Green approach towards the corrosion suppression effect of carbon steel against an aggressive medium of 1 M HCl from peanut shells: Electrochemical examinations coupled with theoretical insights

Abstract

The present work focuses on examining the corrosion inhibition activity of an aqueous green extract derived from peanut shell waste for carbon steel in 1 M HCl. The electrochemical tests evinced a notable inhibitory efficiency of the peanut shell extract (PSE). Total polyphenol and flavonoid content, as well as FT-IR analysis, were performed to explore the phytochemical abundance of the PSE, the results show the existence of polyphenol and flavonoid families in the aqueous extract of PSE. The electrochemical measurements PDP and EIS showed an optimum inhibition efficiency (IE) reaching 81% using 2 g/L of PSE at 293 K. The effect of temperature indicated that the mode of adsorption of PSE is physisorption. SEM-EDX analysis of the carbon steel surface texture was conducted to explore the PSE behavior at the surface. Based on Density Functional Theory (DFT) calculations at B3LYP/6-311 + G (d,p) level of theory, the anticorrosive effect of the main components of the aqueous green extract of peanut shells: Luteolin, (LTN) resveratrol (RVT) and p-hydroxybenzoic acid (HBA) was investigated, The HOMO and LUMO electron densities, as well as the molecular electrostatic potential maps, were used to identify the electron-rich and electron-poor regions. The most relevant global and local quantum chemical reactivity descriptors were also calculated and discussed. The results revealed that the inhibition efficiency of the investigated inhibitor molecules can be arranged as follows: RVT ≈ LTN ≫> HBA.