Peganum Harmala Seeds as A Sustainable Source of Pickling Inhibitor for Zinc: Anti-Oxidant Properties, Adsorption Behaviour, Electrochemical Studies, and Synergistic Effect

Document Type : Original Article


1 Environmental and Structural Molecular Chemistry Research Unit (UR-CHEMS), Faculty of Exact Sciences, University Constantine 1, Constantine 25000, Algeria

2 Department of Chemistry, Faculty of Exact Sciences, University of Constantine 1, Constantine 25000, Algeria


The presence of various antioxidants in the ethanolic extract of Peganum harmala L. (EEH) seeds with different oxidation potentials was confirmed by cyclic voltammetry. The evaluation of the inhibition efficiency of the extract on zinc corrosion in the hydrochloric acid medium was carried out by gravimetry and electrochemical techniques. The results showed that the extract has satisfactory corrosion-inhibiting properties and that its efficiency is controlled by its concentration and medium temperature. The inhibition rate reached 96.8% in the presence of 2200 ppm of the EEH extract at 298K. The potentiodynamic polarization study showed that the extract is classified as a mixed-type inhibitor with a cathodic predominance. A good agreement between the results of the gravimetric study and those of the electrochemical measurements was demonstrated. The studied extract acts by physical adsorption, as indicated by the thermodynamic parameters, and follows the Langmuir model. The inhibition efficiency of the studied extract was improved in the presence of KI through a synergistic effect.


Main Subjects