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International Journal of Corrosion
Volume 2012 (2012), Article ID 768729, 8 pages
http://dx.doi.org/10.1155/2012/768729
Research Article

Inhibitory Action of Artemisia annua Extracts and Artemisinin on the Corrosion of Mild Steel in H2SO4 Solution

1Corrosion and Electrochemistry Research Group, Department of Pure and Applied Chemistry, University of Calabar, PMB 1115, Calabar, Nigeria
2Headquarters Eastern Naval Command, Navy Road, Calabar, Nigeria
3Department of Biochemistry, University of Calabar, PMB 1115, Calabar, Nigeria
4Department of Genetics and Biotechnology, University of Calabar, PMB 1115, Calabar, Nigeria
5Department of Chemistry, North-West University, Mafikeng Campus, Private Bag X2046, Mmabatho 2735, South Africa

Received 24 June 2011; Accepted 9 August 2011

Academic Editor: Ali Y. El-Etre

Copyright © 2012 P. C. Okafor 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

The action of ethanol (EEAA), acid (AEAA), and toluene (TEAA) extracts from Artemisia annua and Artemisinin (ATS) on mild steel corrosion in H2SO4 solutions was investigated using gravimetric and gasometric techniques. The extracts and ATS functioned as good inhibitors, and their inhibition efficiencies (%IE) followed the trend: EEAA > AEAA > TEAA > ATS. %IE increased with increase in inhibitors concentration and decreased with increase in temperature. The enhanced %IE values of the extracts were attributed to synergistic effect of the components of the plant extracts with ATS. The adsorption of the inhibitors was consistent with Langmuir isotherm. Physisorption is proposed as the mechanism of inhibition.