Corrosion inhibition effect of benzaldehyde (Methoxybenzene) for Aluminium in sulphuric acid solution

Abstract

Corrosion inhibitory effect of benzaldehyde (methoxybenzene) on aluminium in sulphuric acid media was studied by weight loss measurement and characterization was carried by FTIR analysis. From the results it was found that increase in inhibitor concentration lead to the increase in inhibition efficiency and decreases when the temperature increased. Plots of ln (wi - Δw) against time gave a linear graphs which confirmed a first order reaction mechanism for aluminium in inhibited and uninhibited acid solution. The activation energy value of uninhibited acid solution was found to be 36.39 kJ/mol which increased to 62.32 kJ/mol when 0.1 M concentration of the inhibitor was added. There was a decreased in the values of the rate constant from uninhibited to inhibited acid solution while those of half-life increased from uninhibited to inhibited acid. The obtained values of entropy change (ΔS), enthalpy change (ΔH) and Gibbs free energy of adsorption (ΔGads) were also evaluated and discussed. The activation energy values and that of Gibbs free energy of adsorption support the physisorption mechanism between the molecules of the inhibitor and Aluminium surface