Abstract
The electrolyte separation behaviour of a supported bi-layered ceramic membrane is investigated experimentally and the measured ion retentions
are compared with the predictions of a site-binding transport model with no adjustable parameters. Due to the difference in iso-electric point
between its two separating layers, the bi-layered system is expected to perform better over a large pH range compared with a membrane with only
one type of selective layer. The separating layers in the membrane are a microporous silica and a mesoporous -alumina (pore sizes of 0.8 and
2 nm, respectively) and their retention is studied for a binary electrolyte solution of NaCl at 1 mol/m3 for pH values between 4 and 10.
Because of its smaller pores and high charge, the silica layer mainly determines the membrane retention at neutral and alkaline pH, while the
-alumina layer has a significant impact on the NaCl retention at 4 < pH< 5. The model predictions are in good agreement with the experimental
data for Na+ at 4 < pH< 9 and for Cl− at the whole pH range. For a pH of 4, the predicted chloride retention is lower than the sodium retention
while the experimental data show the opposite effect.
© 2005 Elsevier B.V. All rights reserved.
Original language | English |
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Pages (from-to) | 18-27 |
Journal | Journal of membrane science |
Volume | 277 |
Issue number | 1-2 |
DOIs | |
Publication status | Published - 2006 |
Keywords
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