Synthesis, Physicochemical and Adsorption Properties of Ti–Ca–Mg Phosphates

Sorbents based on Ti–Ca–Mg phosphates were synthesized, their physicochemical and sorption properties towards Cs(I), Sr(II), Co(II) (in the form of both stable ions and radionuclides 137 Cs, 60 Co, 90 Sr) were investigated. Samples of TiCaMg-1 and TiCaMg-2 were prepared by heterogeneous interaction of acidic and tertiary Ca–Mg phosphates with a solution of titanyl-diammonium sulfate, and a sample of TiCaMg-3 was prepared by heat-treated dolomite with a preliminarily precipitated suspension of titanium hydrogen phosphate. It was shown that the samples have a high affinity for Cs + , Sr 2+ , Co 2+ ions and their radionuclides. The TiCaMg-3 sample has the highest distribution coefficients for 137 Cs, 60 Co, and 90 Sr radionuclides (>10 5 mL/g). It was established that the difference in the properties of composites is due to their phase and chemical composition, as well as textural characteristics (specific surface area, sorption volume, and pore size). The TiCaMg-3 sorbent is characterized by the largest sorption volume (0.410 cm 3 /g) and average pore diameter (10.2 nm), which provides better accessibility of ionogenic groups during exchange reactions.