Abstract
Selectivity coefficients for binding of negative and positive ions
to chitosans of different chemical composition have been determined
by equilibrium dialysis. Chitosans with different fraction of acetylated
units (F-A of 0.01 and 0.49) generally behaved similarly in their
selectivity towards both negative and positive ions. No selectivity
was found in the binding of chloride and nitrate ions, while chitosan
showed a strong selectivity towards molybdate polyoxyanions, with
selectivity coefficients around 100. Chitosan showed a strong selectivity
towards copper (Cu2+) compared to the metal ions zinc (Zn2+), Cadmium
(Cd2+) and nickel (Ni2+), with selectivity coefficients from 10 to
1000, while little or no selectivity could be detected with the other
metal ions. Ionic strength and pH did not influence the selectivity
coefficients of the chitosans towards the metal ions. (C) 2003 Elsevier
Ltd. All rights reserved.
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