Modification of FAU Zeolite through Ion-exchange

Therefore, since the 1960s, the Y zeolite after exchange with mixed rare earth salts (REY) has become the main active component of cracking catalysts. However, under 

From the structural viewpoint this is reasonable because the La(H20)93+ ion has a radius of 7.92 A, and the La(H20)93+ diffused into the faujasite supercages can only exchange the Na+ at the Sn and Sm sites. It is hard for this hydrated ion to pass through [ cage window to interact with the Na+ at the S site, or at 100 °C the reaction rate is very low. 

The ion-exchange isotherms at 100 °C or below are of the D-type, whereas those at 180 °C are of the A-type, indicating that the exchange dynamics changes distinctly with temperature that is, further exchange reaction occurs when the temperature is increased, as shown in Equation (6.4)  

The La(H20)93+ at the Sn, and Sm sites of the faujasite supercage after initial exchange are subject to electrostatic interactions, and when the temperature is increased the La3+-H20 

Through detailed investigation, Xu et al. believed that when the RE3+ represented by La3+ exchange the Na+ in NaY zeolite, Lahydration3+ + NaY(solid) LaY(soUd) + Na+(liquid), the reaction mechanism can be considered to be as shown in Equations (6.7)-(6.10)  

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