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A series of hydrogels based on starch, acrylic acid (AAc) and 2‐hydroxyethyl methacrylate (HEMA), namely AAc/starch and AAc/HEMA/starch hydrogels were synthesized by gamma radiation and used to adsorb acid fast red dye from aqueous solution. Alkali treatment of AAc/starch hydrogels to improve their ionic character was evaluated. The structure and surface morphology of prepared hydrogels were confirmed by Fourier transfer infrared spectra and SEM, respectively. The results indicated that the diffusion of water into the hydrogels pertains a non‐Fickian character. The swelling equilibrium for AAc/starch and NaAc/starch hydrogels was obtained after 10 h whereas for AAc/HEMA/starch hydrogels after 5 h. The effects of the medium pH, initial dye concentration and temperature on the adsorption were studied. The adsorption capacity increases with increasing dye concentration and decreasing medium pH. The increase of temperature leads to higher adsorption capacity for AAc/starch and NaAc/starch hydrogels but lower adsorption capacity for AAc/HEMA/starch hydrogels.

In this study, a nanocomposite of Bismuth/2‐(Dimethylamino)ethyl methacrylate/Starch (Bi/DMAEMA/Starch) is synthesized using ionizing radiation. The prepared nanocomposite is characterized and compared with the parent (DMAEMA/St) hydrogel using Fourier transform infrared spectroscopy (FTIR), X‐ray diffraction (XRD), and Thermogravimetric analysis (TGA). The presence of nanoparticles is confirmed by Transmission Electron Microscopy (TEM). The prepared nanocomposite is used to remove Cobalt ions (Co2+) from their wastes as a simulation of radioactive waste management. The optimization of effective parameters such as initial pH values, contact time, concentration, and temperature (°C) on the adsorption process is studied. The results prove that the Langmuir isothermal model describes well the absorption process. The pseudo‐second‐order kinetic model is suitable for describing the adsorption kinetics. Thermodynamic parameters (ΔHo, ΔGo, and ΔSo) are evaluated for the adsorbent systems. The prepared nanocomposite shows potential behavior for the removal of Co2+ ions.

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