Studies on the inhibitive effect of exudate gum from Dacroydes edulis on the acid corrosion of aluminium

The inhibitive effect of exudate gum from Dacroydes edulis in the corrosion of aluminium in HC1 solutions was studied using weight loss and thermometric methods at 30-60 °C. The results reveal that the exudate gum acts as an inhibitor for corrosion of aluminium in HC1 solution. The inhibition efficiency increases with an increase in the concentration of the exudate gum but decreases with increase in temperature. The Temkim adsorption isotherm was tested for its fit to the experimental data. The result confirms that the corrosion inhibition of the exudate gum from DE is attributed to the adsorption of molecules of phytochemicals present in the exudate gum on the surface of the metal. The free energies and equilibrium constant for the adsorption process were determined. A mechanism of physical adsorption is proposed.