Defect-free high-silica CHA zeolite membranes with high selectivity for light gas separation

Pelin Karakiliç, Xuerui Wang, Freek Kapteijn, Arian Nijmeijer, Louis Winnubst

Research output: Contribution to journalArticleScientificpeer-review

4 Citations (Scopus)

Abstract

A systematic approach is described for the fabrication of defect-free high-silica zeolite membranes with CHA (SSZ-13) topology. Home-made hydrothermally-synthesized CHA seeds were coated on porous α-alumina substrates with a pore diameter of 80 nm and by means of a further hydrothermal treatment a zeolite membrane layer was formed. In order to obtain a thin and defect-free zeolite layer, the influence on the final microstructure of seed concentration during coating, coating method (rubbing, dip- or spin-coating) and crystal growth time was investigated. The template removal procedure was optimized to avoid the formation of cracks or defects. For an optimal thermal treatment, using a step-wise temperature increase to 500 °C, the membranes exhibit CO2/CH4 permselectivities of 25–30 with CO2 permeances of around 2 x 10−7 mol m−2 s−1 Pa−1 at 22 °C and 2 bar of pressure difference. O2 plasma pre-treatment prior to template removal increased the CO2/CH4 permselectivity to 176, while maintaining the same CO2 permeance values when no pre-treatment was used. The SF6 permeances, both at low (22 °C) and high (200 °C) temperatures, were below the detection limit (2 x 10−10 mol m−2 s−1 Pa−1), which in return results in very high N2/SF6 permselectivities of more than 700.

Original languageEnglish
Pages (from-to)34-43
JournalJournal of Membrane Science
Volume586
DOIs
Publication statusPublished - 2019

Keywords

  • CHA zeolite
  • Natural gas purification
  • SF recovery
  • SSZ-13
  • Zeolite membrane

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