Abstract
Certain expired drugs could be used as proficient inhibitors for the corrosion of metals which have both economic and ecological profits. Thus, two selected expired drugs, namely, Ticarcillin and Carbenicillin were tested to inhibit the corrosion of aluminum in 1.0 M HCl solution. The techniques used in this paper were weight-loss (WL), potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS) and scanning electron microscopy (SEM). The results illuminated that the inhibition efficiencies (% IEs) of the examined expired drug were increased as the drugs' concentrations increased, while reduced with rising the corrosive solution concentration and temperature. The acquired higher % IEs were declined on the basis of strong adsorption of the drugs' molecules on the aluminum surface and developing protective layer(s) and such adsorption was obeyed Langmuir isotherm. Both thermodynamic and kinetic parameters were determined that confirmed that the nature of adsorption was physical. The kinetics of aluminum corrosion and its inhibition by the employed drugs were studied that confirm the acquired higher % IEs. The examined drugs were set to act as mixed-kind inhibitors with slight anodic predominance. Results obtained from all used techniques revealed that the % IE of Ticarcillin was found to faintly greater than that of Carbenicillin and such used tools were agreed with each others. Finally, the mechanisms of aluminum corrosion in HCl and its inhibition were explained.