Abstract

ODOEMELAM, S.A.; OGOKO, E.C.; ITA, B.I.  and  EDDY, N.O.. Inhibition of the Corrosion of Zinc in H₂SO₄ by 9-deoxy-9a-aza-9a-methyl-9a-homoerythromycin A (Azithromycin). Port. Electrochim. Acta [online]. 2009, vol.27, n.1, pp.57-68. ISSN 0872-1904.

Inhibition of the corrosion of zinc in various concentrations (0.01 to 0.05 M) of H₂SO₄ was studied using weight loss and hydrogen evolution methods of monitoring corrosion. The results revealed that various concentrations of azithromycin (0.0001 to 0.0005 M) inhibited the corrosion of zinc in H₂SO₄ at different temperatures (303 to 333 K). The concentration of H₂SO₄ did not exert significant impact on the inhibition efficiency of azithromycin, but inhibition efficiencies were found to decrease with increase in the concentration of the inhibitor. Values of inhibition efficiency obtained from the weight loss measurements correlated strongly with those obtained from the hydrogen evolution measurements. The activation energies for the corrosion of zinc inhibited by azithromycin were higher than the values obtained for the blank. Thermodynamic data revealed that the adsorption of azithromycin on the surface of zinc was endothermic (values of enthalpies of adsorption were positive), spontaneous (values of free energies of adsorption were negative) and was consistent with the adsorption model of Langmuir.

Keywords : Corrosion inhibition; zinc; azithromycin.

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