Preparation of Environmental Friendly Composite Inhibitor for Citric Acid Pickling

A kind of efficient and environmental friendly composite pickling inhibitor was prepared with 2-mercaptobenzimidazole (2MBI), potassium iodide, triethanolamine, polyoxyethylene nonylphenyl ether and peregal by orthogonal experiment. The corrosion inhibition effect of the composite inhibitor was investigated by weight loss measurement, polarization curve and electrochemical impedance spectroscopy (EIS). The results show that the complex is a good inhibitor whose efficiency could reach 98.8% for A20 steel citric acid solutionjs. The adsorption of the complex obey Langmuir′s adsorption isotherm.