Experimental and Quantum Chemical Studies on the Corrosion Inhibition Potentials of Xylopia aethiopica extracts

Root and root bark extracts of Xylopia aethiopica (XE) have been evaluated as corrosion inhibitors for mild steel in aerated 0.1 M HCl and H 2SO 4 solutions by gravimetric method. The inhibition efficiency increases with increase in inhibitor concentrations. Adsorption mechanisms for the adsorptions of XE extracts' molecules were predicted using the following adsorption isotherms (Langmuir, Freundlich, Temkin and El-Awady) by linear regression. With the aid of Chi-square (X 2 ) statistic, the best fitted adsorption isotherms were selected. Physisorption mechanisms have been proposed for the extracts in the studied acidic media. Quantum chemical calculations gave some electronic properties of the molecules of XE extracts so as to ascertain any correlation(s) between the corrosion inhibition and molecular structures. Keywords: Quantum Chemical calculation, Xylopia aethiopica, corrosion inhibition