Investigation of imidazole derivatives as corrosion inhibitors of copper in sulfuric acid: Combination of experimental and theoretical researches

Levamisole (LMS) and 4-phenylimidazole (PIZ), used as corrosion inhibitors of copper in sulfuric acid solution were explored by electrochemical tests, morphology analysis and theoretical calculation. At the concentration of 8 mM, the maximum corrosion inhibition efficiencies of LMS and PIZ are 99.03% and 95.84%, respectively. All test data found that LMS had better corrosion inhibition performance than PIZ. LMS is a cathodic corrosion inhibitor, while PIZ belongs to a mixed-type corrosion inhibitor. Electrochemical results indicate that the corrosion inhibition efficiency has the same trend when the concentration of corrosion inhibitor increases. Scanning electron microscope and atomic force microscope were applied to research the surface morphology of copper samples under different conditions. X-ray photoelectron spectroscopy and Langmuir adsorption isotherm model were utilized to explain adsorption means. What is more, Langmuir adsorption isotherm model indicates the coexistence of physisorption and chemisorption for the two inhibitors. Besides, the adsorption between LMS and copper is more prone to chemical adsorption. The mechanism of metallic copper and corrosion inhibitors was explored through quantum chemistry studies and molecular dynamics simulation.