The development of novel Nexar block copolymer/ultem composite membranes for C2-C4 alcohols dehydration via pervaporation

Jian Zuo, Gui Min Shi, Shawn Wei, Tai-Shung Chung*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

28 Scopus citations

Abstract

Novel composite membranes comprising sulfonated styrenic Nexar pentablock copolymers were developed by dip-coating on poly(ether imide) hollow fibers for pervaporation dehydration of C2-C4 alcohols. The advantages of using block copolymers as the selective layer are (1) their effectiveness to synergize the physicochemical properties of different chemical and structural moieties and (2) tunable nanoscale morphology and nanostructure via molecular engineering. To achieve high-performance composite membranes, the effects of coating time, ion exchange capacity (IEC) of the copolymer, and solvent systems for coating were investigated. It is revealed that a minimum coating time of 30 s is needed for the formation of a continuous and less-defective top layer. A higher IEC value results in a membrane with a higher flux and lower separation factor because of enhanced hydrophilicity and stretched chain conformation. Moreover, the composite membranes prepared from hexane/ethanol mixtures show higher separation factors and lower fluxes than those from the hexane solvent owing to microdomain segregation induced by ethanol and a smooth and dense top selective layer. These hypotheses were verified by atomic force microscopy and positron annihilation spectroscopy. The newly developed composite membranes demonstrate impressive separation performance with fluxes exceeding 2 kg/m2 h and separation factors more than 200 for isopropyl alcohol and n-butanol dehydration from 85/15 wt % alcohol/water feed mixtures at 50 °C.

Original languageEnglish (US)
Pages (from-to)13874-13883
Number of pages10
JournalACS Applied Materials and Interfaces
Volume6
Issue number16
DOIs
StatePublished - Jan 1 2014

Keywords

  • alcohols
  • block copolymer
  • composite membrane
  • dehydration
  • pervaporation

ASJC Scopus subject areas

  • Materials Science(all)

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