Resumo

SELVI, J. Arockia et al. Corrosion Inhibition by Beet Root Extract. Port. Electrochim. Acta [online]. 2009, vol.27, n.1, pp.1-11. ISSN 0872-1904.

The inhibition efficiency (IE) of an aqueous extract of beet root (BR) in controlling corrosion of carbon steel in well water in the absence and presence of Zn²⁺ has been evaluated by mass loss method.  The formulation consisting of 4 mL of BR extract and 50 ppm Zn²⁺ offers 98% inhibition efficiency to carbon steel immersed in well water.  A synergistic effect exists between BR extract and Zn²⁺.  Addition of N-Cetyl-N,N,N - trimethylammonium bromide (CTAB) does not change the excellent inhibition efficiency of the BR - Zn²⁺ system.  The BR - Zn²⁺ system shows excellent IE up to 7 days.  Polarization study reveals that this formulation controls the cathodic reaction predominantly.   AC impedance spectra reveal that a protective film is formed on the metal surface. FTIR spectra reveal that the protective film consists of Fe²⁺ - betanin complex and Zn(OH)₂.  The film is found to be UV - fluorescent.

Palavras-chave : carbon steel; corrosion inhibition; plant extract; beet root; beta vulgaris.

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