S.A. Odoemelam,1 E.C. Ogoko,1 B.I. Ita,2 N.O. Eddy3,*
1Department of Chemistry, Michael Okpara University of Agriculture, Umudike, Abia State, Nigeria
2Department of Chemistry, University of Calabar, Calabar, Nigeria
3Department of Chemistry, Ahmadu Bello University, Zaria, Kaduna State, Nigeria
Received 24 September 2008; accepted 6 November 2008
]]> Abstract
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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* Corresponding author. E-mail address: nabukeddy@yahoo.com
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