Aluminum‐Substituted Gyrolite as Cation Exchanger

A successful Al‐substituted gyrolite has been hydrothermally synthesized at 220°C under saturated steam pressure, and its cation exchange characteristics for K⁺ and Cs⁺ ions have been investigated. Al‐substituted gyrolite took up K⁺ and Cs⁺ ions of 14 and 20 mequiv/100 g, respectively, and these removal amounts are smaller than those by Al‐substituted tobermorites (ca. 80 mequiv/100 g). It was found that Al‐substituted gyrolite exhibited selectivity for univalent cations in the following order: Na⁺ < K⁺ < Cs⁺ in the low‐concentration regions of K⁺ and Cs⁺ ions. Al‐substituted gyrolite did not lose its crystallinity and morphology, and its basal spacing did not change in the cation exchange. These results, therefore, suggest that Al‐substituted gyrolite may be useful for separation and waste disposal.