Inhibitive Effect of Bitter Kola Extract on Aluminium Corrosion in Hydrochloric Acid Medium

The inhibitive effect of different concentrations (10%v/v to 50%v/v) of bitter kola water-extract (BK) on the corrosion of aluminum in 0.5M hydrochloric acid was investigated by weight loss technique at 30oC to 50oC. The percentage inhibition efficiency increased with the concentration of the inhibitor and the temperatures. The mechanism of chemical adsorption has been proposed for the inhibitor on the basis of the temperature effect and the values of activation energy obtained. The inhibition is probably due to the adsorption of kola flavonone which is the active component in bitter kola extract on aluminum surface. The adsorption of the inhibitor molecule on aluminum surface was in accordance with Langmuir adsorption isotherm. The results from weight loss technique confirmed that bitter kola water - extract (BK) is effective in reducing the corrosion of aluminum in hydrochloric acid medium and could serve as an effective and non-toxic inhibitor of the corrosion of aluminum in hydrochloric acid solution at the temperatures studied.