Environmentally-friendly imidazolium-derived ionic liquid as a corrosion inhibitor for carbon steel in 1 M HCl: experimental and theoretical approach
A. Marzaq, K. Jrajri, Abderrahim Titi, Ahmad Royani, M. El Faydy, F. Benhiba, Rachid Touzani, Mohammed Assouag, R. Touir, Ismail Warad, Mouslim Messali, Mustapha Allali, A. Zarrouk
Abstract
A novel ecologically friendly imidazolium-derived ionic liquid, 1-benzyl-3-phenethylimidazolium hexafluorophosphate (BPIPF6), was examined as a corrosion inhibitor for carbon steel in 1 M HCl solution by electrochemical measurements, surface characterization techniques, and theoretical calculations. The inhibition efficiency was found to improve with increasing BPIPF6 concentration but declined as the temperature rose, achieving 94.79% at a concentration of 10−3 M and a temperature of 303 K. The results of electrochemical experiments reveal that BPIPF6 acts as a mixed-type inhibitor that can simultaneously inhibit the reaction of the anode and cathode. The surface examination of the substrate before and after being immersed in the inhibited medium was analyzed using Fourier transform infrared spectroscopy (FT-IR), contact angles, X-ray diffraction (XRD), scanning electron microscopy with energy dispersive X-ray (SEM/EDS), and atomic force microscopy (AFM) analyses and confirmed that the surface of carbon steel was protected from corrosion by the adsorption of BPIPF6 ionic liquid. According to density functional theory (DFT) and molecular dynamics simulations (MDS), the values of low energy gap (ΔE) and high binding energy (Ebinding), along with radial distribution function (RDF) analysis, demonstrate the strong chemisorption of BPIPF6 on the iron plane, which accounts for the good anti-corrosion properties of BPIPF6 at the molecular and atomic levels.