Synthesis and evaluation of 1-butyl-3-methylimidazolium chloride based ionic liquid for acid corrosion inhibition of aluminum alloy: Empirical, DFT/MD-simulation and RSM modeling

The present research explores the synthesis of imidazolium based ionic liquid (IL) 1-butyl-3-methylimidazolium chloride ([BMIM][Cl]) and its application for the protection of aluminum alloy (AA) in 1 M H2SO4 electrolyte using gravimetric, potentiodynamic polarization (PDP), electrochemical impedance spectroscopy (EIS), response surface methodology (RSM), density functional theory (DFT) and MD-simulation respectively. The studied (IL) showed appreciable inhibition efficiencies of 84.21 % for gravimetric, 90 % for PDP and 87.10 % for the EIS at 0.80 g/L inhibitor concentration and 313 K, respec-tively. The results of EIS and PDP reveal the corrosion inhibition process is charge transfer controlled, and the studied IL acts as a mixed type inhibitor. The optimization result via RSM model gave an optimum prediction of 84.21 % at 0.8 g/L inhibitor concentration at 313 K. Adsorption of [BMIM][Cl] on the alu-minum surface obeyed the Frumkin adsorption isotherm. The scanning electron microscope (SEM) and atomic force microscopy (AFM) revealed the formation of protective film of the inhibitor on the alu-minum surface. Theoretical modeling were used to correlate the experimental results. The best fit of the theoretical models were functions of molecular structure and fractions of electron transferred from the inhibitor to the aluminum surface.(c) 2022 Elsevier B.V. All rights reserved.

Automated summary

The present research investigates the synthesis of imidazolium based ionic liquid and its application for the protection of aluminum alloy in sulfuric acid electrolyte. The inhibitory performance is evaluated using various analysis methods and theoretical modeling. The studied ionic liquid shows significant inhibition efficiency and can effectively protect the aluminum alloy surface. The experimental results are in good agreement with the theoretical models.