Sol-gel control on mixed network silica membranes for gas separation

Kurt T., TOPUZ B.

SEPARATION AND PURIFICATION TECHNOLOGY, vol.255, 2021 (SCI-Expanded) identifier identifier

  • Publication Type: Article / Article
  • Volume: 255
  • Publication Date: 2021
  • Doi Number: 10.1016/j.seppur.2020.117654
  • Journal Name: SEPARATION AND PURIFICATION TECHNOLOGY
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Aerospace Database, Biotechnology Research Abstracts, Chemical Abstracts Core, Chimica, Communication Abstracts, Compendex, INSPEC, Metadex, Pollution Abstracts, Civil Engineering Abstracts
  • Keywords: Silica membrane, Methyl-linked, Microporous, Ti-incorporated, Mixed network, H-2 separation
  • Ankara University Affiliated: Yes

Abstract

Sol-gel derived Ti-incorporated methyl-linked silica mixed network membranes were successfully prepared by acid catalyzed co-polymerization of methyltriethoxysilane, tetraethylorthosilicate and titanium isopropoxide. The particle size of polymeric mixed oxide sols was in the range of 2-6 nm depending on the titanium content in the sol. As Ti4+/Si4+ mole ratio in the sol increases, DLS polymer cluster size increases slightly due to the different reactivity of precursors. Ti-2p and Si-2p binding energy values obtained by XPS confirmed the evolution of Si-O-Ti bond in the membrane network. Macroporous alpha-alumina ceramic supports with different pore size as a support and mesoporous gamma-alumina coating as an intermediate layer were used for the fabrication of thin titania/methyl-linked mixed network silica membranes. Increase in the number of coating led to an increase in the membrane thickness from 80 nm to 220 nm and this provided an enhancement in the H-2/C3H8 ideal selectivity (from 53 to 124). Decrease in the H-2 permeance, on the other hand, with increased membrane thickness was overcome with the use of coarser supports inhibiting the transport resistance. The membrane exhibited higher H-2 permeance value of 1.6 x 10(-6) mol/m(2) s Pa with almost same H-2/C3H8 ideal selectivity at 150 degrees C compared to its finer counterpart.