Jolda Zotaj, Efrosini Kokalari, Arlinda Caci, Alketa Lame and Sadik Cenolli, Albania
Metal corrosion is a serious problem. It causes serious damage in metallic materials, especially in acid media. We are focused on using green inhibitors, as a good choice for both: corrosion and environment protection. The use of corrosion inhibitors is one of the most practical and economic methods in corrosion inhibition studies. Green inhibitors are biodegradable, environmentally friendly and ecologically acceptable. They do not contain heavy metals or other toxic compounds. One of the green inhibitor is extract of outer onion skin, that content considerable amount of quercetin, among flavonoid compounds on it. In recent years quercetin, is proved to be an efficient inhibitor against the corrosion of metals and alloys. Quercetin is studied as a green corrosion inhibitor, for Aluminium, in acid media (1M HCl). It is extracted by outer onion skin. Quercetin also, has anti-inflammatory, anti-histamine, anti-cancer effects and other biological activities. The corrosion inhibition efficiency of extract from outer onion skin, was investigated using weight loss method and potentiodynamic polarization measurements. By weight loss method the inhibition efficiency (IE) increases with the increase of the inhibitors concentrations, IE is 44.4 % at 0.75 g/L quercetin. By the potentiodynamic polarization measurements the critical concentration is 1 g/l, IE is 75 %, for the further increase of the concentration the inhibition efficiency decrease.