Corrosion Inhibition by Beet Root Extract

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 Zn 2+ has been evaluated by mass loss method. The formulation consisting of 4 mL of BR extract and 50 ppm Zn 2+ offers 98% inhibition efficiency to carbon steel immersed in well water. A synergistic effect exists between BR extract and Zn 2+ . Addition of N-Cetyl-N,N,N – trimethylammonium bromide (CTAB) does not change the excellent inhibition efficiency of the BR – Zn 2+ system. The BR – Zn 2+ 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 Fe 2+ betanin complex and Zn(OH)2. The film is found to be UV fluorescent.