Anticorrosion action of the olive leaf compounds extracted under optimal parameters as determined with experimental design

Abstract

In this study, an agricultural waste product was used to prepare a green corrosion inhibitor based on olive leaves (Olea europaea var. syslvestris). Firstly, an optimization study of antioxidant activity of O. europaea leaves monitored by the DPPH free radical trapping method, was carried out using full factorial design. In the second step, the extract obtained under optimal conditions was tested as a green corrosion inhibitor for steel in 0.5 mol dm-3 HCl, using gravimetric and electrochemical methods. The results obtained by various techniques showed that the extract acted as a mixed-type inhibitor. The adsorption of the inhibitor was spontaneous (?Gads = ?12.443 kJ mol-1), through the mechanism of physical adsorption, and it obeyed the Langmuir adsorption isotherm. The highest corrosion inhibition efficiency of 92 % was obtained for 2.8 10-3 g cm-3of inhibitor, as measured by gravimetric method.