PEG cross-linked Chitosan: a biomacromolecule as corrosion inhibitor for sugar industry

The present work reports the application of polyethylene glycol (PEG) cross-linked chitosan (Cht-PEG) as a green corrosion inhibitor. This is the first study reporting the application of Cht-PEG as corrosion inhibitor for mild steel in 1 M sulphamic acid solution. The results of gravimetric measurements, electrochemical study and surface analysis (SEM) are presented in this work. The adsorption of the inhibitor over the mild steel surface obeyed the Langmuir isotherm. At an optimum concentration of 200 ppm, the maximum corrosion inhibition efficiency obtained was 93.9%. The electrochemical impedance spectroscopy (EIS) study showed an increase in polarization resistance with increase in the concentration of inhibitor justifying the adsorption and inhibition behaviour. Potentiodynamic polarization indicated that the Cht-PEG behaved as a mixed type inhibitor with cathodic predominance. The density functional theory (DFT) based calculations supported the experimental observations. Graphical Abstract: [Figure not available: see fulltext.].