochemical, AFM and XPS studies

Corrosion prevention in the food industry is a significant issue given the harsh conditions under which many production processes are performed. Therefore, we developed a methodology to test and analyze the novel type of green corrosion inhibitors for mild steel (M.S) in an acidic medium based on the Arabic gum (GA) variants from Morocco (GAMo), Mauritania (GAMau), and Senegal (GASe) in which these three variants were characterized by FTIR analysis, Weight loss (WL) measurements and electrochemical tests such as potentiodynamic polarization (PDP) and electrochemical impedance spectroscopy (EIS) methods were also used to investigate the inhibition power of these compounds for the corrosion of M.S in 1 M HCl. The surface characterization of M.S surface submerged in the optimal solution of the three compounds was carried out using XPS and AFM analyses. The results from this corrosion test demonstrate that these chemical compounds might be used as mixed-type corrosion inhibitors achieving the highest inhibition at 1 g/L, and the eta(max) of GAMo, GASe and GAMau reached up to 96%, 95% and 94%, respectively. Spectroscopic and gravimetric analyses revealed that the highest corrosion inhibition for the GAMo variant due to the physical and chemical mechanism according to the pattern: GAMo > GASe > GAMau. The Langmuir adsorption isotherm governs the adsorption of all GA variants on mild steel surfaces, increasing the polarization resistance and inhibition efficiency and decreasing the double-layer capacitance in a concentration-dependent manner. A CPE, Q determined by fit and graphical methods plotted by synthetic data, was utilized. Using atomic force microscopy (AFM) and X-ray photoelectron spectroscopy, the formation of a protective layer on the steel surface was further confirmed (XPS). The final QSAR model for the Arabic gum indicated the same effect of lipophilicity on corrosion inhibition. Overall, the current study provides valuable information on the AG variants to be used as a novel class of green corrosion inhibitors for the biotechnology and food industry. (C) 2021 Elsevier B.V. All rights reserved.