Synthesis and Ion Exchange Properties of Monoclinic Titanic Acid (H2TiO3)

Abstract

A monoclinic titanic acid (M-{TiA}) was synthesized by Li+/H+ ion exchange reaction with an 0.5 M (M=mol dm-3) nitric acid solution from Li2TiO3. The Li2TiO3 was obtained by heating a mixture of Li2CO3 and anatase type {TiO}2 with molar ratio of 1: 1 at 700, 750, 850 or 950°C for 24h. X-ray diffraction pattern of M-{TiA}-750 was indexed to a monoclinic structure (space group C2/c), with the lattice constant a=0.52794, b=0.90859, c=0.96445nm, β=99.461deg. The {pH} titration curves of M-{TiA} on the Li+/H+ exchange system indicated a weak monobasic acid. M-{TiA} showed high uptake for lithium ion in the {pH} range 3.5-10, and relatively low uptake was observed for sodium ion in the {pH} range 5.0-10, whereas no appreciable amount of uptakes were observed for potassium, rubidium, cesium and calcium ions in the {pH} range 3-10. An extremely high selectivity was found for lithium ions as compared with other alkali metal ions.