Theoretically and Experimentally Exploring the Inhibition Effect of Imidazole Sulfonic Acid Derivatives with Multiple Adsorption Sites in 1.0 mol/L HCl

Corrosion inhibitors have played a huge role in daily life and industrial production. Imidazole and sulfonic acid groups have high corrosion inhibition capabilities. To further improve their excellent corrosion inhibition performance, two new sulfonic acid azole corrosion inhibitors (YM and ZM) were synthesized and the effect of carbon chain length on the imidazole sulfonic acid corrosion inhibitor was studied. The weight loss and electrochemical results indicated that the corrosion inhibition efficiency significantly increased with the increase of YM and ZM concentration. At 1.0 g/L of ZM, the corrosion inhibition efficiency of weight loss, EIS and Tafel were 95.02%, 86.61%, and 98.49%, respectively. Electrochemistry further indicated that ZM and YM could form a stable protective film on the surface of Q235 and increased the charge transfer resistance, thereby improving their corrosion inhibition efficiency and belong to cathodic corrosion inhibitors. SEM–EDS, FT-IR, and XPS confirmed that YM and ZM could effectively adsorb on the surface of Q235, and further demonstrated theories through density functional theory and molecular dynamics simulation.