Chemical and thermal modification of natural HEU-type zeolitic materials from Armenia, Georgia and Greece

G. E. Christidis, D. Moraetis, E. Keheyan, L. Akhalbedashvili, N. Kekelidze, R. Gevorkyan, H. Yeritsyan, H. Sargsyan

Research output: Contribution to journalArticle

81 Citations (Scopus)

Abstract

Three HEU-type zeolites from Armenia, Georgia and Greece formed from alteration of volcanic glass were treated with dilute KOH and subsequently either reacted with 6N HCl or heated at 700 °C. The raw materials and the reaction products were examined with X-ray diffraction (XRD), infrared spectroscopy (FTIR) and N2 gas adsorption. The cation exchange capacity (CEC) of the zeolites was also determined. The Greek zeolite has thermal characteristics typical for heulandite I, while the Armenian and Georgian zeolites have characteristics typical for heulandite III (clinoptilolite). KOH treatment increased slightly specific surface area (SSA) and microporosity due to dissolution of amorphous material. Acid treatment increased significantly both specific surface area and microporosity, as determined by t-plots, and decreased CEC. This is attributed to partial dissolution of both Si-tetrahedra and free linkages, which yielded secondary micropores and destroyed specific exchange sites of the HEU-type zeolites. Heating decreased both specific surface area and microporosity.

Original languageEnglish
Pages (from-to)79-91
Number of pages13
JournalApplied Clay Science
Volume24
Issue number1-2
DOIs
Publication statusPublished - 2003

Keywords

  • Clinoptilolite
  • Heulandite
  • Surface modification
  • Treatment

ASJC Scopus subject areas

  • Geology
  • Geochemistry and Petrology

Fingerprint Dive into the research topics of 'Chemical and thermal modification of natural HEU-type zeolitic materials from Armenia, Georgia and Greece'. Together they form a unique fingerprint.

  • Cite this

    Christidis, G. E., Moraetis, D., Keheyan, E., Akhalbedashvili, L., Kekelidze, N., Gevorkyan, R., Yeritsyan, H., & Sargsyan, H. (2003). Chemical and thermal modification of natural HEU-type zeolitic materials from Armenia, Georgia and Greece. Applied Clay Science, 24(1-2), 79-91. https://doi.org/10.1016/S0169-1317(03)00150-9