A new carrageenan based chelating copolymer sorbent was prepared by gamma radiation induced copolymerization and crosslinking of kappa-carrageenan (k-Car) and acrylic acid (AAc). The swelling characteristics of the prepared copolymer were investigated by studying the effect of time, pH, and ionic strength of the swelling medium. The sorption capacities of the chelating copolymer for Fe, Pb, Mn, Zn, Cu, Sr, Cd, and A1 were 172, 202, 202, 216, 221, 230, 239, and 244 mg/g respectively. The Freundlich and Langmuir adsorption isotherms were used to validate the metal uptake data and heats of adsorption for the investigated metal ions were calculated. The re-use experiment showed that the prepared hydrogel could be regenerated upto at least 10 times. Because of the promising data collected from bench scale experiments, the prepared copolymer was examined as chelating sorbent to improve the quality of some groundwater resources. (c) 2006 Wiley Periodicals, Inc.