Synthesis and physico-chemical characterization of cellulose/HO7Sb3 nanocomposite as adsorbent for the removal of some radionuclides from aqueous solutions.

Novel organic-inorganic nanocomposite cellulose/HO7Sb3 was prepared chemically by sol-gel mixing of organic poly cellulose into inorganic Sb(OH)5. The prepared nanocomposite was used as an adsorbent for the adsorption of La (III), Co (II) and Cs (I) from aqueous solutions. The adsorbent was characterized by XRD, FTIR, TEM, SEM and TGA. TEM analysis of cellulose/HO7Sb3 shows some dispersed HO7Sb3 particles in the cellulose matrix; having spherical shapes with different sizes with average particle size less than 21 nm. Furthermore, XRD and FTIR analysis confirm the formation of HO7Sb3 structure on poly-crystalline cellulose. The synthesized cellulose/HO7Sb3 demonstrated bifunctional ion-exchange groups (C-OH and Sb-OH) appearing in the FTIR absorption bands at about 1061 and 560 cm-1, respectively. The impacts of various adsorption parameters such as contact time, pH, initial metal concentrations, the amount of cellulose/HO7Sb3 nanoparticles, competing ions and complexing agent and reaction temperature were investigated using batch adsorption experiments. In terms of saturation capacity, this hybrid material retained about 80.05% of the initial saturation capacity when it irradiated by γ-radiation with dose = 50 kGy, at 150 kGy, sharp capacity loss (~ 96%) was observed. Cellulose/HO7Sb3 exhibits selectivity for La (III), Co (II) and Cs (I) in the order of La3+ > Co2+ > Cs+. The changes in the values of free energy (ΔG°) and enthalpy (ΔH°) indicate the spontaneous, feasible and endothermic nature of the sorption process. Radiometric data shows high removal and decontamination efficiency of the prepared nanocomposite especially for La-140 and Co-60. While, Cs-137 removal is less than the other radionuclides.

Use of activated carbon in removal of some radioisotopes from their waste solutions.

Removal of some radioisotopes namely (152+154)Eu and (65)Zn from radioactive solutions by activated carbon using both batch and column techniques has been performed. Experimental studies were conducted to evaluate and optimize the various process variables, i.e., equilibrium time, carbon dose, solution pH. Sorption data have been interpreted in terms of both Freündlich and Langmuir isotherms. The fixed-bed results indicate the high capacity of the activated carbon for the removal of europium and zinc ions. The data suggest the possible use of activated carbon for the removal of these cations from radioactive waste solutions.