Effect of PBI-HFA surface treatments on Pd/PBI-HFA composite gas separation membranes

Da Hye Kim, Seong Young Kong, Geun Hyuk Lee, Chang Won Yoon, Hyung Chul Ham, Jonghee Han, Kwang Ho Song, Dirk Henkensmeier, Sun Hee Choi

Research output: Contribution to journalArticle

3 Citations (Scopus)

Abstract

For pure hydrogen separation, palladium was deposited on surface-treated polybenzimidazole (PBI-HFA, 4,4′-(hexafluroisopropylidene)bis(benzoic acid)) via the vacuum electroless plating technique (VELP). Since the hydrophobic characteristics of the polymer surface restrict strong adhesion of Pd on it and cause the peel-off of Pd film, various surface treatments have been employed. To increase the number of Pd anchoring sites on the PBI-HFA surface, mechanical abrasion (polishing) was applied, and to increase the hydrophilicity of the PBI-HFA surface, wet-chemical and O2 plasma treatment (dry etching) were used. The thickness and effective permeating area of the deposited Pd films on the PBI-HFA membranes were estimated to be in the range of 160–340 nm and 8.3 cm2, respectively. Among the tested membranes, membranes with Pd layers deposited on O2 plasma treated PBI-HFA surfaces had the most uniform microstructure and the least number of defects compared to the other membranes. Gas permeation experiments were performed as a function of temperature and pressure. The gases used in the permeation measurements were H2, N2, CO2, and CO (99.9% purity). A Pd-O230 m membrane, fabricated by O2 plasma surface treatment during 30 min, exhibited superior gas separation performance (H2 permeability of 275.5 Barrer), and proved to be impermeable to carbon monoxide. Enhancement of H2 permselectivity of Pd/PBI-HFA composite membrane treated by O2 plasma shows promising hydrogen separation membrane.

Original languageEnglish
Pages (from-to)22915-22924
Number of pages10
JournalInternational Journal of Hydrogen Energy
Volume42
Issue number36
DOIs
Publication statusPublished - 2017 Sep 7

Keywords

  • Chemical etching
  • Hydrogen separation
  • O plasma surface treatment
  • Pd composite membrane
  • Polybenzimidazole (PBI-HFA)
  • Vacuum electroless plating (VELP)

ASJC Scopus subject areas

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

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