Chitosan oligosaccharide derivatives as green corrosion inhibitors for 20# steel in 25 °C carbon dioxide environments

Abstract

A vanillin-based chitosan oligosaccharide quaternary ammonium salt (QCO) was synthesized, and its corrosion inhibition performance on 20# steel in a 25 °C 3.0 wt% NaCl CO₂ saturated solution was studied. The adsorption energy of the inhibitor was calculated through molecular dynamics (MD) simulations. QCO showed good corrosion inhibition effects on 20# steel, reaching a maximum inhibition rate of 92.8 % with 100 ppm. Surface studies conducted using Scanning Electron Microscopy (SEM) - Energy Dispersive Spectroscopy (EDS) and Atomic Force Microscopy (AFM) revealed the adsorption protective film on the steel surface. MD results suggested that increasing the concentration of QCO within a certain range can enhance the efficiency of corrosion inhibition.