Green synthesis of novel carbohydrate polymer chitosan oligosaccharide grafted on d-glucose derivative as bio-based corrosion inhibitor

Abstract

A novel chitosan oligosaccharide macromolecule carrying a glucose moiety (COS-g-Glu) has been synthesized and used as a non-toxic, durable, and biodegradable inhibitor of mild steel corrosion in acidic medium (1.0 M HCl). This macromolecule was synthesized by grafting a glucose moiety on Chitosan, and characterized by FT-IR, 1H and 13C NMR. The acid corrosion inhibiting effect of this biodegradable macromolecule is obtained by experimental electrochemical characterization (EIS and PDP), surface [Scanning Electron Spectroscopy (SEM), Energy Dispersive Spectroscopy (EDS), infrared (FT-IR), and Atomic Force Microscopy (AFM)]. Corrosive acidic solutions were identified by UV–visible spectroscopy (UV–vis) and by ICP-OES spectrometry. Electrochemical tests show that the inhibition efficiency increases with increasing concentration of the inhibitor and reaches an optimum value of 97% at 10−3 M. The thermodynamic parameters, and steel surface characterization methods confirmed the adsorption of COS-g-Glu. The results obtained from the DFT, and MD calculations correlate with the results obtained experimentally.