Mixed matrix PVDF hollow fiber membranes with nanoscale pores for desalination through direct contact membrane distillation

Kai Yu Wang, Suay Wei Foo, Tai Shung Chung*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

140 Scopus citations

Abstract

Highly porous hydrophobic hollow fiber membranes with high porosity and sandwich trilayer structure were specially designed to meet the requirements of direct contact membrane distillation (DCMD). Poly(vinylidene fluoride) (PVDF)/Cloisite clay composite hollow fibers were fabricated based on the dry-jet wet phase inversion mechanism by using water as both the external and internal coagulants. Membrane void fraction of up to 90% can be produced to improve the fibers' thermal insulation and reduce vapor transport resistance. The fiber inner surface was full of streaky pores with pore size less than 1.0 μm in diameter, while the pores on the fiber outer surface were much smaller, less than 50 nm in diameter. This demonstrates that membrane pores fabricated at a nanoscale can achieve high water vapor permeation flux with 100% salt rejection. For example, the fabricated PVDF/clay composite hollow fiber was tested by desalinating a 3.5 wt % NaCl solution and permeation flux as high as 79.2 kg/(m2.h) (calculated on the fiber outer diameter) was achieved at the inlet temperatures of 81.5/17.5 °C. The performance shows almost no decay during 220-h continuous tests. The addition of clay particles may enhance the tensile modulus and improve long-term stability compared to those fibers without particles.

Original languageEnglish (US)
Pages (from-to)4474-4483
Number of pages10
JournalIndustrial and Engineering Chemistry Research
Volume48
Issue number9
DOIs
StatePublished - May 6 2009
Externally publishedYes

ASJC Scopus subject areas

  • Chemistry(all)
  • Chemical Engineering(all)
  • Industrial and Manufacturing Engineering

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