Pomegranate peel extract as a sustainable corrosion inhibitor on steel in a simulated concrete pore solution and mortar: Experimental and theoretical studies

Abstract

Various techniques, such as electrochemical impedance spectroscopy, potentiodynamic polarization, linear polarization resistance, and scanning electron microscopy, were used to investigate the inhibitory effect of pomegranate peel extract (PGPE) on the corrosion of carbon steel in a simulated concrete pore solution containing 0.5 M NaCl and in mortar exposed to chlorides. The results obtained revealed that the corrosion resistance of steel, in the presence of the PGPE, was greater than that of the inhibitor-free system, validating the ability of the pomegranate peel extract to produce a protective layer on the steel surface.The optimal concentration of pomegranate peel extract found is around 500 mg/L, with an inhibition efficiency estimated at 97.39%. It is worth indicating that the adsorption of PGPE was found to follow the Langmuir isotherm model. Furthermore, using the principles of quantum chemistry, the adsorption of PGPE constituents on the surface of carbon steel was shown to occur via donor-acceptor interactions.

Graphical Abstract

Highlights

• A plant extract-based inhibitor was developed to prevent steel corrosion in alkaline media.

• The pomegranate peel extract shows a high inhibition efficiency of about 97.39%.

• Passive films on the surface of carbon steel with/without pomegranate peel extract were analyzed by SEM.

• DFT analysis was used to simulate the adsorption processes of the main constituents of pomegranate peel extract.

• Two possible adsorption mechanisms for pomegranate peel extract were proposed.

Keywords:

• Pomegranate peel extract
• corrosion inhibitor
• simulated concrete pore solution
• electrochemical techniques
• inhibitor efficiency
• quantum chemistry

Acknowledgments

The authors gratefully acknowledge the EOLE laboratory, the University of Tlemcen, and the Directorate-General for Scientific Research and Technological Development (DG-RSDT-Algeria) for supporting this work. We also thank the laboratory LRM, Faculty of Science, University of Tlemcen for making the SEM images.

Disclosure statement

The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.

Data availability statement

The data that support the findings of this study are available from the corresponding author, [[email protected]], upon reasonable request.