Hexane extract of Persea schiedeana Ness as green corrosion inhibitor for the brass immersed in 0.5 M HCl

Abstract

The hexane extract of Persea schiedeana Ness (PSN) was analyzed as corrosion inhibitor for the brass surface immersed in 0.5 M HCl. Fourier-transform infrared spectroscopy and a gas chromatographic (GC) and mass spectrometric (MS) were used to identify the PSN extract's functional groups and compound constituents. The functional groups identified were ${\text{CH}}_3$ and ${\text{CH}}_2$ functional alkyl groups, $\text{C=O}$ stretching vibration of aldehydes, ketones, and carbonyl groups. The GC/MS determined the presence of fatty acids in the PSN extract, where palmitic acid, oleic acid, and ethyl oleate were the major constituents. Electrochemical characterizations were conducted to observe the effect of PSN as corrosion inhibitor on the brass surface. The R_p and R_n calculated from EIS and ENA give the same behavior. Based on the OCP behavior, it was determined that the PSN works as a mix inhibitor, affecting both anodic and cathodic reactions. The corrosion current density (I_corr) suggests that the extract of PSN reduces the corrosion rate of the brass with efficiencies above 90% for all concentrations. The efficiency obtained for each PSN concentration was attributed to forming a corrosion scale of $\text{CuO}$ and ${\text{Cu}}_2\text{O}$ , which reacted with the carboxyl group to form copper carboxylates on the metal surface.

Keywords: Persea schiedeana Ness; Brass; Corrosion inhibitor; Electrochemical analyses; Green corrosion inhibitor.