Studies of the Cation Distribution in Dehydrated Na-exchanged Faujasite Zeolites

The simulated annealing method is employed to study the cation distribution in dehydrated Na-exchanged faujasite Zeolites. By use of the same three parameters, i. e. e_Ⅰ′-e_Ⅰ,e_Ⅱ-e_Ⅰ, the site energy level differences getween sites I ’, II and I ; and w, the repulsive energy between cation pairs located on adjacent sites I and I ’, the cation distribution in dehydrated NaHy-type zeolites （with a Si/A1 ratio of 2. 46） with varying cation loading ofr temperatures could be accurately predicted. It is found that the influence of the framework Al content, N_AI, on the site energy level differences can be expressed as e_{I ’}-eI=-23. 0490 + 0. 5605N_AI（kJ/mol） and e_Ⅱ-e_Ⅰ= -22. 4770+O. 4437N_AI （kJ/mol）. By use these linear relations the cation distribution of dehydrated Na-exchanged faujasite with various Al content could be predicted excellently.