The ionic exchange process of cobalt, nickel and copper(II) in alkaline and acid-layered titanates

A series of titanates, K2Ti4O9 and Na2Ti3O7 and their respective acid forms, were prepared and characterized by X-ray diffraction and thermogravimetry. The ion-exchange capacity of the alkaline and acids forms towards Co, Ni and Cu(II) sulphate were studied and it was verified that as a general behavior, the copper cations have the highest ion-exchange capacity. Furthermore, the sodium matrix Na2Ti3O7 exhibits the largest ion-exchange capacity of 2.66 mmol g−1, when compared with the other matrices. Based on the thermogravimetric results and EDTA titration, the stoichiometric formulae were proposed for the synthesized compounds.