Date of Award
Master of Science
Dr. Yining Huang
The behaviour of completely siliceous zeolite ZSM-5 under high pressure up to 16 GPa were investigated by in situ Raman spectroscopy, Infrared spectroscopy and X-ray diffraction with synchrotron radiation using diamond anvil cell. Pressure-induced amorphization was observed in both as-made and calcined siliceous ZSM-5 which transform to a low-density amorphous silica first and then to a high-density amorphous silica. However, transition pressures and reversibility were different for the as-made and calcined siliceous ZSM-5. It was found that the occluded template molecules are the major factor for these differences.
The crystallization mechanism of AIPO4-I6 molecular sieve was preliminarily investigated under dry gel conversion method by X-ray diffraction and Solid-State NMR spectroscopy. The AIPO4-I6 and a crystalline by-product which has similar structure were formed via a semi-crystalline layered A1PO intermediate. The by-product could be transformed to amorphous materials with different structures by calcination and washing with distilled water.
Fu, Yueqiao, "Investigations of Crystallization of Molecular Sieves and their Behaviour under High Pressures" (2009). Digitized Theses. 4281.