A new organic/inorganic composite based on polyacrylonitrile and stannic molybdophosphate (PAN-SMP) as an adsorbent was synthesized under various conditions. The physico-chemical properties of this material were specified by elemental analysis, scanning electron microscope, infrared spectroscopy, and thermogravimetry studies. The synthesized material was found to be stable in demineralized water, dilute acids, under gamma radiation up to the total radiated of 100 kGy doses and in high temperature up to 500 °C. Ion exchange capacity of the synthesized composite and its distribution coefficient (Kd) for several metal ions were determined. The results showed that PAN-SMP has a great affinity toward some metal ions such as, Tl+, Sr2+, Ba2+, UO22+ and La4+. Based on the determined Kd values, two binary quantitative separations of metal ions (Cr6+ from Cu2+ and Pb2+ from Cu2+) have been achieved on columns of this ion exchanger. The ability of PAN-SMP for decontamination of low-level liquid waste (LLLW) was also investigated.