Hydrothermal stability of pure and modified microporous silica membranes

G. P. Fotou, Y. S. Lin, S. E. Pratsinis

Research output: Contribution to journalArticlepeer-review

100 Scopus citations

Abstract

The hydrothermal stability of microporous (0.6 nm) silica membranes prepared by the sol-gel process was studied at 600 and 800 °C in a 50 mol% steam atmosphere. The membranes remained microporous after calcination and hydrothermal treatment at 600 °C for 30 h but a substantial reduction in the specific surface area (48%) accompanied by a 77% decline in the micropore volume was observed. Hydrothermal treatment at 800 °C for 30 h resulted in complete densification of the membranes. The effect of alumina and magnesia on the hydrothermal stability of the membranes was investigated. Both Al2O3 and MgO were introduced into the membranes by doping the starting silica sol with controlled amounts of the corresponding nitrate salts. Alumina did not change the pore structure of the silica membranes which retained a large part of their microporosity after hydrothermal treatment at 600 °C compared to pure silica membranes. Doping with magnesia, however, resulted in lower specific surface areas relative to those of pure and alumina-doped silica membranes after drying and calcination. These effects on the stability of the membranes are explained by assuming structural changes in the membranes catalysed by magnesia.

Original languageEnglish (US)
Pages (from-to)2803-2808
Number of pages6
JournalJournal of Materials Science
Volume30
Issue number11
DOIs
StatePublished - Jan 1 1995
Externally publishedYes

ASJC Scopus subject areas

  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering

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