Carbon steel corrosion inhibition by rind and leaves extracts of grapefruit in 1.0 M hydrochloric acid

Extract of grapefruit rind (gfr) and grapefruit leaves (gfl) was investigated as corrosion eco-friendly inhibitor of carbon steel in 1.0 m hcl acid using a conventional weight loss measurements,electrochemical technique as potentiodynamic polarization methods and electrochemical impedance spectroscopy (eis) techniques. the electrochemical polarization data revealed the mixed mode of inhibition. the obtained results showed that all the extracts are excellent corrosion inhibitors and their adsorption on the carbon steel surface follows the langmuir isotherm model in acidic media. the results of electrochemical impedance spectroscopy have shown that the change in the impedance parameters,charge transfer resistance and double layer capacitance,with the change in concentration of the extract is due to the adsorption of active molecules leading to the formation of a protective layer on the surface of carbon steel. the extracts were found to inhibit the corrosion of carbon steel in 1.0 m hcl solutions and the inhibition efficiencies of the extracts follow the trend: gfr > gfl. some thermodynamic functions of dissolution process were also determined and discussed. © 2017,university of mohammed premier oujda morocco.