Metal complexation by chitosan and its derivatives: a review

One of the major applications of chitosan and its many derivatives is based on its ability to bind strongly heavy and toxic metal ions. This article reviews the various classes of chitosan derivatives and compares their ion binding abilities under varying conditions, as well as the analytical methods to analyze them, the sorption mechanism, and structural analysis of the metal complexes by various methods. Data are also presented exhaustively in tabular form with reference to each individual metal ion and the types of compounds that complex it under various conditions, to help arrive at conclusions regarding the comparative efficacy of various classes of compounds, structure–property relationships, and so on.