Super-hydrated zeolites: Pressure-induced hydration in natrolites

Donghoon Seoung, Yongjae Lee, Chi Chang Kao, Thomas Vogt

Research output: Contribution to journalArticle

31 Citations (Scopus)

Abstract

High-pressure synchrotron X-ray powder diffraction studies of a series of alkali-metal-exchanged natrolites, A16Al16Si 24O80×n H2O (A=Li, K, Na, Rb, and Cs and n=14, 16, 22, 24, 32), in the presence of water, reveal structural changes that far exceed what can be achieved by varying temperature and chemical composition. The degree of volume expansion caused by pressure-induced hydration (PIH) is inversely proportional to the non-framework cation radius. The expansion of the unit-cell volume through PIH is as large as 20.6 % in Li-natrolite at 1.0 GPa and decreases to 6.7, 3.8, and 0.3 % in Na-, K-, and Rb-natrolites, respectively. On the other hand, the onset pressure of PIH appears to increase with non-framework cation radius up to 2.0 GPa in Rb-natrolite. In Cs-natrolite, no PIH is observed but a new phase forms at 0.3 GPa with a 4.8 % contracted unit cell and different cation-water configuration in the pores. In K-natrolite, the elliptical channel undergoes a unique overturn upon the formation of super-hydrated natrolite K16Al16Si24O 80×32 H2O at 1.0 GPa, a species that reverts back above 2.5 GPa as the potassium ions interchange their locations with those of water and migrate from the hinge to the center of the pores. Super-hydrated zeolites are new materials that offer numerous opportunities to expand and modify known chemical and physical properties by reversibly changing the composition and structure using pressure in the presence of water.

Original languageEnglish
Pages (from-to)10876-10883
Number of pages8
JournalChemistry - A European Journal
Volume19
Issue number33
DOIs
Publication statusPublished - 2013 Aug 12

All Science Journal Classification (ASJC) codes

  • Catalysis
  • Organic Chemistry

Fingerprint Dive into the research topics of 'Super-hydrated zeolites: Pressure-induced hydration in natrolites'. Together they form a unique fingerprint.

  • Cite this