Space Limitations and Molecular Sieving

FIGURE 7.4 Characteristic ion-exchange isotherms of zeolites (a) Regular system with selectivity for cation A, (b) incomplete ion exchange of cation A, (c) irregular system with selectivity reversal, (d) regular system with selectivity for cation B, and (e) irregular system with selectivity reversal. 

In other cases, because of molecular sieving, the cation is not accessible to the zeolite and there is no exchange, and in other cases the ion exchange is partial because the cation do not have access to some channel systems or cavities of the zeolite [14], 

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