Application of an ion-exchange model to the synthesis of fibrous titanate derivatives

A thermodynamic model for the ion-exchange reaction process from potassium tetratitanate (K₂Ti₄O₉, or expressed by K₂O·4TiO₂) fibers (Bao et al., 2002) was applied to the synthesis of derivatives of K₂Ti₄O₉ fiber through the hydration process, including H₂Ti₄O₉·1.2H₂O, TiO₂ fiber, K₂Ti₈O₁₇ fiber and K₂Ti₆O₁₃ fiber. A novel viewpoint was proposed that the Ti/K mole ratio (R) of the target products was taken as the controlling aim of the composition of hydrate intermediates in the hydration process. Based on this, the model was successfully used to predict the suitable conditions for the synthesis of phase-pure products. In the ion-exchange reaction process, the composition of hydrate intermediates was quantitatively controlled by the method of adjusting the pH value and K⁺ concentration with ion selective electrodes (ISEs).