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

Abstract

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.

Ce-promoted Fe–Cu–ZSM-5 catalyst: SCR-NO activity and hydrothermal stability

“…This result is expected since the SSIE is the most convenient method for controlling the metal amount in the prepared solids, which is in perfect agreement with our previous works [12][13][14]. The ratio of the parent zeolite stated by Zeolyst (CBV024E, Si/Al=15) was decreased in the case of prepared catalysts and that can be attributed to the reproducibility of routine sequential syntheses which may vary from batch to batch [30].…”

Boosting Dimethylamine Formation Selectivity in a Membrane Reactor by In Situ Water Removal

“…Surprisingly, the H-MOR catalyst showed the opposite behavior: The lattice of the spent catalyst shrunk compared to the fresh H-MOR. We assume either that the adsorption of NH 3 and the amines at the strong acidic sites led to a contraction of the lattice similar to ion exchange experiments in H-MOR , or that dealumination through steaming, which is more significant for the H-MOR due to its high alumina content, is responsible for the decreased lattice spacing.…”

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

“…A similar effect was also observed for a series of Cu/mordenite prepared via the traditional aqueous ion exchange. 35,36 By contrast, the lack of shifts of the diffraction patterns detected in the XRD results of fresh silicalite-1 and Cu/silicalite-1 indicated only copper oxides loaded into silicalite-1 via solid-state impregnation (Supporting Information, Fig. S7).…”