ABSTRACT

Inhibition of the corrosion of zinc in various concentrations (0.01 - 0.05M) of tetraoxosulphate (vi) acid was studied using weight loss and hydrogen evolution methods of monitoring corrosion. Azithromycin, erythrornycin, clarithromycin and lincomycin were the inhibitors used for this research work in the concentration range of 0.000 1 to 0.0005M.The inhibitive properties, adsorption characteristics, the effect of various concentrations of tetraoxosulphate (vi) acid and temperature (303 to 323K) on corrosion of zinc, and some kinetic parameters were studied. The results revealed that the corrosion of zinc in tetraoxo sulphate (vi) acid was dependent on the concentration of the acid, temperature and period of contact. Azithromycin, erythromycin, clarithromycin and lincomycin were good adsorption inhibitors for the corrosion of zinc in H2504.The inhibition efficiencies of these inhibitors increased with increase in their respective concentration but decreased with increase in theperiod of contact. The values of inhibition efficiencies obtained from the weight loss measurements correlated strongly with those obtained from hydrogen evolution measurements. The adsorption of these inhibitors on the surface of zinc strongly favoured the mechanism of physical adsorption. Thermodynamic consideration indicated that the adsorption of these inhibitors was exothermic and spontaneous (values of free energies of adsorption were negative).The adsorption of these inhibitors was best described by langmuir adsorption isotherm.