Inhibition effect of pomelo peel extract for N80 steel in 3.5% NaCl saturated with CO 2 solution

Pomelo peel extract (PPE) has been evaluated as a corrosion inhibitor for N80 steel in 3.5% NaCl saturated with CO 2 solution using weight loss measurements, Fourier transform infrared spectroscopy, potentiodynamic polarization, electrochemical impedance spectroscopy, scanning electron microscopy (SEM), scanning electrochemical microscopy (SECM) and quantum chemical calculations. The inhibition efficiency was found to increase with increasing PPE concentration. Potentiodynamic polarization measurements indicated that the PPE was a mixed type inhibitor. The adsorption of PPE obeyed the Langmuir adsorption isotherm and mainly the physical adsorption. The SECM and SEM studies were used to investigate adsorbed film on the N80 steel surface. Quantum chemical calculation indicated that the major component of the PPE has more tendencies for adsorption.