Seed-assisted template-free synthesis of nano-sized ZSM-5 via two-stage crystallization with related investigation of mechanism

Zhang, Ruizhen; Zhao, Piaorou; Han, Lupeng; Wang, Jiancheng; Zhao, Lei

doi:10.1016/j.micromeso.2020.110754

Cited by 24 publications

(4 citation statements)

References 49 publications

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“…The N 2 adsorption isotherms of all samples were attributed to IUPAC type I with the type-H4 hysteresis loop, confirming the characteristics of microporous solids. 33 The effect of the second metal on the reduction behavior of monometallic catalysts was further investigated by H 2 -TPR.…”

Section: Resultsmentioning

confidence: 99%

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Alloying nickel and cobalt with iron on ZSM-5 for tuning competitive hydrogenation reactions for selective one-pot conversion of furfural to gamma-valerolactone

et al. 2022

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Section: Resultsmentioning

confidence: 99%

“…teristics of microporous solids. 33 The effect of the second metal on the reduction behavior of monometallic catalysts was further investigated by H 2 -TPR.…”

Section: Paper Dalton Transactionsmentioning

confidence: 99%

Alloying nickel and cobalt with iron on ZSM-5 for tuning competitive hydrogenation reactions for selective one-pot conversion of furfural to gamma-valerolactone

et al. 2022

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“…The desorption peak intensity of strong acid site and medium strong acid site in HY-1 zeolite is significantly lower than that of HY-2 zeolite, and the total acid content is also significantly lower than that of HY-2 zeolite. The acidity of molecular sieve is derived from the aluminum adjacent to silicon, and the electronegativity of silicon is large, which makes the electrons of the aluminum adjacent to it transfer to silicon, and the electrons on the hydroxyl group connected to aluminum shift to aluminum, resulting in the hydrogen on the hydroxyl group easy to ionize and show acidity [55] . However, the Si-Al ratio of HY-1 is lower than that of HY-2, and the acid site density will increase with the decrease of Si-Al ratio, resulting in the acid strength of each acid site will decrease.…”

Section: Characterization Of Hy-type Molecular Sievementioning

confidence: 99%

Preparation of Y Zeolite Molecular Sieve Based on Bentonite and its Catalytic Cracking Performance for Shale Oil

Liu,

Wu,

Tuo

et al. 2024

Preprint

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In this paper, Y-type molecular sieve was prepared by hydrothermal synthesis method using bentonite as raw material, which reduced the preparation cost of traditional molecular sieve and improved the comprehensive resource utilization rate of bentonite. The effect of metal composition in bentonite on the preparation of Y-type molecular sieve and the catalytic cracking performance of shale oil was investigated. XRD, SEM, FT-IR, BET and other characterization methods were used to investigate the physicochemical properties. The results showed that the Y-type molecular sieve prepared with bentonite as raw material has good morphology, small grain square block, high crystallinity, high acidity, and better specific surface area, pore size and pore volume. Compared with the Y-type molecular sieve (HY-2) prepared by the bentonite containing Fe, the Y-type molecular sieve catalyst (HY-1) prepared by the bentonite removing impurities such as metal Fe has higher crystallinity, stronger acidity, larger specific surface area, pore size and pore volume. The results show that removing metal Fe and other impurities from bentonite is beneficial to the synthesis of Y-type molecular sieve and can effectively improve its physical property structure. The catalytic cracking performance of the catalyst was investigated by using shale oil >350℃ fractions. The results showed that the content of gasoline and LPG reached 46.03% and 2.51%, the content of diesel oil was 41.14%, the content of dry gas and heavy oil was 0.87% and 8.28%, and the content of coke was as low as 1.16%. Compared with HY-2, the gasoline content of HY-1 reaction products is 56.66%, an increase of 10.63%, while the diesel and heavy oil contents are 32.89% and 6.43%, respectively, a decrease of 8.25% and 1.82%, indicating that HY-1 has stronger catalytic cracking performance and can convert more heavy oil and diesel into gasoline. Compared with commercial Y-type molecular sieve catalyst, the gasoline content of HY-1 is only 3.68% lower, while the coke content is 2% lower, indicating that the Mg and K contained in bentonite are conducive to the catalytic cracking reaction and improve the production of light oil. At the same time, the catalytic cracking performance of HY-1 has reached the performance of commercial products, and has high commercial value and research potential. By optimizing the reaction conditions, the gasoline yield of HY-1 reached 63.38%, an increase of 6.72%. The heavy oil content is only 3.78%, which is reduced by 2.56%, and has a lower coke rate of 0.93%. Therefore, it shows that the bentonite-based Y-type molecular sieve has good catalytic performance, which can reduce the cost of Y-type molecular sieve catalyst, improve the utilization rate of shale oil heavy oil, and create certain economic value.

