DEVELOPMENT OF ENVIRONMENTALLY BENIGN NEW SOLVENT EXTRACTION REAGENTS FROM CHITOSAN, A NATURAL POLYSACCHARIDE

摘要

Two types of lipophilic chitosan, O,O'-decanoyl chitosan (1) and O,O'-decanoyl N,N-didecanoyl chitosan (2) as well as that chemically modified with functional groups of dithiocarbamate (3) were synthesized as solvent extraction reagents for metal ions from chitosan, which is a natural polysaccharide produced from shells of crabs, shrimps, prawns and so on, a biomass waste discharged from marine food industries. Although the reagent (1) was soluble in toluene, the reagents (2) and (3) were soluble not only in toluene but also in kerosene and hexane. In the solvent extraction with the reagent (1), Cu(II) was selectively extracted while only negligible amount of Fe(III) was extracted though it was selectively extracted over Cu(II) in the extraction with the reagent (2). On the other hand, in the extraction with the reagent (3), Cu(II) and Ni(II) were selectively extracted over Fe(III).