Author(s)

A. John Amalraj, J. Wilson Sahayaraj, A. Peter Pascal Regis, Arockia Sahayaraj, P. Pandian, P. Johnraj, A. Kasthuri, C. Kumar

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The corrosion inhibition efficiency (IE) of an aqueous extract Allium cepa (onion) in controlling the corrosion of carbon steel ground water in absence and presence of with Zn²⁺ has been studied by weight loss method. The formulation consisting of 3 mL Allium cepa extract, 50 ppm of Zn²⁺ and 50 ppm of sodium pattassium tartarate which offers 97% inhibition efficiency. The synergistic effect exists between onion-Zn²⁺-tartarate system. The addition of N-cetyl-N,N,N- trimethylammonium bromide on onion-Zn²⁺-tartarate system does not change the excellent inhibition efficiency. Polarization study shows that the onion-Zn²⁺-tartarate system functions as a cathodic inhibitor. AC impedance spectra reveals that a protective film is formed on the metal surface. The UV fluorescent spectra indicate the possibility of formation of Fe²⁺-onion complex and also Zn²⁺-onion complex in solution. Thus the protective film is found to be UV fluorescent.

Carbon Steel; Allium cepa; Corrosion Inhibition Efficiency; Ground Water

A. Amalraj, J. Sahayaraj, A. Regis, A. Sahayaraj, P. Pandian, P. Johnraj, A. Kasthuri and C. Kumar, "Synergistic Effect of Allium cepa-Zn²⁺ System on the Corrosion of Carbon Steel in Ground Water," Engineering, Vol. 5 No. 2, 2013, pp. 178-183. doi: 10.4236/eng.2013.52025.