Corrosion inhibition of SAE 1018 carbon steel in H2S and HCl solutions by lemon verbena leaves extract

H2S and HCl can be noted among the most important corrosive factors existing in different parts of the oil industry. This study was performed to investigate the corrosion taking place in those parts of oil industry which simultaneous presence of both HCl and H2S are considered. The corrosion inhibition behavior of lemon verbena leaves extract on carbon steel in H2S and HCl solutions was studied by means of methods such as, Tafel polarization and electrochemical impedance spectroscopy (EIS). Tafel polarization plots showed that the lemon verbena extract acts as a mixed-type inhibitor. The adsorption mechanism was found physisorption. ΔGads0 and kads were determined and discussed and Langmuir isotherm was selected as the best fitted adsorption isotherm. According to the obtained results, the maximum value of inhibition efficiency was obtained about 95.61% in the presence of 2.7 g/L, lemon verbena extract.