Dextran derivatives as highly efficient green corrosion inhibitors for carbon steel in CO2-saturated oilfield produced water: Experimental and theoretical approaches

Abstract

During the oil and gas exploitation, the corrosion of carbon steel pipes causes great economic loss, heavy casualties, environmental pollution, and waste of resources. The development of highly efficient and stable eco-friendly corrosion inhibitors is of great significance for the corrosion protection of carbon steel in oil and gas exploitation. In this work, two amino acid-modified dextran derivatives (LDT and S-LDT) were synthesized as green inhibitors, and their anti-corrosion performance for carbon steel in CO2-saturated oilfield produced water was studied by electrochemical tests and surface analysis. The electrochemical measurements show that S-LDT exhibits an outstanding inhibition performance with a fairly high inhibition efficiency (99.5% with the concentration of 250 mg/L) and high stability of corrosion inhibition (99.7% after 72 immersion), which is significantly higher than those eco-friendly corrosion inhibitors have been reported so far. The adsorptions of LDT and S-LDT involves physisorption and chemisorption. The adsorption mechanism of LDT and S-LDT was further explored by quantum chemical calculations, molecular dynamics (MD) and Geometry, Frequency, Noncovalent, and eXtended Tight Binding (GFN-xTB) method. It is believed that these novel dextran derivatives would have broad application prospects as eco-friendly corrosion inhibitors in industry.