Hydrothermal conversion of Y-zeolite using alkaline-earth cations

Chiyoda, Osamu; Davis, Mark E.

doi:10.1016/s1387-1811(99)00112-2

Cited by 31 publications

(23 citation statements)

References 10 publications

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“…It must however be noted that concrete pore water also contains small amounts of Ca 2+ cations, in addition to K + and Na + . While Ca 2+ has been demonstrated to exert a stabilizing effect on the FAU structure,[44][45][46] as confirmed by the absence of chabazite formation upon exposure of Caexchanged zeolite Y to KOH (Figure SI 5), it may now be speculated to also influence the ratio of MER/CHA upon hyperalkaline transformation in K + , Na + media. However, for now it remains unclear which parameter facilitated the formation of merlinoite next to chabazite in pore water environment.…”

mentioning

confidence: 93%

Chabazite: Stable Cation-Exchanger in Hyper Alkaline Concrete Pore Water

Tendeloo

Wangermez

Kurttepeli

et al. 2015

Environ. Sci. Technol.

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To avoid impact on the environment, facilities for permanent disposal of hazardous waste adopt multibarrier design schemes. As the primary barrier very often consists of cement-based materials, two distinct aspects are essential for the selection of suitable complementary barriers: (1) selective sorption of the contaminants in the repository and (2) long-term chemical stability in hyperalkaline concrete-derived media. A multidisciplinary approach combining experimental strategies from environmental chemistry and materials science is therefore essential to provide a reliable assessment of potential candidate materials. Chabazite is typically synthesized in 1 M KOH solutions but also crystallizes in simulated young cement pore water, a pH 13 aqueous solution mainly containing K(+) and Na(+) cations. Its formation and stability in this medium was evaluated as a function of temperature (60 and 85 °C) over a timeframe of more than 2 years and was also asessed from a mechanistic point of view. Chabazite demonstrates excellent cation-exchange properties in simulated young cement pore water. Comparison of its Cs(+) cation exchange properties at pH 8 and pH 13 unexpectedly demonstrated an increase of the KD with increasing pH. The combined results identify chabazite as a valid candidate for inclusion in engineered barriers for concrete-based waste disposal.

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confidence: 93%

Chabazite: Stable Cation-Exchanger in Hyper Alkaline Concrete Pore Water

Tendeloo

Wangermez

Kurttepeli

et al. 2015

Environ. Sci. Technol.

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“…8a and Table 1). To the best of our knowledge, the transformations of FAU to other structure zeolites (SOD, ANA, GIS, LBW, etc) were reported elsewhere [11]. Most of above researches were conducted in the presence of alkaline (NaOH, KOH, LiOH, CsOH) or alkaline-earth cations [12].…”

Section: Mechanism Of the Topology Reconstructionmentioning

confidence: 99%

Topology reconstruction from FAU to MWW structure

Shi

Xing

Gao

et al. 2014

Microporous and Mesoporous Materials

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“…Davis and co‐workers have developed a synthesis process in which conventional hydrothermal zeolites are modified by ion exchange and the desired zeolite is obtained by using seed material of the zeolite structure type to be produced 4…”

Section: Channel Diameters [å] Of Synthesized 6‐ring Alumosilicate Zementioning

confidence: 99%