Alkaline Posttreatment of MFI Zeolites. From Accelerated Screening to Scale-up

The extraction of framework silicon, referred to as desilication, has been investigated for controlled mesoporosity development in commercial and synthesized MFI type zeolites. Several variables were successfully identified and optimized using a parallelization approach in the gram-scale. The framework Si/Al ratio of the treated zeolite is crucial for the susceptibility of the zeolite toward desilication. A NaOH solution has proven to be the most efficient medium to achieve substantial and controlled mesopore formation. Descriptors such as treatment temperature and time enable further tailoring of the porous characteristics. Importantly, the acidity and microporosity are preserved upon alkaline treatment under optimized conditions. Finally, the treatment has successfully been scaled up from gram-scale to kilogram-scale for both commercial zeolite powders and extrudates.