Development of Inorganic Ion Exchangers for Separation and Recovering of Valuable and Dilute Monovalent Ions

Abstract

Fluorine micas contain K⁺ at the interlayer in its original form. Therefore, Na⁺-substituted fiuorine micas may be very selective for alkaline metal ions in ion-exchange reactions, i. e. the ion-memorizing effect. In this study, the ion-exchange properties of Na-form taeniolite, NaMg₂LiSi₄O₁₀F₂·nH₂O,(NaT) for K⁺ and other ions are discussed.
NaT demonstrated the ion-memorizing effect for K⁺. Ca²⁺ and Mg²⁺ were also selectively removed from aqueous sohltions. However, the selectivity for K⁺ was hardly affected by the presence of alkaline earth metals in mixed aqueous solutions. NaT selectively took up NH₄⁺ just K⁺ did. It is expected that the changes in the interlayer distance of NaT during the exchange reaction slead to a difference of its exchange properties between K+ and Ca²⁺ or Mg²⁺.
In conclusion, NaT can be used as the selective adsorbent for K⁺ and NH₄⁺ from seawater and living wastewater.