Investigation of the synergistic effect of potassium iodide (KI) on the corrosion inhibition properties of morus alba pendula leaves extract on mild steel in 1 M HCl solution

Morus alba pendula leaves extract (MAPLE) was used as a new green corrosion inhibitor for the corrosion protection of carbon steel in 1M HCl solution. The synergistic effect between potassium iodide (10 mM KI) and MAPLE (0.4 g/l) was studied by electrochemical impedance spectroscopy (EIS). Surface morphology of the steel specimens exposed to the HCl solutions was investigated by an atomic force microscope (AFM). Results obtained from electrochemical measurements revealed that a high inhibition efficiency value of 93% was achieved in the presence of 0.4 g/l MAPLE at room temperature (25 °C). A synergistic effect was observed between KI and MAPLE with optimum concentration of 0.4 g/L MAPLE+ 10 mM KI. The inhibition efficiency was significantly increased (up to 96%) by addition of KI obeying a langmuir adsorption isotherm.