The Evaluation of Counter Diffusion CVD Silica Membrane Formation Process by In Situ Analysis of Diffusion Carrier Gas

Katsunori Ishii, Mikihiro Nomura

Research output: Contribution to journalArticlepeer-review

Abstract

A new evaluation method for preparing silica membranes by counter diffusion chemical vapor deposition (CVD) was proposed. This is the first attempt to provide new insights, such as the decomposition products, membrane selectivity, and precursor reactivity. The permeation of the carrier gas used for supplying a silica precursor was quantified during the deposition reaction by using a mass spectrometer. Membrane formation processes were evaluated by the decrease of the permeation of the carrier gas derived from pore blocking of the silica deposition. The membrane formation processes were compared for each deposition condition and precursor, and the apparent silica deposition rates from the precursors such as tetramethoxysilane (TMOS), hexyltrimethoxysilane (HTMOS), or tetraethoxysilane (TEOS) were investigated by changing the deposition temperature at 400–600C. The apparent deposition rates increased with the deposition temperature. The apparent activation energies of the carrier gas through the TMOS, HTMOS, and TEOS derived membranes were 44.3, 49.4, and 71.0 kJ mol−1, respectively. The deposition reaction of the CVD silica membrane depends on the alkoxy group of the silica precursors.

Original languageEnglish
Article number102
JournalMembranes
Volume12
Issue number2
DOIs
Publication statusPublished - 2022 Feb

Keywords

  • Counter diffusion CVD
  • Deposition rate
  • Mass spectroscopy
  • Silica membrane
  • Silica precursor

ASJC Scopus subject areas

  • Chemical Engineering (miscellaneous)
  • Process Chemistry and Technology
  • Filtration and Separation

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