Experimental and Theoretical Investigations of Adsorption and Inhibitive Properties of Tween 80 on Corrosion of Aluminum Alloy (A5754) in Alkaline Media

Abstract

Abstract The inhibition behavior of Polyoxyethylene (20) sorbitan monooleate (Tween 80) as a non-toxic corrosion inhibitor for aluminum alloy (A5754) was investigated in 0.5 M NaOH solution by means of polarization measurement and quantum chemistry method. A significant inhibition in the corrosion rate of A5754 in NaOH solution was observed in the presence of Tween 80. As a result of adsorption of the inhibitor on the metal surface, the inhibition of this compound increases with its concentration but decreases with temperature. Polarization curves showed that Tween 80 acted as mixed inhibitor. The adsorption of Tween 80 obeys the Langmuir adsorption isotherm. Comprehensive adsorption (physisorption and chemisorption) of the inhibitor molecules on the A5754 surface was suggested based on the thermodynamic adsorption parameters. Correlation between quantum chemical calculations and inhibition efficiency of the investigated compounds was discussed using DFT method.