Thermodynamic and Adsorption Studies of Salvia Officinalis as A Green Corrosion Inhibitor for Steel at 1 M Sulfuric Acid

This study includes the temperature effect on the performance of the corrosion inhibitor (Salvia officinalis) that is used in different concentrations (570, 1119, 1647) ppm in acidic medium (1M H₂SO₄) of mild steel using the weight loss method. The result has shown that the extract is a good inhibitor of the corrosion of mild steel in H₂SO₄. The corrosion rate drops with an increase in the concentration of inhibitors and rises with an increase in temperature. In contrast, the inhibition efficiency grows with an increase in the inhibitor concentration and reduces with an increase in temperature. Standard free energy of adsorption estimated based on the Langmuir model was -26.66 kJ/mol at 22 °C. The adsorption of this inhibitor on the mild steel surface conforms to Langmuir adsorption isotherm.