Monte Carlo simulation studies of cation selectivity in ion exchange of zeolites

Nakamura, Hiroki  ; Okumura, Masahiko   ; Machida, Masahiko  

In order to evaluate the selectivity for specific cations in ion-exchange of zeolites, we calculate the ion-exchange isotherms in various zeolites using Monte Carlo simulation techniques. The calculation results agree well with experiments. Furthermore, we examine the Si/Al-ratio dependence on the cation selectivity and find that the Cs selectivity once increases with the Si/Al ratiobut saturates above a certain value. These results reveal that the selectivity for Cs is enhanced cooperatively by microporous structure and the Si/Al ratio of the zeolite framework. The present simulation scheme is promising in selecting useful materials for Cs decontamination in waste treatments.