Abstract: Water-insoluble carboxyl-containing starch graft polymer(carboxyl-containing starch) was prepared by grafting acrylonitrile onto highly cross-linked starch, followed by base saponifi-cation to convert nitrile group into a mixture of carboxamide and carboxylate groups.Ceric ammonium nitrate was used as initiator for the graft polymerization.The sorption kinetic properties of carboxyl-containing starch for several heavy metal ions have also been studied systematically.It is shown that the sorption rate of carboxyl-containing starch is very rapid and the time of reaching its equilibrium is short.The relationship between the sorption amount and time completely complies with following equationQ/Q_∞=at/(1+at).

Key words: Carboxyl-containing starch, Heavy metal ions, Sorption rate equation