Inhibition of mild steel corrosion in hydrochloric acid by 2-acetylpyridine and 2-acetylpyridine phosphate

Ita BI ¹, Abakedi OU ^2*and Osabor VN ¹

¹Department of Pure and Applied Chemistry, University of Calabar, P.M.B. 1115, Calabar, Nigeria.

²Department of Chemistry, University of Uyo, P.M.B. 1017, Uyo, Nigeria.

*Corresponding Author’s E-mail: ouabakedi@yahoo.com

Accepted 26 February 2013

Abstract

The corrosion of mild steel in hydrochloric acid solution has been significantly inhibited by 2-acetylpyridine and 2-acetylpyridine phosphate at 30°C and 40°C by the weight loss method. The inhibition efficiencies of both compounds increased with increase in inhibitor concentration but decreased with increase in temperature. Physical adsorption mode has been proposed for the adsorption of the inhibitors on mild steel surface. Both compounds obeyed the Langmuir adsorption isotherm and the thermodynamic-kinetic model. The negative values of ΔG_ads indicate the spontaneity of the inhibition process. The difference in the inhibitory actions of the compounds has been incorporated in the present investigation.

Keywords: inhibition, steel, hydrochloric acid, acetylpyridine