Synthesis of SAPO-34 from metakaolin: Crystallization mechanism of SAPO-34 and transformation processes of metakaolin

Wang, Tizhuang; Lu, Xuchen; Yan, Yan

doi:10.1016/j.micromeso.2012.09.040

Cited by 27 publications

(11 citation statements)

References 30 publications

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“…Therefore, the increased number of crystal nuclei at the beginning of crystal growth stage results in the decreased crystal size. According to our previous report of using metakaolin to synthesize SAPO-34 [13], the growth of the crystals began when only a small amount of Si-O layers had dissolved and the Si/P ratio in the crystalizing process increased which resulted in the non-uniform distribution of Si in the crystals. After the addition of β-CD, the growth stage of the crystals was retarded as mentioned above and began when a large amount of Si-O layers had dissolved and the Si/P ratio remained almost unchanged during the growth of the crystals; thus the distribution of Si in the crystals was more uniformly (shown in the results of XRF and EDX).…”

Section: Resultsmentioning

confidence: 99%

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Synthesis of SAPO-34 using metakaolin in the presence of β-cyclodextrin

Zhang

Wang

2015

Journal of Energy Chemistry

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Section: Resultsmentioning

confidence: 99%

“…Synthesis of SAPO-34 was carried out according to the report of our previous work [13]. Pseudoboehmite was added to dilute phosphoric acid solution and stirred.…”

Section: Sample Preparationmentioning

confidence: 99%

Synthesis of SAPO-34 using metakaolin in the presence of β-cyclodextrin

Zhang

Wang

2015

Journal of Energy Chemistry

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“…Then the species migrated from the laponite participated into synthesis system. The primary building units of SAPO‐34 zeolite could be formed by the Mg and Si species depolymerized from laponite, phosphate anions, morpholinium cations and Al–OH at the desirable temperature , . At last, the crystal nucleus began to form, and the primary building units continued to grow rapidly on the crystal nucleus.…”

Section: Resultsmentioning

confidence: 99%

Synthesis of SAPO‐34 Zeolite from Laponite and Its Application in the MTO Reaction

et al. 2020

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In this work, SAPO‐34 zeolite with high catalytic activity was successfully synthesized by hydrothermal method from laponite as the single Si source. Compared with the traditional method of synthesizing zeolites from clay, the laponite after swelling can be directly used in the synthesis process of zeolite. The crystallization behavior of SAPO‐34 synthesized from laponite was investigated by XRD, FTIR, N2 adsorption–desorption, SEM‐EDX, ICP‐MS, and DR‐UV/Vis. The process can be summarized as follows: the Si and Mg elements were produced by the depolymerization of laponite, then the primary building units of SAPO‐34 zeolite were formed under hydrothermal conditions; finally, the crystal nucleus began to form, and crystallization was triggered. Compared with the conventional SAPO‐34 synthesized from TEOS, the SAPO‐34 synthesized from laponite exhibited higher selectivity to light olefins and longer lifetime, which can be attributed to the suitable strength of acidity. This work points to a straightforward route to the synthesis of SAPO‐34 from laponite.

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“…Kaolin [Al 2 Si 2 O 5 (OH) 4 ] is one pf the most important clays, which is connected by one siliconoxygen (SiO 4 ) tetrahedral layer and one alumina [Al(O, OH) 6 ] layer. It has been proved to be a good combinational silicon and aluminum source to synthesize zeolites or functional materials, such as A, 19 X, 20 mesoporous g-Al 2 O 3 , 21 SAPOs, 22,23 ZSM-5, 24À26 etc. To obtain nano-sized zeolites, the key point is to control the concentration and supersaturation of the crystal nucleus.…”

Section: Introductionmentioning

confidence: 99%

“…Kaolin gradually could dissolve into the system and form the crystal nucleus heterogeneously during the crystallization process. 21,22 Therefore, it is difficult to synthesize ZSM-5 with the nano-sized crystals via the traditional hydrothermal method.…”

Section: Introductionmentioning

confidence: 99%