Amélioration de la résistance à la corrosion du cuivre dans un milieu acide par l'utilisation d'un médicament périmé

Abstract

The study of the inhibitory effectiveness of the expired pharmaceutical product (Prédo) against copper corrosion in a 1M acid solution was conducted using the gravimetric method. Several key parameters were examined, including concentration, temperature, and immersion time. The maximum inhibitory efficiency of the pharmaceutical product, reaching 90%, was observed at an inhibitor concentration of 1.25% v/v and a temperature of 323K for one hour. An increase in temperature leads to an increase in inhibitory efficiency, while an increase in the amount of inhibitor also enhances inhibition. However, extending the immersion time has a negative effect on the inhibitor's effectiveness. The adsorption of the inhibitor on the copper surface follows the Langmuir isotherm model. The thermodynamic parameters of adsorption indicate that the process is endothermic and that the inhibitor adsorption occurs spontaneously, forming a protective layer on the metal surface. The study also shows that the activation energy of the inhibited solutions is lower than that of the control solution, suggesting that the copper dissolution process is affected by the increase in temperature. Positive values of ∆Sa indicate that an increase in disorder occurs during the transition from reactants to the activated complex.