Adsorption and corrosion inhibition capability of Rheum ribes root extract (Is?g?n) for mild steel protection in acidic medium: A comprehensive electrochemical, surface characterization, synergistic inhibition effect, and stability study

The adsorption and inhibitory effect of Rheum ribes (RR) root extracts on mild steel (MS) corrosion in 1 M HCI solution were examined by electrochemical techniques. The characteristics of the electrode surface after exposure to corrosive solutions were investigated using scanning electron microscopy (SEM) and atomic force microscopy (AFM). The chemical composition and the distribution of the surface film was examined with energy dispersive X-ray spectroscopy (EDX). The hydrophilic or hydrophobic properties of the MS surface were investigated using contact angle (CA) measurements. According to the findings, molecules of RR root extract adsorb to the metal surface, which form a protective and uniform film. Increasing the concentration of RR root extract improves the resistance of the alloy's surface to corrosion attacks. The extract acts as a mixed-type corrosion inhibitor with dominantly cathodic action. The molecules of the extract predominate the anodic reaction in the presence of iodide ions. Physical interactions are the most important in the extract molecule adsorption. The synergy between the iodide ions and the molecules of the extract improves the extracts protection ability and the film's stability. The film of extract molecules on the surface of the steel reduces surface deterioration and increases hydrophobicity. (c) 2023 Elsevier B.V. All rights reserved.