INFLUENCE OF CONFIGURATION AND SUBSTRATE ON THE PROPERTIES OF DYNAMICALLY FORMED MEMBRANES

Dynamically formed membranes (DFMs) are produced by forming a chemical sub-layer on an inert porous support surface (substrate). In this stu dy, various DFM substrates have been examined: a tubular carbon substr ate coated with a ZrO2-TiO2 layer, a flat sheet ceramic substrate supp orted by a stainless steel mesh, a selection of polypropylene woven me dia and an extruded polymeric microfiltration membrane. The woven medi a used are made from combinations of monofilament, multifilament and s taple fibres and a surface-coated polyester weave has also been examin ed. Zirconium (IV) oxide and polyacrylic acid (ZrO/PAA) are used to fo rm the DFM on the substrates. The influence of the configuration and s ubstrate material on the performance of the DFM has been studied in te rms of the normalised permeate flux and salt rejection. A stable DFM w as formed on the carbon, ceramic and the extruded polymer substrates. An unstable Zr(IV)O membrane was formed on the surface-coated polyeste r substrate and a fumed silica precoat has been used to form a DFM on one of the woven polypropylene media. However, the DFM formed on the l atter did not exhibit a rejection performance comparable to the other DFMs formed. Copyright (C) 1996 IAWQ. Published by Elsevier Science Lt d.