H2/CO2 separation enhancement via chemical modification of polybenzimidazole nanostructure

Ali Naderi, Akbar Asadi Tashvigh, Tai Shung Chung*

*Corresponding author for this work

Research output: Contribution to journalArticleAcademicpeer-review

7 Citations (Scopus)

Abstract

Polybenzimidazole (PBI) thin films were chemically crosslinked using 1,3,5-Tris(bromomethyl)benzene (TBB) to manipulate the microstructure of polymer chains and to achieve a high sieving ability for H2/CO2 separation. By changing the TBB concentration and TBB/PBI molar ratio in the crosslinking solutions, PBI films were modified with different degrees of crosslinking. The increment of crosslinking density in the membranes leads to a decrease in fractional free volume (FFV), indicating the tightening effect of the TBB crosslinking reaction on PBI films. The H2/CO2 mixed gas separation was conducted at 150 °C. The membrane with the highest crosslinking density and the lowest FFV possesses the best performance for H2/CO2 separation with a H2 permeability of 9.6 Barrer and a remarkable H2/CO2 selectivity of 24. It surpasses the Robeson's upper bound and some of other membranes, indicating its promise for hydrogen purification and CO2 capture at elevated temperatures.

Original languageEnglish
Pages (from-to)343-349
Number of pages7
JournalJournal of membrane science
Volume572
Early online date12 Nov 2018
DOIs
Publication statusPublished - 15 Feb 2019
Externally publishedYes

Keywords

  • Chemical crosslinking
  • CO capture
  • Fractional free volume (FFV)
  • Gas separation
  • Hydrogen purification
  • Sieving ability
  • CO2 capture

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