Abstract

The inhibition efficiency of acetone extract of red onion skin on aluminium in hydrochloric acid solutions has been evaluated by weight loss techniques. Values of inhibition efficiency obtained are dependent upon the concentration of inhibitor and temperature. Generally, inhibition was found to increase with inhibitor concentration, half-life, activation energy but decrease with temperature and first-order rate constant at the temperatures studied. Physical adsorption mechanism has been proposed for the inhibition and Langmuir adsorption isotherm was obeyed.  The compound responsible for the inhibitory action of red onion skin is Quercetin. Red onion skin is an inhibitor of aluminium corrosion in 2 M hydrochloric acid solution.

Key words: Corrosion inhibition, aluminium, weight loss, red onion skin, hydrochloric acid.