Application of Expired Alprazolam Drug as Corrosion Inhibitor for Aluminum in 3 M HCl Environment

Abstract

The aim of the present research is to examine the application of expired alprazolam drug as a corrosion inhibitor for aluminum (Al) in 3 M hydrochloric acid (HCl) solution. The corrosion protection of expired alprazolam drug was screened by plotting the Tafel plot and conducting impedance spectroscopy, gasometric and quantum chemical studies. The protection efficiency of the alprazolam drug exceeds 90% at the concentration of 1.2 g/L of the drug at 60◦C. The electrochemical Tafel plot shows that the examined drug acts as mixed type. Impedance spectroscopy results show that increasing the amount of expired alprazolam drug enhances the value of charge transfer resistance around the electrode-solution interface. Gasometric studies show that the presence of expired alprazolam drug decreases the volume of hydrogen (H2) gas evolution. Also, quantum chemical calculations were done to calculate the inhibition mechanism. Thus, the expired alprazolam drug can be used as an inexpensive and nontoxic corrosion inhibitor for the studied system.