Adsorption of IFKhAN-92 Corrosion Inhibitor from Acidic Phosphate Solution on Low Carbon Steel

Abstract

Adsorption of an IFKhAN-92 inhibitor, triazole derivative, on low carbon steel from 2.0 M H3PO4 (22 ± 1°C) has been studied using impedance spectroscopy. It is demonstrated that its adsorption is described by the Temkin isotherm with relatively high free adsorption energy (–ΔGads) = 51 ± 1 kJ/mol. It is suggested that the inhibitor adsorption is of chemisorption pattern, which is confirmed by description of adsorption kinetics by the Roginsky–Zeldovich equation. It is illustrated that the addition of 0.5 mM KCNS into H3PO4 solution increases the rate constant in the Roginsky–Zeldovich equation for adsorption of IFKhAN-92 on a steel surface and, consequently, accelerates this process in time.