The influence of anions on the equilibrium and kinetic uptake of heavy meta
ls from an aqueous solution by a novel nitrogen-type chelating adsorbent wa
s evaluated. Equilibrium experiments revealed that stoichiometric amounts o
f metals and anions are adsorbed by the resin. Kinetic studies showed that
during the initial stage of adsorption, the anions are adsorbed by the adso
rbent prior to the metal ions. This occurred almost simultaneously with an
increase in solution pH. At equilibrium, the pH returned towards its initia
l value. The concentration of anion also fluctuated during the entire equil
ibration process. Following these observations, mechanisms governing the ro
le of anions on enhancing capacity and rate of metal uptake of this type of
chelating adsorbent type were established. (C) 2001 Elsevier Science Ltd.
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