Ion-exchange Behavior between Sodium Ion and Other Metal Cations in Hydrated Molybdenum Bronzes

Abstract

Ion-exchange behavior between sodium ion and various metal cations (alkali, alkaline earth and a few transition metal cations) in hydrated molybdenum bronzes were investigated in [NaCl] +n [M (n+) Cln] =1M solution. The selectivity of ion exchange was in the order of Cs>Rb>K>Li for alkalin metal and Ba>Sr>Ca>Mg for alkaline earth metals. Transition metal cations gave similar ion exchange behavior to each other. The effect of the change in structure was hardly observed. The results suggest that the ion exchange behavior depends on the property of metal ions. The change in MoO3 interlayer spacing depends on the hydration energy, i.e. the surface charge density of metal cations. Hydrated sodium bronze can exchange with other metals and can extract metal ions in the solution. This property may be useful as the ion exchanger