Effect of Saffron Flower Petal Extract as an Eco-Friendly Corrosion Bioinhibitor for Carbon Steel in 1 mol. L−1 HCl Solution

Abstract

In this report, saffron flower petal extract (SFPE) as an inexpensive, natural, and green corrosion inhibitor for carbon steel in 1 mol. L−1 HCl solution is introduced. Gas chromatography coupled with a mass spectrometry detector (GC–MS) was used to identify the main compounds of saffron flower petal extract. Potentiodynamic polarization and electrochemical impedance spectroscopy as electrochemical techniques were investigated for the determination of corrosion resistance. Morphology and so elemental analysis of surface were analyzed by scanning electron microscopy equipped with energy-dispersive spectroscopy (SEM–EDS). The results showed that by increasing the concentration, the obtained inhibition efficiency is almost 81% and the alloy surface is less corroded. The effect of different temperatures of the solution (298–338 K) on the inhibitor efficiency was investigated that revealed increasing of temperature led to reduces inhibition efficiency, however, it is a suitable value at the highest temperature (74%). The values of positive enthalpy changes show that the corrosion process occurs as endothermic. Results of the Arrhenius plot showed that adsorption of SFPE on the alloy surface is defined as a physicochemical mechanism and so adsorption isotherm is best fitted with the Langmuir model.