Adsorbability of Thiourea on Iron Cathodes

Abstract

Abstract The adsorption of thiourea on iron cathodes has been studied in 0.1 N sulphuric acid solution containing 10 −1 and 10 −2 Mol of thiourea at 30, 40 and 50 °C. The surface coverage has been calculated by comparing current density (at constant potential and temperature) of solutions with and without inhibitor. The results show that adsorption is due to specific adsorption forces of molecules and HS − anions as well as to electrostatic forces of cations. The authors have determined the adsorption energy and the enthalpy, free standard energy and entropy of adsorption. On the basis of these results it is feasible to presume that thiourea would be rather efficient an inhibitor of the corrosion for iron acid solution.