The use of methanol extract of Rheum Ribes (Is?g?n) flower as a natural and promising corrosion inhibitor for mild steel protection in 1 M HCl solution

There is a tendency towards natural products with the increase in sensitivity to the environment, people and other living things around the world. In recent years, there has been a similar trend regarding inhibitors used in the metals protection against corrosion. In this study, the adsorption and protection ability of Rheum ribes (RR) flower extract on mild steel (MS) corrosion in 1 M HCl solution were investigated with the help of many electrochemical techniques. The MS surface after exposing to the test solutions was examined by energy dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM) and contact angle measurements. Some thermodynamic parameters corresponding to the adsorption of extract molecules on the MS surface and excess surface charge of the steel in the extract containing solution were calculated and a possible mechanism of the corrosion inhibition process was discussed. The durability of the extract film formed on the MS surface was examined under potentiodynamic and potentiostatic conditions. It was found that an adherent and uniformly distributed extract film formed on the MS surface, which is responsible for the inhibition of corrosion. The flower extract provided 94.7 % and 98.4 % protection efficiencies at 1000 ppm concentration after 1 h and 6 h exposure. RR flower extract mitigated both anodic and cathodic reactions, predominantly cathodic process. The extract molecules interact and bond to the MS surface via physical and chemical interactions. The extract could be suggested as a promising natural corrosion inhibitor for MS protection in 1 M HCl solution. (c) 2023 The Korean Society of Industrial and Engineering Chemistry. Published by Elsevier B.V. All rights reserved.