Sol-gel synthesized titanosilicates for the uptake of radionuclides

Harnessing the power of nuclear reactions has brought huge benefits in terms of nuclear energy, medicine, and defense, as well as risks including the management of nuclear wastes. One of the main issues for radioactive waste (RW) management is liquid RW (LRW). Different methods have been applied to remediate LRW, thereunder ion exchange and adsorption. Comparative studies have demonstrated that Na₂Ti₂O₃SiO₄2H₂O titanosilicate sorption materials are the most promising in terms of Cs⁺ and Sr²⁺ retention from LRW. Therefore, these TiSi materials became the object of this study. The recently developed in Ukraine sol-gel method of synthesizing these materials was chosen among the other reported approaches as it allows obtaining the TiSi materials in the form of particles with size ≥ 4mm utilizing inexpensive and bulk stable inorganic precursors and yielded the materials with desirable properties by alteration of the comparatively mild synthesis conditions.The main aim of this study was to investigate the physicochemical properties of sol-gel synthesized titanosilicates for radionuclide uptake from aqueous solutions. The effect of synthesis conditions on the structural and sorption parameters of TiSi xerogels was planned to determine in order to obtain a highly efficient sorption material. The ability of the obtained TiSis to retain Cs⁺, Sr²⁺, and other potentially toxic metal cations from the synthetic and real aqueous solutions was intended to assess. To our expectations, abovementioned studies will illustrate the efficiency and profitability of the chosen synthesis approach, synthesis conditions, and the obtained materials.X-ray diffraction, low temperature adsorption/desorption surface area analysis, X-ray photoelectron spectroscopy, infrared spectroscopy, and scanning electron microscopy with energy dispersive X-ray spectroscopy was used for xerogel characterization. The sorption capability of the synthesized TiSi gels was studied as a function of pH, adsorbent mass, initial concentration of target ion, contact time, temperature, composition, and concentration of the background solution.It was found that the applied sol-gel approach yielded materials with a poorly crystalline sodium titanosilicate structure under relatively mild synthesis conditions. The temperature of hydrothermal treatment has the strongest influence on the structure of the materials and consequently was concluded to be the control factor for the preparation of gels with the desired properties. The obtained materials proved to be effective and selective for both Sr²⁺ and Cs⁺ decontamination from synthetic and real aqueous solutions like drinking, ground, sea, and mine waters, blood plasma, and LRWs.