Synthesis and characterization of poly(hydroxamic acid) chelating resin from poly(methyl acrylate)-grafted sage starch

A new chelating ion-exchange resin containing the hydroxamic acid functiona l group was synthesized from poly(methyl acrylate) (PMA)-grafted sage starc h. The PMA grafted copolymer was obtained by a free-radical initiating proc ess in which eerie ammonium nitrate was used as an initiator. Conversion of the ester groups Of the PMA-grafted copolymer into hydroxamic acid was car ried out by treatment of an ester with hydroxylamine in an alkaline solutio n. The characterization of the poly(hydroxamic acidi chelating resin was pe rformed by FTIR spectroscopy, TG, and DSC analyses. The hydroxamic acid fun ctional group was identified by infrared spectroscopy. The chelating behavi or of the prepared resin toward some metal ions was investigated using a ba tch technique. The binding capacities of copper, iran, chromium, and nickel mere excellent and the copper capacity was maximum (3.46 mmol g(-1)) at pH 6. The rate of exchange of the copper ion was very fast that is, t(1/2) < 5 min. It was also observed that the metal ion-sorption capacities of the r esin were pH-dependent and its selectivity toward the metal ions used is in the following order: Cu2+ > Fe3+ > Cr3+ > Ni2+ > Co2+ > Zn2+ > Cd2+ > As3 > Pb2+. (C) 2000 John Wiley & Sons, Inc.