In situ fabrication of cross-linked PEO/silica reverse-selective membranes for hydrogen purification

Lu Shao*, Tai-Shung Chung

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

74 Scopus citations

Abstract

Targeting at hydrogen purification, cross-linked organic-inorganic reverse-selective membranes containing poly(ethylene oxide) (PEO) are fabricated in situ by using functional oligomers (O,O′-bis(2-aminopropyl) polypropylene glycol-block-polyethylene glycol-block-polypropylene glycol: Jeffamine® ED-2003) with a high content of PEO and epoxy-functional silanes (3-glycidyloxypropyltrimethoxysilane: GOTMS). Changes in physicochemical properties due to varying silica content have been characterized; including a great decline in melting temperature; an improvement in glassy and degradation temperature, and the suppression of PEO crystallinity. The strong affinity between quadrupolar CO2 and polar ethylene oxide (EO) groups enhances the CO2/H2 separation performance of hybrid membranes, which can be further tuned by controlling the organic/inorganic ratio. The organic-inorganic hybrid membrane with 90 wt% of ED-2003 demonstrates an appealing CO2 permeability of 367 Barrer with an attractive CO2/H2 selectivity of 8.95 at 3.5 atm and 35 °C. The transport performance trend with composition variations is explained by analyzing the calculated solubility and diffusivity based on the solution-diffusion mechanism. Moreover, CO2 permeability increases with applied pressure in pure gas tests because of CO2 plasticization phenomena, which is beneficial for CO2/H2 separation. Attributing to CO2 plasticization and CO2 dominant sorption, the mixed gas test results of the membrane containing only 25 wt% ED-2003 show greatly improved CO2/H2 selectivity of 13.2 with CO2 permeability of 148 Barrer at 35 °C compared to pure gas results. Interestingly, at a stipulated CO2 pressure, the inherent tension in cross-linked networks maintains the CO2 permeability stable with the time. The cross-linked organic-inorganic membranes with enhancements in mechanical and thermal properties are promising for industrial-scale hydrogen purification.

Original languageEnglish (US)
Pages (from-to)6492-6504
Number of pages13
JournalInternational Journal of Hydrogen Energy
Volume34
Issue number15
DOIs
StatePublished - Aug 1 2009

Keywords

  • Cross-linked network
  • Hydrogen purification
  • PEO
  • Reverse-selective membrane
  • Silica

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Fuel Technology
  • Condensed Matter Physics
  • Energy Engineering and Power Technology

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