Colloidal zeolite suspensions

Schoeman, Brian J.; Sterte, Johan; Otterstedt, Jan-Erik

doi:10.1016/0144-2449(94)90004-3

Cited by 280 publications

(167 citation statements)

References 9 publications

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“…However, relatively small individual micropores in zeolites such as Beta, ZSM-5, and Y strongly influence mass transport to and from the active sites located within them, severely limiting the performance of industrial catalysts. [1,2] To overcome this problem, various strategies have been successfully pursued, such as the synthesis of nanosized zeolites, [3] ultralarge-pore zeolites and zeolite analogues (VPI-5, [4] JDF-20, [5] UTD-1, [6,7] CIT-5, [8] SSZ-53, [9] ECR-34, [10] UCSB, [11] ITQ-21, [12] IM-12, [13] and SU-M, [14,15] among others), and ordered mesoporous materials (e.g. MCM-41, [17] SBA-15, [18] and FSM-16, [19]).…”

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confidence: 99%

Catalytic Properties of Hierarchical Mesoporous Zeolites Templated with a Mixture of Small Organic Ammonium Salts and Mesoscale Cationic Polymers

Xiao¹,

Wang²,

Yin³

et al. 2006

Angew Chem Int Ed

434

133

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Crystals of zeolites with intricate micropores have been widely used in industry as heterogeneous catalysts, in particular as solid acid catalysts in the fields of oil refining and petrochemistry. However, relatively small individual micropores in zeolites such as Beta, ZSM-5, and Y strongly influence mass transport to and from the active sites located within them, severely limiting the performance of industrial catalysts. [1,2] [19]). However, the use of these materials is rather limited owing to the difficult separation of nanosized zeolite crystals from the reaction mixture,[3] the complexity of the templates used for the synthesis of ultralarge-pore zeolites, [6][7][8][9] and the relatively low thermal and hydrothermal stability of ordered mesoporous materials. [17][18][19][20][21][22][23][24][25][26][27][28] More recently, mesoporous zeolites from nanosized carbon templates have also been successfully synthesized, [29][30][31][32] but their industrial applications are still limited by the complexity of the synthetic procedure involved and the hydrophobicity of the carbon templates.Herein, we demonstrate a facile, controllable, and universal route for the synthesis of hierarchical mesoporous zeolites templated from a mixture of small organic ammonium salts and mesoscale cationic polymers. The route involves a one-step hydrothermal synthesis, and the templated mixture is homogeneously dispersed in the synthetic gel. Importantly, these novel zeolites exhibit excellent catalytic properties compared with conventional zeolites. This work may give an entry to the synthesis of hierarchical mesoporous zeolites that reveal fast mass transport, with potential application in industrial catalysis.Beta zeolite is generally synthesized from a small organic template of tetraethylammonium hydroxide (TEAOH). In the present strategy, hierarchical mesoporous Beta zeolite (Beta-H) was crystallized in the presence of TEAOH and a mesoscale cationic polymer, polydiallyldimethylammonium chloride (PDADMAC). For comparison, conventional Beta zeolite was prepared in the absence of cationic polymer by a similar procedure.The X-ray diffraction (XRD) pattern of calcined Beta-H (Figure 1a) shows well-resolved peaks in the 4-40° range, characteristic for the Beta zeolite structure.

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mentioning

confidence: 99%

Catalytic Properties of Hierarchical Mesoporous Zeolites Templated with a Mixture of Small Organic Ammonium Salts and Mesoscale Cationic Polymers

Xiao¹,

Wang²,

Yin³

et al. 2006

Angew Chem Int Ed

434

133

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“…The solution was heated in an oven at 333 K for 24 h. Seed B was prepared using the same solution as used in preparing seed A, but was heated with microwave at 363 K for 60 min [34]. Seed C was prepared using a solution with molar ratio of 2(TMA) 2 O:0.5Na 2 O:1Al 2 O 3 :3.4SiO 2 :370H 2 O [20]. The solution was heated in an oven at 353 K for 24 h. In all cases, the zeolite product was filtered, washed and dried (seed C was calcined at 773 K for 8 h).…”

Section: Preparation Of Colloidal Suspensionmentioning

confidence: 99%

“…One is how to prepare colloidal suspension of zeolite particles, and the other is how to coat the seeds onto the support surface. A lot of studies have been reported to prepare stable colloidal suspension [19,20], and many methods have been explored to coat the seeds onto the support surface, which include dip coating [21][22][23][24], rub coating [25], spraying coating [26], spinning coating [27] and pulsed laser deposition [28,29]. Although these seeding methods improve membrane synthesis modestly, they had their own limitations.…”

Section: Introductionmentioning

confidence: 99%

Synthesis and properties of A-type zeolite membranes by secondary growth method with vacuum seeding

Huang

Lin

Yang

2004

Journal of Membrane Science

160

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“…There have been several reports recently on the synthesis of small zeolite crystallites, such as zeolites A, X, L, Beta, ZSM-5 and Silicalite [1][2][3][4][5][6][7]. However, there are only few articles about synthesis of nano-sized zeolite Y [ 1,2].…”

Section: Introductionmentioning

confidence: 99%

“…However, there are only few articles about synthesis of nano-sized zeolite Y [ 1,2]. Those articles explored the possibility of the synthesis of nano-sized particles [1] and the effect of Na 2 O/Al 2 0 3 on the particle size [2]. The influence of the Si/Al ratio, aging time, the sodium content and TMA content in starting solution on the purity, crystal size, Si/Al ratio in crystals and yield of nano-sized zeolite Y was investigated.…”

Section: Introductionmentioning

confidence: 99%

Synthesis of Zeolite Y Nanocrystals from Clear Solutions

et al. 2002

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Synthesis of zeolite nano-sized crystals has attracted much attention because of their properties, some of which maybe different from the normal sized crystals. A synthesis adopted by Voltchev and Mintova was used as the starting point: 0.078 Na 2 O: 4.35 SiO 2 : 1.0 A1 2 0 3 : 2.35 (TMA)20: 248 H20. Both the silicate and aluminum starting solutions were clear. Zeolite Y nanocrystals with zeolite A nanocrystals as an impurity were obtained with a size range of 20-100 nmn through this synthesis technique.

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Colloidal zeolite suspensions

Cited by 280 publications

References 9 publications

Catalytic Properties of Hierarchical Mesoporous Zeolites Templated with a Mixture of Small Organic Ammonium Salts and Mesoscale Cationic Polymers

Catalytic Properties of Hierarchical Mesoporous Zeolites Templated with a Mixture of Small Organic Ammonium Salts and Mesoscale Cationic Polymers

Synthesis and properties of A-type zeolite membranes by secondary growth method with vacuum seeding

Synthesis of Zeolite Y Nanocrystals from Clear Solutions

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