Molecular design of double crosslinked sulfonated polyphenylsulfone /polybenzimidazole blend membranes for an efficient hydrogen purification

Ali Naderi, Akbar Asadi Tashvigh, Tai Shung Chung*, Martin Weber, Christian Maletzko

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

11 Citations (Scopus)

Abstract

This study, for the first time, demonstrates a new double-crosslinking approach to manipulate the microstructure and gas separation performance of PBI membranes for H2/CO2 separation at 150 °C. The PBI membranes were firstly blended with sulfonated polyphenylsulfone (sPPSU) as an ionic-crosslinker and then α,α′-dibromo-p-xylene (DBX) as a covalent crosslinker with the aid of thermal annealing. Experiments show that PBI and sPPSU interact on the molecular level. Different from conventional blends, the PBI/sPPSU blend membranes show both enhanced chemical resistance and greater fractional free volume (FFV) after annealing at elevated temperatures because of chain motion and ionic crosslinking. As a result, the blend membranes maintain their high permeability after annealing. The DBX addition further improves the chemical resistance and tightens the inter-chain spacing that results in membranes with a small FFV and pore size. Consequently, the DBX cross-linked blend membranes retain their high gas pair selectivity at high temperatures. The 50/50 PBI/sPPSU blend membrane crosslinked by 0.7 wt% DBX at 300 °C possesses the best separation performance surpassing the Robeson's upper bound. It has an impressively H2 permeability of 46.2 Barrer and a high H2/CO2 selectivity of 9.9 at 150 °C.

Original languageEnglish
Pages (from-to)726-733
Number of pages8
JournalJournal of membrane science
Volume563
Early online date22 Jun 2018
DOIs
Publication statusPublished - 1 Oct 2018
Externally publishedYes

Keywords

  • UT-Hybrid-D
  • Double crosslinking
  • Fractional free volume (FFV)
  • Gas separation
  • Homogeneous blend
  • Hydrogen purification
  • CO capture

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