Nanospace breakthrough in membrane technology

A team of Australian and US scientists has announced a world advance in the use of membrane technology to filter and separate various gases and vapours.

The breakthough has implications for many activities, ranging from water purification and environmental cleanup, to better fuels and petrochemicals, purer medicines and desalination of seawater for drinking.

The team, involving CSIRO scientists, reported in the journal Science the discovery of a new type of nanoparticle-enhanced filter for spearating compunds at the molecular level.

"Just as astrophysicists are exploring 'wormholes' in space-time through which people might one day be able to pass, we're looking at ways to create wormholes at the tiniest level, just millionths of a millimeter in size, in a filter medium so that we can control precisely what passes through and what doesn't," explains CSIRO's Dr Anita Hill.

The new filtration media are created by combining organic polymers normally used to make membrane filters with inorganic substances - in this case a mist of siclica nanoparticles.

The team discovered that this combination gives the membrane a quite extraordinary ability to separate large organic molecules from the gases in which they might be floating.

This new class of organic/inorganic materials, known as nanocomposites, has already been shown to be remarkable for enhanced conductivity, being extremely tough, having valuable optical properties and acting as catalysts.

The team has now demonstrated a new and potentially even more useful trait - the ability to filter gases and organic vapours at the molecular level.

As a rule, the more selective a polymer is at extracting a pure gas, the less permeable it tends to be - and the more expensive it is to use.

The new nanoparticle-enhanced polymers promise to deliver both high filtering efficiency and high throughput, making them much more cost-efficient.

Item provided courtesy of CSIRO