Synthesis of titanosilicate ETS-4 with controlled morphology and investigation of its crystallization kinetics

Crystal Shape Engineering

“…Low accelerating voltage FE-SEM studies have provided clear images of growth terraces and spirals on faces of zeolite and zeo-type materials. [113][114][115] These studies have been important in determining growth mechanisms for these systems. [114][115][116] Atomic force microscopy has been used to characterize the surface microstructure of a variety of It is also well known that foreign molecules (additives or impurities) influence the growth shape of crystals.…”

Synthesis of large ETS-4 crystals in the Na and Na/K systems: the effects of alkali metal ion and synthesis mixture alkalinity

“…The other was formulated by mixing N-Brand sodium silicate (28.8% SiO 2 , 9.14% Na 2 O, PQ Corp.), sodium hydroxide (97+% NaOH, Aldrich), potassium hydroxide (85%, KOH, Acros) (when necessary), and deionized water. Additional details on synthesis mixture preparation and product recovery are given elsewhere [8]. In all cases the initial pH of the synthesis mixtures was varied by altering their acid (H 2 SO 4 ) and/or base (NaOH) content.…”

“…However, their method involved the initial formation of another crystalline phase, GTS-1, followed by its recrystallization [4]. We have previously reported the direct synthesis of ETS-4 crystals with controlled morphology [8] and their physicochemical characterization [9]. The initial pH of the synthesis mixture was varied in the range of 11.50-12.90 by modifying the sulfuric acid content [8].…”

“…We have previously reported the direct synthesis of ETS-4 crystals with controlled morphology [8] and their physicochemical characterization [9]. The initial pH of the synthesis mixture was varied in the range of 11.50-12.90 by modifying the sulfuric acid content [8]. As a result, a progressive change of ETS-4 morphology from spherulitic particles of submicron crystallites to monolithic crystals with rectangular prism morphology and relatively small average dimensions $1 Â 15 Â 2 mm was achieved [8].…”

“…The initial pH of the synthesis mixture was varied in the range of 11.50-12.90 by modifying the sulfuric acid content [8]. As a result, a progressive change of ETS-4 morphology from spherulitic particles of submicron crystallites to monolithic crystals with rectangular prism morphology and relatively small average dimensions $1 Â 15 Â 2 mm was achieved [8]. The Ti content of these ETS-4 crystals increased with increasing pH [9].…”