Adsorption and Inhibitive Properties of Camellia Sinensis for Aluminium Alloy in HCI

This study reports the effect of Camellia Sinensis (green tea) extract as a green inhibitor on the corrosion of aluminium alloy in 0.5M hydrochloric acid. Weight loss/corrosion rate and potential measurement techniques were used for the experimental work. The results were further analysed using the two-factor ANOVA test. Potential measurement was performed using a digital voltmeter and a saturated calomel reference electrode. The tea extract was obtained from the green tea leaves. The results obtained showed effective corrosion inhibition of the extract on the aluminium alloy test specimens in the different concentrations of hydrochloric acid used. The extracts gave appreciable corrosion inhibition performance of aluminium at 100 and 80 % concentrations with the weight loss of 652mg (0.652g) and 674 mg (0.674g) respectively. ANOVA test confirmed the results at 95% confidence, and further showed that concentration of green tea extract had greater effect on potential measurements whereas test exposure time had greater influence on weight loss measurements. The value of Gibb’s free energy of adsorption obtained signified that the mechanism of adsorption of plant extract molecules on the metal surface was by physiosorption. The adsorption of Camellia Sinensis extract on the surface of aluminium obeys the Freundlich isotherm model