A blend of block
copolymers creates a nanofiltration material to produce
a cheap way of
removing contaminants from water.
Reproduced with
permission from Ref 1.© 2015
(December 14, 2015) A
method of fabricating polymer membranes with nanometer-scale holes that
overcomes some practical challenges has been demonstrated by KAUST researchers.
Porous membranes can filter pollutants from a liquid, and
the smaller the holes, the finer the particles the membrane can remove. The
KAUST team developed a block copolymer membrane with pores as small as 1.5
nanometers but with increased water flux, the volume processed per hour by a
membrane of a certain area.
A nanofilter needs to be efficient at rejecting specific
molecules, be producible on a large scale, filter liquid quickly and be
resistant to fouling or the build-up of removed micropollutants on the surface.
Block copolymers have emerged as a viable material for this
application. Their characteristics allow them to self-assemble into regular
patterns that enable the creation of nanoporous materials with pores as small
as 10 nanometers.
However, reducing the size further to three nanometers has
only been possible by post-treating the membrane (depositing gold, for
example2). Moreover, smaller holes usually reduce the water flux.
Klaus-Viktor Peinemann from the KAUST Advanced Membranes
& Porous Materials Center and Suzana Nunes from the KAUST Biological and
Environmental Science and Engineering Division formed a multidisciplinary team
to find a solution.