Egyptian licorice extract as a green corrosion inhibitor for copper in hydrochloric acid solution

• We evaluated the corrosion inhibition of copper in HCl by Egyptian licorice extracts.
• Egyptian licorice extracts act as a mixed-type inhibitor.
• The adsorption of licorice extracts obey Temkin adsorption isotherm.
• The inhibition efficiency increased with the extract concentration.
• The inhibition efficiency of inhibitor depends on extraction solvent composition.

The inhibition of copper corrosion in 0.1 M HCl by Egyptian licorice extract was investigated by dc polarization, ac impedance techniques. A significant decrease in the corrosion rate of copper in 0.1 M HCl was observed in the presence of licorice extract. The corrosion rate was found to depend on the concentration of licorice extract, temperature and extraction solvent composition. The adsorption of licorice extract on copper surface obeys Temkin isotherm. Polarization data indicated that the licorice extract acts as a mixed-type inhibitor. The values of activation energy for copper corrosion and various thermodynamic parameters were calculated and discussed.

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