Study of Bitter Leaves Extract as Inhibitive Agent in HCl Medium for the Treatment of Mild Steel through Pickling

Abstract

Bitter leaves extract as inhibitive agent in HCl me dium for the treatment of mild steel through pickling was studied. Thermometric, gravime tric and potentiodynamic polarization methods were employed in the corrosion inhibition study. The bitter leaves extract was analyzed using gas chromatography-mass spectrometer. The analysis of the extract revealed the presence of C 6H8O (96 g/mole: 2,4-Hexadienal); C 7H12 (96 g/mole: 3,4-Heptadiene; 1,3-Diethylallene) and C 10H18O2 (170 g/mole: 2-Decenoic acid) as the predominant chemical constituents. The activation e nergy for the corrosion inhibition process ranged from 39.831 to 77.533 kJ/mol, while t e heat of adsorption ranged from -16.093 to -30.224 kJ/mol. These values showed that exothermic and spontaneous adsorption of the extract on the mild steel followe d the mechanism of physical adsorption. Maximum inhibition efficiency of 85.4% was obtained. The extract was highly efficient in the corrosion inhibition functi on. The plant-based inhibitor of bitter leaves extract is a suitable additive for pickling, cleaning and descaling operations.