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“…In contrast, improved crystallinity accompanied by the large size of zeolite crystals is accessible at high crystallization temperature. It is proven that a two-step crystallization process is able to solve the contradiction between small crystal size and good crystallinity. − For example, through this method, Yu et al prepared ultrasmall single-crystalline MFI nanozeolites (10–55 nm) with the help of l -lysine after heating at 70–80 °C for 2 days and 170 °C for 1 day . It is noted that long-time crystallization and additional additives were necessary due to high water content (H 2 O/SiO 2 = 9) in this synthesis.…”

Section: Introductionmentioning

confidence: 99%

Rapid and Facile Synthesis of Nanosized Silicalite-1 Zeolites from Solid Silica in a Semisolid-like System via a Two-Step Crystallization Method

Zheng,

Zhang,

Tan

et al. 2024

Ind. Eng. Chem. Res.

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Nanosized zeolites have been found in extensive applications. Herein, a rapid two-step crystallization process (8 h) in a semisolid-like gel system, constructed by simply mixing and grinding solid silica gel, NaOH with TPAOH aqueous solution without extra water addition and any other additives, for the first time is demonstrated to synthesize nanosized silicalite-1 zeolites (∼66 nm) with high crystallinity and high product yield (>90%). The obtained nanosized silicalite-1 zeolites exhibit a large BET surface area (418 m 2 g −1 ), a high micropore surface area (316 m 2 g −1 ), and a rich micropore volume (0.14 cm 3 g −1 ). The rapid evolution process of nanosized zeolites could be decoupled into the nucleation stage at low temperatures and the crystallization stage at high temperatures during the two-step crystallization process. Importantly, the semisolid-like gel ensures fast nucleation. Moreover, in the later crystallization period, the fast crystal growth and inhibited ripening endow nanosized zeolite crystals with good crystallinity through a mass transfer-confined space. The obtained silicalite-1 zeolites were successfully applied in the preparation of (h0h)-oriented MFI zeolite membranes on hollow fibers, showing the flux up to 5.44 kg m −2 h −1 and the separation factor of 70 during the pervaporation test (5 wt % ethanol/water solution, 60 °C). This research develops a state-of-the-art synthetic approach for the efficient preparation of high-quality MFI-type nanozeolites.

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Seed-assisted template-free synthesis of nano-sized ZSM-5 via two-stage crystallization with related investigation of mechanism

Cited by 24 publications

References 49 publications

Alloying nickel and cobalt with iron on ZSM-5 for tuning competitive hydrogenation reactions for selective one-pot conversion of furfural to gamma-valerolactone

Alloying nickel and cobalt with iron on ZSM-5 for tuning competitive hydrogenation reactions for selective one-pot conversion of furfural to gamma-valerolactone

Preparation of Y Zeolite Molecular Sieve Based on Bentonite and its Catalytic Cracking Performance for Shale Oil

Rapid and Facile Synthesis of Nanosized Silicalite-1 Zeolites from Solid Silica in a Semisolid-like System via a Two-Step Crystallization Method

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