Steel Corrosion Inhibition by Bupleurum lancifolium (Apiaceae) Extract in Acid Solution

The ethyl acetate extract of the aerial parts of Bupleurum lancifolium (Apiaceae) is tested as corrosion inhibitor of carbon steel (API 5L Gr B) in 1.0 M HCl and 0.5 M H 2 SO 4 solutions using weight loss measurement, electrochemical impedance spectroscopy and potentiodynamic polarization techniques. The results revealed that the corrosion inhibition efficiency increases with increasing extract concentration. Potentiodynamic polarization curves indicated that the plant extract behaves as a mixed-type inhibitor. The adsorption of inhibitor on carbon steel surface was found to follow Langmuir isotherm. The effect of temperature on the corrosion behavior of API 5L Gr B steel in acid solutions with and without plant extract was studied in the range 293–333 K. Surface analyses via scanning electron microscope shows a significant improvement on the surface morphology of the steel.