Preparation of zeolite P by desilication and recrystallization of zeolites ZSM-22 and ZSM-35

Sousa, Lenivaldo V.; Silva, Antônio Osimar Sousa da; Silva, Bruno J. B.; Quintela, Paulo Henrique Leite; Barbosa, Celmy B.M.; Fréty, R.; Pacheco, José Geraldo A.

doi:10.1016/j.matlet.2018.01.069

Cited by 15 publications

(7 citation statements)

References 22 publications

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“…In terms of specific surface area, a larger difference between T75.M8.H15 and the other samples is seen, since samples with high P-zeolite content usually have lower specific surface area than samples containing faujasite zeolite. In fact, in T75.M8.H15 samples, the BET was 19.05 ± 0.17 m 2 /g, a value consistent with those in the literature 23,[55][56][57] and much lower than the others containing faujasite (~100 m 2 /g). This shows that the compositional factor crucially affects the type of the zeolite developed and this in turn mainly affects the surface properties of the material obtained.…”

Section: Influence Of the Activator Molaritysupporting

confidence: 88%

Zeolites‐containing geopolymers obtained from biomass fly ash: Influence of temperature, composition, and porosity

et al. 2020

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In this research, compositional and processing parameters were varied to obtain zeolites-containing geopolymers using mainly biomass fly ash wastes. In addition to curing temperatures, another primary factor affecting the typologies of the resulting zeolites was composition. The mixture composition used in the synthesis crucially affects the nature of the zeolitic crystalline phases in the geopolymeric matrix. Using 10 mol/L NaOH solution, faujasite-type zeolites produced in geopolymers show a surface area of ~100 m 2 /g (BET), while those prepared by 8 mol/L NaOH solution have a much lower surface area of ~19 m 2 /g.

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Section: Influence Of the Activator Molaritysupporting

confidence: 88%

Zeolites‐containing geopolymers obtained from biomass fly ash: Influence of temperature, composition, and porosity

et al. 2020

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“…The impurity phases from the conventional synthesis method can be minimized by recrystallization, also called double crystallization. For example, Sousa et al [19] recrystallized ZSM-22 (structure type TON) and ZSM-35 (structure type FER) by basic treatment to produce a pure phase of zeolite NaP1. Nevertheless, there are no reports about the synthesis of zeolite NaP2 from recrystallization.…”

Section: Gel Compositionmentioning

confidence: 99%

“…These results suggest that the synthesis condition of MH90A150 is suitable to transform the gel of zeolite NaY to NaP2. Concurrently, the second crystallization under microwave heating causes NaY to depolymerize the small building units [19] of NaP2 which has the denser structure. Figure 6 compares the FTIR spectra of MH90 and MH90A150 and the interpretations are summarized in Table 2.…”

Section: Comparison Of Conventional and Microwave-assisted Hydrothermmentioning

confidence: 99%

Synthesis of Pure Phase NaP2 Zeolite from the Gel of NaY by Conventional and Microwave-Assisted Hydrothermal Methods

et al. 2020

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The gel of zeolite NaY has potential as a precursor of other zeolites. The particular interest in this work is to convert the gel of NaY to NaP2. We found that the pure phase NaP2 can be produced simply by the conventional hydrothermal (CH) method at 150 °C for 24 h. This NaP2 sample, named CH150, has an average particle size of 10.3 µm and an Si/Al ratio of 1.82. In the case of single crystallization via microwave-assisted hydrothermal (MH) method, various parameters were studied, including the crystallization temperature (90, 150, 175 °C) and time (15, 30, 45, 60 min). The samples were analyzed by X-ray diffraction and scanning electron microscopy. However, mixed phases of P1 and P2 or ANA were obtained from all samples. Another attempt was made by a double crystallization via MH method as followed: at 90 °C for 1 h, quickly cooled down to room temperature in the microwave chamber and aged for 23 h, and finally at 150 °C for 1 h. The sample, named MH90A150, has an average crystal size of 16.45 µm and an Si/Al ratio of 1.85. The high Al content of NaP2 in both samples (CH150 and MH90A150) could lead to interesting applications.

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“…Despite the broad literature on the subject, the articles do not report the effects of desilication on crystals of different sizes [7][8][9][10][11][12][13][14][15][16] . In this context, the main goal of this study was to characterize the ZSM-5 and ZSM-12 zeolites with different crystals sizes and Si/Al ratio ideal for the generation of intracrystalline porosity by silicon removal.…”

Section: Introductionmentioning

confidence: 99%

Desilication of ZSM-5 and ZSM-12 Zeolites with Different Crystal Sizes: Effect on Acidity and Mesoporous Initiation

et al. 2019

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In the present work, the desilication of the H-ZSM-5 and H-ZSM-12 zeolites with Si/AL ratios of 28 and 56 and crystal sizes of around 200 and 600 nm, respectively, was performed. Through electron transmission microscopy analysis, it was possible to verify the influence of aluminium gradients on smaller crystals in addition to the exact moment at which the formation of mesoporous is initiated inside the zeolitic framework. Moreover, the crystal size exerts a significant influence on the total amount of acid sites remaining after alkaline treatment, as verified by means of temperature-programmed desorption of ammonia. This is because the presence of larger crystals during desilication may increase the likelihood of reinsertion of aluminium atoms in the zeolite framework and, consequently, maintain the same total amount of acid sites in the zeolite as before alkaline treatment. Meanwhile, aluminium atoms tend to be removed from smaller crystals, thereby decreasing the total amount of acid sites.

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Preparation of zeolite P by desilication and recrystallization of zeolites ZSM-22 and ZSM-35

Cited by 15 publications

References 22 publications

Zeolites‐containing geopolymers obtained from biomass fly ash: Influence of temperature, composition, and porosity

Zeolites‐containing geopolymers obtained from biomass fly ash: Influence of temperature, composition, and porosity

Synthesis of Pure Phase NaP2 Zeolite from the Gel of NaY by Conventional and Microwave-Assisted Hydrothermal Methods

Desilication of ZSM-5 and ZSM-12 Zeolites with Different Crystal Sizes: Effect on Acidity and Mesoporous Initiation

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