Mild steel deterioration inhibition in 1.0M and 5.0M tetraoxosulphate (VI) acid using leaf extract of Pterocarpus santaliniodes

Abstract

The prevention of deterioration of mild steel in 1.0M and 5.0M H₂SO₄ solution by leaf extracts of Pterocarpus santaliniodes was investigated in this study using gravimetric and gasometric methods. Data obtained from the study revealed that leaf extracts had a maximum inhibition efficiency of 88.70% and 96% for weight loss and gasometric analysis, respectively for 1.0M H₂SO₄, and an inhibition efficiency of 71.76% and 79.66% for weight loss and gasometric analysis respectively for 5.0M H₂SO₄. It was observed that the gasometric method gave the optimum protection. The average activation energy was 73.71KJ/mol in 1.0M H₂SO₄, and 74.41KJ/mol in 5.0M H₂SO₄. The adsorption of the phytochemicals on the surface of the mild steel were further assessed by the Langmuir and Freundlich isotherms. The extract was found to be good inhibitor for mild steel corrosion in the H₂SO₄ solutions. The amount of material loss decreased in the in the presence of the extract when compared to the blank acid solution.

Keywords: Mild steel, Corrosion inhibition, H₂SO₄, Pterocarpus santaliniodes