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

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 TiO2 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.