Результаты исследований: Научные публикации в периодических изданиях › статья › Рецензирование
Mobility of water molecules in sodium- and copper-exchanged mordenites : Thermal analysis and H-1 NMR study. / Krylova, Ekaterina; Shelyapina, Marina; Nowak, P.; Harańczyk, H.; Chislov, Mihail; Zvereva, Irina; Privalov, A.F.; Becher, M.; Vogel, M.; Petranovskii, V.
в: Microporous and Mesoporous Materials, Том 265, 15.07.2018, стр. 132-142.Результаты исследований: Научные публикации в периодических изданиях › статья › Рецензирование
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TY - JOUR
T1 - Mobility of water molecules in sodium- and copper-exchanged mordenites
T2 - Thermal analysis and H-1 NMR study
AU - Krylova, Ekaterina
AU - Shelyapina, Marina
AU - Nowak, P.
AU - Harańczyk, H.
AU - Chislov, Mihail
AU - Zvereva, Irina
AU - Privalov, A.F.
AU - Becher, M.
AU - Vogel, M.
AU - Petranovskii, V.
N1 - Funding Information: The structural and thermal analyses were carried out at the Research Park of Saint Petersburg State University: Centre for X-ray Diffraction Studies, Centre of Thermal Analysis and Calorimetry, Interdisciplinary Resource Centre for Nanotechnology. The authors thank the G-RISC program for the support of the stay of E.A.K. at TU Darmstadt and bilateral mobility program of student and staff exchange between St Petersburg and Jagiellonian Universities for the support of the stays of E.A.K. and M.G.S. at Jagiellonian University. This work was partially supported by DGAPA-UNAM IN107817 Grant. The 1 H-NMR spectra were recorded with the equipment purchased thanks to the financial support of the European Regional Development Fund in the framework of the Polish Innovation Economy Operational Program (contract no. POIG.02.01.00-12-023/08 ). Appendix A
PY - 2018/7/15
Y1 - 2018/7/15
N2 - Comprehensive research of water behavior in Na- and Cu-mordenites with different Na/Cu ratio was done. Several steps of dehydration process were detected and analyzed, taking into account difference in chemical composition of the samples, reaction models and corresponding kinetic equations. Activation energies for these steps were calculated. It was shown that the majority of dehydration steps for all zeolite samples studied might be associated with chemical reaction mechanism corresponding to the second order kinetic model, except for the most high-temperature step for Cu-mordenite, for which the third-order model has the higher correlation coefficient. A detailed analysis of rehydration processes was studied by proton NMR spectroscopy. The obtained results allow one to distinguish different types of water and to associate them with a certain localization of water molecules in zeolite voids: the main channel for both Na and Cu-mordenites; a side pocket of Na-mordenite; molecules coordinated with Cu2+ cations in Cu-mordenite. The diffusion measurements carried out using static field gradient NMR technique proved that the water diffusion character below 300 K is essentially intracrystalline, whereas above 300 K it becomes intercrystalline. The activation energy of intercrystalline diffusion is about 28 kJ/mol and does not depend on the Na/Cu ratio. That allows us to suppose that in the studied zeolites the intercrystalline diffusion is governed by the morphology of the sample mainly.
AB - Comprehensive research of water behavior in Na- and Cu-mordenites with different Na/Cu ratio was done. Several steps of dehydration process were detected and analyzed, taking into account difference in chemical composition of the samples, reaction models and corresponding kinetic equations. Activation energies for these steps were calculated. It was shown that the majority of dehydration steps for all zeolite samples studied might be associated with chemical reaction mechanism corresponding to the second order kinetic model, except for the most high-temperature step for Cu-mordenite, for which the third-order model has the higher correlation coefficient. A detailed analysis of rehydration processes was studied by proton NMR spectroscopy. The obtained results allow one to distinguish different types of water and to associate them with a certain localization of water molecules in zeolite voids: the main channel for both Na and Cu-mordenites; a side pocket of Na-mordenite; molecules coordinated with Cu2+ cations in Cu-mordenite. The diffusion measurements carried out using static field gradient NMR technique proved that the water diffusion character below 300 K is essentially intracrystalline, whereas above 300 K it becomes intercrystalline. The activation energy of intercrystalline diffusion is about 28 kJ/mol and does not depend on the Na/Cu ratio. That allows us to suppose that in the studied zeolites the intercrystalline diffusion is governed by the morphology of the sample mainly.
KW - цеолиты
KW - Copper exchange
KW - Mordenite
KW - NMR
KW - TGA
KW - Water diffusion
KW - SOLID-STATE KINETICS
KW - NMR DIFFUSOMETRY
KW - DECOMPOSITION
KW - ION
KW - COMPUTATIONAL ASPECTS
KW - SELECTIVE CATALYTIC-REDUCTION
KW - THERMOGRAVIMETRIC DATA
KW - ZEOLITE-X
KW - PART
KW - ICTAC KINETICS PROJECT
UR - http://www.scopus.com/inward/record.url?scp=85042115517&partnerID=8YFLogxK
UR - http://www.mendeley.com/research/mobility-water-molecules-sodium-copperexchanged-mordenites-thermal-analysis-and1h-nmr-study
U2 - 10.1016/j.micromeso.2018.02.010
DO - 10.1016/j.micromeso.2018.02.010
M3 - Article
VL - 265
SP - 132
EP - 142
JO - Zeolites
JF - Zeolites
SN - 1387-1811
ER -
ID: 16332153