Green Car Congress: Researchers at the US Department of Energy’s Argonne National Laboratory have created new aerogels that could cleanse contaminated water and potentially purify hydrogen for use in fuel cells.
Argonne materials scientists Peter Chupas and Mercouri Kanatzidis, along with colleagues at Northwestern and
The researchers formed the gels from various sulfide and selenide clusters with platinum as the linking metal ion. Because the gels formed are based on all-chalcogenide species (molecules centered on the elements found directly under oxygen in the periodic table), they termed the new gels “chalcogels”. A report on the work appears in 27 July issue of Science.
The researchers 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% 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 chalcogels 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. The unique chemical and physical structure of the gels will allow researchers to tune their pore sizes or composition in order to separate particular poisons from the hydrogen stream.
…Kanatzidis and his co-workers recognized that aerogels offered one remarkable advantage over powders: because the material maintained its cohesion, it possessed an enormous surface area. One cubic centimeter of the aerogel could have a surface area as large as a football field, according to Kanatzidis. The bigger the surface area of the material, the more efficiently it can bind other molecules, he said….