Influence of eco friendly plant material (Cucurbita maxima) on mild steel corrosion

Abstract

PurposeThis paper aims to examine the influence of leaves of Cucurbita maxima (LCM) extract on the corrosion of mild steel (MS) in 1N H2SO4 by gravimetric measurement and electrochemical study. The inhibition efficiency increased with increase in concentration of LCM. The corrosion rate increased with increase in temperature and decreased with increase in concentration of inhibitor compared to blank. The maximum inhibition efficiency of 96 per cent was obtained at 3 per cent v/v LCM at 343K for 1 h. The inhibitory action was explained on the basis of adsorption of secondary metabolites in the plant extract on the mild steel surface. The adsorption process obeys Langmuir, El-Awady, Temkin and Freundlich adsorption isotherms and was best fitted by Langmuir adsorption isotherm. Some kinetic and thermodynamic parameters are also discussed.Design/methodology/approachWeight loss measurements were conducted under total immersion of already weighed mild steel coupons in 100 ml of the test solution containing 0.05, 0.5, 1, 1.5, 2, 2.5 and 3 per cent of LCM extract and in blank solution at different temperature range (303, 313, 323, 333 and 343 K) for 1h. The electrochemical experiments were conducted at room temperature and at various concentrations of LCM extract. The electrochemical experiments were performed using a potentiostat. A three-electrode cell was used for the impedance measurements conducted at open circuit potential.FindingsThe inhibitor (LCM) shows good inhibition performance for the corrosion of mild steel in 1N H2SO4 solution. The inhibition efficiency increased and the corrosion rate decreased with increasing concentrations of inhibitor.Originality/valueThe studied plant material is a new one in mild steel corrosion. The influence of the plant material is clearly explained in the submitted paper.