New sorption materials based on polysiloxane xerogels with incorporated calix[4]arene: Synthesis and structure

Polysiloxane xerogels with incorporated (without covalent binding) 25,26,27,28-tetrahydroxycalix[4]arene molecules are prepared by hydrolytic polycondensation. The elemental analysis indicates the presence of incorporated macrocyclic molecules, as well as solvent molecules used in synthesis, in the composition of materials synthesized. These conclusions agree with the data of thermal analysis, IR spectroscopy, and ¹³C CP/MAS NMR. The adsorbents synthesized are characterized by the developed porous structure and are capable of extracting cesium ions from acidic aqueous media. It is found that the maximal amount of calix[4]arene molecules participating in cesium sorption is 40%.