Investigation of the Effect of Penicillin as a Green Corrosion Inhibitor for Mild Steel Using Electrochemical Techniques

In this paper, the effect of penicillin G drug as a green corrosion inhibitor on mild steel in 1.0 M hydrochloric acid solution has been investigated using potentiodynamic polarization, electrochemical impedance spectroscopy (EIS) and electrochemical noise (EN) techniques. The inhibition efficiency was found to increase with increasing inhibitor concentration. Potentiodynamic polarization measurements indicated that penicillin G is a mixed type inhibitor. Furthermore, it has been demonstrated that the electrochemical noise (EN) technique under open circuit conditions as the only truly noninvasive electrochemical method can be employed for the quantitative evaluation of corrosion inhibition. This can be done using the standard deviation of partial signal (SDPS) for calculation of the amount of noise charges at the particular interval of frequency, thereby calculate the inhibition efficiency (IE) of an inhibitor. These IE values show a reasonable agreement with those obtained from potentiodynamic polarization and EIS measurements.