New composite nanomaterials of cellulose, chitin, and chitosan modified with titanium or nickel nanoparticles were developed and tested for removal of Cs-137, Sr-85, Co-60, and Eu152+154 from aqueous solutions. The composite nanomaterials were characterized by X-ray diffraction, high-resolution scanning electron microscopy, infrared spectroscopy, and nitrogen adsorption-desorption isotherms. The influencing factors of metal adsorption were investigated, including contact time, pH, and metal ions concentration. Freundlich and Langmuir models were applied to fit the Sr(II) equilibrium adsorption data. All Ti modified biopolymers are promising adsorbents for Sr-85, Co-60, and Eu152+154 removal from radioactive wastewater.