Fabrication of polybenzimidazole (PBI) nanofiltration hollow fiber membranes for removal of chromate

Kai Yu Wang, Tai-Shung Chung*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

132 Scopus citations

Abstract

The feasibility of employing nanofiltration for the removal of chromate from wastewater was investigated. Polybenzimidazole (PBI) was used to fabricate nanofiltration hollow fiber membrane with outstanding mechanical strength and chemical stability through the phase-inversion technique. The PBI NF membranes have a mean effective pore size of 0.348 nm in radius, the molecular weight cut off of 525 Da, and pure water permeability of 1.86 × 10-5 l m-2 h-1 Pa-1 (1.86 l m-2 h-1 bar-1). The PBI membranes showed different rejection to electrolytes in the order of RMgC l2 > RMgS O4 > RN a2 S O4 > RNaCl. The surface charge properties were clarified by filtering NaCl solution and the PBI membranes showed a V-shape trend of NaCl rejection with an increase in pH. In addition, higher separation ratios of (SO4 2-/Cl-) and (Mg2+/Na+) were obtained from investigating the ion fractionation performance of the PBI membranes when using binary model solutions of NaCl/Na2SO4 and NaCl/MgCl2. Effect of pH on the chromate rejection was rationalized based on an equilibrium diagram of the Cr(VI)-H2O system. It is concluded that chromates can be effectively separated from their basic solutions by the PBI NF hollow fibers while maintaining their chemical and mechanical stability under high pressures and alkalinity.

Original languageEnglish (US)
Pages (from-to)307-315
Number of pages9
JournalJournal of Membrane Science
Volume281
Issue number1-2
DOIs
StatePublished - Sep 15 2006

Keywords

  • Chromate
  • Hollow fiber
  • Membrane separations
  • Nanofiltration
  • Polybenzimidazole

ASJC Scopus subject areas

  • Filtration and Separation
  • Polymers and Plastics

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