Thorough Examination of Polygonum Aviculare L. Plant Leaf Extract as a Green Corrosion Inhibitor for Mild Steel in 1m Hcl: Synthesis, Characterization, Observations From Surface Analysis, Experimental and Dft Studies

Abstract

Some industrial applications such as oil well acidification, steel pickling, acid descaling and chemical cleaning are carried out in acid environments. During these processes, corrosion of steel is inevitable. This study focuses on the extraction and corrosion behavior of Polygonum aviculare L. (PA) leaf extract as a novel corrosion inhibitor and developing a highly effective, eco-system friendly corrosion inhibitor for mild steel (MS). Corrosion behavior and mechanism of PA leaf extract are revealed on MS in 1 M HCl by Tafel curves, electrochemical impedance spectroscopy (EIS), linear polarization resistance (LPR), zero charge potential, structural and surface analysis and density functional theory (DFT). According to findings, FT-IR results reflected some groups such as -OH, -CH, C-O, C=C, C=O and ether. LC-ESI-MS/MS detected the phenolic acids, flavonoids, phytosteroids and phenolic aldehyde characterized as phytochemicals. PDP, EIS and LPR underscored that corrosion current densities decreased to 0.06 mA cm-2, polarization resistances increased to 457 ohm cm2 and inhibition efficiency increased to 96 %. In the comparison of the inhibition efficiency with the literature, PA extract exhibited outstanding corrosion inhibition efficiency (96 %). The adsorption property of PA extract matched the Langmuir process. PA extract showed an adsorption layer even at high temperatures. This behavior is confirmed by a high value of Ea (53.04 kJ/mol). Almost smooth, more compact, and homogenous surfaces were revealed by SEM. Molecules of phytochemicals in PA extract showed both physical and chemical adsorption. These interactions reduced the MS deterioration from corrosion. According to quantum chemical calculation, chlorogenic acid had the highest corrosion inhibitor efficiency among the other phytochemicals. The findings obtained from this study have the potential to contribute to the advancement of sustainable corrosion protection strategies and can provide basic guidance for industrial applications.