A novel strategy for surface modification of polyimide membranes by vapor-phase ethylenediamine (EDA) for hydrogen purification

Lu Shao, Cher Hon Lau, Tai-Shung Chung*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

70 Scopus citations

Abstract

In this study, vapor-phase ethylenediamine (EDA) is utilized to specifically modify the physicochemical properties of the outer surface of polyimide membranes without modifying the internal membrane structure for hydrogen purification. The surfaces of polyimide membranes before and after EDA-vapor modification have been characterized by Fourier transform infrared-attenuated total reflectance (FTIR-ATR), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD), which confirmed the modification mechanism including the conversion of imide groups into amide groups with simultaneous cross-linking between polymer chains and a physical decrement in d-space. Based on pure gas permeation tests, only a 10-min vapor-phase EDA treatment can significantly improve H2/CO2 selectivity (up to ∼100). This is attributed to intensive surface modification by EDA vapor, hence rendering this simple and yet novel technique more effectively for hydrogen purification than the conventional solution approach. Although the H2/CO2 separation performance in mixed gas tests is not as superior as that in pure gas permeation tests, mixed gas results affirmed impressive H2/CO2 separation performance of vapor-phase EDA modified polyimide membranes. This novel vapor modification strategy appears to be promising for large-scale processes, especially the modification of hollow fiber membranes for industrial hydrogen purification.

Original languageEnglish (US)
Pages (from-to)8716-8722
Number of pages7
JournalInternational Journal of Hydrogen Energy
Volume34
Issue number20
DOIs
StatePublished - Oct 1 2009

Keywords

  • Gas separation
  • Hydrogen purification
  • Modification
  • Polyimide membrane
  • Vapor-phase EDA

ASJC Scopus subject areas

  • Renewable Energy, Sustainability and the Environment
  • Fuel Technology
  • Condensed Matter Physics
  • Energy Engineering and Power Technology

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