Chlorine tolerant, multilayer reverse-somosis membranes with high permeate flux and high salt rejection
Colquhoun, H. M., Chappell, D., Lewis, A. L., Lewis , D. F., Finlan, G. T. and Williams , P. J. (2010) Chlorine tolerant, multilayer reverse-somosis membranes with high permeate flux and high salt rejection. Journal of Materials Chemistry, 20 (22). pp. 4629-4634. ISSN 0959-9428
To link to this article DOI: 10.1039/B926352G
A new class of high molecular weight polyethersulfone ionomers is described in which the ionic content can be varied, at will, over a very wide and fully-controllable range. A novel type of coating process enables these materials to be deposited from alcohol-type solvents as cohesive but very thin (50 – 250 nm) films on porous support-membranes, giving high-flux membranes (3.3 – 5.0 L m-2 h-1 bar-1) with very good, though not outstanding salt rejection (typically 92 - 96%). A secondary layer, of formaldehyde-cross-linked polyvinyl alcohol, can be deposited from aqueous solution on the surface of the ionomer membrane, and this layer increases salt rejection to greater than 99% without serious loss of water permeability. The final multi-layer membrane shows excellent chlorine tolerance in reverse-osmosis operation.