Study on Ag ion exchange mechanism of NaY

In this paper, a comparative study was conducted on the ion exchange properties of several representative FAU-type molecular sieves. The investigation revealed that NaX and NaY exhibit outstanding ion exchange capabilities, with a clear trend indicating that a lower Si/Al ratio correlates with enhanced ion exchange performance. Additionally, the presence of extra-framework cations was found to significantly influence the ion exchange behavior. Kinetic analysis showed that the ion exchange process of NaY follows a quasi-second-order kinetic model. A notable migration phenomenon of silver ions within the NaY framework was observed, driven by a concentration potential difference that facilitates the movement of Ag+ from super cages into hexagonal prism cages. The internal diffusion model was applied to accurately describe the exchange and migration process of Ag+. This study offers valuable theoretical guidance and technical reference for optimizing the preparation of silver-exchanged molecular sieves.