Datura stramonium plant seed extracts as a new green corrosion inhibitor for mild steel in 1M HCl solution: Experimental and surface characterization studies

The influence of different seed extracts of Datura stramonium plant obtained by different solvents (hexane, ether, chloroform, and methanol) on the corrosion of mild steel in 1 M HCl solution was investigated. The corrosion rate and inhibition efficiency of the extracts were investigated using the gravimetric method (weight loss), potentiodynamic polarization, and electrochemical impedance spectroscopy. The results demonstrated Datura stramonium extracts high performance, with a maximum of 94.2% percent for the methanolic extract at a concentration of 0.2 g L−1. The polarization curves obtained in the presence of different extracts of Datura stramonium seeds revealed that the inhibitors were of mixed type in nature and preferentially blocked the active sites responsible for corrosion. Inhibited analysis of the electrolyte by UV-visible spectroscopy provides concrete evidence of the complexation of the iron cation with the extracts in 1 M HCl. In addition, four different adsorption isotherm were used to model the corrosion inhibitor on the carbon steel surface and the analysis shows that the type of adsorption is mainly physical adsorption. The formation of a protective layer of inhibitor on the surface of mild steel was confirmed using scanning electron microscopy (SEM/EDX).