Zeolites are a class of microporous solids with well-defined crystalline structures. Due to their ability to distinguish molecules on the basis of size and shape, zeolites are often referred to as molecular sieves. There has been considerable interest in the synthesis of zeolite nanocrystals (or nanozeolites), because they can serve as a model system for fundamental understanding of zeolite nucleation and growth mechanisms, as seeds for secondary growth of zeolite films and membranes, as

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... g blocks for construction of hierarchical porous nanostructures, and for preparation of mixed matrix membranes (MMMs). Presently, in the synthesis of zeolite crystals, it is well-known that the addition of organic additives or polymers has an effect on the zeolite nucleation and crystallization. Despite several synthetic strategies of using some polymers (e.g. polyacrylamide and methylcellulose) have been developed to grow zeolites, there has been no research on the synthesis with crosslinked chitosan hydrogels or uncrosslinked chitosan polymers, which is one primary goal of this thesis. Therefore, chitosan (crosslinked or uncrosslinked polymers) was introduced into zeolite crystallization process. The zeolite crystal sizes were significantly affected by formulation of silica-containing crosslinked hydrogels and alkaline solution, and by aging and heating conditions. Importantly, a novel method of using hydrogen peroxide solution was developed to remove crosslinked hydrogels after zeolite synthesis, which was considered as an effective way for removal of hydrogels. The resultant zeolite nanocrystals were readily redispersed in deionized water and some other solvents, and therefore they may be useful for some applications, e.g. in the fabrication of zeolite-polymer mixed matrix membranes (MMMs) and hierarchical porous zeolitic structures. In this thesis, the effect of uncrosslinked chitosan hydrogels on zeolite nucleation and crystallization was also studied. Cubic zeolite with a single crystalline shell and an amorphous co [...]