Synthesis of structured filamentous zeolite materials via ZSM-5 coatings of glass fibrous supports

Louis, Benoît; Tezel, C.; Kiwi‐Minsker, Lioubov; Renken, Albert

doi:10.1016/s0920-5861(01)00393-5

Cited by 38 publications

(31 citation statements)

References 13 publications

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“…Fortunately, the triple-scale design is possible, if these molecular and microscopic properties are conjugated with an appropriate macroscopic characteristics of structured reactors [8,27].…”

Section: Modelling Of Zeolite Acidity By the Hammett Acidity Functionmentioning

confidence: 99%

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Synthesis of ZSM-5 zeolite in fluoride media: an innovative approach to tailor both crystal size and acidity

Louis

Kiwi‐Minsker

2004

Microporous and Mesoporous Materials

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ZSM-5 zeolites were prepared at neutral pH by fluoride-mediated synthesis. The degree of crystallinity, the specific surface area and the crystal size are higher than those of the zeolites prepared under alkaline conditions. Moreover, by varying the F/Si ratio from 0.3 to 1.6, the H-[F]-ZSM-5 zeolites with crystal size ranging from 10 to 75 lm and the specific surface areas from 60 up to 350 m 2 /g were obtained.Temperature programmed desorption of pyridine was applied to characterize the zeolite acidity. A decrease of the number of Brö nsted acid sites with a higher F/Si ratio in the starting synthesis solution was observed. Based on the Hammett acidity function H 0 , a model has been developed to correlate the Brö nsted acidity of the resulting zeolitic material with the amount of fluoride anions introduced. Thus, ZSM-5 zeolites with tailored properties both at the molecular and microscopic levels are obtained.

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Section: Modelling Of Zeolite Acidity By the Hammett Acidity Functionmentioning

confidence: 99%

“…In reactors containing such packings, the pressure drop, the flow characteristics, the mass and heat transfers are found to be improved if compared to randomly packed catalytic beds. Our previous studies reported the in situ growth of ZSM-5 crystals on well-arranged macroscopic supports (metals or ceramics) [8,27,28].…”

Section: Introductionmentioning

confidence: 99%

Synthesis of ZSM-5 zeolite in fluoride media: an innovative approach to tailor both crystal size and acidity

Louis

Kiwi‐Minsker

2004

Microporous and Mesoporous Materials

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“…The initial parent HZSM-5 200Fe and HZSM-5 70Fe zeolites with Si/Al ratio 36-42 (Table 1) were synthesized as reported elsewhere [20,21]. The synthesis solution was prepared by adding sodium aluminate (52.5 wt% NaAlO 2 , Riedel-de Haën), sodium chloride (99.5 wt%, Fluka), and tetrapropylammonium hydroxide (20 wt% in water, Fluka), in deionized water at room temperature.…”

Section: Catalyst Preparationmentioning

confidence: 99%

Active sites in HZSM-5 with low Fe content for the formation of surface oxygen by decomposing N2O: is every deposited oxygen active?

Kiwi‐Minsker

2003

Journal of Catalysis

131

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Surface-active centers were detected in HZSM-5 with a low content of iron (< 1000 ppm) activated by steaming and high-temperature calcination in inert atmospheres (up to 1323 K). These centers lead to the formation of surface oxygen (O) ad species from N 2 O and were characterized quantitatively by the transient response method. The total amount of active centers was proportional to the content of iron in the zeolites. Only a part of (O) ad deposited by decomposing N 2 O was active in CO oxidation at 523 K and appeared as sharp O 2 peaks at 666 K during the TPD measurements. A binuclear Fe center is suggested featuring a "diamond core" structure, similar to that of the monooxygenase enzyme, as an active center. The active O atoms were assigned to the paired terminal oxygen atoms each bonded to one Fe site (ferryl groups) in the diferric [Fe 2 O 2 H] + cluster. Oxygen pretreatment at 823 K decreases somewhat the total amount of active sites but does not affect the ratio of active/inactive oxygen. Zeolite presaturated by water vapor at 473-523 K generates (O) ad species from N 2 O completely inactive in the CO oxidation. Part of it appears as a broad peak at 940 K in the TPD profile. The total amount of the deposited oxygen corresponds to half of the stoichiometric amount of the surface Fe atoms and suggests that water blocks a half of the binuclear [Fe 2 O 2 H] + center, the remaining acting as a single Fe site.

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“…Some of these involve the modification of the glass surface, the use of neutral reaction mixtures or indirect coating methods, such as dip-coating to prevent the dissolution of glass during synthesis. ZSM-5 could be deposited on glass fibrous supports (Louis et al, 2001). Here, a homogeneous coverage of the support filaments was obtained by the synthesis of zeolite crystals in fluoride-containing media at neutral pH of about 7.…”

Section: Introductionmentioning

confidence: 99%

Preparation of Zeolite X Coatings on Soda-Lime Type Glass Plates

Tatlıer

Atalay-Oral

2017

Braz. J. Chem. Eng.

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-The dissolution of glass in highly alkaline reaction mixtures and the impact of this phenomenon on zeolite coating formation were investigated. Coating samples were prepared and characterized by X-ray diffraction (XRD), field emission gun scanning electron microscopy (FEGSEM) and thermogravimetry (TG). It was demonstrated that zeolite X coatings might be prepared on soda-lime glass. Glass dissolved to some degree, up to 2% of its original mass, in the reaction mixtures for the conditions investigated. This dissolution affected the zeolite synthesis taking place on the glass surface, resulting in phases different from those obtained on inert metal surfaces in some cases, especially for the use of reaction mixtures with relatively high Si/Al ratios. The percentage of dissolution of glass plates increased with their decreasing thickness, indicating a surface phenomenon for the dissolution. The stabilities of the coatings, which varied with the synthesis conditions, benefited from the addition of extra thin layers of polyacrylic acid.

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Synthesis of structured filamentous zeolite materials via ZSM-5 coatings of glass fibrous supports

Cited by 38 publications

References 13 publications

Synthesis of ZSM-5 zeolite in fluoride media: an innovative approach to tailor both crystal size and acidity

Synthesis of ZSM-5 zeolite in fluoride media: an innovative approach to tailor both crystal size and acidity

Active sites in HZSM-5 with low Fe content for the formation of surface oxygen by decomposing N2O: is every deposited oxygen active?

Preparation of Zeolite X Coatings on Soda-Lime Type Glass Plates

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