The influence of the alkaline treatment on the acidity of zeolite ZSM-5 (SiO2/Al2O3 = 23, 50 and 80) modified by desilication was investigated. The samples were characterized by X-ray diffraction, low temperature adsorption of nitrogen and solid-state Al-27 MAS NMR. Acidity of the samples was investigated using microcalorimetry-volumetry of ammonia adsorption at 423 K. Acid sites accessibility and intracrystalline diffusion were estimated by the thermokinetic parameter. The desilication process was shown to be Si/Al ratio dependant. Relative enhancement of mesopore surface decreased in the following order of SiO2/Al2O3: 50 >80 >23. Pore size distribution broadened and mesopore sizes increased with increasing Si/Al ratio. For samples with SiO2/Al2O3 = 50 and 80 almost full preservation of acid sites strength and distribution was achieved. Significant alteration of the acidity was found for the mesoporous sample with SiO2/Al2O3 = 23. Thermokinetic parameter values indicate facilitated in...tracristalline diffusion for mesoporous samples.
TY - JOUR
AU - Rac, Vladislav
AU - Rakić, Vesna
AU - Miladinović, Zoran
AU - Stošić, Dušan
AU - Auroux, Aline
PY - 2013
UR - http://aspace.agrif.bg.ac.rs/handle/123456789/3289
AB - The influence of the alkaline treatment on the acidity of zeolite ZSM-5 (SiO2/Al2O3 = 23, 50 and 80) modified by desilication was investigated. The samples were characterized by X-ray diffraction, low temperature adsorption of nitrogen and solid-state Al-27 MAS NMR. Acidity of the samples was investigated using microcalorimetry-volumetry of ammonia adsorption at 423 K. Acid sites accessibility and intracrystalline diffusion were estimated by the thermokinetic parameter. The desilication process was shown to be Si/Al ratio dependant. Relative enhancement of mesopore surface decreased in the following order of SiO2/Al2O3: 50 >80 >23. Pore size distribution broadened and mesopore sizes increased with increasing Si/Al ratio. For samples with SiO2/Al2O3 = 50 and 80 almost full preservation of acid sites strength and distribution was achieved. Significant alteration of the acidity was found for the mesoporous sample with SiO2/Al2O3 = 23. Thermokinetic parameter values indicate facilitated intracristalline diffusion for mesoporous samples.
PB - Elsevier, Amsterdam
T2 - Thermochimica Acta
T1 - Influence of the desilication process on the acidity of HZSM-5 zeolite
EP - 78
SP - 73
VL - 567
DO - 10.1016/j.tca.2013.01.008
ER -
@article{
author = "Rac, Vladislav and Rakić, Vesna and Miladinović, Zoran and Stošić, Dušan and Auroux, Aline",
year = "2013",
abstract = "The influence of the alkaline treatment on the acidity of zeolite ZSM-5 (SiO2/Al2O3 = 23, 50 and 80) modified by desilication was investigated. The samples were characterized by X-ray diffraction, low temperature adsorption of nitrogen and solid-state Al-27 MAS NMR. Acidity of the samples was investigated using microcalorimetry-volumetry of ammonia adsorption at 423 K. Acid sites accessibility and intracrystalline diffusion were estimated by the thermokinetic parameter. The desilication process was shown to be Si/Al ratio dependant. Relative enhancement of mesopore surface decreased in the following order of SiO2/Al2O3: 50 >80 >23. Pore size distribution broadened and mesopore sizes increased with increasing Si/Al ratio. For samples with SiO2/Al2O3 = 50 and 80 almost full preservation of acid sites strength and distribution was achieved. Significant alteration of the acidity was found for the mesoporous sample with SiO2/Al2O3 = 23. Thermokinetic parameter values indicate facilitated intracristalline diffusion for mesoporous samples.",
publisher = "Elsevier, Amsterdam",
journal = "Thermochimica Acta",
title = "Influence of the desilication process on the acidity of HZSM-5 zeolite",
pages = "78-73",
volume = "567",
doi = "10.1016/j.tca.2013.01.008"
}
Rac, V., Rakić, V., Miladinović, Z., Stošić, D.,& Auroux, A.. (2013). Influence of the desilication process on the acidity of HZSM-5 zeolite. in Thermochimica Acta
Elsevier, Amsterdam., 567, 73-78.
https://doi.org/10.1016/j.tca.2013.01.008
Rac V, Rakić V, Miladinović Z, Stošić D, Auroux A. Influence of the desilication process on the acidity of HZSM-5 zeolite. in Thermochimica Acta. 2013;567:73-78.
doi:10.1016/j.tca.2013.01.008 .
Rac, Vladislav, Rakić, Vesna, Miladinović, Zoran, Stošić, Dušan, Auroux, Aline, "Influence of the desilication process on the acidity of HZSM-5 zeolite" in Thermochimica Acta, 567 (2013):73-78,
https://doi.org/10.1016/j.tca.2013.01.008 . .
