Juliet Munn

In-situ studies of the hydrothermal synthesis of zeolites using synchrotron energy-dispersive X-ray diffraction

Abstract Energy-dispersive X-ray diffraction has been used to monitor, for the first time in situ, the hydrothermal synthesis of sodalite and zeolite A from kaolinite and from an amorphous aluminosilicate gel respectively. The synthesis can be undertaken and monitored using a previously described hydration cell with appropriate modifications. The penetrating power of the wiggler synchrotron radiation and the superior pattern capture rate available with energy-dispersive diffraction are both essential elements of the method. Additional modifications currently being applied to the “In-situ hydrothermal cell” should now enable the kinetics of a wider range of zeolite syntheses to be studied.

Autoclave synthesis and thermal transformations of the aluminophosphate molecular sieve VPI-5: an in situ X-ray diffraction study

Abstract The synthesis of DPA-VPI-5 and TBA-VPI-5 and their phase transformation to AlPO 4 -8 have been studied by X-ray diffraction in situ. The synchrotron radiation-energy dispersive diffraction is shown to be able to monitor these two fast reactions in real time. The results indicate that nucleation may occur already during the aging of the synthesis gel. The different rates of transformtion of DPA-VPI-5 and TBA-VPI-5 show that the microstructure of the two materials is different.