Synthesis and evaluation of omeprazole-based derivatives as eco-friendly corrosion inhibitors for Q235 steel in hydrochloric acid. Issue 6 (December 2022) - Liu, Ying
Abstract: The application of expired drugs as corrosion inhibitors is a low-cost, cost-effective and environment-friendly alternative to the expensive degradation process. Against this background, the corrosion inhibition performance and mechanism of imidazole drugs omeprazole (OMP) and its by-products omeprazole sulfide (OMP-1) and omeprazole sulfonate (OMP-2) on Q235 steel in 1 M HCl is investigated by weight loss experiment, electrochemical technology, surface analysis methods (SEM and XPS), quantum chemical calculation and molecular dynamics simulation. The results demonstrate that OMP, OMP-1 and OMP-2 are effective corrosion inhibitors for Q235 steel in 1 M HCl. The inhibition efficiency above 95% is achievable at 298 K with 0.2 mM inhibitor concentration. The test results and fitting data show that they are mixed-type corrosion inhibitors, which comply with Langmuir adsorption isotherm. Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) further confirmed these three inhibitor molecules playing the role of corrosion inhibition by adsorbing on the surface of Q235 steel to form a film barrier. The corrosion inhibition mechanism of omeprazole on metal surface is also discussed. Graphical Abstract: ga1 Highlights: Using OMP drugs as corrosion inhibitors is a safe and convenient method. Similar structures are to investigate the spatial effects and electronic orbital. SEM and XPS confirmed OMPs adsorption to protect the metal. High corrosion inhibition efficiency is at a small dosage: ≧ 95.0% at 0.2 mmol L − 1 . Active sites and corrosion inhibition mechanism were discussed via DFT and MD.