SYNTHETIC INORGANIC ION-EXCHANGE MATERIALS .28. ION-EXCHANGE PROPERTIES OF NA+ AND K+ IONS ON CRYSTALLINE AND AMORPHOUS ANTIMONIC(V) ACIDS TREATED THERMALLY AT ELEVATED-TEMPERATURES

The change in selectivities by thermal treatment was studied on crystalline (C-SbA) and amorphous (A-SbA) antimonic(V) acids. The equilibrium distribution coefficients (Kd) of Na+ and K+ ions in HNO3 solution showed a maximum on the C-SbA heated at 330 °C. An inverse relationship was noticed between the changes in Kd values and in the lattice constants for the heated C-SbA. A-SbA heated at 20-500°C showed two steps of time dependence of adsorption for Na+, while a maximum for K+. This behavior can be explained in terms of the transformation from amorphous material to C-SbA. © 1979 Akadémiai Kiadó.