Inhibition of the corrosion of iron in acidic solution by the oligomeric surfactant N, N, N′, N″, N″-pentamethyl diethyleneamine-N, N″-di-[tetradecylammonium bromide]

Abstract

[Purpose] The purpose of this investigation is the evaluation of the inhibitive performance of a new "gemini" surfactant in the series of bis-quat: N, N, N′, N″, N″-pentamethyl diethyleneamine-N, N″-di-[tetradecylammonium bromide] on the corrosion of iron in 1 M HCl by gravimetric, potentiodynamic and electrochemical impedance measurements. The effect of the temperature on the corrosion behavior of iron in 1 M HCl without and with inhibitor is studied in the temperature range (298-333 K). This work also attempts to correlate thermodynamic and kinetic parameters with the inhibition effect.

[Design/methodology/approach] The inhibition efficiency of gemini synthesized is investigated by weight loss, potentiodynamic polarization and impedance spectroscopy methods.

[Findings] The synthesized gemini bis-quat acted as a good inhibitor in 1 M HCl, and inhibition efficiency increased with inhibitor concentration and temperature. Polarization curves showed that the surfactant was a mixed-type inhibitor in hydrochloric acid. Impedance spectroscopy measurements showed that the inhibitor acted through the formation of a multilayer film at the iron surface. The adsorption of inhibitor on the iron surface obeyed the Langmuir adsorption isotherm equation. The inhibition effect was satisfactorily explained by both thermodynamic and kinetic parameters.

[Originality/value] The adsorption of surfactants in the metal surface can markedly change the corrosion resisting property of the metal. So the study of the relation between the adsorption and corrosion inhibition is of a great importance. This was the first attempt to study the inhibition properties of gemini surfactants at the host laboratory.