Joint effect of halides and Ethanol Extract of Sorghum on the Inhibition of the Corrosion of Aluminum in HCl

Abstract

In order to applied the principle of resource recovery to the management of sorghum waste from a brewery industry in Nigeria, ethanol extract of the waste was investigated for their corrosion inhibition efficiency towards aluminum in solution of HCl . Weight loss and gasometric methods were used for the study. The results obtained indicated that ethanol extract of sorghum waste inhibited the corrosion of aluminum in solution of HCl with maximum inhibition efficiency of 44.99, 39.95, 38.95 and 38.42% at 303, 313, 323 and 333 K respectively. However, through synergistic combination of KBr, KI and KCl, the inhibition efficiencies at 303 K was increase to 78.59, 54.22 and 79.04% respectively. Maximum efficiency obtained from gasometric experiment was 79.32%. The inhibitor acted as adsorption inhibitor and its adsorption behaviour obeyed Temkin, Freundlich, El awardy et al and Dubinin-Raduskevich isotherm. Data obtained with respect to trends of variation of inhibition efficiency with temperature, calculated activation and free energies as well as thermodynamic parameters confirmed that the adsorption of the inhibitor is spontaneous, exothermic and is consistent with the mechanism of charge transfer from charged inhibitor to charged metal surface, which favour physical adsorption.