Chitosan and its composites for remediation purposes

This chapter deals with the use of chitosan and chitosan-based materials as adsorbents of organic and inorganic pollutants in contaminated waters. A critical overview of the literature data published in the last decade was done, considering the relevant articles and reviews sourced from the main scientific databases. Each paragraph of the chapter concerns a class of contaminants: toxic metal ions, dyes, emerging organic micropollutants, including pesticides, herbicides, Per- and Poly- Fluoro Alkyl substances, and pharmaceuticals, and inorganic anions. The maximum adsorption abilities (qm) of literature chitosan-based adsorbents were collected and statistically analyzed to determine their relative frequencies (%) for the most studied pollutants of each category. The composition, the kinetics, and thermodynamics of adsorption, as well as the mechanism of removal of the best adsorbents have been discussed. The very high qm values, which in some cases reached the thousands of mg of pollutant per g of adsorbent, classify the chitosan-based materials among the most promising adsorbents of the main pollutant classes.