Highly porous and macrovoid-free PVDF hollow fiber membranes for membrane distillation by a solvent-dope solution co-extrusion approach

Sina Bonyadi, Tai-Shung Chung*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

133 Scopus citations

Abstract

Highly porous and macrovoid-free PVDF hollow fiber membranes are of great interest for membrane contactor applications such as sea water desalination by membrane distillation in order to enhance the flux and long term stability of the process. For the first time in this paper, porous PVDF hollow fiber membranes with high outer surface porosity were fabricated by applying a two-phase flow consisting of a solvent and a dope solution in the air-gap region of spinning through a non-solvent induced phase separation process (NIPS). In this approach, the dope solution and the N-methylpyrrolidone (NMP) solvent were co-discharged from the middle and outer channels of a triple orifice spinneret, respectively. Then, the two-phase flow went through an air-gap region and finally entered the coagulation bath. It was observed that the introduction of the two-phase flow greatly increased the outer surface porosity of the PVDF fibers and eliminated the formation of macrovoids in the cross-section of the fibers as well. It was also found that the energy efficiency and the flux of the fibers spun through the solvent-dope solution co-exterusion were two to three times higher than the standard dry jet wet-spun fibers. A water vapor flux as high as 67 kg/(m 2 h) at 80 °C was obtained through the newly spun fibers.

Original languageEnglish (US)
Pages (from-to)66-74
Number of pages9
JournalJournal of Membrane Science
Volume331
Issue number1-2
DOIs
StatePublished - Apr 1 2009

Keywords

  • Hollow fiber
  • Membrane contactor
  • Membrane distillation
  • Polyvinylidene flouride (PVDF)
  • Two-phase flow

ASJC Scopus subject areas

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

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