Chelation capability of chitosan and chitosan derivatives: Recent developments in sustainable corrosion inhibition and metal decontamination applications

Chemically, chitosan is composed of random distributed D-glucosamine and N-acetyl-D-glucosamine units joint together by β-1,4-glycosidic linkage. Chitosan and its derivatives are widely used as corrosion inhibition and removal metallic impurities. Numerous experimental and computational methods are used to demonstrate the chelation capability of chitosan and its derivatives. Chitosan can be regarded as a biocompatible, non-toxic, environmental friendly and cost-effective alternative at the place of synthetic polymers. The anticorrosive applications of chitosan and chemically modified chitosan are demonstrated for different metal/electrolyte systems however its use is restricted because of its low solubility. Therefore, the use of chemically modified chitosan with enhanced solubility is preferred. Outcomes of the literature study suggest that chemically modified chitosan exhibits surprisingly high anticorrosive and metal binding activities as compared to the purified chitosan. Chitosan acts as mixed- and interface-type corrosion inhibitors and their adsorption on the metallic surface follows the Langmuir adsorption isotherm. Adsorption of these compounds is widely investigated using surface studies. Chitosan and chemically modified chitosan adsorb spontaneously and form hydrophobic protective films.