Synthesis and Study of Si–Ti Mixed Oxides Modified with Dibenzo-18-Crown-6 Complexes with Metal Cations

Composites based on SiO 2 –TiO 2 and dibenzo-18-crown-6 (DBC) complexes with rare earth element (REE), sodium, cesium, barium, and strontium cations, including ion-imprinted composites, were prepared by sol–gel process. According to thermogravimetric analysis data, the greater part of water and dimethylformamide in the composites with DBC complexes were bound into a complex with the crown ether and the metal cation, which decomposed at 210–230°C. The possibility of fabricating efficient and selective sorbents for REEs by imprinting REE cations or cheap Na(I) cation, which has a similar size, into the DBC/SiO 2 –TiO 2 composite was demonstrated; such sorbents could be used in practice.