ALUMINIUM CORROSION ABATEMENT USING NON TOXIC AND ECO-FRIENDLY ORGANIC INHIBITORS
B. U. UGI *
Department of Chemical Sciences, Cross River University of Technology, P.M.B. 1123, Calabar, Nigeria.
M. E. OBETEN
Department of Chemical Sciences, Cross River University of Technology, P.M.B. 1123, Calabar, Nigeria.
I. E. UWAH
Department of Pure and Applied Chemistry, University of Calabar, P.M.B. 1115, Calabar, Nigeria.
P. C. OKAFOR
Department of Pure and Applied Chemistry, University of Calabar, P.M.B. 1115, Calabar, Nigeria.
*Author to whom correspondence should be addressed.
Abstract
The corrosion inhibition performance of the alkaloid and non alkaloidleaf extracts of Cnidoscolus aconitifolius (AECAL and NAECAL) on the corrosion of aluminium in 1 M HCl solution at 303K and elevated temperatures of 303, 313 and 333K was investigated and compared. The experimental work was performed by the use of weight loss method (gravimetric), hydrogen evolution (gasometric) and electrochemical techniques respectively. The results indicate that both extracts inhibit the corrosion of mild steel in the medium. However, AECAL exhibits higher maximum inhibition efficiency (83.3%) than NAECAL (57.1%) at 2.0 g/L. Generally inhibition efficiency was found to increase with increase in concentration of both leave extracts but decreased with rise in temperature. However, 2.0 g/L concentration showed a better performance in the inhibition of 1M HCl for both samples. Inhibition mechanism was deduced from the temperature dependence of the inhibition efficiency as well as from activation parameters that govern the process. Adsorption of both extracts on the aluminium coupon was found to obey the Langmuir adsorption isotherm. The phenomenon of physical adsorption is proposed from the obtained thermodynamic parameters.
Keywords: Weight loss, Langmuir isotherm, activation energy, corrosion current density, inhibition efficiency, EIS