Aerogels make a clean sweep

Scientists at the US Department of Energy's Argonne National Laboratory have identified a new technique for cleansing contaminated water and potentially purifying hydrogen for use in fuel cells, thanks to the discovery of a innovative type of porous material.

Argonne materials scientists Peter Chupas and Mercouri Kanatzidis, along with colleagues at Northwestern and Michigan State universities, created and characterised porous semiconducting aerogels at Argonne's Advanced Photon Source (APS).

The researchers then submerged a fraction of a gram of the aerogel in a solution of mercury-contaminated water and found that the gel removed more than 99.99 percent of the heavy metal.

The researchers believe that these gels can be used not only for this kind of environmental cleanup but also to remove impurities from hydrogen gas that could damage the catalysts in potential hydrogen fuel cells.

The aerogels, which are fashioned from chalcogenides - molecules centred on the elements found directly under oxygen in the periodic table - are expected to be able to separate out the impurities from hydrogen gas much as they did the mercury from the water: by acting as a kind of sieve or selectively permeable membrane.