Poly(isobutyl methacrylate) (PiBMA) microspheres with a 800- to 1500-mu m diameter range synthesized by suspension polymerization technique were used as the trunk polymer in the preparation of a highly efficient new adsorbent. Glycidyl methacrylate (GMA) was grafted onto the trunk polymer by pre-irradiation grafting technique. Grafting conditions were optimized, and GMA grafted PiBMA beads were modified with iminodiacetonitrile (IDAN) in ethanol at 80 degrees C. The nitrile groups were then amidoximated by using 6% (m/v) hydroxylamine hydrochloride in methanol solution. The MAN modification and the conversion of the nitrile groups to amidoxime were followed by FT-IR spectroscopy. The surface morphology and thermal behavior of the PiBMA and its modificated forms were also characterized by scanning electron microscopy (SEM) and thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC) techniques further confirming modification and amidoximation. (c) 2007 Elsevier Ltd. All rights reserved.