Table of Contents
ISRN Corrosion
Volume 2012 (2012), Article ID 425878, 8 pages
http://dx.doi.org/10.5402/2012/425878
Research Article

Synergistic Effect of KI on Corrosion Inhibition of Mild Steel by Polynuclear Schiff Base in Sulphuric Acid

Research Division, Department of Chemistry, St. Thomas' College, University of Calicut, Thrissur, Kerala, India

Received 17 October 2012; Accepted 1 November 2012

Academic Editors: A. Y. El-Etre and H. Sarpoolaky

Copyright © 2012 K. S. Shaju et al. 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

Synergistic effect of KI on the corrosion inhibition efficiency of polynuclear Schiff base, anthracene-9(10H)-one-3-aminopropanoic acid (A9O3AP), on mild steel (MS) in 0.5 M sulphuric acid solution has been investigated using weight loss measurements, electrochemical impedance spectroscopy (EIS), and potentiodynamic polarization studies. The results show that inhibition efficiencies on MS increase with increase in concentration of the inhibitor and enhancement in inhibition efficiency was observed on addition of potassium iodide due to synergism. The adsorptions, of inhibitor and inhibitor + KI on the surfaces of the corroding metal obey Freundlich and Langmuir isotherms, respectively. Polarization studies revealed that A9O3AP acts as a mixed type inhibitor. Thermodynamic parameters ( ; ) were calculated using the adsorption isotherms. A probable synergismtic mechanism is proposed.