Organic compound as inhibitor for corrosion of aluminum in sulphuric acid solution

Abstract

The corrosion behavior of aluminum in H2SO4 solution was investigated by weight loss method in absence and presence of organic compound (glutaraldehyde) as inhibitor. Inhibition efficiency (I.E) was found to increase with increasing inhibitor concentration from 0.02 to 0.10 M and decrease as temperature increased. The activation energy value was 36.91 kJ/mol in uninhibited acid solution which increased to 61.80 kJ/mol in the presence of the inhibitor. The values of activation energy were found to increase with increase in inhibitor concentration due to the adsorption of more inhibitor molecules on the metal surface. The positive and negative values of enthalpy and entropy signified the endothermic adsorption process and formation of an ordered system. The negative value and low values of Gibbs’s free energy of adsorption indicate the spontaneous and physical adsorption mechanism of the adsorption process. The adsorption of inhibitor on the metal surface was found to accord with Langmuir adsorption isotherm. Fourier transform infrared spectroscopic analysis, scanning electron microscopic analysis, surface and functional group characterization supported the inhibitive effect of the glutaraldehyde at the metal surface