Inhibitory effects of marigold leaves extract on the mild steel corrosion in 0.5 M sulphuric acid solution

Abstract

The corrosion inhibition function of extract of marigold leaves on mild steel in 0.5 M H₂SO₄ was investigated using weight loss measurements, UV-Visible and scanning electron microscope (SEM) surface analysis as well. The adsorption mechanism follows Langmuir’s adsorption isotherm. The inhibition efficiency was found to be 90.51% at optimum concentration of inhibitor at 298 K in 0.5 M H₂SO_4. The values of the free energy of adsorption strongly supported physisorption mechanism of inhibitor components on the mild steel surface. SEM analysis shows a significant improvement on the mild steel surface morphology in the presence of inhibitor.

Keywords: Adsorption; Corrosion; marigold leaves; SEM