Study of the efficiency of Orbignya oleifera as a green corrosion inhibitor for low carbon steel compared to commercial inhibitor in 1M HCl solution

ABSTRACT The aim of this work is to compare the efficiency of babassu coconut oil (Orbignya oleifera) used as a green corrosion inhibitor and a commercial inhibitor tested on ABNT 1020 steel in hydrochloric acid medium. The search evaluation was accomplished with electromechanical techniques of linear polarizations and Tafel Extrapolation Method altogether with electrochemical impedance spectroscopy. The concentrations of the inhibitors were 3, 4 and 5 g/L in a solution of IM hydrochloric acid (HCI). The results of electrochemical impedance spectroscopy shows that Orbignya oleifera acts as an adsorption inhibitor and its inhibition efficiency value (56.45%) is higher when compared to the level of efficiency of the commercial inhibitor (36.08%) in the concentration of 3 g/L once that presented higher charge transfer resistance (47.3Ω) when compared to the HPAA (32.23Ω). The results of Linear Polarization Resistance shows Orbignya oleifera oil increased the inhibition efficiency in ABNT 1020 steel in 1M HCl solution at 3 and 4g/L concentrations. The level maximum inhibitory efficiency of Orbignya oleifera in this test was 48%. That percentage must be associated to chemical composition of that oil which contains lauric acid in a concentration of 47% - that probably contributed to a high efficiency of inhibition layer.