Effects of ultrasonic irradiation on crystallization kinetics, morphological and structural properties of zeolite FAU

Mendoza, Heidy Ramirez; Jordens, Jeroen; Pereira, Mafalda Valdez Lancinha; Lutz, Cécile; Gerven, Tom Van

doi:10.1016/j.ultsonch.2020.105010

Cited by 17 publications

(4 citation statements)

References 40 publications

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“…Ultrasonication of the gel composition generates a localized high temperature and high-pressure sonic waves, which causes the breaking down of the complex precursors of silica and alumina to very fine fragments, leading to enhanced nucleation rate, which results in an efficient and rapid decrease in the crystal size. , The average crystal size of the three catalysts is evaluated from the characteristic diffraction peaks using the Debye-Scherrer formula, and the values are 10.3, 22.6, and 9.1 nm (Table ) for ZB-1, ZB-2, and ZB-3, respectively. The sharp and high intense reflection at 2θ = 22.6 due to a rapid increase in the crystallite size of ZB-2 compared to ZB-1 and ZB-3.…”

Section: Resultsmentioning

confidence: 99%

Nanocrystallite Zeolite BEA for Regioselective and Continuous Acetyl Functionalization of Anisole Using Acetic Anhydride: Catalyst Deactivation Studies

Naresh,

Madhu Krushna,

Kondaiah

et al. 2023

ACS Omega

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Ultrasonic pretreatment of gel composition followed by hydrothermal synthesis produces the nanocrystallite zeolite beta (ZB) with crystal sizes of 10.3, 22.6, and 9.1 nm for ZB-1, ZB-2, and ZB-3, respectively. The effect of ultrasonic pretreatment and the (SiO2/Al2O3) ratio of gel composition on physical, textural properties, and also on the catalytic activity of ZB catalysts with increasing time on stream (TOS) was investigated. The specific surface area and mesopore volume for ZB-1, ZB-2, and ZB-3 are 438, 380, and 429 m2/g and 0.17, 0.05, and 0.14 cm3/g, respectively. The activity studies of ZB-1 and ZB-3 catalysts were confirmed that the anisole conversion initially increased with TOS until it attained the maximum value and then started decreasing further with TOS due to the deactivation of the catalyst caused by the strong interaction of the product with the acidic sites in the mesopore region. However, in the case of ZB-2, the anisole conversion (>45%) was sustained for a longer TOS due to its smaller particle size, low mesopore volume, and more acidic sites in the micropore volume that are inclusively made for retardation in the catlytic deactivation rate. The CHNS and TGA analysis of the spent catalysts confirm that ZB-1 and ZB-3 catalysts are susceptible for a significant coke formation attributed due to strong product retention in their large mesopore volume, which lead to the catalytic deactivation.

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Section: Resultsmentioning

confidence: 99%

Nanocrystallite Zeolite BEA for Regioselective and Continuous Acetyl Functionalization of Anisole Using Acetic Anhydride: Catalyst Deactivation Studies

Naresh,

Madhu Krushna,

Kondaiah

et al. 2023

ACS Omega

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“…Perhaps, there is competition between the hydrolysis and deconstruction of siloxane groups by energy exposure on the one hand, with the polymerization process of silicate anions forming new siloxane groups on the other. Several earlier studies [65][66][67] also found that increasing sonication time or hydrothermal duration increased or decreased product crystallinity in the synthesis of various materials.…”

Section: Ftir Spectra Analysismentioning

confidence: 93%

Optimizing Rice Husk Silica Mass and Sonication Time for a More Efficient and Environmentally Friendly Synthesis of SBA-15

Suyanta

Mudasir²

2022

Indones. J. Chem.

