Use of licorice plant extract for controlling corrosion of steel rebar in chloride-polluted concrete pore solution

The possibility of using licorice extract as a green inhibitor for steel reinforcements in chloride-contaminated simulated concrete pore solution was explored in this study. Different licorice amounts were added to alkaline solutions and then 1% NaCl was also added. Electrochemical studies, up to 24 h, and surface analysis (X-ray photoelectron spectroscopy, Fourier transform infrared spectroscopy and scanning electron microscopy) were performed. Results demonstrated the inhibition effectiveness of the plant extract on steel rebar corrosion, regardless of the concentration, being detected an inhibition efficiency higher than 80 % with electrochemical techniques for 0.1% licorice extract, which showed the most effective performance. Surface analysis methods confirmed the presence of licorice on the surface, through the deposition of organic molecules present in the plant extract on the surface oxide/hydroxide. DFT calculations confirmed that compounds present in licorice can be chemically adsorbed on steel oxide surface. (C) 2021 The Authors. Published by Elsevier B.V.

Automated summary

This study explored the possibility of using licorice extract as a green inhibitor for steel reinforcements in chloride-contaminated simulated concrete pore solution. The results demonstrated the effective inhibition of steel rebar corrosion by licorice extract, with an inhibition efficiency of over 80% for 0.1% licorice extract measured by electrochemical techniques. Surface analysis methods confirmed the presence of licorice on the surface through the deposition of organic molecules on the surface oxide/hydroxide.