Ultrafast synthesis of high-silica Beta zeolite from dealuminated MOR by interzeolite transformation for methanol to propylene reactions

Regulation of the Si/Al ratios and Al distributions of zeolites and their impact on properties

“…2). 49 These results clearly demonstrate that the right gel chemistry combing the seeding strategy if necessary is of the utmost important to regulate the Si/Al ratios of the resultant zeolites, which can be achieved via modifying the recipe of the initial reaction mixture or interzeolite transformation. Besides changing the Si/Al ratios of the initial mixture or dissolving the zeolites to modify the Si/Al ratios of the oligomers, introducing extra species to alter the condensation of Si-O-Si(Al) bonds, such as anions, metal ions, and hydroxyl radicals can also modify the Si/Al ratios of the oligomers and further regulate (mostly increase) the Si/Al ratios of the resultant zeolites.…”

Controlling Nucleation Pathways in Zeolite Crystallization: Seeding Conceptual Methodologies for Advanced Materials Design

“…112,113 The role of inorganics in directing nucleation of the daughter phase was highlighted by Kirschhock and co-workers, 89 who reported transformations of Na-FAU seeds in growth mixtures containing four different alkali metals (Figure 3A), each promoting the formation of a different zeolite: Li-ABW, K-CHA, Cs-ANA, and Rb-MER. In some seed-assisted syntheses, IZT can dramatically reduce crystallization time, 68,114 such as a 3 day synthesis of K-CHA using zeolite HY (FAU) seeds compared to 14 days in the absence of seeds (for syntheses at 100 °C). 115 At different synthesis conditions, the same seeds (zeolite HY) can undergo IZT to Na-MFI (Figure 3B) in the absence of organics or MFI seeds.…”

“…When seeds are used as the sole source of silica and alumina, their dissolution and subsequent nucleation of the daughter phase can be facilitated by the presence of an inorganic − or organic ,,− structure-directing agent, a small quantity of seeds with identical structure as the daughter, ,,, or in some cases neither seeds nor organics are required to achieve the desired product. , The role of inorganics in directing nucleation of the daughter phase was highlighted by Kirschhock and co-workers, who reported transformations of Na-FAU seeds in growth mixtures containing four different alkali metals (Figure A), each promoting the formation of a different zeolite: Li-ABW, K-CHA, Cs-ANA, and Rb-MER. In some seed-assisted syntheses, IZT can dramatically reduce crystallization time, , such as a 3 day synthesis of K-CHA using zeolite HY (FAU) seeds compared to 14 days in the absence of seeds (for syntheses at 100 °C) . At different synthesis conditions, the same seeds (zeolite HY) can undergo IZT to Na-MFI (Figure B) in the absence of organics or MFI seeds .…”

β Zeolite Nanostructures with a High SiO2/Al2O3 Ratio for the Adsorption of Volatile Organic Compounds

“…Wu et al. reported a new strategy for high-silica β zeolite via the interzeolite transformation, requiring dealuminated or pure-silica MWW zeolites as the silicon source, and the dealuminated β as the seed crystal or in the F medium, as well as the tetraethylammonium hydroxide as the structure-directing agent. , Therefore, the entire synthesis process requires a lot of preparatory work, which invisibly increases resource consumption.…”

“…reported a new strategy for high-silica β zeolite via the interzeolite transformation, requiring dealuminated or puresilica MWW zeolites as the silicon source, and the dealuminated β as the seed crystal or in the F medium, as well as the tetraethylammonium hydroxide as the structure-directing agent. 23,24 Therefore, the entire synthesis process requires a lot of preparatory work, which invisibly increases resource consumption. With the decrease in particle size from micron to nanometer, properties of zeolite significantly change and affect their performance, such as in the adsorption of organic pollutants; therefore, the nanozeolite has attracted more applications.…”