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High-pressure spectroscopic study of hydrous and anhydrous Cs-exchanged natrolites
journal contribution
posted on 2012-01-01, 00:00 authored by Dan LiuDan Liu, D Seoung, Y Lee, Z Liu, J W Lee, J H YoonStructural phase transitions in hydrous Cs-exchanged natrolite (Cs-NAT-hyd) and anhydrous Cs-exchanged natrolite (Cs-NAT-anh) have been investigated as a function of pressure and temperature using micro-Raman scattering and synchrotron infrared (IR) spectroscopy with pure water as the penetrating pressure medium. The spectroscopic results indicate that Cs-NAT-hyd undergoes a reversible phase transition around 4.72 GPa accompanied by the discontinuous frequency shifts of the breathing vibrational modes of the four-ring and helical eight-ring units of the natrolite framework. On the other hand, we observe that Cs-NAT-anh becomes rehydrated at 0.76 GPa after heating to 100 °C and then transforms into two distinctive phases at 2.24 and 3.41 GPa after temperature treatments at 165 and 180 °C, respectively. Both of these high-pressure phases are characterized by the absence of the helical eight-ring breathing modes, which suggests the collapse of the natrolite channel and formation of dense high-pressure polymorphs. Together with the fact that these high-pressure phases are recoverable to ambient conditions, our results imply a novel means for radionuclide storage utilizing pressure and a porous material.
History
Journal
Journal of physical chemistry CVolume
116Issue
3Pagination
2159 - 2164Publisher
American Chemical SocietyLocation
Washington, D.C.Publisher DOI
ISSN
1932-7447eISSN
1932-7455Language
engPublication classification
C1.1 Refereed article in a scholarly journalCopyright notice
2012, American Chemical SocietyUsage metrics
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No categories selectedKeywords
Science & TechnologyPhysical SciencesTechnologyChemistry, PhysicalNanoscience & NanotechnologyMaterials Science, MultidisciplinaryChemistryScience & Technology - Other TopicsMaterials ScienceX-RAY-DIFFRACTIONVIBRATIONAL-SPECTRAINDUCED HYDRATIONZEOLITESNA2AL2SI3O10-CENTER-DOT-2H(2)OTRANSFORMATIONSAMORPHIZATIONTEMPERATUREDEHYDRATIONCALIBRATION
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