Optimized Synthesis and Evaluation of Composite Beads for Antimony Removal from Acidic Nuclear Reprocessing Effluent

Epichlorohydrin cross-linked titania-chitosan composite (TA-Cts-Epi) beads that are stable under high acidic conditions (3 to 4 M of nitric acid) were synthesized and evaluated in detail with the objective of effectively removing antimony from high-level liquid waste (HLW), a highly acidic and radioactive effluent generated in a nuclear reprocessing plant. An optimized synthesis procedure, which is scalable for the large-scale synthesis of the beads, was brought out. The TA-Cts-Epi beads were shown to efficiently remove antimony, a key active nuclide, from HLW.Heterogeneous cross linking with an epichlorohydrin-to-chitosan ratio of 0.2 mL·g−1 was found to be optimum. Detailed batch and column studies involving antimony removal from HLW streams using TA-Cts-Epi beads were carried out. The physical stability of the beads, the selective removal of different oxidation states of antimony in the presence of other competing ions, and the factors that affect the performance of the beads under flow conditions were brought out.The TA-Cts-Epi beads showed the high and preferential removal of antimony in the presence of excess competing ions from simulated HLW containing high acidity and high levels of dissolved solids. The typical Sb(V) uptake capacity was found to be 840 ± 100 µmol·g−1. A decrease in the flow rate and an increase in the column length enhanced the antimony selectivity over molybdenum. Elution of the bound antimony was found to be difficult, indicating the strong binding of antimony by the beads. A batch sorption experiment with actual HLW raffinate further demonstrated the suitability of the sorbent for the removal of antimony from HLW.