Synthesis, characterization and ion exchange properties of the framework sodium titanium germanate Na3H(TiO)(3)(GeO)(GeO4)(3)center dot 7H(2)O

Sodium titanium germanate with a semicrystalline framework (STG) of the for mula Na3H(TiO)(3)(GeO)(GeO4)(3). 7H(2)O was synthesized under mild hydrothe rmal conditions and its proton form, H-4(TiO)(3)(GeO)(GeO4)(3). 8H(2)o (STG -H), was prepared by acid treatment of the sodium compound The STG was char acterized by elemental analysis, TGA, FT-IR, and X-ray. powder diffraction. A comparative ion exchange examination of the STG-H towards alkali and alk aline earth metals in a broad pll and concentration range was carried out. It was found that the STG is a moderately weal; cation exchanger. possessin g high ion exchange capacity (up to 4.0 meq/g) and showing preference for h eavy alkali and alkaline earth metals. The STG selectivity rewards Cs+ and Sr2+ ions in the presence of competitive metal ions and certain organic com pounds was also studied. The data obtained suggest that the sodium titanium germanate is a more selective exchanger for Sr2+ ion than its titanium sil icate analogue, K3H(TiO)(4)(SiO4)(3). 4H(2)O.