Evaluation of Purple Onion (Allium cepa L.) Extract as a Natural Corrosion Inhibitor for Carbon Steel in Acidic Media

Abstract

© 2020, The Korean Institute of Metals and Materials.Abstract: The capacity of the Allium cepa L. extract from peel (ACP) and bulb (ACB) as a natural corrosion inhibitor for carbon steel was evaluated. The corrosion characterization was performed by a gravimetric test, showing an inhibitor efficiency of 60% (ACP) and 67% (ACB). Electrochemical tests indicated higher corrosion resistance for carbon steel in the presence of the extracts, and the SEM images of steel samples confirm the results. These extracts were analyzed by the DPPH (2,2-diphenyl-1-picrylhydrazyl) method, confirming the antioxidant activity. The chemical characterization of the extracts by FTIR measurements revealed the presence of phenolic compounds with antioxidant capacity. Graphic Abstract: [Figure not available: see fulltext.]