Microwave assisted versus convention Cu2+ exchange in mordenite

Zhukov, Yu. M.; Shelyapina, Marina G.; Zvereva, Irina A.; Efimov, A. Yu.; Petranovskii, Vitalii

doi:10.1016/j.micromeso.2017.10.013

Cited by 13 publications

(19 citation statements)

References 21 publications

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“…(AR equal to 10.0). A similar effect of the lower real AR (5.9 instead of 6.5) was observed for the earlier studied sample Na-MOR-6.5 [27], supplied by the same fabricator. As this material was ordered from an industrial manufacturer, their method of composition analysis, permissible deviations from the nominal values, and reproducibility of sequential routine syntheses are unknown.…”

Section: Resultssupporting

confidence: 78%

“…Nevertheless, after multiple ion exchange procedures, the MW treatment proved itself to be more effective, especially for CuH-MOR-10-M Y series. However, in contrast to the previously studied copper-exchanged mordenites obtained from Na-MOR-6.5 [27], even six subsequent MW-assisted ion exchange procedures did not lead to an over-exchange. This discrepancy between the ammonia and proton forms of mordenite, unlike sodium, is an interesting fact, but its cause is not yet clear; one of the reasons, as we can assume, is due to the different Si/Al ratio and its effect on the exchange properties of mordenite.…”

Section: Discussioncontrasting

confidence: 78%

“…This means that the deformation of the mordenite crystal lattice occurred in a plane perpendicular to the c -axis. A similar, but more pronounced, effect was observed for the Na-series of Cu-exchanged mordenites [27]. For a better description of this lattice deformation upon copper loading we introduced the contraction parameter K = a / b , which is also listed in Table 2 and will be discussed further.…”

Section: Resultsmentioning

confidence: 63%

“…This can be attributed to the Cu 2+ ion bound to ligands by covalent bonds [24,29]. An additional peak of low intensity that is shifted towards higher binding energy values (near 935 eV) can be associated with Cu 2+ coordinated by water [27].…”

Section: Resultsmentioning

confidence: 99%

“…Earlier, we analyzed the influence of various factors in the preparation of copper exchange mordenites on the properties of the materials obtained [24,25,26,27,28]. In [27], we reported the results of our comprehensive study of two sets of copper-exchanged samples of mordenites prepared from the sodium form of this zeolite and obtained by two different methods: conventional and MW assisted. It was found that the MW-assisted procedure resulted in a deeper and even over-exchange.…”

Section: Introductionmentioning

confidence: 99%

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Comprehensive Analysis of the Copper Exchange Implemented in Ammonia and Protonated Forms of Mordenite Using Microwave and Conventional Methods

et al. 2019

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This article presents the results of a comprehensive study of copper-exchanged mordenite samples prepared from its ammonia and protonated forms (Si/Al = 10) using two different ion exchange methods: conventional and microwave (MW)-assisted. The protonated H-MOR-10 sample was obtained by calcination of commercial NH4-MOR-10; in this case, a slight degradation of the mordenite framework was observed, but the resulting defects were partially restored after the first ion-exchange procedure of protons for copper ions. The level of copper exchange in the studied materials was found to be limited to 70%. Regardless of the exchange procedure, the replacement of ammonium or proton ions with copper led to a linear increase in the a/b ratio of cell parameters in accordance with an increase in the level of copper exchange, which means that all Cu2+ cations are ion-exchangeable and enter the main mordenite channel. Thermal analysis indicated a correlation between the replacement of various ammonium and hydroxyl groups by copper ions during the exchange treatment and their dehydroxylation energy during thermal decomposition. As a conclusion: MW-assisted treatment proved itself as an efficacious method for the synthesis of copper-exchanged mordenites, which not only significantly reduces preparation time but leads to a systematically higher copper exchange level.

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Section: Resultssupporting

confidence: 78%

Section: Discussioncontrasting

confidence: 78%

Section: Resultsmentioning

confidence: 63%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Comprehensive Analysis of the Copper Exchange Implemented in Ammonia and Protonated Forms of Mordenite Using Microwave and Conventional Methods

et al. 2019

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Stepwise conversion of methane to methanol on Cu and Fe/zeolites prepared in solid state: the effect of zeolite type and activation temperature

Trunschke

et al. 2023

J of Chemical Tech & Biotech

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BACKGROUNDGrand efforts have been recently devoted to the development of catalysts based on the excellent performance of Cu‐ and Fe‐dependent enzymes in methanotrophic bacteria for the partial oxidation of methane to methanol under ambient conditions. As a continuation of the study on the stepwise manner for this conversion over zeolite‐based catalysts, in this work, the effects of zeolite topology and activation temperature on the catalytic performance of Cu‐ and Fe‐containing zeolites were investigated.RESULTSCu species exchanged in the medium‐pore zeolites (mordenite, ZSM‐5, and ferrierite) afforded better methanol production, while large‐pore zeolites (zeolite β and zeolite γ) were inappropriate to accommodate active Cu sites. Notably, Cu/silicalite‐1 containing CuO species was also reactive to methane after the activation in O2, yielding a minor methanol amount. Furthermore, the activity of Fe/mordenite towards the methanol in the O2‐assisted procedure was reported for the first time but with a much lower yield as compared to that of Cu/mordenite. The methanol yield over Cu/mordenite increased with the activation temperature because increasing the activation temperature favored the Cu‐exchange degree with a higher priority at the side pockets as compared to the main channels of mordenite, as evidenced from infrared analysis.CONCLUSIONThe selective oxidation of methane to methanol by O2 via a stepwise manner can be obtained over both ion‐exchanged Cu species and well‐dispersed CuO nanoparticles with better activity being recorded for the former. The activity of Cu‐exchanged zeolites was considerably dependent on the zeolite topology and the charge‐balancing position of the Cu2+ cations. © 2023 Society of Chemical Industry (SCI).

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Analysis of theoretical and experimental X-ray diffraction patterns for distinct mordenite frameworks

et al. 2019

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Microwave assisted versus convention Cu2+ exchange in mordenite

Cited by 13 publications

References 21 publications

Comprehensive Analysis of the Copper Exchange Implemented in Ammonia and Protonated Forms of Mordenite Using Microwave and Conventional Methods

Comprehensive Analysis of the Copper Exchange Implemented in Ammonia and Protonated Forms of Mordenite Using Microwave and Conventional Methods

Stepwise conversion of methane to methanol on Cu and Fe/zeolites prepared in solid state: the effect of zeolite type and activation temperature

Analysis of theoretical and experimental X-ray diffraction patterns for distinct mordenite frameworks

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