The corrosion inhibition effect of Licorice hydroalcoholic extract (Licorice extract) was investigated as a green corrosion inhibitor for API 5L Gr.B carbon steel in CO2 environment, using Tafel polarization and electrochemical impedance spectroscopy (EIS) methods. The results showed that Licorice extract can be effective corrosion inhibitor in the CO2 environment and act as an anodic inhibitor. The measurement data revealed that inhibition efficiency increased with the increase of Licorice extract concentration. Thermodynamic calculations indicated that adsorption behavior of Licorice extract on the steel surface obeys Langmuir adsorption isotherm and Licorice extract physically-chemically adsorbed on the steel surface in which adsorption process was spontaneous.
