Synergistic effect of iodide ions on the corrosion inhibition of mild steel in 1 M HCl by Cardaria Draba leaf extract

Abstract

In pickling or descaling processes, plant extracts have the potential to operate as corrosion inhibitors due to their low impact on the environment, high rate of renewable availability, and plenty of available resources. It was found that mild steel in 1 M HCl can be protected from corrosion by the application of Cardaria Draba leaves (CDL) and potassium iodide (KI). The weight loss method was adopted to study the influences of temperature and blend concentration. Using a CDL-KI blend, the results reveal that the inhibitory efficacy increases with the concentration and temperature of the inhibitor. At higher concentrations and temperatures, 96 % inhibition efficiency was obtained. The Langmuir isotherm model predicted that the mixture would form a monolayer on the metal surface upon adsorption. It was discovered that the adsorption-free energy ranged from 20 to 40 kJ/mol, demonstrating the presence of chemical adsorption. Antagonism was indicated by synergistic parameter (SΘ) values lower than unity. Weight loss data is verified using FTIR and SEM.