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E-Journal of Chemistry
Volume 6 (2009), Issue 3, Pages 887-897
http://dx.doi.org/10.1155/2009/859218

Corrosion Inhibition by Sodium Gluconate-Zn2+-DTPMP System

P. Manjula

Department of Chemistry, APA College for Women, CK Pudur, Palani, India

Received 18 November 2008; Accepted 1 January 2009

Copyright © 2009 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

Abstract

The inhibition efficiency of a phosphonic acid, Diethylene Triamine Pentamethylene Phosphonic acid (DTPMP) in controlling corrosion of carbon steel immersed in an aqueous solution containing 60 ppm of Cl- has been evaluated by weight loss method in the absence and presence of Zn2+. The formulation consisting of DTPMP and Zn2+ has excellent inhibition efficiency (IE). A synergistic effect is noticed between Zn2+ and DTPMP. Addition of sodium gluconate (SG) enhances the IE of Zn2+ and DTPMP system. The DTPMP-Zn2+-SG system function as a mixed inhibitor as revealed by polarization study. AC impedance spectrum, optical and atomic force micrographs reveal the formation of a protective film on the metal surface. FTIR spectra reveal that the protective film consists of Fe2+-DTPMP complex, Fe2+-SG complex and Zn(OH)2.