Adsorption and inhibiting properties of Cleome Droserifolia extract on the corrosion of AISI 1018 carbon steel in hydrochloric acid solution

The inhibitory effect using Cleome droserifolia extract as corrosion inhibitor for 1018 carbon steel (CS) in one molar hydrochloric acid has been studied. This study was carried out using chemical methods such as mass loss method (ML), DC potentiodynamic polarization (PDP), AC impedance (EIS), and electrochemical frequency modulation (EFM) techniques. Results obtained from these methods showed that with increasing the concentration of Cleome droserifolia extract the inhibition efficiency (%IE) increases and reaches 92.1% at 600 ppm, 25 degrees C from the ML method. The adsorption of these derivatives on the CS surface was used to explain the inhibition. According to the values of Delta G(ads)(0), which ranged from 16.8 to 018.3 kJ center dot mol(-1), the adsorption of the extract molecules on the CS surface is physical adsorption. The inhibitor was of mixed kind according to the polarization curves (it affects both anodic and cathodic processes). It was found that these derivatives follow Langmuir adsorption isotherm. Several surface inspection methods have been used. Also, surface checks were utilized to illustrate the importance of this Cleome droserifolia extract to prevent corrosion process for CS. It was found that all of these used methods are in agreement with each other.