Dehydration of tetrafluoropropanol (TFP) by pervaporation via novel PBI/BTDA-TDI/MDI co-polyimide (P84) dual-layer hollow fiber membranes

Kai Yu Wang, Tai-Shung Chung*, Raj Rajagopalan

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

43 Scopus citations

Abstract

A novel PBI/P84 co-polyimide dual-layer hollow fiber membrane has been specifically fabricated through the dry-jet wet phase inversion process, for the first time, for the dehydration pervaporation of tetrafluoropropanol (TFP). Polybenzimidazole (PBI) was chosen as the outer selective layer because of its superior hydrophilic nature and excellent solvent-resistance together with robust thermal stability, while P84 co-polyimide was employed as the inner supporting layer because of its good solvent-resistance and thermal stability. The PBI/P84 membrane exhibits superior water selectivity and relatively high permeation flux. At 60 °C, the PBI/P84 dual-layer hollow fiber membrane shows a permeation flux of 332 g/(m2 h) and a separation factor of 1990 for a feed solution containing of 85 wt% TFP. The preferential water sorption and the significant diffusivity difference between TFP and water are the main causes of high separation factor. However, an increase in feed temperature will greatly increase the permeation flux but seriously decrease the water selectivity. The activation energy data verify that water can preferentially permeate the PBI membrane due to the strong water affinity of PBI and a much smaller molecular size of water.

Original languageEnglish (US)
Pages (from-to)60-66
Number of pages7
JournalJournal of Membrane Science
Volume287
Issue number1
DOIs
StatePublished - Jan 5 2007

Keywords

  • Dual-layer hollow fiber
  • Membrane separation
  • Pervaporation
  • Polybenzimidazole
  • Tetrafluoropropanol (TFP)

ASJC Scopus subject areas

  • Filtration and Separation
  • Polymers and Plastics

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