ChemInform Abstract: Synthesis, Characterization, and Ion Exchange Behavior of a Framework Potassium Titanium Trisilicate K2TiSi3O9×H2O and Its Protonated Phases.

Abstract

A framework potassium titanium silicate K2TiSi3O9·H2O, compound I, was synthesized by the reaction of a titanium−hydrogen peroxide complex and SiO2 in alkaline media under mild hydrothermal conditions (180 °C). This compound was converted to the corresponding sodium phase, Na2TiSi3O9·H2O (IV) and two proton-containing phases, K1.26H0.74TiSi3O9·1.8H2O (II) and K0.3H1.7TiSi3O9·2.4H2O (III) by ion exchange. These products were characterized by elemental analysis, TGA, FT-IR, MAS 29Si NMR, and X-ray diffraction. The ion exchange behavior of K2TiSi3O9·H2O and K0.3H1.7TiSi3O9·2H2O toward alkali, alkaline earth, and some transition metal ions solutions was studied. A high affinity of the protonic form of titanium trisilicate exchanger for cesium and potassium makes it promising for radionuclide-contaminated groundwater treatment and certain analytical separations. The crystal structure of K2TiSi3O9·H2O was found to be isomorphous with that of the zirconium analogue and contains a framework enclosing two types of...