Electrochemical Study of Inhibition of Corrosion of Copper by Ofloxacin in Acid Media

The inhibition efficiency of ofloxacin, a fluoroquinolone on the corrosion of copper in acids has been studied employing polarisation, EIS and weight loss measurements. Ofloxacin exhibited good inhibition efficiency and the inhibition action was observed to be of mixed type, but with more of cathodic nature. Determination of Potential of zero charge established the mechanism of adsorption of the inhibitor onto the metal surface. From the temperature dependence of the corrosion rates, the activation energy (Ea) and the thermodynamic parameters such as the adsorption equilibrium constant (Kads) and the free energy of adsorption (ΔGads) were calculated. The free energy of adsorption close to -40kJmol-1 indicates that the adsorption is through electrostatic coulombic attraction and chemisorptions, and it obeyed Langmuir adsorption isotherm. Among the potassium halides, only KI improved the inhibition efficiency of ofloxacin by synergism. The structural features obtained by quantum chemical calculations were also supportive of the experimental results.