Cefixime: A drug as Efficient Corrosion Inhibitor for Mild Steel in Acidic Media. Electrochemical and Thermodynamic Studies.

Abstract

The corrosion inhibition of mild steel in 1M HCl solution by Cefixime was studied ate temperature range 303–333K by weight loss measurement and electrochemical techniques i.e. Polarization Resistance, Potentiodynamic Polarization and Electrochemical Impedance Spectroscopy (EIS). The results obtained at 30oC divulged that this pharmaceutical compound had established > 90% inhibition efficiency at an optimum concentration of 8.8×10−4M. The outcomes show that inhibition takes place by adsorption of the inhibitor on metal surface without altering the mechanism of corrosion process. The adsorption of Cefixime takes place according to Langmuir`s adsorption isotherm. Kinetic parameters (activation energy, and pre-exponential factor, X) as well as thermodynamic parameters (enthalpy, entropy and free energy of adsorption; , and respectively) were calculated and discoursed. Potentiodynamic polarization studies indicate that Cefixime acts as a mixed type of inhibitor. Data collected from EIS studies has been analyzed to model the appropriate equivalent circuit for better explanation of corrosion inhibition process. The inhibition mechanism of Cefixime has also been discussed.