Preparation of ion exchangers in the hydrogen form from M1+xTi2P3−xSixO12 (M = Li, Na) crystals and glass-ceramics and their characterization
Abstract
Inorganic ion exchangers in the hydrogen form were prepared by two different methods and their properties were investigated. The first method was a conventional one; the precursors, LiTi2(PO4)3 and Na1+xTi2P3¬xSixO12
(x
= 0, 1, 1.5), were prepared by solid-phase reactions and the corresponding ion exchangers in the hydrogen form, HTP(Li) and HTPS(Na)
(x
= 0, 1, 1.5), were obtained by acid treatment of the precursors. In the other method, Na1+xTi2P3¬xSixO12–β-Ca3(PO4)2
(x
= 0, 1) glass-ceramics were first formed by the crystallization of Na2O–CaO–TiO2–P2O5–(SiO2) glasses and then sodium ions in the Na1+xTi2P3¬xSixO12
(x
= 0, 1) phases were displaced by protons and the β-Ca3(PO4)2 phase was dissolved out by acid treatments to obtain ion exchangers in the hydrogen form, gcHTPS(Na)
(x
= 0, 1). The