Sol-Gel Production and Properties of Spherical Biomaterials for the System TiO2–SiO2 /CaO

The physicochemical properties of the carboxylic cationite Tokem-200 and the sulfo-cationite Tokem-140 as well as their Ca2+-ion selectivity under equilibrium conditions were investigated and Tokem-200 based biomaterials of spherical form were synthesized from solutions by the sol-gel method. The material frame is represented by TiO2–SiO2; the inner part is filled with the oxide Ca2+ (sample TiO2–SiO2 /CaO). Unlike Tokem-140, the carboxylic cationite Tokem-200 possesses the highest Ca2+-ion selectivity, which makes it promising for the development of biomaterials. The solutions were found to remain suitable for up to 5 days for obtaining materials. To obtain a homogeneous material stepped heat-treatment is required (after drying at 60°C) at 150, 250, and 350°C (30 min at each step) and at 600°C for 6 h. Additional post-drying immersion of the samples into phosphoric acid does not favorably affect the properties of the material.