Synthesis of titanium phosphates from unconventional solid precursor and their ion-exchange and electrochemical properties

Abstract

A new low-cost and simple synthesis of titanium phosphate functional materials of desired composition has been developed. The route of material transformation is unconventional solid precursor-sorbent-anode material. The synthesis is based on the heterogeneous interaction between phosphoric acid and the solid (NH4)2TiO(SO4)2·H2O precursor. The influence of the synthesis conditions on the titanium phosphate composition has been thoroughly studied using NMR, FTIR spectroscopy, XRD, and DTA techniques, and mechanism of TiP formation has been established. Optimal synthesis conditions to provide obtaining of a pure TiO(OH)(H2PO4)·H2O (TiHP) phase have been found. In contrast to existing methods that require rigid synthesis conditions and high reagent consumption, the new synthesis lasts 4 h and no special equipment is needed. The sorption and electrochemical capabilities of TiHP have been investigated. The obtained material exhibits the highest sorption capacity toward Cs+ and Sr2+ ions among other TiP-based ion exchangers. Furthermore, TiHP has been tested as a sorbent for treatment of multicomponent liquid radioactive waste and distribution coefficients of the radionuclides have been found to be 105 mL·g–1. New approach to the synthesis of precursor for Li-ion batteries has been proposed. The substitution of protons of the dihydrogen phosphate group in TiHP by lanthanum (III) cations and subsequent calcination at 900 °C result in formation of nanoparticles of the final powder and provide the good electrochemical characteristics of obtained electrode material.