High performance PIM-1/Matrimid hollow fiber membranes for CO2/CH4, O2/N2 and CO2/N2 separation

Wai Fen Yong, Fu Yun Li, You Chang Xiao, Tai-Shung Chung*, Yen Wah Tong

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

82 Scopus citations

Abstract

Polymers of intrinsic microporosity (PIM-1) have received worldwide attention but most PIM-1 researches have been conducted on dense flat membranes. For the first time, we have fabricated PIM-1/Matrimid membranes in a useful form of hollow fibers with synergistic separation performance. The newly developed hollow fibers comprising 5-15wt% of highly permeable PIM-1 not only possess much higher gas-pair selectivity than PIM-1 but also have much greater permeance than pure Matrimid fibers. Data from positron annihilation lifetime spectroscopy (PALS), field emission scanning electron microscopy (FESEM) and apparent dense layer thickness indicate that the blend membranes have an ultrathin dense layer thickness of less than 70nm. PIM-1 and Matrimid are partially miscible. The effect of partial miscibility on dense selective layer was studied. Defect-free hollow fibers with gas pair selectivity more than 90% of the intrinsic value can be spun directly from dopes containing 5wt% PIM-1 with proper spinning conditions, while post annealing and additional silicone rubber coating are needed for membranes containing 10 and 15wt% PIM-1, respectively. Comparing to Matrimid, the CO2 permeance of as-spun fibers containing 5 and 10wt% PIM-1 increases 78% and 146%, respectively (e.g., from original 86.3GPU (1GPU=1×10-6cm3 (STP)/cm2scmHg=7.5005×10-12ms-1Pa-1) to 153.4GPU and 212.4GPU) without compromising CO2/CH4 selectivity. The CO2 permeance of the fiber containing 15wt% PIM-1 improves to 243.2GPU with a CO2/CH4 selectivity of 34.3 after silicon rubber coating. Under mixed gas tests of 50/50 CO2/CH4, this fiber shows a CO2 permeance of 188.9GPU and a CO2/CH4 selectivity of 28.8. The same fiber also has an impressive O2 permeance of 3.5 folds higher than the pristine Matrimid (e.g., from original 16.9GPU to 59.9GPU) with an O2/N2 selectivity of 6.1. The newly developed membranes may have great potential to be used for natural gas purification, air separation and CO2 capture.

Original languageEnglish (US)
Pages (from-to)156-169
Number of pages14
JournalJournal of Membrane Science
Volume443
DOIs
StatePublished - Sep 15 2013

Keywords

  • Gas separation
  • Hollow fibers
  • Matrimid
  • PIM-1
  • Polymer blends

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Materials Science(all)
  • Biochemistry
  • Filtration and Separation

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