An environmentally friendly formulation based on Cannabis sativa L. seed oil for corrosion inhibition of E24 steel in HCl medium: Experimental and theoretical study

Abstract

The poor corrosion resistance of carbon steel (CS) has long been an urgent challenge to its industrial applications. Green corrosion inhibitors are among the most widely used and economically viable methods to protect metals and alloys against corrosion. In the present work, a new green corrosion inhibitor formulation (CIF) based on Cannabis sativa L. seed oil (noted CSL) was prepared for protecting E24 carbon steel against corrosion in 1.0 mol/L HCl. Experiments were carried out using weight loss (WL), and electrochemical methods at different concentrations of CSL and immersion times. The surface morphology of corroded and inhibited CS was investigated using the scanning electron microscope (SEM), while Density Functional Theory (DFT) and molecular dynamics (MD) simulation were used to assess the reactivity of CSL’s components and their interactions with Fe(110) plane. The gas chromatographic analysis of the CSL indicated that the Linoleic acid (C18:2) is the most abundant fatty acid (51.3%), followed by Oleic acid ((C18:1) (20.3%)), α-Linolenic acid (C18:3 (15.7%)) and saturated Palmitic acid (C16:0 (7.9%)). According to WL and electrochemical results, an inhibition efficiency of over 92% was achieved using 1 g/L of CSL, indicating higher corrosion mitigation properties. Electrochemical results revealed that the tested formulation had a mixed-type inhibition effect, with a cathodic predominance. In addition, the charge transfer resistance of the CS electrode increased from 46 Ω cm2 in blank solution to 1115 Ω cm2 in HCl solution inhibited with 1 g/L of CSL and 24 h immersion. SEM images showed the formation of a protective barrier on CS surface, which prevented the corrosion attack. DFT and MD studies showed that CSL’s components have excellent donor-acceptor properties and exhibited a close contact with Fe(110) surface upon adsorption.