Adsorption and inhibition effect of 2-thiohydantoin on mild steel corrosion in 0.1 M HCl

2-Thiohydantoin (2-THD) was investigated as a corrosion inhibitor of mild steel (MS) in 0.1 M HCl solution using potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), and linear polarization resistance (LPR) measurements. The effects of temperature, hydrogen gas evolution and change of open circuit potential with immersion time were also studied. The MS surfaces with, and without inhibitor has been characterized by SEM. The results showed that 2-THD acts as a mixed type inhibitor in 0.1 M HCl by suppressing simultaneously the cathodic and anodic processes via physical adsorption on the MS surface followed by the Langmuir adsorption isotherm.

► 2-Thiohydantoin (2-THD) is investigated as a corrosion inhibitor of mild steel.
► 2-THD inhibits corrosion of mild steel in 0.1 M HCl solution.
► 2-THD behaves as mixed-type inhibitors.
► The adsorption of 2-THD on mild steel surface obeys Langmuir adsorption isotherm.