Adsorption behavior of cationic and anionic species on chitosan resins possessing amino acid moieties.

Chitosan resins modified with amino acids, such as glycine, valine, leucine, and serine, were synthesized for investigating the adsorption behavior of cationic and anionic species, and showed good abilities for the adsorption of trace elements in aquatic media as follows: glycine for lanthanoids at pH 7, leucine for molybdenum at pH 1-5, serine for uranium at pH 2-7, and amino acids for bismuth at pH 1-7. Cationic and anionic species could be adsorbed by a chelating mechanism and an anion-exchange mechanism.