Asian Basic and Applied Research Journal

Corrosion of alloys and metals has become a global concern. In recent times, ways of controlling corrosion has become area of interest to many researchers. The use of corrosion inhibitors is known to be a reliable method of controlling corrosion of materials. However synthetic inhibitors are known to the toxic in nature, hence a threat to the environment but green inhibitors are environmentally friendly. The main aim of this research work is to determine the inhibitor efficiencies of Chromolaena odorata leaf extract as corrosion inhibitor for Brass in acidic medium. The weight loss measurement shows that the inhibitor efficiency of the leaf extract increases with increase in the concentration of inhibitor and decreases with temperature rise while the rate of corrosion decreases with the increase in the concentration of the inhibitor and increases with increase in temperature. The adsorption isotherm plot of this research fit the Langmuir adsorption isotherm plot more than Temkin as the R² coefficient of the Langmuir plot was is greater than 0.95. The inhibitor efficiency of Chromolaena odorata was also confirmed with the (EIS) Electrochemical Impendence Spectroscopy and the result was in perfect agreement with the one of weight loss. At the highest concentration (1000mg/L), the Inhibitor efficiency of the plant extract was seen to be optimum in weight loss and EIS. Physisorption has been proposed in this study because the values of activation energies are lower than 40kJ mol^-1 and the heat of adsorption, Q_ad is also negative which means that the reaction was spontaneous and exothermic. SEM was used to study the Brass surface before inhibition and after inhibition to confirm the level of adsorption of the leaf extracts on the Brass surface and XRD was used to determine the crystalline nature of Brass.