Silicalite-l Synthesis from Silicate Aqueous Solutions Including Amines as a Base

Mechanism of crystallization of zeolite A microcrystals from initially clear aluminosilicate solution: A population balance analysis

“…13 and 14) indicate that the crystallization process generally takes place by a chain of processes: (i) formation of a small proportion of amorphous aluminosilicate at the very start of the crystallization process [25][26][27][28][29][30][31][32][33][34][35][36][37][38][39] (see also Fig. 1), (ii) formation of nuclei in the matrix of the amorphous aluminosilicate [13,[19][20][21][22]25,29,[40][41][42][43][44], (iii) release of nuclei from the matrix of amorphous aluminosilicate dissolved during the early stage of crystallization (autocatalytic nucleation [48,50,53,62,63,65,[70][71][72]), by the dynamics shown in Figs.…”

“…Hence, for a long time, a general meaning was that crystallization of zeolites from clear (alumino)silicate solutions takes place in a direct way, i.e., by nucleation and growth of zeolite crystals in/from the liquid phase [11,16,17], and thus without the formation of an intermediate amorphous (alumino)silicate. On the other hand, many recent studies of crystallization of different types of zeolites from clear (alumino)silicate solutions demonstrated the presence of (nano-scale) amorphous (alumino)silicate agglomerates formed during the room-temperature ageing [13,[18][19][20][21][22][23][24] or at the early stages of hydrothermal treatment of the synthesis solutions [25][26][27][28][29][30][31][32][33][34][35][36][37][38][39]. Formation and evolution of structurally ordered phase (potential nuclei) in the amorphous solids precipitated from initially clear (alumino)silicate solutions was evidenced by various experimental methods such as electron diffraction [13,40,41], highresolution transmission electron-microscopy [20][21][22]27], infrared spectroscopy [19][20][21][22], optical/electron-microscopy [42], small-angle X-ray scattering [25,29,…”

“…Formation and evolution of structurally ordered phase (potential nuclei) in the amorphous solids precipitated from initially clear (alumino)silicate solutions was evidenced by various experimental methods such as electron diffraction [13,40,41], highresolution transmission electron-microscopy [20][21][22]27], infrared spectroscopy [19][20][21][22], optical/electron-microscopy [42], small-angle X-ray scattering [25,29,43,44], wide-angle X-ray scattering [25,29] and small-angle neutron scattering [43]. However, although the formation of (nano-scale) amorphous aluminosilicate agglomerates in the starting clear (alumino)silicate synthesis solutions [25][26][27][28][29][30][31][32][33][34][35][36][37][38][39] and the formation of nuclei in the gel matrix are intensively researched and well documented in the appropriate publications [13,[19][20][21][22]25,29,[40][41][42]…”

Assembly of oriented iron oxide and zeolite crystals via biopolymer films

“…Assembly of zeolite micro-crystals into oriented monolayers has also attracted much attention in recent years because these materials can be applied as membranes, 14 chemical sensors 15 and hosts for supramolecular organization of guest molecules or nanostructures. 16 LTA (pore size $0.41 nm) and MFI type (pore size $0.55 nm) zeolite crystals were previously prepared in the form of oriented monolayers by various methods, [17][18][19][20] mostly on nonporous (glass, Si wafer, etc.) 18 or mesoporous (SiO 2 film) 20 materials as substrates.…”