New adsorbents for nitrate were successfully prepared from ground tire rubber by the use of Wijs' reagent and polyamines by the microwave heating method. The modified ground tire rubber presented an increase in adsorption capacity for nitrate ion (NO3-) than the unmodified ground tire rubber and was reusable by regeneration similarly to ion exchange resin. Moreover, referring to the isotherm studies of the NO3- adsorption, all of modified ground tire rubber showed a good agreement with Langmuir isothern model. Regarding the effect of polyamines, it was found that PHA-300 W, which was modified by pentaethylenehexamine, showed the highest maximum adsorption capacity (3.61 mg/g), following by DTA-450 W, which was modified by diethylenetriamine (3.08 mg/g), and EDA-300 W which was modified by ethylenediamine (2.16 mg/g). The results from the elemental analysis and FT-IR confirmed that polyamines were successfully introduced into the structure of ground tire rubber after the aminolysis reaction. The SEM images revealed that the particles of all samples were in irregular shapes. The average particles size the modified ground tire rubber was 240 mu m, and decreased to 196, 149 and 148 mu m for EDA-300 W, DTA-450 W and PHA-300 W, respectively. The decrease of average particles size may be explained by the shrinking of rubber material by heating in the aminolysis reaction.