Analysis of the salt retention of nanofiltration membranes using the Donnan-steric partitioning pore model

Johan Schaep, Carlo Vandecasteele, Abdul Wahab Mohammad, W. Richard Bowen

Research output: Contribution to journalArticle

110 Citations (Scopus)

Abstract

The performance of four commercial nanofiltration membranes was analyzed by the Donnan-steric partitioning pore model (DSPM) that describes solute transport through a membrane using the extended Nernst-Planck equation. Retention measurements were carried out as a function of the permeate flux for uncharged solutes, which allowed characterization of the membranes in terms of an effective membrane pore radius and the ratio of an effective membrane thickness to the porosity. Retention measurements with single salt solutions of NaCl, Na2SO4, MgCl2, and MgSO4 clearly showed the effect of ion concentration and ion valence on the retention. The DSPM model was used to evaluate the effective membrane charge density by analyzing the retention of single salt solutions. The analysis showed that the charge density is not constant but depends very much on the salt and its concentration. This is attributed to ion adsorption on the membrane material. For magnesium salts this could lead to a positive membrane charge. This phenomenon was found for each of the membrane materials.

Original languageEnglish
Pages (from-to)3009-3030
Number of pages22
JournalSeparation Science and Technology
Volume34
Issue number15
DOIs
Publication statusPublished - 1999
Externally publishedYes

Fingerprint

Nanofiltration membranes
Salts
Membranes
Ions
Charge density
Solute transport
Magnesium Chloride
Magnesium
Porosity
Fluxes
Adsorption

Keywords

  • Membrane Charge
  • Nanofiltration
  • Nernst-Planck equation
  • Retention
  • Salt solutions

ASJC Scopus subject areas

  • Chemical Engineering(all)
  • Filtration and Separation
  • Process Chemistry and Technology
  • Chemistry(all)

Cite this

Analysis of the salt retention of nanofiltration membranes using the Donnan-steric partitioning pore model. / Schaep, Johan; Vandecasteele, Carlo; Mohammad, Abdul Wahab; Bowen, W. Richard.

In: Separation Science and Technology, Vol. 34, No. 15, 1999, p. 3009-3030.

Research output: Contribution to journalArticle

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