Butanol isomer separation using polyamide-imide/CD mixed matrix membranes via pervaporation

Yan Wang, Tai-Shung Chung*, Huan Wang, Suat Hong Goh

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

50 Scopus citations


Mixed matrix membranes (MMMs) comprising polyamide-imide (PAI) and α-, β- or γ-cyclodextrin (CD) have been investigated experimentally and computationally for isomeric n-butanol/tert-butanol (n-BuOH/t-BuOH) separation via pervaporation. Consistent with molecular simulation, experimental results show that the CD inclusion ability and butanol discrimination ability are dependent on both CD cavity size and butanol molecular size. The PAI membrane incorporated with α-CD has the smallest cavity and has the highest discrimination ability for the n-BuOH/t-BuOH pair but with a low butanol flux. The mixed matrix membrane embedded with γ-CD has the lowest selectivity and the highest flux. The PAI/β-CD membrane has a comparable selectivity and flux, and exhibits preferential sorption and diffusion selectivity toward n-BuOH. A maximum separation factor of 1.53 with a corresponding flux of 4.4 g/m2 h are obtained at an optimal β-CD loading of 15 wt%. Further increments in the CD content eventually lead to a decrease in separation performance because of CD agglomeration and severe phase separation. To better understand the influence of CD on the separation performance of mixed matrix membranes, SEM, FTIR and XRD have been employed for membrane characterizations. The effect of n-butanol/t-butanol ratio in the feed composition has also been studied. It is found that both flux and separation factor decrease with increasing n-butanol content in the feed. The decline is attributed to the change in total vapor pressure at the upstream and the mutual drag effect of isomeric butanol molecules.

Original languageEnglish (US)
Pages (from-to)5198-5209
Number of pages12
JournalChemical Engineering Science
Issue number24
StatePublished - Sep 21 2009


  • Butanol isomer
  • Membranes
  • Pervaporation
  • Selectivity
  • Separations
  • Simulation

ASJC Scopus subject areas

  • General Chemistry
  • General Chemical Engineering
  • Industrial and Manufacturing Engineering


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