International Journal of Chemical Studies
Vol. 2, Issue 1 (2014)
Corrosion inhibition of Vitex negundo extract as a green corrosion inhibitor for carbon steel in well water
Author(s): P. Angel, A. Sahaya Raja, J. Sathiyabama and V. Prathipa
Abstract: The inhibition efficiency (IE) of an aqueous extract of Vitex negundo, in controlling corrosion of carbon steel in well water has been evaluated by the weight loss method. The Vitex negundo extract shows good IE. In the presence of Zn2+ excellent IE is shown by the Vitex negundo Extract. A synergistic effect exists between the Vitex negundo extract and Zn2+. The mechanistic aspects of corrosion inhibition have been investigated by polarization study, AC impedance spectra. Polarization study reveals that the formulation consisting of Vitex negundo extract and Zn2+ functions as mixed inhibitor with predominantly cathodic effectiveness. AC impedance spectra reveal that a protective film is formed on the metal surface. The active principle in the Vitex negundo extract is 5-hydroxy-2-(3-hydroxy-4-methoxyphenyl)-3, 6, 7 -trimethoxychromen-4-one. The protective film formed on the metal surface has been analyzed by FT-IR, SEM and EDAX Spectra. It is found that the protective film consist of Fe2+ - 5-hydroxy-2-(3-hydroxy-4-methoxyphenyl)-3,6,7-trimethoxychromen-4-one complex and Zn(OH)2.
Fig. 1: Carbon steel
Fig. 2: Carbon steel immersed in well water
Fig. 3: Carbon steel immersed in well water +10 ml Vitex negundo extract + 5 ppm Zn2+.
Pages: 31-37 | 1271 Views 21 Downloads
How to cite this article:
P. Angel, A. Sahaya Raja, J. Sathiyabama, V. Prathipa. Corrosion inhibition of Vitex negundo extract as a green corrosion inhibitor for carbon steel in well water. Int J Chem Stud 2014;2(1):31-37.