Enthalpy of formation and dehydration of alkaline earth cation exchanged zeolite beta

Pingping Sun, Alexandra Navrotsky

Research output: Contribution to journalArticlepeer-review

16 Scopus citations

Abstract

Cationic variants of zeolite beta (Mg-BEA 14, Ca-BEA 14, Sr-BEA 14, Ba-BEA 14, Mg-BEA 4 and Ca-BEA 4) were achieved by alumination and ion exchange processes, and characterized by XRD, NMR and TG-DSC. Mg-BEA 14/Ca-BEA 14, Sr-BEA 14/Ba-BEA 14, and Mg-BEA 4/Ca-BEA 4 have distinct thermal behavior. The low silica zeolites Mg-BEA 4 and Ca-BEA 4 were observed to have octahedral Al atoms and less crystallinity compared with high silica Mg-BEA 14 and Ca-BEA 14. High temperature oxide melt solution calorimetry determined the dehydration enthalpy and the formation enthalpy from the constituent oxides. For alkaline earth zeolite beta with the same Si/Al ratio, both the integral dehydration enthalpy and formation enthalpy from oxides becomes more endothermic with increasing average ionic potential. Mg-BEA 4 and Ca-BEA 4 have very endothermic formation enthalpies, in both dehydrated and hydrated forms, indicating a likely thermodynamic barrier to their direct synthesis, despite the natural occurrence of their analog, tschernichite.

Original languageEnglish (US)
Pages (from-to)147-155
Number of pages9
JournalMicroporous and Mesoporous Materials
Volume109
Issue number1-3
DOIs
StatePublished - Mar 1 2008
Externally publishedYes

Keywords

  • Al coordination
  • Calorimetry
  • Formation and dehydration enthalpy
  • Thermal behavior
  • Zeolite BEA

ASJC Scopus subject areas

  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials

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