In this study, xanthan gum-g-2-acrylamido2-methyl-1 -propane sulfonic acid (AMPS) was synthesized by free radical polymerization using bromate/thiourea redox pair in inert atmosphere. Various studies have been conducted to observe the effect of reactants on grafting parameters by varying the reactant concentration and to understand the physical-chemical properties. Grafting ratio, add on, and conversion showed a decrease on increasing the concentration of xanthan. gum. The grafting parameters increased on increasing the concentration of AMPS from 3 x 10(-2) to 6 X 10(-2) mol dm(-3), BrO3 from 2 x 10(-3) to 8 x 10(-3) mol dm(-3), and thiourea from 1 x 10(-3) to 2.8 x 10(-3) mol dm(-3), respectively. Optimum temperature and time for grafting of AMPS on xanthan gum were found to be 35 degrees C and 120 min. Water swelling capacity, swelling ratio, metal ion uptake, and metal retention capacity were also studied, and it was found that grafted polymer shows better enhancement in these properties than substrate. Graft copolymer was characterized by FTIR and thermal analysis. (c) 2007 Wiley Periodicals, Inc.