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By optimizing rice husk silica mass and sonication time, SBA-15 was successfully synthesized in a more efficient and environmentally friendly way. The solution of Pluronic P-123 was mixed with the solution containing NaOH and various masses of rice husk silica (4–12 g), followed by sonication for a certain time (30–150 min). The mixture was filtered and washed with distilled water and ethanol until neutral, then dried at 110 °C for 2 h and calcined at 500 °C for 6 h. The results showed that the optimal mass of rice husk silica was 8 g, while the optimal sonication time was 30 min. The product has a cylindrical pore shape with good crystallinity and pore structure regularity. The specific surface area (SBET), the pore diameter (DBJH), the specific pore volume (VBJH), and the wall thickness (WT) of the product were 601 m2 g–1, 4.76 nm, 0.88 mL g–1, and 5.02 nm, respectively. These results are not considerably different from the porosity of SBA-15, synthesized previously using conventional hydrothermal techniques from various silica sources. In addition, it is also comparable to the porosity of SBA-15 produced from TEOS by sonochemical methods as well as with commercial SBA-15.

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“…(2018) reported similar results, synthesizing SAPO-34 via ultrasonic-assisted aging and testing their MTO catalytic performance. 246 Other sonochemistry studies have focused on EMT nanocrystals, 247 zeolite T (OFF/ERI), 248 and NaX (FAU) 249 with similar conclusions. In the case of NaX, irradiated volume, sonication time, and power were thoroughly investigated and sonication was also applied to reduce the agglomeration degree of the final powders.…”

Section: Chemistry Of Materialsmentioning

confidence: 99%

Zeolite Synthesis under Nonconventional Conditions: Reagents, Reactors, andModi Operandi

Deneyer

Devos

et al. 2020

Chem. Mater.

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A myriad of tetrahedral molecular sieve frameworks, often siliceous, can be calculated in silico. Only a tiny fraction (<0.1%) of these can be synthesized on purpose. Only a small fraction of these available frameworks, mostly those composed of only Si and Al as T-atoms, i.e. true zeolites, are used commercially. A gap thus exists between what should be possible (thermodynamically) and what can be produced (kinetically) and used in real life. Even if a synthesis is successful (in industry or academia), flexibility with regard to synthesis parameters -in terms of time, amount of unit operations, OSDA-efficiency, etc. -as well as the obtained material properties -in terms of Si/Al ratio, Al-distribution, T-atom variety, crystal size, etc. -remains limited. These limitations are not surprising since conventional zeolite syntheses, i.e. hydrothermal synthesis in batch from amorphous or soluble Si-and Al-sources, have limited degrees of freedom (DOF). Typically, the type of ingredients, their ratios, a constant temperature, synthesis time and the absence or presence of agitation are varied. In order to take new steps towards more cost-competitive syntheses, and more importantly, zeolites with a greater flexibility in terms of structural properties, this review highlights all DOFs that can be introduced in addition to or on top of the conventional way of synthesis. By doing this, a distinction is made between non-conventional DOFs that influence the chemistry of the system (e.g. interzeolite conversion, charge density mismatch approach, ionothermal or free-radical assisted synthesis) and non-conventional DOFs that influence the physical environment (e.g. ultrasounds, alternative energy via microwaves or continuous set-ups). The review concludes with learnings, practical insights and future opportunities. In other words: which zeolite synthesis strategies really make a difference and which ones are just tweaking around the edges?

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Effects of ultrasonic irradiation on crystallization kinetics, morphological and structural properties of zeolite FAU

Cited by 17 publications

References 40 publications

Nanocrystallite Zeolite BEA for Regioselective and Continuous Acetyl Functionalization of Anisole Using Acetic Anhydride: Catalyst Deactivation Studies

Nanocrystallite Zeolite BEA for Regioselective and Continuous Acetyl Functionalization of Anisole Using Acetic Anhydride: Catalyst Deactivation Studies

Optimizing Rice Husk Silica Mass and Sonication Time for a More Efficient and Environmentally Friendly Synthesis of SBA-15

Zeolite Synthesis under Nonconventional Conditions: Reagents, Reactors, andModi Operandi

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