ION EXCHANGE PROPERTIES OF OXIDES AND HYDROUS OXIDES OF PENTAVALENT METALS

摘要

The major objective of this paper was to demonstrate the selectivities of hydrous oxides of pentavalent as inorganic ion exchange materials. The characteristics of hydrous oxides greatly depend on the preparative conditions; e. g., starting substances, temperature of preparation, concentration, aging, drying temperature etc. The acidities of these amorphous oxides are increased in the order, Sb>Ta>Nb. The selectivity depends on the crystallinity of the hydrous oxides. The rigid structure of C-SbA causes specific and unusual selectivities, because of limited space of the cavity in the pyrochlore structure. Thus, there is an ion size preference on the C-SbA by a balance between electrostatic and dehydration effect. The lithium ion memory preference can be seen on the M-SbA, C-TaA and C-NbA, which have all tunnel structures. The Li~+ is exchanged as dehydrated ions in these acids.